[EVDL] EVLN: Solar powered Green MotorSport EVs ride in European WAVE
http://mhwmagazine.co.uk/LatestNews/AGM_routeMASTER_and_Green_MotorSport_ride_European_WAVE-18773.html
AGM routeMASTER and Green MotorSport ride European WAVE
09 June 2015
[image
http://mhwmagazine.co.uk/MHWMagazine/AGM-routeMASTER-and-Green-MotorSport-ride-European-WAVE_18773.jpg
]
Green MotorSport, the electric vehicle technology innovator, is preparing
for its annual drive across the heart of Europe powered by solar energy, in
the World Advanced Vehicle Expedition (WAVE) and will be monitored all the
way in real-time by AGM’s routeMASTER vehicle tracking system.
Two, solar powered electric cars, designed and built by Green MotorSport,
will set off on June 13th from Plauen near Berlin and join the WAVE as it
travels on its fifth annual tour through twenty or so towns and cities
across four countries, in difficult off-road terrain to finish in the high
Alps on June 21st.
Along the way, the expedition will pause to give demonstrations for
schools, local businesses, government offices and communities regarding the
merits of sustainable energy and the part which solar-powered eco-friendly
vehicles can play in the global drive to conserve energy and protect the
environment.
“The purpose of WAVE is to evaluate the latest advances with battery
electric vehicles powered by renewable energy and to give awards in several
categories.” Says Green MotorSport MD and founder Gordon Foat. “We have
participated every year and I’m pleased to say that AGM have been with us,
providing essential vehicle monitoring and tracking for the last three”
Green MotorSport (GMS) was founded by Gordon Foat in 2001 and is the first
company specifically set up to research “Green motor sport”. Gordon and his
team have won a number of prestigious awards during the WAVE tours including
the People and Environment Achievement award, 2012 for sustainable sport. In
2014 the WAVE was accepted by the Guinness Book of World Records as the
event with the largest number of electric vehicles.
AGM Telematics, based in Corby, has worked closely with GMS to provide an
effective method of monitoring the electric car’s speed and location so that
progress can be accurately charted by everyone who follows the WAVE
expedition.
“The Green MotorSport philosophy – to provide sustainable alternatives to
conventional and less environmentally friendly vehicles - fits well with our
own” comments AGM Director George Weston. “Our routeMASTER telematics system
is a cloud-based modular tool set which comprises three core modules –
planning, dispatch and tracking - all of which are designed to improve
vehicle efficiency and in turn help to reduce energy consumption. The
real-time tracking module which is being used by GMS and many commercial
vehicle fleets throughout the UK, has the ability to provide automatic
updates regarding speed, location, acceleration, braking and even hard
cornering. For GMS, the live monitoring is important in order that key
vehicle data can be instantly reported and also used for later performance
analysis.”
Experts and enthusiasts alike will be able to monitor the progress of GMS
throughout the tour by visiting AGM’s website www.route-master.com.
[© mhwmagazine.co.uk]
http://www.transportengineer.org.uk/transport-engineer-news/green-motorsport-and-agm-ride-european-wave/86077/
Green MotorSport and AGM ride European WAVE
09 June 2015 Brian Tinham
Electric vehicle technology specialist Green MotorSport is preparing for its
annual drive across Europe powered by solar energy in the World Advanced
Vehicle Expedition (WAVE).
Two, solar powered electric cars, will set off on 13 June 2015 from Plauen,
near Berlin, monitored all the way in real-time by AGM's routeMaster vehicle
tracking system.
They will join the WAVE as it travels on its fifth annual tour through towns
and cities across four countries, finish in the Alps on 21 June.
Along the way, the expedition will pause to give demonstrations for schools,
local businesses, government offices and communities – extolling the virtues
of sustainable energy and the part solar-powered eco-friendly vehicles can
play.
"The purpose of WAVE is to evaluate the latest advances with battery
electric vehicles powered by renewable energy and to give awards in several
categories," says Green MotorSport managing director and founder Gordon
Foat.
"We have participated every year and I'm pleased to say that AGM have been
with us, providing essential vehicle monitoring and tracking for the last
three."
[© transportengineer.org.uk]
...
[dated]
[video
https://www.youtube.com/watch?v=pQ04JKOYxyo
Green MotorSport electric gokart
kartelec Jun 5, 2009
CNN NEWS presents the electic gokart produced by Green MotorSport.
Green MotorSport brings technology and environmental issues to everyones
attention making learning about renewable energy and energy efficiency
interesting and exciting.
http://www.greenmotorsport.com
]
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V
[EVDL] EVLN: Volkswagen E-Up! is late in entering the EV market r:90mi
http://www.cartrade.com/blog/2015/greens/volkswagen-e-up-the-new-generation-green-car-1416.html
Volkswagen E-Up! – late in entering the EV market
June 09, 2015 by Eliza Lobo
[image
http://imagecdn2.cartrade.com/img/400/cars/generic/Volkswagen-E-Up.jpg
Volkswagen e-up
]
Volkswagen might be a little late in entering the electric vehicle market,
but it has been making its mark. The car maker plans to lead the market with
zero-emission cars in next 2-3 years. Volkswagen e-up! is just the first
chapter of this ride. Bestowed with an amazing range of 90 miles in one full
charge, e-up! Is no less than a blessing for urban dwellers. The driving
dynamics are quite similar to regular Volkswagen cars but it takes an edge
over other electric vehicles for its speed and efficiency. Visually it looks
very much similar to VW Up! apart from a its aero-optimized alloy wheels and
some extra VW badges.
Unlike Renault Zoe, e-up! isn’t a standalone car in green car segment, it
makes an equal appeal like all those desirable good looking cars. The wheels
are proportional and taut lines look good, the black glass embedded in
tailgate leaves no doubt that it is one of the most smartly designed small
cars. Over the inner end, its upholstery captures attention in blue in
contrast with its colorful dials and plug-in screen. The build quality is
top notch with amazing switchgear. If you are well versed with the regular
Up! you wouldn’t face any problem with its electric version.
In terms of driving and handling, Volkswagen green car exhibits excellent
control and precise turn-in at all points. It is 200kg heavier than its
regular version, the weight offers added stability to its profile. The
steering is sharp and more natural as compared to its contemporaries. It
propels on a an electric motor that churns 81bhp for 210Nm. Though the
figures are slightly shy than ZOE but its lighter weight compensates for
that. The small electric vehicle sprints from 0-60mph in just 10.3 seconds
and can effortlessly attain a top speed of 80mph. it is a silent rider that
makes minimal noise over roads and the gentle whir of its electric motor is
nothing than a lullaby to put you to rest.
The German car maker has made hefty investments over its machinery. All
electrical equipment of this car comes with a 100, 000 mile for 8 years
warranty. The warranty can be further extended by 75, 000 miles for 4 years
or 90, 000 for five years by paying a minimal amount of £205 and £495
respectively.
[© cartrade.com]
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http://www.thecarconnection.com/news/1098697_six-month-e-golf-road-test-why-were-doing-it
Six-Month e-Golf EV Long-term Road Test
http://www.autoblog.com/2015/06/15/vw-e-golf-carbon-neutral-video/
VW uses NorCal Forest to make e-Golf EV carbon neutral
... some purchase money goes to support three carbon offset projects ...
