EV Digest 3930
Topics covered in this issue include:
1) Re: After a simple voltmeter circuit using LEDs
by Chris Zach <[EMAIL PROTECTED]>
2) RE: After a simple voltmeter circuit using LEDs
by "Don Cameron" <[EMAIL PROTECTED]>
3) Re: After a simple voltmeter circuit using LEDs
by Rod Hower <[EMAIL PROTECTED]>
4) 200sx guess
by Jeff Shanab <[EMAIL PROTECTED]>
5) Re: 200sx 0-60 estimates - a friendly little contest]
by "John Westlund" <[EMAIL PROTECTED]>
6) Re: After a simple voltmeter circuit using LEDs
by James Massey <[EMAIL PROTECTED]>
7) article: Panasonic car runs on two AA batteries
by Paul Wujek <[EMAIL PROTECTED]>
8) Re: After a simple voltmeter circuit using LEDs
by Ken Lange <[EMAIL PROTECTED]>
9) Soneil charger information, was Re: Modular Charger
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
10) Re: After a simple voltmeter circuit using LEDs
by "Joe Smalley" <[EMAIL PROTECTED]>
11) Re: 200sx 0-60: more specs
by Ryan Bohm <[EMAIL PROTECTED]>
12) AC-ing in the Snow; Battery Questions
by [EMAIL PROTECTED]
13) RE: After a simple voltmeter circuit using LEDs
by "Mark Fowler" <[EMAIL PROTECTED]>
14) Re: Modular Charger
by "MYLES ANTHONY TWETE" <[EMAIL PROTECTED]>
15) Re: AC-ing in the Snow; Battery Questions
by "Joe Smalley" <[EMAIL PROTECTED]>
16) Re: After a simple voltmeter circuit using LEDs
by Aaron NMLUG-EV <[EMAIL PROTECTED]>
17) Re: After a simple voltmeter circuit using LEDs
by Chris Zach <[EMAIL PROTECTED]>
18) Re: After a simple voltmeter circuit using LEDs
by Dave Cover <[EMAIL PROTECTED]>
19) Hybrid electric vehicle offers eco-friendly commuting
by Lee Dekker <[EMAIL PROTECTED]>
20) Re: Hybrid electric vehicle offers eco-friendly commuting
by Rod Hower <[EMAIL PROTECTED]>
21) Re: Hybrid electric vehicle offers eco-friendly commuting
by Gordon Niessen <[EMAIL PROTECTED]>
22) Re: After a simple voltmeter circuit using LEDs
by Chris Zach <[EMAIL PROTECTED]>
23) Re: Modular Charger
by "John Bryan" <[EMAIL PROTECTED]>
24) Re: fuel gauge and clutchless shifting
by Lee Hart <[EMAIL PROTECTED]>
25) charge algorithm question (related to modular chargers)
by "Markus L" <[EMAIL PROTECTED]>
26) RE: Modular Charger
by "Markus L" <[EMAIL PROTECTED]>
--- Begin Message ---
I think this is a *GREAT* idea, since the important thing is not
necessarially the battery voltage, but the relationship of the battery
voltage to other batteries.
Problem is one really needs sharp cut-offs when things go "bad". Where
bad is less than 10.66 volts per battery under any load and bad is above
15.0 volts (and 15.6 volts) per battery under any charge load.
Thus the issue with opto-isolators: Since 50 of them would never work in
perfect sync; the relationship of voltages is lost.
I will say that my monitor system on the Elec-Trak (with the 3 dual
color LEDs) is unbelievable. I can now run the batteries out of balance
and *know* when this spells trouble on any one battery. When a light
comes on alone I know I'm out of balance and I reduce power (turning off
the light) and head for home. When charging, if one light doesn't come
on and the other two are turning yellow I know to stop charging and
manually charge up the laggard.
I can't wait till spring to put this system on my 50 batteries in the
Prizm. Current isolation under test is a light pipe of 50 fibers going
from the outside firewall to the interior. Should be interesting, since
the eye can pick out one red light in a cluster of 50 very very quickly.
Chris
Dave Cover wrote:
--- [EMAIL PROTECTED] wrote:
I'm in the build and torture phase at the moment, so the specifics are subject
to change if
something goes poof in the torture test.<grin>
I'll post a link to the circuits to all this stuff when I get it finalized.
This sounds like an excellent project. I think it would be pretty cool to have
a grid of LEds on
the dash showing you real time what your pack is doing. If it gets too bright
you could semi-hide
it behind a smoke glass window to subdue it a little. Just enough to keey an
eye on the pack, but
not enough to blind you at night. And if you have a stinker in the pack, it
will stand out.
