EV Digest 5784
Topics covered in this issue include:
1) Re: Potbox problems
by Lee Hart <[EMAIL PROTECTED]>
2) Re: Potbox problems
by Lee Hart <[EMAIL PROTECTED]>
3) Re: I don't need a dc-dc converter, YES ya DO!
by Jeff Shanab <[EMAIL PROTECTED]>
4) Late Night Nationals raffle motor pics
by Jim Husted <[EMAIL PROTECTED]>
5) Re: I don't need a dc-dc converter, YES ya DO!
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
6) 84v Lester
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
7) dc/dc converter with common ground
by elaine chiu <[EMAIL PROTECTED]>
8) DC-DC converters
by "Neil Garcia-Sinclair" <[EMAIL PROTECTED]>
9) RE: Making it more efficient
by "Jody Dewey" <[EMAIL PROTECTED]>
10) Re: I don't need a dc-dc converter, YES ya DO!
by Jack Murray <[EMAIL PROTECTED]>
11) Re: 84v Lester
by Bill & Nancy <[EMAIL PROTECTED]>
12) Re: I don't need a dc-dc converter
by John Wayland <[EMAIL PROTECTED]>
13) Re: connectors for NiMH batteries?
by Jim Coate <[EMAIL PROTECTED]>
14) Re: I don't need a dc-dc converter
by Jack Murray <[EMAIL PROTECTED]>
15) Re: Roll call: International price comparison, was: Re: Driving habbits
by Matthew Milliron <[EMAIL PROTECTED]>
16) Re: Potbox problems
by Otmar <[EMAIL PROTECTED]>
17) The stinker in my pack
by "steve clunn" <[EMAIL PROTECTED]>
18) Electric AC compressor (HFC134a)
by [EMAIL PROTECTED]
19) Hall Efect Pedal Assembly (was RE: Potbox problems)
by Mike Willmon <[EMAIL PROTECTED]>
20) Re: dc/dc converter with common ground
by "Ev Performance (Robert Chew)" <[EMAIL PROTECTED]>
21) A Big Plug
by Peter Eckhoff <[EMAIL PROTECTED]>
22) Re: Ego Scooters. Battery replacement.
by "Aaron NMLUG" <[EMAIL PROTECTED]>
23) Re: connectors for NiMH batteries?
by Matthew Milliron <[EMAIL PROTECTED]>
24) Lion fires
by "Mark Fisher" <[EMAIL PROTECTED]>
--- Begin Message ---
Ken Albright wrote:
> Lee, I think I agree with you about the quality of the pot in the
> PB-6... However, I wonder about having the exact same failure mode
> on two pots in short order.
It's easy to check them. Measure their resistance with an ohmmeter as
you slowly move it from off to full throttle. See if there are "dead"
places where the resistance doesn't change with movement, or suddenly
goes to an open circuit.
> When I do replace the pot again I would like to go to something
> more robust and reliable. I would appreciate more detail on the
> Allen Bradley pots that you mention. A quick search turned up a
> lot of choices.
Yes, there are many. I'm not home now, so can't check my catalogs; but
with all the mergers and acquisitions I think Allen Bradley sold its
potentiometer business to someone, who renamed it, so the type "AB" is
called something else now.
No matter. What you want is a MIL-spec'ed sealed pot with a long defined
life (like 100,000 rotations or more). It's going to cost something like
$10.
> Also, it seems to me that the arm of the potbox rotates about 45
> degrees which is 1/8 of a turn
Mine is more like 90 degrees rotation.
> my pots have a large portion of their rotation that does nothing
> at both ends of the range. Is that typical for pots?
No. But it's what Curtis ordered (special) for their potbox pot.
> And is that why you need a 25k pot?
Yes. You want 90 degrees of rotation to cause the resistance to go from
about 0 to 5k ohms. A 25k pot will do this.
> In my search I came across Hall effect pots that would seem to be
> even better because there is no contact at all. Are there problems
> with these?
It's all about quality. A good-quality hall effect sender beats a
junk-quality pot. But a high-quality pot beats a good-quality hall
effect sender.