http://www.itbusinessnet.com/article/Volta-Debuts-New-Community-Engagement-Model-for-Free-Electric-Car-Charging-3932508
Volta Debuts New Community Engagement Model for Free EV Charging
+
EVLN: FCA recalls Fiat 500e to fix cruise control
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[EVDL] EVLN: FCA recalling ~4000 500e EVs to upgrade cruise-control software
http://www.autoblog.com/2015/06/11/fiat-500e-recall-fix-cruise-control/ FCA recalls Fiat 500e to fix cruise control Jun 11th 2015 Danny King [video flash] 2014 Fiat 500e No Injuries, Complaints From Issue, Which May Put EV Into Neutral When It Shouldn't Fiat is recalling almost 4,000 of its 500e electric vehicles because of a malfunction related to the model's cruise-control feature. The glitch causes the car's powertrain to be put into neutral under certain situations. It's the second recall on the 500e this year. Specifically, Chrysler-Fiat is recalling 3,975 cars. The issue is that the car's system can misread the motor's torque figures in cruise control, causing the sprightly EV to mistakenly shift into neutral in what was designed as a safety-precaution measure. The good news is that restarting the vehicle gets the car back to normal, but being dropped into neutral in highway mode is certainly no fun. Chrysler-Fiat said in a statement this week that it was "unaware" of injuries, accidents, or customer complaints caused by the issue. In April, the 500e was subject to a recall that impacted about 5,600 vehicles and stemmed from a March 2015 update. The update allowed the car to go into so-called "Limp Home Mode" to better extend range. The problem is that it inadvertently caused the car to stall. Range anxiety, indeed. Take a look at Chrysler-Fiat's press release on the most recent recall below. Statement: Software Upgrade June 9, 2015 , Auburn Hills, Mich. - FCA US LLC is voluntarily recalling an estimated 3,975 cars to upgrade cruise-control software. A review of warranty data led to an investigation by FCA US LLC engineers. The investigation discovered certain Fiat 500e hatchbacks were inadvertently equipped with software that may misread torque levels generated by their motors, causing them to shift into neutral – a prescribed failsafe mode. This condition may occur only while cruise-control is engaged and the driver attempts to override the feature with accelerator-pedal applications or rapid tapping of the accelerate/decelerate buttons. Restarting the vehicle restores normal function. The campaign is limited to certain model-year 2013-2015 vehicles. The Company is unaware of any related injuries, accidents or customer complaints. New software will be available when affected customers are advised of this action by FCA US. Service instructions are being sent to FCA US dealers today. Customers with questions may call the FCA US Customer Information Center at 1-800-853-1403. [© autoblog.com] http://www.topspeed.com/cars/car-news/fiat-recalls-electric-500e-for-cruise-software-update-ar169864.html Fiat Recalls Electric 500e For Cruise Software Update 06.13.2015 by James Wolfcale [images http://pictures.topspeed.com/IMG/crop/201506/fiat-recalls-electri_800x0w.jpg http://pictures.topspeed.com/IMG/crop/201211/fiat-500e_600x0w.jpg (Fiat 500e) ] Fiat Chrysler Automotive has issued a voluntary recall for 3,975 2014 Fiat 500e electric hatchbacks. The issue is related to faulty cruise-control software that was installed on some 500es that could potentially misread torque levels of the electric motors. This can cause the motors to engage a fail-safe mode and shift to neutral. The fault can occur when cruise control is being used and the driver attempts to override it by stepping on the accelerator. FCA engineers discovered the problem after an investigation and review of warranty data. The recall affects roughly 40 percent of the 10,462 Fiat 500es sold in the United States between 2013 and 2015, and FCA says no known injuries, fatalities or customer complaints have occurred as a result of the problem. FCA is providing a software update to dealers as well as service instructions and will notify owners of affected vehicles. The fix is being provided at no cost to owners. Why it matters This is third recall for the 500e. The first was issued in 2014 to replace cooling plates mounted for the power inverter module that could potentially leak coolant onto high-voltage circuitry, causing a short circuit and the corresponding service fuse to blow. Like the current recall, the issue resulted in a complete loss of power. The second was another software problem that caused miscommunication between the electric vehicle control unit and battery pack. This caused the 500e to either engage limp-home mode or completely shut down its drivetrain. Like the most recent one, both problems were fixed at no cost to owners. Press Release FCA US LLC is voluntarily recalling an estimated 3,975 cars to upgrade cruise-control software. A review of warranty data led to an investigation by FCA US LLC engineers. The investigation discovered certain Fiat 500e hatchbacks were inadvertently equipped with software that may misread torque levels generated by their motors, causing them to shift into neutral – a prescribed failsafe mode. This condition may occur only while cruise-control is engaged and the driver
[EVDL] Autopods nEVs bring micro transport to Pittsburgh-PA
http://www.bizjournals.com/pittsburgh/blog/innovation/2015/06/autopods-bringing-microtransport-to-pittsburgh.html
Autopods bringing micro transport to Pittsburgh
Jun 9, 2015 Justine Coyne
[images / Autopods
http://media.bizj.us/view/img/6111591/img0246jpg*750xx4096-2304-0-214.jpg
Autopods' electric pedicabs are custom designed and manufactured in order to
operate on U.S. streets
http://media.bizj.us/view/img/6111611/img0249jpg*180xx3643-2732-227-0.jpg
Autopods operate on a flat rate of $5 per one-mile trip and $8 per two-mile
trip
]
Pittsburgh's latest transportation option is the first of its kind in the
city, and potentially the U.S., according to the company's CEO.
Meet Autopods Inc., a zero-emission electric pedicab service that provides
flat-rate, short-distance trips.
"What we're trying to do is introduce micro transport to Pittsburgh," said
Tanuj Apte, CEO of Autopods.
While the concept of the electric pedicab has become more popular in Europe,
it hasn't seen the same traction in the U.S., according to Apte.
One reason is that the vehicles being used in Europe aren't street legal in
the U.S. to provide commercial rides, he said. Last year, while studying at
Carnegie Mellon University, Apte and the Autopods team worked to reengineer
the vehicles from the ground up, adding a stronger fiberglass frame and turn
signals in order to qualify for operation on U.S. streets.
The company, which has performed beta testing over the last year around the
CMU campus, introduced 11 vehicles to its fleet at the start of June,
according to Apte. Currently operating as a ride hail service, Autopods
offers rides within one-mile for $5 and within two-miles for $8. The
vehicles, which operate using an electric assist, can travel at up to
20-miles-per-hour.
[© bizjournals.com]
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Re: [EVDL] Bicycle battery
That was a very good summary. Cell balancing is something that was done with other chemistry a and many have tried to apply it to Li Ion chemistries but it doesn't work with Lithium since cells do self discharge or drift. If one wanted to balance them it has to be done below 3.38 volts otherwise you are still charging the cell. Thanks for your input. Sent from my iPad > On Jun 17, 2015, at 10:53 PM, David Nelson via EV wrote: > > That is a reason I don't use a cell level BMS. With a cell level BMS > like the miniBMS there is a constant drain on the cells running the > BMS boards and it is nearly impossible to make sure that each board > uses the _exact_ same current regardless of voltage in the cell. > Furthermore, boards like the miniBMS expect that you will balance at > the end of every charge and last I saw, that balance voltage was at > 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 > cells which leads to potential overcharging of the cells on every > charge cycle. If you stop charging without the balancing taking place > and/or let the pack sit for extended periods of time then the > different current draw of each board working 24/7 introduces an > imbalance in the SOC of the cells in the pack. > > Willie, > > If you had made sure that you had a set of good LiFePO4 cells (ie > discharge to about 2.7V and let them sit for a week or so and then > measure voltage to see if it is dropping or stable then remove any > cells which still drop in voltage). Then assembled the pack with only > connecting to the most positive and most negative end of the pack. > Next, charge the pack while monitoring individual cell voltages and > note when the first cell went over 3.5V and then had the charger hold > that pack voltage and taper current down to 0.05C (5A for a 100Ah > cell) and then shut off. Finally, have a master cutoff switch like a > BRB which totally breaks the battery circuit to eliminate any > parasitic loads that you would still have a trouble free setup. > > That is how I setup my electric push mower. I can let it sit all > winter and it is still charged when I go to use it in the spring. It > has sat for two winters now with no issues. Other than doing a top > balance on my Gizmo that is how I have my Gizmo setup except for the > master cutoff switch. It hasn't had any balancing for 4 years and when > I check it it still is in balance. My pack now has over 20k miles on > it and has been in use since January 2010. > > I know many here think I'm crazy and seem to want to discount my data > or say I'm just lucky but you aren't the only one with problems with > your LiFePO4 pack. All the ones I hear about with problems have cell > level BMS boards on them or they don't do a proper initial balance on > the pack. The only other common item is that they over charge their > packs. > > Basically, don't over charge or over discharge, don't put ANY > imbalanced load on the pack, undercharge slightly, and don't pull > extreme currents from your cells and they will last a long time. A > properly fully charged LiFePO4 cell like those from CALB will rest at > 3.38V when at room temperature. Any higher and the cell has been > overcharged. > > >> On Wed, Jun 17, 2015 at 1:15 PM, Willie2 via EV wrote: >>> On 06/17/2015 01:55 PM, EVDL Administrator via EV wrote: >>> >>> Can you be a little more specific here? What makes them so expensive? >> >> The miniBMS modules suffer from exposure to the elements and they are not >> well protected in golf carts or the Zap. Or my Ranger. Rodents have chewed >> a lot of the signal wires, which have been too light a gauge. I've been >> told that the cells self discharge at quite different rates so that, when >> left sitting, the battery gets badly out of balance or some cells go to zero >> and self destruct. Also, I seem to have some vampire loads that lead to >> discharge in a few months or less of non-use. The real problem is that I'm >> not willing to jump on a problem as soon as it develops; I tend to let it >> sit for months. By that time, I'm likely to have lost some cells. I may >> use only one or two of these farm EV conversions at a time but I've been >> trying to keep about five ready to use at any one time. Right now, I have >> two golf carts, the Zap, and the Ranger all dead and I am able to use only a >> golf cart and the imiev. The imiev is WONDERFUL, completely trouble free. >> So far. I believe the imiev is going to be considerably cheaper than the >> Zap. Or even a golf cart. >> >> My experience is that the big cells with miniBMS have a mean time to failure >> of about two months. Maybe less. I'm looking for a year or more with no >> more maintenance other than charging every couple of months. >>> >>> >>> Golf cars are pretty economical and reliable with lead golf car batteries. >> >> I can not agree. In my experience, lead in golf carts is FAR more demanding >> in terms of maintenance. Monthly watering, bad batter