I'd love to do the same but my electronics abilities don't go much farther than
wiring and
soldering what someone else has figured out for me. If you post more info about
this project could
you also include details of how you incorporate the opto isolators and details
like that?
Thanks
Dave Cover
--- End Message ---
--- Begin Message ---
How big is the light pipe?
Also, want to share your circuit? This sounds like fun and easy to build.
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Chris Zach
Sent: November 24, 2004 2:53 PM
To: [EMAIL PROTECTED]
Subject: Re: After a simple voltmeter circuit using LEDs
I think this is a *GREAT* idea, since the important thing is not
necessarially the battery voltage, but the relationship of the battery
voltage to other batteries.
Problem is one really needs sharp cut-offs when things go "bad". Where bad
is less than 10.66 volts per battery under any load and bad is above 15.0
volts (and 15.6 volts) per battery under any charge load.
Thus the issue with opto-isolators: Since 50 of them would never work in
perfect sync; the relationship of voltages is lost.
I will say that my monitor system on the Elec-Trak (with the 3 dual color
LEDs) is unbelievable. I can now run the batteries out of balance and *know*
when this spells trouble on any one battery. When a light comes on alone I
know I'm out of balance and I reduce power (turning off the light) and head
for home. When charging, if one light doesn't come on and the other two are
turning yellow I know to stop charging and manually charge up the laggard.
I can't wait till spring to put this system on my 50 batteries in the Prizm.
Current isolation under test is a light pipe of 50 fibers going from the
outside firewall to the interior. Should be interesting, since the eye can
pick out one red light in a cluster of 50 very very quickly.
Chris
Dave Cover wrote:
> --- [EMAIL PROTECTED] wrote:
>
>>I'm in the build and torture phase at the moment, so the specifics are
>>subject to change if something goes poof in the torture test.<grin>
>>
>>I'll post a link to the circuits to all this stuff when I get it
finalized.
>>
>
>
> This sounds like an excellent project. I think it would be pretty cool
> to have a grid of LEds on the dash showing you real time what your
> pack is doing. If it gets too bright you could semi-hide it behind a
> smoke glass window to subdue it a little. Just enough to keey an eye on
the pack, but not enough to blind you at night. And if you have a stinker in
the pack, it will stand out.
>
> I'd love to do the same but my electronics abilities don't go much
> farther than wiring and soldering what someone else has figured out
> for me. If you post more info about this project could you also include
details of how you incorporate the opto isolators and details like that?
>
> Thanks
>
> Dave Cover
>
>
--- End Message ---
--- Begin Message ---
I connected 6 voltmeters (that I bought at Harbor
Freight for $25 each on sale) to each battery tray in
the TEVan. If there is a problem I know which tray to
drop, however I don't know which battery is a problem
until I check them once the tray is dropped.
Obviously this doesn't work at night with an LCD
display unless you have a light shining on the meters.
The $25 meters have been very reliable, I have one
that I've used for 1.5 years. They are also pretty
accurate for this application (I check them against my
Fluke 87).
The only drawback is the space for 6 meters the same
size as a Fluke 87.
Rod
--- End Message ---
--- Begin Message ---
Without any math I'll say 15.9.
--- End Message ---
--- Begin Message ---
I guess 11.5 seconds 0-60, if you do your shifting right.
You'll probably want to upgrade later if you happen to want
more range. Imagine having 2 strings of 156V from the
Orbitals. That would get you about 20-25 miles to 80% DoD.
--- End Message ---
--- Begin Message ---
At 06:20 PM 24/11/04 +0000, "Mad" Mike Shipway wrote:
I'm in the build and torture phase at the moment, so the specifics are
subject to change if something goes poof in the torture test.<grin>
I'll post a link to the circuits to all this stuff when I get it finalized.
Hi Mike, Lee and all.
I am in the process of doing something similar using LM3914 ICs, but I am
putting one per battery, at the batteries, coming off using optocouplers
(20 batteries x 10 = 200, plus enable back the other way and other stuff -
got 'em cheap, surplus), then scanning the outputs of those optos at a
fairly slow speed onto a buss. At the end of the buss (behind the
instrument cluster) a simple load-and-hold to drive the leds in the
instrument cluster. Set up in dot-mode, a weak battery should be
immediately obvious.
And everything to do with this system is only referenced to the 12V of the
vehicle.
10 Leds for the outputs of the voltmeters, 2 per Rudman reg for the low
battery indication and regulating, then another group to indicate the
charging status. maybe a 2-second update time, but should be fine. Still
gotta build a bunch of bits yet.
How does this compare with other peoples schemes?