--
"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
--- End Message ---
--- Begin Message ---
Bob Bath wrote:
> Tried Jameco for the model you list, but no dice.
When you see "Jameco", think "JunkCo". They specialize in very cheap
imported parts. Some stuff is good, but most is cheap no-brand imported
junk. Low prices, but you get what you pay for.
> Should I try Digi-Key? Other?
Digikey, Mouser, Allied, and other big electronics distributors will
have a good selection of higher-quality pots. Look closely at the specs
and the prices.
> Does it come with the mount & swing arm like the PB-6?
No, you get just the "naked" potentiometer itself. You'll have to mount
in the old PB6 box with the old control arm, spring, and wiring.
--
"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
--- End Message ---
--- Begin Message ---
You are flirting with disaster.
Isolation, isolation, isolatation !!!
As soon as you connect the negative to the vehicle negative you
reference that point on the pack to the body, One brush up against any
battery post and the car body and you will get it (as in understand).
get a dc-dc, you need more than 12V
unless you get a "made for road use" dc-dc a small 12V battery is the
backup that gets you home.
my dc-dc went out at a stoplight on the way home. I didn't have to walk
home, No towtruck required.
And since I have an aux battery, I just charge it each day with the ole
sears charger and I am still driving EV. Remember, I can't get these
parts locally. YET.
--- End Message ---
--- Begin Message ---
Hey all
Well I just finished building the motor that Roy's going to raffle off during
the event this weekend. Sorry it's not a 9" motor, but hey it's his smaller
brother 8^) I hope it can bring in a few bucks for NEDRA and find a happy
home! Now this ain't no average motor being that Mr. Wayland himself dumster
dove for this! SO a big shout out to PlasmaBoy Racing for helping to sponsor
this motor and for saving it from being recycled. Anyway it's my little carrot
on a stick addressed to any who might be on the fence to come on out and have a
great time with us! With PIR letting the guys install charging plugs this year
it will be quiet (er) and I can't wait to support their efforts by attending!
So take a look at the pics and I'll see you there!
Jim Husted
Hi-Torque Electric
http://www.hitorqueelectric.com
PS: Everyones invited but Marvin Campbell for calling me an ignorant slut 8^P
I still split a side when I think about it, hehehe. Actually Marvin you're
double invited, set you up in a ride with WZ or GP, then going 75 would feel
like you're crawling, Hell you'd be doing burnout and chit, hehehe 8^o
---------------------------------
Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates
starting at 1¢/min.
--- End Message ---
--- Begin Message ---
This would also cause a balance problem unless you had Lee Harts Battery
Balancers. Then your idea might work & maybe without the DC/DC. Lawrence
Rhodes.....
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, August 22, 2006 10:03 AM
Subject: Re: I don't need a dc-dc converter, YES ya DO!
> A hybrid alternative not discussed for 12v on an EV is to use a DC/DC
converter whose 12v output goes to one of the 12v batteries in the pack,
either end or the middle, your choice. So while you get the advantage of
having a bodacious amount of pulse load capacity offfered by having a real
battery, you don't have to carry an extra battery, nor do you have to worry
about having your string get unbalanced.
>
> Advantages include:
> 1) Size the DC/DC to your average load needs, not peak
> 2) No need to carry additional battery for 12v
> 3) Benefits of having a battery for high pulsed loads
> 4) Battery can be at the upper, lower or middle of the pack---you choose.
> 5) Easy to convert to this from an existing DC/DC config or a tapped pack
config
>
> I don't really see a downside except to add the DC/DC (if you have a
tapped or separate batt config now) and you'd likely want to disable this
when charging.
>
> -Myles Twete, Portland, Or.
>
--- End Message ---
--- Begin Message ---
Is an 84v Lester A 72v charger or is it is what it is? Lawrence Rhodes......
--- End Message ---
--- Begin Message ---
I was rewiring things in my citicar and noticed that the Astron dc/dc
converter I am using has a common ground. It came with two black
wires, but it turns out they are spliced together.
isn't this dangerous to have my pack voltage grounded to chassis?
thanks to all that corrected my mis-wiring with the dc/dc after the
main contactor. it's moved back to before the contactor and things
work again. I just have to remember to unplug the dc/dc if the
truck's sitting for awhile without charging.