[EVDL] good range for SOC on used leaf
if i were to use something like the LEAFSPY to measure the SOC on a used leaf what would be a good value for a 2013 model? maybe for different mileages like 10k and 20k for example? harry Albuquerque, NM current bike: http://www.austinev.org/evalbum/1179 current non-bike: http://evalbum.com/1000 ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
[EVDL] Dahm + TSLA
http://www.businessfinancenews.com/22722-tesla-motors-inc-partners-with-researcher-to-reduce-battery-costs/ ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] good range for SOC on used leaf
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Here is a link to pictures of the LeafSpy output from the 2013 Nissan Leaf that I purchased used at an auto auction after it was totaled. It had under 19K miles on it, and the battery health was reported as very good (98%) and it had all "bars" on the gauge http://www.summet.com/blog/2015/03/28/booting-up-a-nissan-leaf/ Jay On 06/18/2015 03:21 PM, harry henderson via EV wrote: > if i were to use something like the LEAFSPY to measure the SOC on a > used leaf what would be a good value for a 2013 model? maybe for > different mileages like 10k and 20k for example? > > > harry > > Albuquerque, NM current bike: > http://www.austinev.org/evalbum/1179 current non-bike: > http://evalbum.com/1000 > ___ UNSUBSCRIBE: > http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing > discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) > -BEGIN PGP SIGNATURE- Version: GnuPG v1 iEYEARECAAYFAlWC5zIACgkQSWJjSgPNbM9yxACfcv0rfqIPB70lscnB0Zzrw25p ZQIAnitJh3A8ctVeg0ZQVrtjw/tOhMGx =JWEA -END PGP SIGNATURE- ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
David Nelson via EV wrote: That is a reason I don't use a cell level BMS. With a cell level BMS like the miniBMS there is a constant drain on the cells running the BMS boards and it is nearly impossible to make sure that each board uses the _exact_ same current regardless of voltage in the cell. Furthermore, boards like the miniBMS expect that you will balance at the end of every charge and last I saw, that balance voltage was at 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 cells which leads to potential overcharging of the cells on every charge cycle. If you stop charging without the balancing taking place and/or let the pack sit for extended periods of time then the different current draw of each board working 24/7 introduces an imbalance in the SOC of the cells in the pack. Yes, this is a problem in the BMS market. Like quack medicine, it's full of customers worried about a problem that they don't understand very well. So there are marketeers only too happy to throw together some piece of junk that purports to solve it. It doesn't have to actually work -- it only needs to *sound* like it works, to separate the customer from his money. So some BMS work -- and some don't. The bad ones are so bad that they give the whoel BMS market a bad name. I've written about this over and over... check my old posts. It mostly seems to be of no avail, so I won't repeat myself again. Anything I say is overwhelmed by the noise of the internet. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Paul Dove via EV wrote: That was a very good summary. Cell balancing is something that was done with other chemistry a and many have tried to apply it to Li Ion chemistries but it doesn't work with Lithium since cells do self discharge or drift. If one wanted to balance them it has to be done below 3.38 volts otherwise you are still charging the cell. Thanks for your input. Lithiums need balancing even more than other chemistries! You can only get by without a BMS if the cells are so well matched that they accidentally stay in balance. (Do you feel lucky?) Look at my own balancer at http://www.sunrise-ev.com/balancer.htm I built it to *use*, not to sell. It doesn't load the cells, or clamp the voltage at some arbitrary level, and doesn't have failure modes that murder cells. It basically does what you would do yourself, if you had the time and inclination. It measures the voltage of every cell, and charges the ones that are low. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
This is why I have my lead cobalt cells or Li Ion pre balance at the factory. Its seems they do that any more unless you double the cost of the cell. When I received my new Li Ion cells from Nissan, all of them read between 4.0 to 4.01 volt! It was about three weeks before I had them install, So I connected them all in parallel which acted like one big cell at 4.0 volts which kept them equalized. When I was running a military battery shop, we use this same method for the Ni Cad aircraft cells. I am using the Orion BMS which you can see the data from there manual at OrionBMS.com Roland - Original Message - From: Lee Hart via EV<mailto:ev@lists.evdl.org> To: Electric Vehicle Discussion List<mailto:ev@lists.evdl.org> Sent: Thursday, June 18, 2015 9:46 AM Subject: Re: [EVDL] Bicycle battery David Nelson via EV wrote: > That is a reason I don't use a cell level BMS. With a cell level BMS > like the miniBMS there is a constant drain on the cells running the > BMS boards and it is nearly impossible to make sure that each board > uses the _exact_ same current regardless of voltage in the cell. > Furthermore, boards like the miniBMS expect that you will balance at > the end of every charge and last I saw, that balance voltage was at > 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 > cells which leads to potential overcharging of the cells on every > charge cycle. If you stop charging without the balancing taking place > and/or let the pack sit for extended periods of time then the > different current draw of each board working 24/7 introduces an > imbalance in the SOC of the cells in the pack. Yes, this is a problem in the BMS market. Like quack medicine, it's full of customers worried about a problem that they don't understand very well. So there are marketeers only too happy to throw together some piece of junk that purports to solve it. It doesn't have to actually work -- it only needs to *sound* like it works, to separate the customer from his money. So some BMS work -- and some don't. The bad ones are so bad that they give the whoel BMS market a bad name. I've written about this over and over... check my old posts. It mostly seems to be of no avail, so I won't repeat myself again. Anything I say is overwhelmed by the noise of the internet. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com<http://www.sunrise-ev.com/> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -- next part ------ An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/cd4318c8/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
No one has convinced me that top balancing is even possible much less that a BMS can achieve this. If you hold a cell above the Open circuit voltage you are charging it even if you are trying to shunt the current with a Mosfet From: Lee Hart via EV To: Electric Vehicle Discussion List Sent: Thursday, June 18, 2015 10:46 AM Subject: Re: [EVDL] Bicycle battery David Nelson via EV wrote: > That is a reason I don't use a cell level BMS. With a cell level BMS > like the miniBMS there is a constant drain on the cells running the > BMS boards and it is nearly impossible to make sure that each board > uses the _exact_ same current regardless of voltage in the cell. > Furthermore, boards like the miniBMS expect that you will balance at > the end of every charge and last I saw, that balance voltage was at > 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 > cells which leads to potential overcharging of the cells on every > charge cycle. If you stop charging without the balancing taking place > and/or let the pack sit for extended periods of time then the > different current draw of each board working 24/7 introduces an > imbalance in the SOC of the cells in the pack. Yes, this is a problem in the BMS market. Like quack medicine, it's full of customers worried about a problem that they don't understand very well. So there are marketeers only too happy to throw together some piece of junk that purports to solve it. It doesn't have to actually work -- it only needs to *sound* like it works, to separate the customer from his money. So some BMS work -- and some don't. The bad ones are so bad that they give the whoel BMS market a bad name. I've written about this over and over... check my old posts. It mostly seems to be of no avail, so I won't repeat myself again. Anything I say is overwhelmed by the noise of the internet. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/9258c414/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Excerpt:In theory, all batteries are identical. If wired in series, you would therefore expect them all to charge and discharge equally. But in practice, there are differences. New batteries that are all the same brand, same model, same date code (and without "lemons" or quality control defects) will still have small differences. Each cell 's self-discharge rate, amphour capacity, internal resistance, and charge/discharge efficiency will be slightly different. This makes them drift to different states of charge. For example, cells with a higher self-discharge rate run down faster just from sitting. Cells with a lower amphour capacity get more deeply discharged on each cycle, which lowers their efficiency (so they need a bit more current to fully recharge). Cells with a higher internal resistance run a little hotter, which affects their efficiency and self-discharge rate. These differences tend to get larger over time. If not corrected, you can have a pack with some cells almost full, and some almost empty! Ok, here's the deal this is fiction. Self discharge is so low (milivolts over years) as to be non-existant.Secondly, if they are in series then all current passing through cells is equal. It is impossible to draw more current from one cell than another in a series pack. It can short and pass all current or it can open and pass no current but it cannot discharge faster or slower. If it has higher resistance then it will cause cells to heat faster that is all. Please show evidence that your theory is possible. The only person I spoke with having issues with new cells is when they were placed in parallel with old cells. In that case the wires melted because the new cell was handling more of the current. You may damage cells if there is a big difference in resistance only if you exceed the max current draw from the cell. If one never approaches the max current draw this will not be an issue. From: Lee Hart via EV To: Electric Vehicle Discussion List Sent: Thursday, June 18, 2015 10:53 AM Subject: Re: [EVDL] Bicycle battery Paul Dove via EV wrote: > That was a very good summary. Cell balancing is something that was > done with other chemistry a and many have tried to apply it to Li Ion > chemistries but it doesn't work with Lithium since cells do self > discharge or drift. > > If one wanted to balance them it has to be done below 3.38 volts > otherwise you are still charging the cell. Thanks for your input. Lithiums need balancing even more than other chemistries! You can only get by without a BMS if the cells are so well matched that they accidentally stay in balance. (Do you feel lucky?) Look at my own balancer at http://www.sunrise-ev.com/balancer.htm I built it to *use*, not to sell. It doesn't load the cells, or clamp the voltage at some arbitrary level, and doesn't have failure modes that murder cells. It basically does what you would do yourself, if you had the time and inclination. It measures the voltage of every cell, and charges the ones that are low. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/dc23c230/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