James Massey
Launceston, Tasmania, Australia.
'78 Daihatsu 1300kg truck under conversion.
--- End Message ---
--- Begin Message ---
Yes, it's a rather wild claim, and really the car doesn't get very far
(1.23km), but you still might find this interesting, link:
http://www.theinquirer.net/?article=19872
--
Paul Wujek
--- End Message ---
--- Begin Message ---
Hi Mike,
I built a system like you described and have used it for over 4 years. It
is great and well worth having.
I also used the LM3914, optoisolators with high value resistors (30 kohm)
in series with the diodes. I made a matrix using surface mount LEDs, with
the top seven for each battery being green, the next 2 being yellow, and
the last row bright red. You can set up the circuit so that any voltage
below, say, 10.5 volts keeps the red led on.
I also switch ranges between charge and discharge, and it's useful to keep
resolution.
I used a clever analog optoisolator circuit I saw in EDN magazine which
uses two isolators to balance out the temperature effects. It works quite
well.
My display of LEDs is mounted where a rectangular voltmeter was meant to be
in an instrument option for the Fiero. There is a smoke/bronze piece of
plastic in front that I got a TAP Plastics. I found that using bar mode
can cause a lot of heat dissipation which would be tough for the
LM3914s. I ended up always using dot mode and really love the
display. This analog display gives real time indications as you're
driving, and you quickly spot a bright red led that lights out of the
corner of your eye.
As I mentioned in a post some time ago, the first thing I discovered with
the display was that the crimped cables were starting to pick up
resistance. After soldering all of the connectors, the display showed that
there was not excessive voltage drop with current draw (and this has
remained good).
This is part of the plan for the modular charger system I'm building. The
proto is there; I'm now starting the mass production.
Best regards,
Ken Lange
1988 Electric Fiero
--- End Message ---
--- Begin Message ---
>Date: Wed, 24 Nov 2004 08:25:50 -0800
>From: Eric Poulsen <[EMAIL PROTECTED]>
>
>I sent an email to them asking about their reliability testing
>methodology. If I don't get a response in a week or so, I'll call them.
Eric and All,
Looking back at my notes, I talked to an enganeer at Soneil named Sach Khan
around August of 2001 with some EV specific questions. He faxed me 15 pages
of specifications on the 1205SR and 1212SR chargers. US phone number in
Canada is (905)565-0360. Reading back through old e-mail communications,
the distributor I talked to at the time mentioned that this engineer worked
for Cliplight, which built the Zap chargers that John Bryan is using in his
Ghia. Also, from looking at my old e-mail, Chuck Hendrick was using the
1212SR model and his pack prematurely died. As I recall, he wasn't doing an
occasional equalize (and neither was I), and he wasn't humping 20-30 amps
in either with any kind of bulk charger, which I'm doing with the
FrankenLesters. The AGM's seem to like high currents once in awhile, and
John Bryan can chime in on waking up YT's with a 100 amp charger! From
talking to John Olsen, the former electrochemist with Optima, Bill Dube'
has posted about YT's needing the one amp over-charge with unlimited
voltage, "and" venting occasionally, or they will loose capacity. Bill
mentioned that the length of the over-charge is based on D(epth) O(f)
D(ischarge). Bill also said that if you do the over-charge too often,
they'll dry out before end-of-life. I think this is why the Zivan YT
algorithm was murdering YT's, along with the fact that each battery needed
Rudman type regulators (or communication from each battery to a PFCxx
charger would be nice!).
I only have a couple of problems with the Soneil chargers. When they've
finished the bulk mode, and have pulsed for awhile, they'll pop my GFCI
outlet occasionally. When this first happened, I started switching off
banks of them looking for a bad one, but realized that it has to do with
using all 16 of them at once. The other problem, which Chuck can chime in
on, is they get really hot during bulk mode, so plan on some sort of
cooling, and don't stack them on top of each other.
They were designed for on-board wheel chair use, so they're built rugged.
When I was trying to decide on modular chargers, I had asked Optima about
the Soneil charger, and the tech support person said they knew of them and
approved there use on YT's. I believe others on the list have used these on
AGM scooter batteries, so maybe they'll chime in too.
Hope this helps,
Dave (B.B.) Hawkins
Member of the Denver Electric Vehicle Council:
http://www.devc.org/
Card carrying member and former racer with The National Electric Drag
Racing Association:
http://www.nedra.com/
Lyons, CO
1979 Mazda RX-7 EV (192V of YT's for the teenagers)
1989 Chevy S10 Ext. Cab (144V of floodies, for Ma and Pa only!)
--- End Message ---
--- Begin Message ---
I vaguely recall the circuit. It had a problem with the LED brightness
changing with voltage. There was a solution for the brightness issue but
that part gets fuzzy.