I found one of those silver canister solenoids for 12v. Can I use
that to switch the dc/dc converter on with the ignition?
elaine c.
berkeley, CA
76 citicar
86 converted pickup
--- End Message ---
--- Begin Message ---
If anyone is interested I have some 72 vdc - 12 vdc converters, originally
part of the Zebra production. I will make accept a reasonable offer. They
are brand new.
Neil Garcia-Sinclair
President, CyberTran International
(510) 864-3221
--- End Message ---
--- Begin Message ---
Lower the car an inch or so if you can. It will lower your wind resistance.
Also, if you don't already, drive with your windows rolled up. Driving with
them rolled down is like driving with a big air scoop.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ricky Suiter
Sent: Saturday, August 19, 2006 3:19 AM
To: EV List
Subject: Making it more efficient
Some observations on picking up efficiency with my Saturn SC conversion.
It's a 144 volt pack of Trojan 30XHS batteries, not that much energy on board
Zilla 1K controller (limited to 500 pack murdering battery amps)
9" ADC motor
Stock "performance" manual transmission... performance version has higher
gear ratios which is more ideal for electric motors
When I first got the car converted it has some no name tires on it. I don't
do a whole lot of highway cruising with it so my baseline is amps at 40mph
steady on flat ground int he city. It took about 70 amps to hold 40mph
initially.
First modification was to get the old horrible rubber off of it and put some
decent tires with lower rolling resistance characteristics on it, and the old
tires were in bad shape too. Going to Goodyear Integrity tires in 185/60R15's
dropped 10 amps now requiring 60 amps to hold 40mph.
Second and third mod's happened at about the same time, I had it alligned for
0 toe in and removed the stock wing from the car. I noticed a little more from
the wing being gone on the highway, but overall these dropped the car down to
50 amps.
Fourth and fifth mod occured both pretty recently, but close enough together
to notice a difference with each. Fourth was playing with the brakes. The
flexible brake lines looked to be original. These rubber hoses will tend to
expand with age and not let all the brake fluid go back in to the resivor, I
replaced all of them and at the same time got the caliper rebuild kits for the
front disk brakes. This consisted basically of new rubber O-rings which help
retract the piston from the pads. I only drove it some before making
modification number 5, but this in itself made another good 5 amp difference.
Modification number five happened today, which was installing light weight
wheels. I found some 15X7" wheels weighing in at only 12.6 lbs! And even better
they didn't totally break the bank. They are Kosei K1's, tire rack sells them
and they are about $150 a piece, which included all necessary hardware, and
they look really good to boot. While at discount tire getting them installed I
observed three people crouched around the box the wheels came in writing the
information down. I chatted with one of the guys and they said the shop manager
had never felt a wheel so light weight and wanted to know what they were and
where I got them because he wanted a set. I should also mention that the 14"
version of these wheels weights in at 9.5 lbs for those of you with smaller
wheels and tires. I requested 40psi, which didn't happen. As I drove home the
amps had actually increased a tad, but upon checking the tire pressure it was
less than 30lbs so I pumped them back up and about an
hour later left for work. I'm now down to about 40 amps to hold 40mph.
Acceleration uses way less power. 150 amps accelerates quicker than 200 amps
used to! And the car already had alloy wheels, which upon lifting them by
theirselves it was apparent I had saved a lot of rotational mass (I need to
weigh the old wheels to see just how big of a difference I made, but it feels
like about half!).
So in short over the last year I've taken the car from 70 amps to hold 40mph
down to 40 amps to hold the same speed. This is a HUGE improvement! At this
point my pack is already on it's way out, however the range when I get a new
pack (probably in another year) will be far greater than what it was before.
This is nearing almost a 50% improvement over how it was when the car first
moved under it's own power as an electric conversion! Ok so granted that 3/8"
overall toe out wasn't helping any, but there are things you can to to gain
efficiency and therefore range.