a EV To: Electric Vehicle Discussion List Sent: Thursday, June 18, 2015 10:53 AM Subject: Re: [EVDL] Bicycle battery Paul Dove via EV wrote: > That was a very good summary. Cell balancing is something that was > done with other chemistry a and many have tried to apply it to Li Ion > chemistries but it doesn't work with Lithium since cells do self > discharge or drift. > > If one wanted to balance them it has to be done below 3.38 volts > otherwise you are still charging the cell. Thanks for your input. Lithiums need balancing even more than other chemistries! You can only get by without a BMS if the cells are so well matched that they accidentally stay in balance. (Do you feel lucky?) Look at my own balancer at http://www.sunrise-ev.com/balancer.htm I built it to *use*, not to sell. It doesn't load the cells, or clamp the voltage at some arbitrary level, and doesn't have failure modes that murder cells. It basically does what you would do yourself, if you had the time and inclination. It measures the voltage of every cell, and charges the ones that are low. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/dc23c230/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
run a little hotter, which > affects their efficiency and self-discharge rate. These differences tend to > get larger over time. If not corrected, you can have a pack with some cells al most full, and some almost empty! > Ok, here's the deal this is fiction. Self discharge is so low (milivolts over > years) as to be non-existant.Secondly, if they are in series then all current > passing through cells is equal. It is impossible to draw more current from > one cell than another in a series pack. It can short and pass all current or > it can open and pass no current but it cannot discharge faster or slower. > If it has higher resistance then it will cause cells to heat faster that is > all. > Please show evidence that your theory is possible. > The only person I spoke with having issues with new cells is when they were > placed in parallel with old cells. In that case the wires melted because the > new cell was handling more of the current. You may damage cells if there is a > big difference in resistance only if you exceed the max current draw from the > cell. If one never approaches the max current draw this will not be an issue. > > > From: Lee Hart via EV > To: Electric Vehicle Discussion List > Sent: Thursday, June 18, 2015 10:53 AM > Subject: Re: [EVDL] Bicycle battery > > Paul Dove via EV wrote: >> That was a very good summary. Cell balancing is something that was >> done with other chemistry a and many have tried to apply it to Li Ion >> chemistries but it doesn't work with Lithium since cells do self >> discharge or drift. >> >> If one wanted to balance them it has to be done below 3.38 volts >> otherwise you are still charging the cell. Thanks for your input. > > Lithiums need balancing even more than other chemistries! You can only get by > without a BMS if the cells are so well matched that they accidentally stay in > balance. (Do you feel lucky?) > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > I built it to *use*, not to sell. It doesn't load the cells, or clamp the > voltage at some arbitrary level, and doesn't have failure modes that murder > cells. > > It basically does what you would do yourself, if you had the time and > inclination. It measures the voltage of every cell, and charges the ones that > are low. > -- > The greatest pleasure in life is to create something that wasn't there > before. -- Roy Spence > -- > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > > > > -- next part -- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/dc23c230/attachment.htm> > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Paul, How familiar are you with electronics? My wife's eBike has a nice pack with a built-in BMS that simply starts shunting current above a certain voltage and presumably (but I can't verify) also reduces charging current, so you can take care that the shunting cells are receiving zero current and no longer rise in voltage. The trick is to find a good voltage at which your BMS will protect the cells. That pack is very nicely top-balanced and I expect that many more BMSs that you are not even aware of in daily appliances such as power tools will all top-balance. Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove via EV Sent: Thursday, June 18, 2015 9:40 AM To: Lee Hart; Electric Vehicle Discussion List Subject: Re: [EVDL] Bicycle battery No one has convinced me that top balancing is even possible much less that a BMS can achieve this. If you hold a cell above the Open circuit voltage you are charging it even if you are trying to shunt the current with a Mosfet From: Lee Hart via EV To: Electric Vehicle Discussion List Sent: Thursday, June 18, 2015 10:46 AM Subject: Re: [EVDL] Bicycle battery David Nelson via EV wrote: > That is a reason I don't use a cell level BMS. With a cell level BMS > like the miniBMS there is a constant drain on the cells running the > BMS boards and it is nearly impossible to make sure that each board > uses the _exact_ same current regardless of voltage in the cell. > Furthermore, boards like the miniBMS expect that you will balance at > the end of every charge and last I saw, that balance voltage was at > 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 > cells which leads to potential overcharging of the cells on every > charge cycle. If you stop charging without the balancing taking place > and/or let the pack sit for extended periods of time then the > different current draw of each board working 24/7 introduces an > imbalance in the SOC of the cells in the pack. Yes, this is a problem in the BMS market. Like quack medicine, it's full of customers worried about a problem that they don't understand very well. So there are marketeers only too happy to throw together some piece of junk that purports to solve it. It doesn't have to actually work -- it only needs to *sound* like it works, to separate the customer from his money. So some BMS work -- and some don't. The bad ones are so bad that they give the whoel BMS market a bad name. I've written about this over and over... check my old posts. It mostly seems to be of no avail, so I won't repeat myself again. Anything I say is overwhelmed by the noise of the internet. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/9258c414/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
On 18 Jun 2015 at 10:46, Lee Hart via EV wrote: > I've written about this over and over... check my old posts. It mostly > seems to be of no avail, so I won't repeat myself again. Anything I say > is overwhelmed by the noise of the internet. Lee Hart is one of the EVDL stalwarts. He's been here longer than I have, and that's over 20 years now. Lee is a true scientist, an electronic engineer. He's thoughtful, deliberate, and focused. He's not averse to recent developments, he just evaluates them carefully rather than jumping on the bandwagon that younger engineers often join. He's not going to use a microprocessor where a relay works just fine. Lee doesn't speak very loudly, but he has more years of engineering and EV design and building than most of the net's rambling loudmouths put together. Lee beats any of them in battery research too. I'm not talking about anecodotal "it works for me so far" stuff, I'm talking about actual rigorous testing. You can get a taste for the battery work Lee does in his meager spare time here : http://www.motherjones.com/environment/2008/05/charge-keep Lee also has an extensive background in designing real world commercial products that MUST be safe and reliable and not catch fire. So pipe down for a minute, and LISTEN to Lee. He's offering you wisdom. This is gold, freely given. Don't let it pass you by. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
On 18 Jun 2015 at 11:43, Cor van de Water via EV wrote: > That pack is very nicely top-balanced and I expect that many more BMSs > that you are not even aware of in daily appliances such as power tools > will all top-balance. One more time. There is a really good reason that the only place you find aversion to BMSes is among EV hobbyists. Real world electronics manufacturers -- the ones who build millions of laptops, mobile phones, power tools and yes, commercial EVs -- know that you don't sell a product with a lithium battery unless it has ample smarts to protect the battery, the user, and the manufacturer. Trust me, these guys have bean counters looking over their shoulders. They wouldn't be using BMSes if they weren't necessary. BMSes protect the battery from early failure, the user from hazard to life and limb, and the manufacturer from the lawyers! David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
destruction now! >> >> 2. If charging does not harm the pack, what about discharging hundreds of >> Amps through a >> resistor that is nicely embedded in the pack, insulated from the outside by >> the cells >> around it? If it even drops 10V across it at hundreds of Amps, you now have a >> multi-kiloWatt heater inside your pack without much cooling. What do you >> think will happen? >> >> Just some easy illustration of the *need* for a cell-level BMS, from >> practice by measuring >> what happened to a used set of Lithiums (that indeed was run without BMS) >> and I have been >> monitoring since taking it out of service. Learn from it or get your own >> experience, your choice. >> >> Cor van de Water >> Chief Scientist >> Proxim Wireless >> >> office +1 408 383 7626Skype: cor_van_de_water >> XoIP +31 87 784 1130private: cvandewater.info >> www.proxim.com >> >> >> This email message (including any attachments) contains confidential and >> proprietary information of Proxim Wireless Corporation. If you received >> this message in error, please delete it and notify the sender. Any >> unauthorized use, disclosure, distribution, or copying of any part of this >> message is prohibited. >> >> >> -Original Message- >> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove via EV >> Sent: Thursday, June 18, 2015 9:57 AM >> To: Lee Hart; Electric Vehicle Discussion List >> Subject: Re: [EVDL] Bicycle battery >> >> Excerpt:In theory, all batteries are identical. If wired in series, you >> would therefore expect them all to charge and discharge equally. But in >> practice, there are differences. New batteries that are all the same brand, >> same model, same date code (and without "lemons" or quality control defects) >> will still have small differences. Each cell 's self-discharge rate, amphour >> capacity, internal resistance, and charge/discharge efficiency will be >> slightly different. This makes them drift to different states of charge. For >> example, cells with a higher self-discharge rate run down faster just from >> sitting. Cells with a lower amphour capacity get more deeply discharged on >> each cycle, which lowers their efficiency (so they need a bit more current >> to fully recharge). Cells with a higher internal resistance run a little >> hotter, which affects their