The simple solution was to put the LEDs in series and put various values of
resistors in parallel with the LEDs. As the voltage came up, each resistor
dropped more voltage and allowed the LED in parallel with the resistor to
come on when the voltage got high enough to conduct and illuminate. The
problem with this approach is that the LED brightness varies as the voltage
changes. To get away from this problem, the circuit requires a current
regulator for each LED. There was a fairly simple circuit that would do
this, but I can't recall it enough of it to write it down.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Mark Fowler" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, November 24, 2004 2:32 PM
Subject: RE: After a simple voltmeter circuit using LEDs
> OK, once again I've done a pitiful job of explaining myself...
>
> The circuit that I recall had a bunch of LEDs in series and some
> resistors coming off the side? so that what happened was that as the
> voltage increased, each LED would light up.
>
> Does this make sense?
>
> Anyway, the requirement for accuracy is roughly 0%.
> I just need something that will light up more LEDs as the kids at school
> spin the hand generator faster.
>
> Mark
>
--- End Message ---
--- Begin Message ---
I knew someone would ask for more information to get a better estimate.
Joe Smalley asked about the following for the 200sx:
What gear ratios do you have?
I can't tell you exactly, but with P205/60 R15 tires, the engine would
be at 6000 rpm in 1st gear at around 30mph, 2nd at 45mph, and 3rd at 70.
Which gears to you use? (1,3,5 or 3,5 or 1,2,3,4,5)
I imagine I'll use 2nd and 3rd.
What are your shift points?
?? I'll have to play around with it to get a feel for what works best,
but I imagine I'll start in second, and shift to third when I'm at about
30mph.
What are the Z1K settings?
Uhhh...once again, I'll have to play around with them. Of course
eventually I'll work up to 1000amps, I've been told to set the low
battery voltage at around 70V.
What are the motor constants? (Milliohms at a stop and milliohms per 1000
RPM)
What is the battery pack internal resistance?
I'll have to get back with you on this. I don't have my batteries yet
(arrgghh!! They were supposed to be at the Salt Lake warehouse by now).
Have a good Thanksgiving everyone!
-Ryan
--
- EV Source -
Zillas, PFC Chargers, and other EV stuff at great prices
5% off all items in our Top-Line Shop from November to Christmas!
E-mail: mailto:[EMAIL PROTECTED]
Toll-free: 1-877-215-6781
--- End Message ---
--- Begin Message ---
Hi All,
Upon my finishing classes for the week, I took a trip to Jackson, MI to
reinstall my drive system. Besides a sticky homemade throttle box, everything
went well - on the grass, that is. The front-wheel-drive Renault performed
well at its lower 48Vin-maximum-speed of 3MPH (!!!) during the first snow of
the year (3" almost). I continue to utilize my four 110Ah Sears DieHard Marine
batteries - but I continue to be worried about them.
They have been sitting in the non-heated garage for a couple months now, after
last being used. They hadn't been charged for a few weeks at least, but were
basically full when I left them. I try to top them off when I can, but it is
difficult while taking classes. When I got to them today they were at almost
exactly 12.50V each, with a temperature of 35-40 deg. F. I turned on the
charger that came with the DC conversion and saw its current meter jump to
about 10A, then fade down to 5A after a minute. At this time I noticed the
batteries bubbling strongly! I turned the current down to 3A after measuring
14.50V on one. This seemed like an awfully high internal resistance. I left
the charger on for about 20 more minutes, then drove the car up my yard and
back. There was noticably less power due to the strong dependance of torque on
bus voltage. Under a 75-100A draw, the pack meter was less than 43V. Usually
the meter stays above 46V under these conditions.
These units continually perplex me. I've recently checked all the water
levels, and filled them to where Trojan recommends (I assume it is a similar
technique for any brand). I have not been able to find any documentation on
them. I want to be proactive to not destroy them, while/if I still have an
opportunity. I charge often but I notice tons of bubbling at fairly low
voltages (13.6V at 80 deg. F). The capacity seems decent, but it is hard to
tell when they're empty. I've had one occurrance of thermal runaway, during
the middle of the summer. This is the only time the current has been above 15A
each; this current almost always results in bubbling unless the pack is
completely drained. I have never intentionally equalized them. They've seen
no more than 10 >50% cycles. The most recent cycle was 14 miles on grass, at
5MPH average, with the fairly efficient AC drive+regen. Does this sound
reasonable for 90% of 5280Wh?