I'm not 100% sure where I can go from here now. I'm thinking other
aerodynamic modificaitons are about all I can do. I suppose making a belly pan
is about all there if left. Anyone else have any other ideas?
Here are the wheels:
http://www.tirerack.com/wheels/DisplayWheel.jsp?wheelMake=Kosei&wheelModel=K1+TS&wheelFinish=Silver+Painted
Here's the manufacturers page for the wheels:
http://www.koseijp.co.jp/engfl/n_p5_k1.htm
Weight performance
[EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]
The only wheels ligher I've ever found are Volk TE37's at abotu $300-$400 a
piece! And they aren't $300 a piece lighter either.
It's a totally different car with those wheels, highly recommended.
Later,
Ricky
02 Insight
92 Saturn SC2 EV 144 Volt
Glendale, AZ USA
---------------------------------
Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+
countries) for 2¢/min or less.
--- End Message ---
--- Begin Message ---
Remember that running the accessories from the traction battery pack
will reduce your driving range...put another way, using a seperate
battery pack for the accessories will increase your driving range.
Now if you don't have sufficient capacity of your accessory battery
maybe you need to extend it by recharging it when driving using a small
onboard gas powered generator... :)
Jack
[EMAIL PROTECTED] wrote:
A hybrid alternative not discussed for 12v on an EV is to use a DC/DC converter
whose 12v output goes to one of the 12v batteries in the pack, either end or
the middle, your choice. So while you get the advantage of having a bodacious
amount of pulse load capacity offfered by having a real battery, you don't have
to carry an extra battery, nor do you have to worry about having your string
get unbalanced.
Advantages include:
1) Size the DC/DC to your average load needs, not peak
2) No need to carry additional battery for 12v
3) Benefits of having a battery for high pulsed loads
4) Battery can be at the upper, lower or middle of the pack---you choose.
5) Easy to convert to this from an existing DC/DC config or a tapped pack config
I don't really see a downside except to add the DC/DC (if you have a tapped or
separate batt config now) and you'd likely want to disable this when charging.
-Myles Twete, Portland, Or.
--- End Message ---
--- Begin Message ---
It's an 84 volt charger, I have the manual around here somwwhere,
probably filed under the ev stuff if you want it. I was told it could
be made into a 96 volt charger by changing the wiring around. The manual
says 84 volts.
Bill
Lawrence Rhodes wrote:
Is an 84v Lester A 72v charger or is it is what it is? Lawrence Rhodes......
--- End Message ---
--- Begin Message ---
Hello to Jack and All,
Jack Murray wrote:
I can appreciate the isolation of the chassis ground from the
high-voltage pack.
Good, it will keep you and everyone else around your EV safe.
There are losses associated with a DC-DC converter.
True, but very small ones, as most DC-DC converters are at least 90%
efficient. Some are close to 94%. A 90% efficient 350 watt DC-DC would
only give up 35 watts of energy in heat at full output. The combination
of this converter with a small backup AGM might weigh 14 lbs. together
and would source 14+ crisp volts and keep lights bright from start to
finish during an hour evening ride in your EV.
I think using a NiMH battery for accessories makes more sense, you can
increase its voltage by using 12 cells, it will weigh less and have
more power than using a DC-DC getting power from lead-acid batteries
Minus the 14 lb. DC-DC with 12V AGM setup, you'd need at least a 50 lb.
12V lead acid battery for an unassisted 12V supply, or perhaps 34 lbs.
in NiMH. How do you come up with less weight?