efficiency and self-discharge rate. These >> differences tend to get larger over time. If not corrected, you can have a >> pack with some cells al > most full, and some almost empty! >> Ok, here's the deal this is fiction. Self discharge is so low (milivolts >> over years) as to be non-existant.Secondly, if they are in series then all >> current passing through cells is equal. It is impossible to draw more >> current from one cell than another in a series pack. It can short and pass >> all current or it can open and pass no current but it cannot discharge >> faster or slower. >> If it has higher resistance then it will cause cells to heat faster that is >> all. >> Please show evidence that your theory is possible. >> The only person I spoke with having issues with new cells is when they were >> placed in parallel with old cells. In that case the wires melted because the >> new cell was handling more of the current. You may damage cells if there is >> a big difference in resistance only if you exceed the max current draw from >> the cell. If one never approaches the max current draw this will not be an >> issue. >> >> >> From: Lee Hart via EV >> To: Electric Vehicle Discussion List >> Sent: Thursday, June 18, 2015 10:53 AM >> Subject: Re: [EVDL] Bicycle battery >> >> Paul Dove via EV wrote: >>> That was a very good summary. Cell balancing is something that was >>> done with other chemistry a and many have tried to apply it to Li Ion >>> chemistries but it doesn't work with Lithium since cells do self >>> discharge or drift. >>> >>> If one wanted to balance them it has to be done below 3.38 volts >>> otherwise you are still charging the cell. Thanks for your input. >> >> Lithiums need balancing even more than other chemistries! You can only get >> by without a BMS if the cells are so well matched that they accidentally >> stay in balance. (Do you feel lucky?) >> >> Look at my own balancer at http://www.sunrise-ev.com/balancer.htm >> I built it to *use*, not to sell. It doe
Re: [EVDL] Bicycle battery
tion of Proxim Wireless Corporation. If you received this > message in error, please delete it and notify the sender. Any unauthorized > use, disclosure, distribution, or copying of any part of this message is > prohibited. > > > -Original Message- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove via > EV > Sent: Thursday, June 18, 2015 9:57 AM > To: Lee Hart; Electric Vehicle Discussion List > Subject: Re: [EVDL] Bicycle battery > > Excerpt:In theory, all batteries are identical. If wired in series, you would > therefore expect them all to charge and discharge equally. But in practice, > there are differences. New batteries that are all the same brand, same model, > same date code (and without "lemons" or quality control defects) will still > have small differences. Each cell 's self-discharge rate, amphour capacity, > internal resistance, and charge/discharge efficiency will be slightly > different. This makes them drift to different states of charge. For example, > cells with a higher self-discharge rate run down faster just from sitting. > Cells with a lower amphour capacity get more deeply discharged on each cycle, > which lowers their efficiency (so they need a bit more current to fully > recharge). Cells with a higher internal resistance run a little hotter, which > affects their efficiency and self-discharge rate. These differences tend to > get larger over time. If not corrected, you can have a pack with some cells > almost full, and some almost empty! > Ok, here's the deal this is fiction. Self discharge is so low (milivolts over > years) as to be non-existant.Secondly, if they are in series then all current > passing through cells is equal. It is impossible to draw more current from > one cell than another in a series pack. It can short and pass all current or > it can open and pass no current but it cannot discharge faster or slower. > If it has higher resistance then it will cause cells to heat faster that is > all. > Please show evidence that your theory is possible. > The only person I spoke with having issues with new cells is when they were > placed in parallel with old cells. In that case the wires melted because the > new cell was handling more of the current. You may damage cells if there is a > big difference in resistance only if you exceed the max current draw from the > cell. If one never approaches the max current draw this will not be an issue. > > > From: Lee Hart via EV > To: Electric Vehicle Discussion List > Sent: Thursday, June 18, 2015 10:53 AM > Subject: Re: [EVDL] Bicycle battery > > Paul Dove via EV wrote: >> That was a very good summary. Cell balancing is something that was >> done with other chemistry a and many have tried to apply it to Li Ion >> chemistries but it doesn't work with Lithium since cells do self >> discharge or drift. >> >> If one wanted to balance them it has to be done below 3.38 volts >> otherwise you are still charging the cell. Thanks for your input. > > Lithiums need balancing even more than other chemistries! You can only > get by without a BMS if the cells are so well matched that they > accidentally stay in balance. (Do you feel lucky?) > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > I built it to *use*, not to sell. It doesn't load the cells, or clamp the > voltage at some arbitrary level, and doesn't have failure modes that murder > cells. > > It basically does what you would do yourself, if you had the time and > inclination. It measures the voltage of every cell, and charges the ones that > are low. > -- > The greatest pleasure in life is to create something that wasn't there > before. -- Roy Spence > -- > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > > > > -- next part -- An HTML attachment was > scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/dc > 23c230/attachment.htm> ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
resistor that is nicely embedded in the pack, > > insulated from the outside by the cells around it? If it even drops > > 10V across it at hundreds of Amps, you now have a multi-kiloWatt heater > inside your pack without much cooling. What do you think will happen? > > > > Just some easy illustration of the *need* for a cell-level BMS, from > > practice by measuring what happened to a used set of Lithiums (that > > indeed was run without BMS) and I have been monitoring since taking it > out of service. Learn from it or get your own experience, your choice. > > > > Cor van de Water > > Chief Scientist > > Proxim Wireless > > > > office +1 408 383 7626Skype: cor_van_de_water > > XoIP +31 87 784 1130private: cvandewater.info > > www.proxim.com > > > > > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received > this message in error, please delete it and notify the sender. Any > unauthorized use, disclosure, distribution, or copying of any part of this > message is prohibited. > > > > > > -Original Message- > > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove via > > EV > > Sent: Thursday, June 18, 2015 9:57 AM > > To: Lee Hart; Electric Vehicle Discussion List > > Subject: Re: [EVDL] Bicycle battery > > > > Excerpt:In theory, all batteries are identical. If wired in series, you > would therefore expect them all to charge and discharge equally. But in > practice, there are differences. New batteries that are all the same brand, > same model, same date code (and without "lemons" or quality control > defects) will still have small differences. Each cell 's self-discharge > rate, amphour capacity, internal resistance, and charge/discharge > efficiency will be slightly different. This makes them drift to different > states of charge. For example, cells with a higher self-discharge rate run > down faster just from sitting. Cells with a lower amphour capacity get more > deeply discharged on each cycle, which lowers their efficiency (so they > need a bit more current to fully recharge). Cells with a higher internal > resistance run a little hotter, which affects their efficiency and > self-discharge rate. These differences tend to get larger over time. If not > corrected, you can have a pack with some cells almost full, and some almost > empty! > > Ok, here's the deal this is fiction. Self discharge is so low (milivolts > over years) as to be non-existant.Secondly, if they are in series then all > current passing through cells is equal. It is impossible to draw more > current from one cell than another in a series pack. It can short and pass > all current or it can open and pass no current but it cannot discharge > faster or slower. > > If it has higher resistance then it will cause cells to heat faster that > is all. > > Please show evidence that your theory is possible. > > The only person I spoke with having issues with new cells is when they > were placed in parallel with old cells. In that case the wires melted > because the new cell was handling more of the current. You may damage cells > if there is a big difference in resistance only if you exceed the max > current draw from the cell. If one never approaches the max current draw > this will not be an issue. > > > > > > From: Lee Hart via EV > > To: Electric Vehicle Discussion List > > Sent: Thursday, June 18, 2015 10:53 AM > > Subject: Re: [EVDL] Bicycle battery > > > > Paul Dove via EV wrote: > >> That was a very good summary. Cell balancing is something that was > >> done with other chemistry a and many have tried to apply it to Li Ion > >> chemistries but it doesn't work with Lithium since cells do self > >> discharge or drift. > >> > >> If one wanted to balance them it has to be done below 3.38 volts > >> otherwise you are still charging the cell. Thanks for your input. > > > > Lithiums need balancing even more than other chemistries! You can only > > get by without a BMS if the cells are so well matched that they > > accidentally stay in balance. (Do you feel lucky?) > > > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > > I built it to *use*, not to sell. It doesn't load the cells, or clamp > the voltage at some arbitrary level, and doesn't have failure modes that > murder cells. > > > > It basically does what you would do yourself, if you had the time and > inclination. It measures the voltage of every cel
Re: [EVDL] Bicycle battery