I consulted my sailing friend about his marine battery - and he said the
instructions recommend he refill the water level quite often. This suggests
lots of bubbling but doesn't seem to make a whole lot of sense as to what this
design would benefit.
One of my favorite online sites is the Deep Cycle Battery FAQ. Is the picture
below basically what I should be following? Is the FAQ sensible?
http://www.uuhome.de/william.darden/deltran4.gif
from http://www.uuhome.de/william.darden/carfaq9.htm
My questions are... Does the cold affect the internal resistance that much
(about double), or just the capacity? Am I too worried about the
bubbling/gurgling, and should I let it go on for over a half-hour? Are there
any tests, simple or involved, that I can do to find out more information?
Thank you much in advance!
Arthur Matteson
- 1980 Renault LeCar, "Little Homebrew AC"
- Custom Auto Electronics - Jackson, MI
http://mywebpages.comcast.net/awmatt
--- End Message ---
--- Begin Message ---
Yes, this sounds like it.
I don't care about the brightness issue - like I said it is just so that
kids can see a difference between turning a generator slow and fast.
Ok - so there will be a series of diode-resistor buddy pairs :-)
I'll have a play around with some parts on a breadboard and see what I
can do...
Mark
-----Original Message-----
From: Joe Smalley [mailto:[EMAIL PROTECTED]
Sent: Thursday, 25 November 2004 2:51 PM
To: [EMAIL PROTECTED]
Subject: Re: After a simple voltmeter circuit using LEDs
I vaguely recall the circuit. It had a problem with the LED brightness
changing with voltage. There was a solution for the brightness issue but
that part gets fuzzy.
The simple solution was to put the LEDs in series and put various values
of
resistors in parallel with the LEDs. As the voltage came up, each
resistor
dropped more voltage and allowed the LED in parallel with the resistor
to
come on when the voltage got high enough to conduct and illuminate. The
problem with this approach is that the LED brightness varies as the
voltage
changes. To get away from this problem, the circuit requires a current
regulator for each LED. There was a fairly simple circuit that would do
this, but I can't recall it enough of it to write it down.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
> MTBF 50,000 power-on-hours (POH) or greater.
Let's see:
* MTBF of 50,000 for each charger.
* 10 chargers.
Each charger's failure rate =1 / MTBF = 20 failures/10^6 hours
Assuming individual failures in each charger are independent and ignoring
cascading failures between chargers,
cumulative failure rate = #chargers * failure rate
= 200 failures / 10^6 hours.
i.e. the charging system failure rate is expected to be 1 failure/5,000hours
or, system MTBF = 5000hours.
At 10hrs/charge, this would be 500 charge cycles between charger failure.
Right around the same magnitude of cycles as battery life.
Hmmm.
-Myles Twete
--- End Message ---
--- Begin Message ---
Lots of questions.
1. Leaving the batteries in a charged state for a couple months is not an
issue. Leaving them in an uncharged state will slowly destroy them.
2. The battery impedance under charge always goes up near end of charge.
This is normal.
3. Vigorous gassing in a flooded battery is normal at end of charge. As long
as the current is under C/20 and under a half hour, don't worry about it.
You are just stirring the electrolyte.
4. The cold raises the impedance of the battery pack making the bus voltage
drop under load. When it warms up, the battery should be back to normal.
5. Many flooded batteries gas vigorously as a fairly low voltage. As long as
the current is under C/20, there is enough water in the cells and the
duration is short (under an hour) you will not damage the battery.
6. Marine batteries usually need a lot of watering because the cheap
chargers float the batteries at a voltage that is too high resulting in
quite a bit of water consumption. They need to be watered often so the
plates do not get exposed and damaged.
7. My experience with flooded batteries was that the capacity decreased by
1% per degree F and the impedance went up by 1% per degree F.
8. You can see how your batteries like to be charged with the following
technique:
-Run the battery down at least 10% of its capacity (11 AHr for a 110 AHR
battery)
-Charge the battery at 5% of its capacity (5.5 amps for a 110 AHR battery)
-Measure and record the battery voltage every 10 minutes.
-Rate the gassing on a scale of zero to ten.
-Plot the voltage and gassing as a function of time.
-Stop the charge when the voltage reaches a plateau. This should take over
two hours.
-The plateau voltage is the maximum acceptance voltage you should use and
should probably be a few percent less.
-As the battery changes temperature, the plateau voltage will change.
-As the battery ages, the plateau voltage will change.
-Your acceptance voltage will need to be set to different voltages as the
temperature changes and the batteries age.
-You can charge with as much current as you can make as long as you do not
go over the acceptance voltage.