To get 350 watts of 12V accessory power (lights on, blower fan on,
wipers on scenario) for one hour requires a battery with ~30 ahrs of
capacity if you ran things to brown-out levels. You wouldn't want to do
this of course, as your headlights would fade to black. To keep the
lights and other devices running well then, you'd want headroom as far
as your unassisted 12-14V source is concerned, so now we're talking 40
ahrs of capacity. A 40 ahr NiMH 12-14V battery weighs about 34
lbs....here's the proof: The 144V pack of NiMH batteries in my Insight
(120 D cells) weigh 55 lbs. and gives 6.5 ahrs. The exact same number
of batteries reconfigured to 14 volts makes 65 ahrs, so if a 65 ahr NiMH
14 volt battery weighs 55 lbs., then a 40 ahr NiMH 14 volt battery will
weigh 34 lbs....20 more lbs. than the 14 lb. DC-DC w/backup battery
combo. Now, this extra 20 lbs. of weight alone in your EV could drink up
20 watts in extra traction energy requirements, so taking this into
account, the DC-DC loss is really only about 15 watts, with the
efficiency nod going to your unassisted battery idea. If your EV can do
250 whrs per mile and it has, say 40 miles range, it would consume 10
kwhrs at 40 mph during a one hour drive. The DC-DC's 15 watt losses over
that one hour drive is 15 whrs. You can see that 10,000 watt hrs minus a
microscopic 15 watt hrs, is still pretty much 10,000 watt hrs., so using
an unassisted 12V or even 14V battery vs a DC-DC because of a
'hoped-for' energy savings standpoint, is pointless.
Most importantly, as I said in my previous post, an unassisted battery
to act as your 12V system supply will sag and drop in voltage as each
device is powered on and used, so headlights dim, wipers slow down, etc.
In addition, as this battery drains over the one hour drive, you're in a
constantly declining level of performance as sag continues to dim
lights. I can't for the life of me, understand why you would prefer this
condition, when a DC-DC setup completely eliminates it all.
.....cost less as well given what appears to be some rather expensive
DC-DC converters being talked about.
6.5 ahr 1.2V NiMH batteries are about $10 each for new condition D
cells, so a single 14V module of these would be a $120, 6.5 ahr 12V
battery...and don't forget this battery will need a BMS that adds more
cost. You'd need 6 of these to get to ~ 40 ahrs needed to run everything
for one hour without browning-out at the end of the drive, so we're
looking at $720 of NiMH batteries! That's $720 for constantly dimming
headlights. You're 40 ahr battery is now 70+ NiMH cells arranged in a
series/parallel pack that will absolutely 'have' to have a BMS on lots
of the cells, so there goes the 'simplicity' of not using a DC-DC and
here comes a lot more dollars spent on the BMS to add to that $720,
probably upping the price to near $1000. Now let's again compare...a
good DC-DC with a new 13-15 ahr backup AGM take sup far less space,
weighs 1/3 the amount, will cost about 1/3 what the NiMH packs costs,
and it will offer superior performance that keeps 14+ steady volts
available, from start to finish.
Jack, those of us who have been designing, building and driving EVs for
26 years have a bit of 'accumulated' knowledge. From the been there,
done that file...I've been down the road of an unassisted 12V source
before. I also was one of the first EVers to run a 14V source...did that
back in 1980 and did it with a whopping 105 ahrs of battery capacity (a
6 volt and an 8 volt in series to serve as the 14V supply). Guess what?
It provided sub-standard lighting, took up a lot of space, required a
special charger, and added an extra 85 lbs. to my EV! With the headlight
circuit on and a fan and wipers running, it immediately sagged to 13.8V
or so, and after a half hour drive, the battery was into the low 13V
range...dimming headlights, slowing wipers....argghh! When DC-DC
supplies became available in the 90's, I switched over to 14+ constant
volts at a fraction of the weight, dissed the special 14V charger, and
never looked back.
See Ya.....John Wayland
--- End Message ---
--- Begin Message ---
Groan... I was afraid of that. And add salt from ocean spray as what can
make the 'electrolyte' for those of us who have lived near the coast.
So the question becomes: where does one get nickel (plated) battery lugs?
And... are the terminals on a NiMH battery *solid* nickel? As in can
they be polished thoroughly to remove corrosion without fear of wearing
off plating?
These questions are coming up as I'm dealing with my factory S-10
battery pack. The computer keeps reporting impossible voltages on the
individual batteries - in particular one battery is too low and it's
immediate neighbor is too high. The computer has a sense lead with an
in-line resistor (30.9K) going to each battery. The suspect lead had a
corroded connector just before the resistor which I spliced out,
although even the copper wire seems to be somewhat corroded inside the
insulation and hard to solder so I used a mechanical pressure splice.