will be slightly different. This makes > them drift to different states of charge. For example, cells with a > higher self-discharge rate run down faster just from sitting. Cells > with a lower amphour capacity get more deeply discharged on each > cycle, which lowers their efficiency (so they need a bit more current > to fully recharge). Cells with a higher internal resistance run a > little hotter, which affects their efficiency and self-discharge rate. > These differences tend to get larger over time. If not corrected, you > can have a pack with some cells almost full, and some almost empty! > > Ok, here's the deal this is fiction. Self discharge is so low > > (milivolts > over years) as to be non-existant.Secondly, if they are in series then > all current passing through cells is equal. It is impossible to draw > more current from one cell than another in a series pack. It can > short and pass all current or it can open and pass no current but it > cannot discharge faster or slower. > > If it has higher resistance then it will cause cells to heat faster > > that > is all. > > Please show evidence that your theory is possible. > > The only person I spoke with having issues with new cells is when > > they > were placed in parallel with old cells. In that case the wires melted > because the new cell was handling more of the current. You may damage > cells if there is a big difference in resistance only if you exceed > the max current draw from the cell. If one never approaches the max > current draw this will not be an issue. > > > > > > From: Lee Hart via EV > > To: Electric Vehicle Discussion List > > Sent: Thursday, June 18, 2015 10:53 AM > > Subject: Re: [EVDL] Bicycle battery > > > > Paul Dove via EV wrote: > >> That was a very good summary. Cell balancing is something that was > >> done with other chemistry a and many have tried to apply it to Li > >> Ion chemistries but it doesn't work with Lithium since cells do > >> self discharge or drift. > >> > >> If one wanted to balance them it has to be done below 3.38 volts > >> otherwise you are still charging the cell. Thanks for your input. > > > > Lithiums need balancing even more than other chemistries! You can > > only get by without a BMS if the cells are so well matched that they > > accidentally stay in balance. (Do you feel lucky?) > > > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > > I built it to *use*, not to sell. It doesn't load the cells, or > > clamp > the voltage at some arbitrary level, and doesn't have failure modes > that murder cells. > > > > It basically does what you would do yourself, if you had the time > > and > inclination. It measures the voltage of every cell, and charges the > ones that are low. > > -- > > The greatest pleasure in life is to create something that wasn't > > there before. -- Roy Spence > > -- > > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > > > > > > > > -- next part -- An HTML attachment was > > scrubbed... > > URL: > > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/ > > dc 23c230/attachment.htm> > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Sean Korb spk...@spkorb.org http://www.spkorb.org '65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera #1382 "The more you drive, the less intelligent you get" --Miller "Computers are useless. They can only give you answers." -P. Picasso -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/5175d1ba/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
ate something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/9258c414/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
e small differences. Each cell 's > self-discharge rate, amphour capacity, internal resistance, and > charge/discharge efficiency will be slightly different. This makes > them drift to different states of charge. For example, cells with a > higher self-discharge rate run down faster just from sitting. Cells > with a lower amphour capacity get more deeply discharged on each > cycle, which lowers their efficiency (so they need a bit more current > to fully recharge). Cells with a higher internal resistance run a > little hotter, which affects their efficiency and self-discharge rate. > These differences tend to get larger over time. If not corrected, you > can have a pack with some cells almost full, and some almost empty! > > Ok, here's the deal this is fiction. Self discharge is so low > > (milivolts > over years) as to be non-existant.Secondly, if they are in series then > all current passing through cells is equal. It is impossible to draw > more current from one cell than another in a series pack. It can > short and pass all current or it can open and pass no current but it > cannot discharge faster or slower. > > If it has higher resistance then it will cause cells to heat faster > > that > is all. > > Please show evidence that your theory is possible. > > The only person I spoke with having issues with new cells is when > > they > were placed in parallel with old cells. In that case the wires melted > because the new cell was handling more of the current. You may damage > cells if there is a big difference in resistance only if you exceed > the max current draw from the cell. If one never approaches the max > current draw this will not be an issue. > > > > > > From: Lee Hart via EV > > To: Electric Vehicle Discussion List > > Sent: Thursday, June 18, 2015 10:53 AM > > Subject: Re: [EVDL] Bicycle battery > > > > Paul Dove via EV wrote: > >> That was a very good summary. Cell balancing is something that was > >> done with other chemistry a and many have tried to apply it to Li > >> Ion chemistries but it doesn't work with Lithium since cells do > >> self discharge or drift. > >> > >> If one wanted to balance them it has to be done below 3.38 volts > >> otherwise you are still charging the cell. Thanks for your input. > > > > Lithiums need balancing even more than other chemistries! You can > > only get by without a BMS if the cells are so well matched that they > > accidentally stay in balance. (Do you feel lucky?) > > > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > > I built it to *use*, not to sell. It doesn't load the cells, or > > clamp > the voltage at some arbitrary level, and doesn't have failure modes > that murder cells. > > > > It basically does what you would do yourself, if you had the time > > and > inclination. It measures the voltage of every cell, and charges the > ones that are low. > > -- > > The greatest pleasure in life is to create something that wasn't > > there before. -- Roy Spence > > -- > > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > > > > > > > > -- next part -- An HTML attachment was > > scrubbed... > > URL: > > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/ > > dc 23c230/attachment.htm> > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Sean Korb spk...@spkorb.org http://www.spkorb.org '65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera #1382 "The more you drive, the less intelligent you get" --Miller "Computers are useless. They can only give you answers." -P. Picasso -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/5175d1ba/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
ents) contains confidential > > > and > > proprietary information of Proxim Wireless Corporation. If you > > received this message in error, please delete it and notify the > > sender. Any unauthorized use, disclosure, distribution, or copying of > > any part of this message is prohibited. > > > > > > > > > -Original Message- > > > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove > > > via EV > > > Sent: Thursday, June 18, 2015 9:57 AM > > > To: Lee Hart; Electric Vehicle Discussion List > > > Subject: Re: [EVDL] Bicycle battery > > > > > > Excerpt:In theory, all batteries are identical. If wired in series, > > > you > > would therefore expect them all to charge and discharge equally. But > > in practice, there are differences. New batteries that are all the > > same brand, same model, same date code (and without "lemons" or > > quality control > > defects) will still have small differences. Each cell 's > > self-discharge rate, amphour capacity, internal resistance, and > > charge/discharge efficiency will be slightly different. This makes > > them drift to different states of charge. For example, cells with a > > higher self-discharge rate run down faster just from sitting. Cells > > with a lower amphour capacity get more deeply discharged on each > > cycle, which lowers their efficiency (so they need a bit more current > > to fully recharge). Cells with a higher internal resistance run a > > little hotter, which affects their efficiency and self-discharge rate. > > These differences tend to get larger over time. If not corrected, you > > can have a pack with some cells almost full, and some almost empty! > > > Ok, here's the deal this is fiction. Self discharge is so low > > > (milivolts > > over years) as to be non-existant.Secondly, if they are in series then > > all current passing through cells is equal. It is impossible to draw > > more current from one cell than another in a series pack. It can > > short and pass all current or it can open and pass no current but it > > cannot discharge faster or slower. > > > If it has higher resistance then it will cause cells to heat faster > > > that > > is all. > > > Please show evidence that your theory is possible. > > > The only person I spoke with having issues with new cells is when > > > they > > were placed in parallel with old cells. In that case the wires melted > > because the new cell was handling more of the current. You may damage > > cells if there is a big difference in resistance only if you exceed > > the max current draw from the cell. If one never approaches the max > > current draw this will not be an issue. > > > > > > > > > From: Lee Hart via EV > > > To: Electric Vehicle Discussion List > > > Sent: Thursday, June 18, 2015 10:53 AM > > > Subject: Re: [EVDL] Bicycle battery > > > > > > Paul Dove via EV wrote: > > >> That was a very good summary. Cell balancing is something that was > > >> done with other chemistry a and many have tried to apply it to Li > > >> Ion chemistries but it doesn't work with Lithium since cells do > > >> self discharge or drift. > > >> > > >> If one wanted to balance them it has to be done below 3.38 volts > > >> otherwise you are still charging the cell. Thanks for your input. > > > > > > Lithiums need balancing even more than other chemistries! You can > > > only get by without a BMS if the cells are so well matched that they > > > accidentally stay in balance. (Do you feel lucky?) > > > > > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > > > I built it to *use*, not to sell. It doesn't load the cells, or > > > clamp > > the voltage at some arbitrary level, and doesn't have failure modes > > that murder cells. > > > > > > It basically does what you would do yourself, if you had the time > > > and > > inclination. It measures the voltage of every cell, and charges the > > ones that are low. > > > -- > > > The greatest pleasure in life is to create something that wasn't > > > there before. -- Roy Spence > > > -- > > > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > > > ___ > > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > > http://lis
Re: [EVDL] Bicycle battery
ents) contains confidential > > > and > > proprietary information of Proxim Wireless Corporation. If you > > received this message in error, please delete it and notify the > > sender. Any unauthorized use, disclosure, distribution, or copying of > > any part of this message is prohibited. > > > > > > > > > -Original Message- > > > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove > > > via EV > > > Sent: Thursday, June 18, 2015 9:57 AM > > > To: Lee Hart; Electric Vehicle Discussion List > > > Subject: Re: [EVDL] Bicycle battery > > > > > > Excerpt:In theory, all batteries are identical. If wired in series, > > > you > > would therefore expect them all to charge and discharge equally. But > > in practice, there are differences. New batteries that are all the > > same brand, same model, same date code (and without "lemons" or > > quality control > > defects) will still have small differences. Each cell 's > > self-discharge rate, amphour capacity, internal resistance, and > > charge/discharge efficiency will be slightly different. This makes > > them drift to different states of charge. For example, cells with a > > higher self-discharge rate run down faster just from sitting. Cells > > with a lower amphour capacity get more deeply discharged on each > > cycle, which lowers their efficiency (so they need a bit more current > > to fully recharge). Cells with a higher internal resistance run a > > little hotter, which affects their efficiency and self-discharge rate. > > These differences tend to get larger over time. If not corrected, you > > can have a pack with some cells almost full, and some almost empty! > > > Ok, here's the deal this is fiction. Self discharge is so low > > > (milivolts > > over years) as to be non-existant.Secondly, if they are