-Beware of thermal runaway! As the batteries heat up, the battery acceptance
voltage requirement goes down, sometimes causing the charger to put an
excessive amount of power into the battery for the actual cell temperature.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, November 24, 2004 10:10 PM
Subject: AC-ing in the Snow; Battery Questions
> Hi All,
>
> Upon my finishing classes for the week, I took a trip to Jackson, MI to
reinstall my drive system. Besides a sticky homemade throttle box,
everything went well - on the grass, that is. The front-wheel-drive Renault
performed well at its lower 48Vin-maximum-speed of 3MPH (!!!) during the
first snow of the year (3" almost). I continue to utilize my four 110Ah
Sears DieHard Marine batteries - but I continue to be worried about them.
>
> They have been sitting in the non-heated garage for a couple months now,
after last being used. They hadn't been charged for a few weeks at least,
but were basically full when I left them. I try to top them off when I can,
but it is difficult while taking classes. When I got to them today they
were at almost exactly 12.50V each, with a temperature of 35-40 deg. F. I
turned on the charger that came with the DC conversion and saw its current
meter jump to about 10A, then fade down to 5A after a minute. At this time
I noticed the batteries bubbling strongly! I turned the current down to 3A
after measuring 14.50V on one. This seemed like an awfully high internal
resistance. I left the charger on for about 20 more minutes, then drove the
car up my yard and back. There was noticably less power due to the strong
dependance of torque on bus voltage. Under a 75-100A draw, the pack meter
was less than 43V. Usually the meter stays above 46V under these
conditions.
>
> These units continually perplex me. I've recently checked all the water
levels, and filled them to where Trojan recommends (I assume it is a similar
technique for any brand). I have not been able to find any documentation on
them. I want to be proactive to not destroy them, while/if I still have an
opportunity. I charge often but I notice tons of bubbling at fairly low
voltages (13.6V at 80 deg. F). The capacity seems decent, but it is hard to
tell when they're empty. I've had one occurrance of thermal runaway, during
the middle of the summer. This is the only time the current has been above
15A each; this current almost always results in bubbling unless the pack is
completely drained. I have never intentionally equalized them. They've
seen no more than 10 >50% cycles. The most recent cycle was 14 miles on
grass, at 5MPH average, with the fairly efficient AC drive+regen. Does this
sound reasonable for 90% of 5280Wh?
>
> I consulted my sailing friend about his marine battery - and he said the
instructions recommend he refill the water level quite often. This suggests
lots of bubbling but doesn't seem to make a whole lot of sense as to what
this design would benefit.
>
> One of my favorite online sites is the Deep Cycle Battery FAQ. Is the
picture below basically what I should be following? Is the FAQ sensible?
> http://www.uuhome.de/william.darden/deltran4.gif
> from http://www.uuhome.de/william.darden/carfaq9.htm
>
> My questions are... Does the cold affect the internal resistance that
much (about double), or just the capacity? Am I too worried about the
bubbling/gurgling, and should I let it go on for over a half-hour? Are
there any tests, simple or involved, that I can do to find out more
information?
>
> Thank you much in advance!
>
> Arthur Matteson
> - 1980 Renault LeCar, "Little Homebrew AC"
> - Custom Auto Electronics - Jackson, MI
> http://mywebpages.comcast.net/awmatt
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>
> On Wed, 2004-11-24 at 20:51, Joe Smalley wrote:
> > I vaguely recall the circuit. It had a problem with the LED brightness
> > changing with voltage. There was a solution for the brightness issue but
> > that part gets fuzzy.
> >
> > The simple solution was to put the LEDs in series and put various values of
> > resistors in parallel with the LEDs. As the voltage came up, each resistor
> > dropped more voltage and allowed the LED in parallel with the resistor to
> > come on when the voltage got high enough to conduct and illuminate. The
> > problem with this approach is that the LED brightness varies as the voltage
> > changes. To get away from this problem, the circuit requires a current
> > regulator for each LED. There was a fairly simple circuit that would do
> > this, but I can't recall it enough of it to write it down.
>
> The solution I implemented was:
>
> ---------VVVVV-------+------VVVVVV---+
> | |
> ----- -----
> \ / \ /
> \ / \ /
> ___V___ __V__
> | |
> | |
> _____/ _____/
> / ^ / ^
> / \ / \
> / \ / \
> ------- -------
> | |
> | |
> ---------------------+---------------+
>
> The left leg is a "regulator" with the zenner voltage
> higher than the zenner on the right leg. This limits
> the voltage on the right leg s.t. it does not exceed
> 30mA. As voltage continues to rise (charge)
> the left (regulator) leg lights up, dropping all
> the extra voltage over the leftmost resistor.