There may still be something flaky in the sense lead and or the
resistor. And the lugs that GM used are tending to corrode, especially
on the "-" terminals; attempting to clean wears off what is left of the
plating and exposes copper.
I'm not sure if the lugs are nickel-plated or tin-plated. Any easy way
to test?. The truck was originally equipped with PbA batteries, so GM
may have used tin?
At this point I'm considering making replacement cables, at least for
the misbehaved ones, but I'd need to get a source of nickel parts.
* The ideal lug: nickel or nickel plated battery lugs to crimp on 4
gauge copper welding cable, closed on one end (shaped like MagnaLugs) so
when heat shrink tubing is added no copper is exposed.
Lee Hart wrote:
Jim Coate wrote:
I recall discussion that using copper lugs to connect to NiMH (or
other Nickel- based) batteries would be a bad thing as the copper
would soon corrode.
Would the typical MagnaLugs(tm) lugs which are tin plated copper
hold up? Or will the tin react too? If so, what other choices are
there?
You'll get corrosion whenever you place two different metals in contact
with each other, and get an electrolyte on it. An "electrolyte" is
wather with anything that makes it conduct electricity better; could be
sulfuric acid (from a lead-acid battery), potassium hydroxide (from a
nicad or nimh), or even just rain water and road salt.
Since the terminals of nicad and nimh cells are nickel, using copper for
the terminals provides the dissimilar metals. Any leakage or gassing
from the cell provides the electrolyte. Corrosion is inevitable.
So, you're better off using nickel or nickel-plated hardware.
--
Jim Coate
1970's Elec-Trak's
1997 Solectria Force
1998 Chevy S-10 NiMH BEV
1997 Chevy S-10 NGV Bi-Fuel
http://www.eeevee.com
--- End Message ---
--- Begin Message ---
The fact remains that if you use the traction pack for accessories it is
reducing your range. Now if you have more range than you need, then
using the traction pack for accessories is not a big deal and would
weigh less than adding an accessory pack. But from what I see, range is
always an issue, and an "easy" way to extend it is to essentially add
more batteries by having an accessory pack, and using NiMH effectively
lowers the weight of the additional battery capacity (over lead) it
could even be a lithium pack as well, since it is independent of the
traction system.
What I get the most here is that you are concerned about sagging voltage
and this condition reduces the quality of the accessories. I'm not
convinced this is an issue, but I will accept your experience on this
that it is. The solution would actually be a DC-DC run on an accessory
pack of higher voltage. So a 16+v pack that regulates down to 14v.
Electronics for low-voltage are relatively cheap.
I think what I'm trying to avoid is an expensive high-voltage
(140v-310v) DC-DC converter. When I hear of large heat-sinks on these
big DC-DC converters, and didn't someone talk about water-cooling their
DC-DC, I have to wonder about 94% efficiency.
If one upgrades their traction pack to higher voltage, they now need to
be concerned if their DC-DC will handle it. Again, the independence of
the accessory system is an advantage.
I always appreciate experience, but in my view questioning authority and
conventional wisdom is how progress is made, although often it is just
being a pain in the ass. :)
Best Regards,
Jack
John Wayland wrote:
Hello to Jack and All,
Jack Murray wrote:
I can appreciate the isolation of the chassis ground from the
high-voltage pack.
Good, it will keep you and everyone else around your EV safe.
There are losses associated with a DC-DC converter.
True, but very small ones, as most DC-DC converters are at least 90%
efficient. Some are close to 94%. A 90% efficient 350 watt DC-DC would
only give up 35 watts of energy in heat at full output. The combination
of this converter with a small backup AGM might weigh 14 lbs. together
and would source 14+ crisp volts and keep lights bright from start to
finish during an hour evening ride in your EV.
I think using a NiMH battery for accessories makes more sense, you can
increase its voltage by using 12 cells, it will weigh less and have
more power than using a DC-DC getting power from lead-acid batteries
Minus the 14 lb. DC-DC with 12V AGM setup, you'd need at least a 50 lb.