in series then > > all current passing through cells is equal. It is impossible to draw > > more current from one cell than another in a series pack. It can > > short and pass all current or it can open and pass no current but it > > cannot discharge faster or slower. > > > If it has higher resistance then it will cause cells to heat faster > > > that > > is all. > > > Please show evidence that your theory is possible. > > > The only person I spoke with having issues with new cells is when > > > they > > were placed in parallel with old cells. In that case the wires melted > > because the new cell was handling more of the current. You may damage > > cells if there is a big difference in resistance only if you exceed > > the max current draw from the cell. If one never approaches the max > > current draw this will not be an issue. > > > > > > > > > From: Lee Hart via EV > > > To: Electric Vehicle Discussion List > > > Sent: Thursday, June 18, 2015 10:53 AM > > > Subject: Re: [EVDL] Bicycle battery > > > > > > Paul Dove via EV wrote: > > >> That was a very good summary. Cell balancing is something that was > > >> done with other chemistry a and many have tried to apply it to Li > > >> Ion chemistries but it doesn't work with Lithium since cells do > > >> self discharge or drift. > > >> > > >> If one wanted to balance them it has to be done below 3.38 volts > > >> otherwise you are still charging the cell. Thanks for your input. > > > > > > Lithiums need balancing even more than other chemistries! You can > > > only get by without a BMS if the cells are so well matched that they > > > accidentally stay in balance. (Do you feel lucky?) > > > > > > Look at my own balancer at http://www.sunrise-ev.com/balancer.htm > > > I built it to *use*, not to sell. It doesn't load the cells, or > > > clamp > > the voltage at some arbitrary level, and doesn't have failure modes > > that murder cells. > > > > > > It basically does what you would do yourself, if you had the time > > > and > > inclination. It measures the voltage of every cell, and charges the > > ones that are low. > > > -- > > > The greatest pleasure in life is to create something that wasn't > > > there before. -- Roy Spence > > > -- > > > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > > > ___ > > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > > http://lis
Re: [EVDL] Bicycle battery
I did not say it was impossible. As long as you stay below the open circuit voltage it's possible. However, if you hold the voltage at 3.6 for LiFePO4 while shunting the current you will still be charging the cell. In essence all you are doing is modifying the charge procedure and loosing track of actual charge time. CC CV charging dictates holding the voltage and tapering the current which is not achieved in this scenario. I said its unnecessary. I am not really concerned about what engineers are doing in commercial products it's clear from the laptop fires the airplane fires the car fires etc. that there is still a lot of false beliefs about these cells. I know dewalt bottom balances their battery and has no cell BMS Sent from my iPad > On Jun 18, 2015, at 1:43 PM, Cor van de Water via EV > wrote: > > Paul, > How familiar are you with electronics? > My wife's eBike has a nice pack with a built-in BMS > that simply starts shunting current above a certain voltage > and presumably (but I can't verify) also reduces charging current, > so you can take care that the shunting cells are receiving zero current > and no longer rise in voltage. The trick is to find a good voltage at > which your BMS will protect the cells. > That pack is very nicely top-balanced and I expect that many more BMSs > that you are not even aware of in daily appliances such as power tools > will all top-balance. > > Regards, > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626Skype: cor_van_de_water > XoIP +31 87 784 1130private: cvandewater.info > www.proxim.com > > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received this > message in error, please delete it and notify the sender. Any unauthorized > use, disclosure, distribution, or copying of any part of this message is > prohibited. > > > -Original Message- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of paul dove via EV > Sent: Thursday, June 18, 2015 9:40 AM > To: Lee Hart; Electric Vehicle Discussion List > Subject: Re: [EVDL] Bicycle battery > > No one has convinced me that top balancing is even possible much less that a > BMS can achieve this. > If you hold a cell above the Open circuit voltage you are charging it even if > you are trying to shunt the current with a Mosfet > > From: Lee Hart via EV > To: Electric Vehicle Discussion List > Sent: Thursday, June 18, 2015 10:46 AM > Subject: Re: [EVDL] Bicycle battery > > David Nelson via EV wrote: >> That is a reason I don't use a cell level BMS. With a cell level BMS >> like the miniBMS there is a constant drain on the cells running the >> BMS boards and it is nearly impossible to make sure that each board >> uses the _exact_ same current regardless of voltage in the cell. >> Furthermore, boards like the miniBMS expect that you will balance at >> the end of every charge and last I saw, that balance voltage was at >> 3.6V or so which is over the theoretical 100% SOC level for LiFePO4 >> cells which leads to potential overcharging of the cells on every >> charge cycle. If you stop charging without the balancing taking place >> and/or let the pack sit for extended periods of time then the >> different current draw of each board working 24/7 introduces an >> imbalance in the SOC of the cells in the pack. > > Yes, this is a problem in the BMS market. Like quack medicine, it's full of > customers worried about a problem that they don't understand very well. So > there are marketeers only too happy to throw together some piece of junk that > purports to solve it. It doesn't have to actually work -- it only needs to > *sound* like it works, to separate the customer from his money. > > So some BMS work -- and some don't. The bad ones are so bad that they give > the whoel BMS market a bad name. > > I've written about this over and over... check my old posts. It mostly seems > to be of no avail, so I won't repeat myself again. Anything I say is > overwhelmed by the noise of the internet. > -- > The greatest pleasure in life is to create something that wasn't there > before. -- Roy Spence > -- > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > > > > -- next part -- > A
Re: [EVDL] Bicycle battery
Even Boeing burned up dream liners with a BMS. Got any other argument besides everyone is doing it? Sent from my iPad > On Jun 18, 2015, at 2:02 PM, EVDL Administrator via EV > wrote: > >> On 18 Jun 2015 at 11:43, Cor van de Water via EV wrote: >> >> That pack is very nicely top-balanced and I expect that many more BMSs >> that you are not even aware of in daily appliances such as power tools >> will all top-balance. > > One more time. There is a really good reason that the only place you find > aversion to BMSes is among EV hobbyists. > > Real world electronics manufacturers -- the ones who build millions of > laptops, mobile phones, power tools and yes, commercial EVs -- know that you > don't sell a product with a lithium battery unless it has ample smarts to > protect the battery, the user, and the manufacturer. > > Trust me, these guys have bean counters looking over their shoulders. They > wouldn't be using BMSes if they weren't necessary. BMSes protect the > battery from early failure, the user from hazard to life and limb, and the > manufacturer from the lawyers! > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > EVDL Information: http://www.evdl.org/help/ > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not > reach me. To send a private message, please obtain my > email address from the webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Bill Dube via EV wrote: A Lee Hart "Batt-Bridge" is an excellent addition to a BMS. "Belt and suspenders" type approach. Redundant systems. Cor and Bill are right. The Batt-Bridge is the simplest "BMS" I could devise. Dirt cheap. It does nothing about imbalances, but at least it *warns* you before something goes seriously wrong. I documented it at http://www.sunrise-ev.com/LeesEVs.htm#battbridge The resistive divider does load the cells; but at least it's a constant load current across *all* cell, and not different loads for different cells. But Cor is right that you want to disconnect it when the pack is not being used. A zero-center microammeter, or even a digital multimeter can also replace the LEDs. This gets the load current down to microamps; low enough to ignore. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Sean Korb via EV wrote: That is Brilliant! I love living in the future :) And I love that my pack will cost somewhat less for the same KVA. Actually, I designed the Batt-Bridge decades ago, in the last century. And it's simply using LEDs in place of the meter in the same circuit used in EVs a hundred years ago! -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
one wanted to balance them it has to be done below 3.38 volts >>> otherwise you are still charging the cell. Thanks for your input. >> >> Lithiums need balancing even more than other chemistries! You can only >> get by without a BMS if the cells are so well matched that they >> accidentally stay in balance. (Do you feel lucky?) >> >> Look at my own balancer at http://www.sunrise-ev.com/balancer.htm >> I built it to *use*, not to sell. It doesn't load the cells, or clamp the >> voltage at some arbitrary level, and doesn't have failure modes that murder >> cells. >> >> It basically does what you would do yourself, if you had the time and >> inclination. It measures the voltage of every cell, and charges the ones >> that are low. >> -- >> The greatest pleasure in life is to create something that wasn't there >> before. -- Roy Spence >> -- >> Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) >> >> >> >> >> -- next part -- An HTML attachment was >> scrubbed... >> URL: >> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/dc >> 23c230/attachment.htm> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) >> >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Paul, I presume you never ride in a car, because Ford's Pinto was a bomb on wheels and unsafe at any speed. Your line of reasoning does not warrant a serious response and I have given many reasons why a BMS is a good thing - I like to discuss based on arguments and data, not on lore and incidents. BTW, last I heard the root cause of the dreamliner fires is still unknown, there is suspicion about the quality of the batteries, similar to what caused laptop batteries to catch fire due to impurities embedded in the cells and trigger thermal runaway. I have helped to investigate a fire in a converted EV with Lithium-Ion prismatic cells that I suspect (but it was never conclusively proven) was caused by manufacturing defects. There was no BMS on that pack and it was not being charged, still it caught fire just sitting. One thing that I found was that what appeared to be a hotspot also showed severely deformed (folded crooked as if they were rammed into the prismatic case) cell plates (the original pouches that are contained in a bundle inside the prismatic cell) in one of the cells. But you can't say "they used a BMS so that caused the fire". If you have a source that proves that it was in fact the BMS causing the fire then I would be interested in a link. Here is what I have: http://arstechnica.com/business/2013/02/investigation-reveals-cause-of-battery-fire-on-boeing-787-dreamliner/ https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems http://www.ifsecglobal.com/dreamliner-lithium-battery-fire-cause-still-unknown/ Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Paul Dove via EV Sent: Thursday, June 18, 2015 6:31 PM To: EVDL Administrator; Electric Vehicle Discussion List Subject: Re: [EVDL] Bicycle battery Even Boeing burned up dream liners with a BMS. Got any other argument besides everyone is doing it? Sent from my iPad > On Jun 18, 2015, at 2:02 PM, EVDL Administrator via EV > wrote: > >> On 18 Jun 2015 at 11:43, Cor van de Water via EV wrote: >> >> That pack is very nicely top-balanced and I expect that many more >> BMSs that you are not even aware of in daily appliances such as power >> tools will all top-balance. > > One more time. There is a really good reason that the only place you > find aversion to BMSes is among EV hobbyists. > > Real world electronics manufacturers -- the ones who build millions of > laptops, mobile phones, power tools and yes, commercial EVs -- know > that you don't sell a product with a lithium battery unless it has > ample smarts to protect the battery, the user, and the manufacturer. > > Trust me, these guys have bean counters looking over their shoulders. > They wouldn't be using BMSes if they weren't necessary. BMSes protect > the battery from early failure, the user from hazard to life and limb, > and the manufacturer from the lawyers! > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL > Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = > = = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not reach me. > To send a private message, please obtain my email address from the > webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