>
> If there is interest, I can look up the zenner
> and resistor values I settled on.
> The LEDs go dark around 10-10.5 volts.
> The regulator leg doesn't start conducting
> anything significant until around 13.5-14v,
> which only happens on charge, when I don't care
> much about an extra 20mA draw from the batteries.
--
Aaron Birenboim \ I have an inferiority complex,
Albuquerque, NM, USA \ but its not a very good one.
aaron at birenboim.com \
http://aaron.birenboim.com \
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The schematic is below. Thanks to Lee Hart for making such cool ascii
art and helping out with the values.
_________________________
| D1 | |
| 6.2v _|_/ green > R2
| zener //_\ __|\|__ > 1k
+__|__ | | |/| | >
12v ___ A |___| |___| B
- | | | red | |
| > |__|/|__| _|_/ D2
| R3 > R1 |\| //_\ 6.2v
| 47 > 1k | zener
|__/\/\___|_______________|
The key here is to use a red/green LED that comes in one package. At
first we were fiddling with simple resistor ladders, but they were too
boring and sensitive.
At 12.4 volts, the voltages across the diodes are a perfect zero since
the current between R1-D1 matches R2-D2. Now when the voltage goes above
12.4, current starts to flow thru the diode on the green side. When the
voltage hits 14.7, the green LED is lit and you know you're overcharging.
Likewise, when the voltage drops below 12.4, current starts to flow
"backwards" thru the red LED. When the voltage hits 10.9 volts, the red
LED lights on, and you know you're running low.
It's really a simple circuit, but very clever. Normally all lights are
off, and you know things are good. When you see a flicker of red, your
eye picks up on it fast and you know something's wrong (ie: batteries
are going low). See one RED led without the two others, and you have a
battery imbalance issue to address with a hard overcharge.
Likewise if you see two greens and one dark while charging you know
something's up there as well.
Joe Smalley wrote:
I vaguely recall the circuit. It had a problem with the LED brightness
changing with voltage. There was a solution for the brightness issue but
that part gets fuzzy.
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--- Chris Zach <[EMAIL PROTECTED]> wrote:
> _________________________
> | D1 | |
> | 6.2v _|_/ green > R2
> | zener //_\ __|\|__ > 1k
> +__|__ | | |/| | >
> 12v ___ A |___| |___| B
> - | | | red | |
> | > |__|/|__| _|_/ D2
> | R3 > R1 |\| //_\ 6.2v
> | 47 > 1k | zener
> |__/\/\___|_______________|
>
Can this be expanded to include a few more LEDs? Maybe a red LED at the high
end to warn of
overcharge, a few greens in the middle to show normal fluctuations and an amber
and a red at the
bottom end. This could give a general idea of how the pack sags under heavy
load, if you have any
batteries out of balance with the rest and if you are overcharging anything. It
could look like
the display on a graphic equalizer. One vertical row of LEDs per battery. I'm
not expecting it to
replace a voltmeter, just be a gentle reminder when you need to pull out the
meter. And maybe add
a little coolness factor for your passengers.
Thanks
Dave Cover
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http://www.gizmo.com.au/go/3494/
I still think, with a little more effort, someone can come up with an uglier
unit.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
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> I still think, with a little more effort, someone
> can come up with an uglier unit.
This guy tried,
http://www.austinev.org/evalbum/548a.jpg
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Why are they calling it a Hybrid? It is a NEV. The only power is electrical.
At 11/25/2004 10:57 AM, you wrote:
http://www.gizmo.com.au/go/3494/
I still think, with a little more effort, someone can come up with an
uglier unit.
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Actually when you drive the green LED over 15.6 volts it turns yellow
and keeps getting brighter till burnout.
Likewise at 10.9 volts the red is *just barely* coming on, on bright by
10.6 and brighter as the battery sinks into reverse-ville.
My orig design called for a 3 color LED, but with the yellow option on
the green/red ones, I didn't need it.
A row of LEDs per battery would mean 500+ LEDs and 500 wires running
around. Too complex and too much space.
Chris
Can this be expanded to include a few more LEDs? Maybe a red LED at the high
end to warn of
overcharge, a few greens in the middle to show normal fluctuations and an amber
and a red at the
bottom end. This could give a general idea of how the pack sags under heavy
load, if you have any
batteries out of balance with the rest and if you are overcharging anything. It
could look like
the display on a graphic equalizer. One vertical row of LEDs per battery. I'm
not expecting it to
replace a voltmeter, just be a gentle reminder when you need to pull out the
meter. And maybe add
a little coolness factor for your passengers.