gt; = = = = = = = = = = = = = > > Note: mail sent to "evpost" and "etpost" addresses will not reach me. > > To send a private message, please obtain my email address from the > > webpage http://www.evdl.org/help/ . > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > > > ___ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA > > (http://groups.yahoo.com/group/NEDRA) > > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/d4c725e6/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
We already covered how to tell is a cell has internal defects. You drain the cell to 2.5 volts and then if the cell voltage rises it's good if it keeps falling don't use it. I did think this up This is what NASA does. I read it in one of their presentations. I can dig it up if you like. As for the Dreamliner I followed that carefully. My favorite chart that they presented to the FAA said - the only thing that causes lithium battery fires is overchargeing - we can find no evidence we are over charging - therefore the cause of the fire is unknown One of those statements has to be wrong. And the fire was the evidence of overcharging. The open circuit voltage of their battery was 29.6 volts. The system voltage was 32 volts. They were charging the cells the whole time the APU was running and wondering why it burned. As for laptops they were overcharging as well. The paper I read the designer claimed that leaving a small amount of current flowing or trickle charge as they call it would not hurt lithium batteries. Sent from my iPad > On Jun 18, 2015, at 9:59 PM, Cor van de Water via EV > wrote: > > This message has no content. -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/c4bcfdcb/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
ufacturer. >>> >>> Trust me, these guys have bean counters looking over their shoulders. >>> They wouldn't be using BMSes if they weren't necessary. BMSes protect >>> the battery from early failure, the user from hazard to life and limb, >>> and the manufacturer from the lawyers! >>> >>> David Roden - Akron, Ohio, USA >>> EVDL Administrator >>> >>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL >>> Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = >>> = = = = = = = = = = = = = >>> Note: mail sent to "evpost" and "etpost" addresses will not reach me. >>> To send a private message, please obtain my email address from the >>> webpage http://www.evdl.org/help/ . >>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = = >>> >>> >>> ___ >>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>> For EV drag racing discussion, please use NEDRA >>> (http://groups.yahoo.com/group/NEDRA) >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) >> >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) > > > -- > To invent, you need a good imagination and a pile of junk. > Thomas A. Edison > <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > A public-opinion poll is no substitute for thought. > *Warren Buffet* > > Michael E. Ross > (919) 585-6737 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone > (919) 631-1451 Cell > > michael.e.r...@gmail.com > > -- next part -- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/d4c725e6/attachment.htm> > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
is what I have: >> >> http://arstechnica.com/business/2013/02/investigation-reveals-cause-o >> f-battery-fire-on-boeing-787-dreamliner/ >> https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems >> >> http://www.ifsecglobal.com/dreamliner-lithium-battery-fire-cause-stil >> l-unknown/ >> >> Regards, >> >> Cor van de Water >> Chief Scientist >> Proxim Wireless >> >> office +1 408 383 7626 Skype: cor_van_de_water >> XoIP +31 87 784 1130 private: cvandewater.info >> www.proxim.com >> >> >> This email message (including any attachments) contains confidential >> and proprietary information of Proxim Wireless Corporation. If you >> received this message in error, please delete it and notify the >> sender. Any unauthorized use, disclosure, distribution, or copying >> of any part of this message is prohibited. >> >> >> -Original Message- >> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Paul Dove >> via EV >> Sent: Thursday, June 18, 2015 6:31 PM >> To: EVDL Administrator; Electric Vehicle Discussion List >> Subject: Re: [EVDL] Bicycle battery >> >> Even Boeing burned up dream liners with a BMS. >> >> Got any other argument besides everyone is doing it? >> >> >> >> Sent from my iPad >> >>>> On Jun 18, 2015, at 2:02 PM, EVDL Administrator via EV < >>> ev@lists.evdl.org> wrote: >>> >>>> On 18 Jun 2015 at 11:43, Cor van de Water via EV wrote: >>>> >>>> That pack is very nicely top-balanced and I expect that many more >>>> BMSs that you are not even aware of in daily appliances such as >>>> power tools will all top-balance. >>> >>> One more time. There is a really good reason that the only place >>> you find aversion to BMSes is among EV hobbyists. >>> >>> Real world electronics manufacturers -- the ones who build millions >>> of laptops, mobile phones, power tools and yes, commercial EVs -- >>> know that you don't sell a product with a lithium battery unless it >>> has ample smarts to protect the battery, the user, and the manufacturer. >>> >>> Trust me, these guys have bean counters looking over their shoulders. >>> They wouldn't be using BMSes if they weren't necessary. BMSes >>> protect the battery from early failure, the user from hazard to life >>> and limb, and the manufacturer from the lawyers! >>> >>> David Roden - Akron, Ohio, USA >>> EVDL Administrator >>> >>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL >>> Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = >>> = = = = = = = = = = = = = = >>> Note: mail sent to "evpost" and "etpost" addresses will not reach me. >>> To send a private message, please obtain my email address from the >>> webpage http://www.evdl.org/help/ . >>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = = >>> >>> >>> ___ >>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>> For EV drag racing discussion, please use NEDRA >>> (http://groups.yahoo.com/group/NEDRA) >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) >> >> ___ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) > > > -- > To invent, you need a good imagination and a pile of junk. > Thomas A. Edison > <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > > A public-opinion poll is no substitute for thought. > *Warren Buffet* > > Michael E. Ross > (919) 585-6737 Land > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > Phone > (919) 631-1451 Cell > > michael.e.r...@gmail.com > > -- next part -- An HTML attachment was > scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/d4 > c725e6/attachment.htm> ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
Paul, the 29.6V is not the max charge voltage of the pack. It is the nominal voltage: 8 x 3.7V (these were Cobalt cells) = 29.6V So the max 32V on the bus is actually only 4V per cell and that means that they keep those cells below max charge voltage of 4.2V So, it was not possible that the battery was over-charged, unless a cell shorted and the 32V was applied to 7 cells in series instead of 8! Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Paul Dove via EV Sent: Thursday, June 18, 2015 8:21 PM To: Cor van de Water via EV Subject: Re: [EVDL] Bicycle battery We already covered how to tell is a cell has internal defects. You drain the cell to 2.5 volts and then if the cell voltage rises it's good if it keeps falling don't use it. I did think this up This is what NASA does. I read it in one of their presentations. I can dig it up if you like. As for the Dreamliner I followed that carefully. My favorite chart that they presented to the FAA said - the only thing that causes lithium battery fires is overchargeing - we can find no evidence we are over charging - therefore the cause of the fire is unknown One of those statements has to be wrong. And the fire was the evidence of overcharging. The open circuit voltage of their battery was 29.6 volts. The system voltage was 32 volts. They were charging the cells the whole time the APU was running and wondering why it burned. As for laptops they were overcharging as well. The paper I read the designer claimed that leaving a small amount of current flowing or trickle charge as they call it would not hurt lithium batteries. Sent from my iPad > On Jun 18, 2015, at 9:59 PM, Cor van de Water via EV > wrote: > > This message has no content. -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/c4bcfdcb/attachment.htm> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Bicycle battery
very >> charge cycle. If you stop charging without the balancing taking place >> and/or let the pack sit for extended periods of time then the >> different current draw of each board working 24/7 introduces an >> imbalance in the SOC of the cells in the pack. > > Yes, this is a problem in the BMS market. Like quack medicine, it's full of > customers worried about a problem that they don't understand very well. So > there are marketeers only too happy to throw together some piece of junk that > purports to solve it. It doesn't have to actually work -- it only needs to > *sound* like it works, to separate the customer from his money. > > So some BMS work -- and some don't. The bad ones are so bad that they give > the whoel BMS market a bad name. > > I've written about this over and over... check my old posts. It mostly seems > to be of no avail, so I won't repeat myself again. Anything I say is > overwhelmed by the noise of the internet. > -- > The greatest pleasure in life is to create something that wasn't there > before. -- Roy Spence > -- > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > > > > -- next part -- An HTML attachment was > scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/92 > 58c414/attachment.htm> ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > ___ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