Thanks
Dave Cover
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> > MTBF 50,000 power-on-hours (POH) or greater.
>
> Let's see:
> * MTBF of 50,000 for each charger.
> * 10 chargers.
Hello All,
There is another way of looking at this, it depends on what
constitutes a failure. If a failure is having a charger quit working,
then these calculations are correct. However, if a failure is
defined as having the car down and undrivable, then having
multiple chargers on board lowers the chance of a failure dramatically.
They are usually cheap enough to consider keeping a spare on the
shelf, or to use around the shop. Even if there isn't a spare on hand,
one of the chargers in the car could be rewired and do double duty
until either the bad charger is fixed or replaced.
I don't know what the MTBF ratings are on my little chargers,
but since they are designed to run in a small plastic box with some
vents and no fan, and now have their large heatsinks in wide open
space with a temperature controlled hurricane of fan cooling, I've
likely improved the ratings considerably. Also they are quite simple
and would be easy to repair - just replace the black part that didn't
used to be black.
Consider driving an EV in a 'Mad Max' world, where nothing
that breaks can be repaired, and further assuming that the EV doesn't
even have a series charger (not recommended!) up to 1/2 of the
modular chargers could fail and only double the charge time. That
to me, is extreme failure resistance.
Happy Thanksgiving......
John
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brian baumel wrote:
> What voltage should I pick for "empty" i.e. what % of the total
> voltage is ok for a discharge? It is a 120V gel cell bank...
> I know less discharge the better... but what is a good standard?
Voltage by itself is not a good indicator of state of charge. You also
need to take the battery current (and to a lesser extent, temperature)
into account.
You can measure voltage alone under no load. After a several-hour rest,
13.0v is about 100% SOC, and 12.0v is 0% SOC.
You can measure voltage under load, and use 10.5v as the 0% SOC "dead"
ending point.
Or, you can have your microcomputer monitor battery voltage, current,
and temperature, and use a more complicated algorithm.
> This micro controller will be doing clutchless shifting... the
> motor speed needs to be the drive shaft * the gear ratio of the
> destination gear.
Yes; that sounds right.
> I've recently made a DC-DC converter out of a normal switching
> power supply, a MOSFET and a simple pulse circuit. The pulse
> circuit pulses (120HZ) the input of the pwr supply and fools it
> into thinking it is rectified AC.
Most switchers run fine on DC, so I don't understand what the MOSFET is
for. The main problem I see is that some switchers use a voltage doubler
configuration on their input, and this circuit does need AC. So, are you
inverting the AC input so you can keep the voltage doubler?
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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I am about to purchase my second modular charger
set (only 3 12V chargers) have mostly boiled down
the decision between two different soneil chargers,
the 1212SR and the 1214S.
The 1214 as well as other soneil "low cost" chargers
have a 4 stage charging algorithm:
perform a pulse type deep discharge charging up until
about 5V, then constant current until 14.4V, followed
by a constant voltage at 14.4V and, once the current
falls to 50% (3.5A) of constant current (7A), switch to "true
float" at 13.8. To me this sounds like a sophisticated
charging algorithm.
The 1212SR in turn has a 3 stage approach: deep discharge
charging starts at
1.7A until 5V, then constant current up until 14.4V,
followed by a pulsing float charge stage where the
pulse is activated when battery voltage reaches 13.8V
and turned off when the voltage reaches 14.4V. This
seems like a slightly simpler charging approach?
Which algorithm is better. It seems to me that the
4 stage approach is better and should charge the
battery faster (because of the constant voltage phase).
Or is the pulsing float charge something that
people believe is a better approach at finish
charging.
Thanks for any hints.
Markus
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Their datasheet for the 1212 charger lists
30,000h MTBF. The 1212 is from what I understand
their higher quality charger (most of the
smaller ones are marked "low cost").
Markus
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Eric Poulsen
> Sent: Mittwoch, 24. November 2004 11:26
> To: [EMAIL PROTECTED]
> Subject: Re: Modular Charger
>
>
>
> I sent an email to them asking about their reliability testing
> methodology. If I don't get a response in a week or so, I'll
> call them.
>
> Lee Hart wrote:
>
> >Eric Poulsen wrote:
> >
> >
> >>I've been looking closely at the Soneil brand... For their 24V 8A
> >>charger, Soneil claims... MTBF 50,000 power-on-hours (POH) or
> >>greater.
> >>
> >>
> >
> >That's a pretty good number. Lambda, Vicor, and the other premium
> >supplies generally have an MTBF of 100,000 hours or more. But most
> >consumer supply MTBF aren't even 10,000 hours.
> >
>
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