12V lead acid battery for an unassisted 12V supply, or perhaps 34 lbs.
in NiMH. How do you come up with less weight?
To get 350 watts of 12V accessory power (lights on, blower fan on,
wipers on scenario) for one hour requires a battery with ~30 ahrs of
capacity if you ran things to brown-out levels. You wouldn't want to do
this of course, as your headlights would fade to black. To keep the
lights and other devices running well then, you'd want headroom as far
as your unassisted 12-14V source is concerned, so now we're talking 40
ahrs of capacity. A 40 ahr NiMH 12-14V battery weighs about 34
lbs....here's the proof: The 144V pack of NiMH batteries in my Insight
(120 D cells) weigh 55 lbs. and gives 6.5 ahrs. The exact same number
of batteries reconfigured to 14 volts makes 65 ahrs, so if a 65 ahr NiMH
14 volt battery weighs 55 lbs., then a 40 ahr NiMH 14 volt battery will
weigh 34 lbs....20 more lbs. than the 14 lb. DC-DC w/backup battery
combo. Now, this extra 20 lbs. of weight alone in your EV could drink up
20 watts in extra traction energy requirements, so taking this into
account, the DC-DC loss is really only about 15 watts, with the
efficiency nod going to your unassisted battery idea. If your EV can do
250 whrs per mile and it has, say 40 miles range, it would consume 10
kwhrs at 40 mph during a one hour drive. The DC-DC's 15 watt losses over
that one hour drive is 15 whrs. You can see that 10,000 watt hrs minus a
microscopic 15 watt hrs, is still pretty much 10,000 watt hrs., so using
an unassisted 12V or even 14V battery vs a DC-DC because of a
'hoped-for' energy savings standpoint, is pointless.
Most importantly, as I said in my previous post, an unassisted battery
to act as your 12V system supply will sag and drop in voltage as each
device is powered on and used, so headlights dim, wipers slow down, etc.
In addition, as this battery drains over the one hour drive, you're in a
constantly declining level of performance as sag continues to dim
lights. I can't for the life of me, understand why you would prefer this
condition, when a DC-DC setup completely eliminates it all.
.....cost less as well given what appears to be some rather expensive
DC-DC converters being talked about.
6.5 ahr 1.2V NiMH batteries are about $10 each for new condition D
cells, so a single 14V module of these would be a $120, 6.5 ahr 12V
battery...and don't forget this battery will need a BMS that adds more
cost. You'd need 6 of these to get to ~ 40 ahrs needed to run everything
for one hour without browning-out at the end of the drive, so we're
looking at $720 of NiMH batteries! That's $720 for constantly dimming
headlights. You're 40 ahr battery is now 70+ NiMH cells arranged in a
series/parallel pack that will absolutely 'have' to have a BMS on lots
of the cells, so there goes the 'simplicity' of not using a DC-DC and
here comes a lot more dollars spent on the BMS to add to that $720,
probably upping the price to near $1000. Now let's again compare...a
good DC-DC with a new 13-15 ahr backup AGM take sup far less space,
weighs 1/3 the amount, will cost about 1/3 what the NiMH packs costs,
and it will offer superior performance that keeps 14+ steady volts
available, from start to finish.
Jack, those of us who have been designing, building and driving EVs for
26 years have a bit of 'accumulated' knowledge. From the been there,
done that file...I've been down the road of an unassisted 12V source
before. I also was one of the first EVers to run a 14V source...did that
back in 1980 and did it with a whopping 105 ahrs of battery capacity (a
6 volt and an 8 volt in series to serve as the 14V supply). Guess what?
It provided sub-standard lighting, took up a lot of space, required a
special charger, and added an extra 85 lbs. to my EV! With the headlight
circuit on and a fan and wipers running, it immediately sagged to 13.8V
or so, and after a half hour drive, the battery was into the low 13V
range...dimming headlights, slowing wipers....argghh! When DC-DC
supplies became available in the 90's, I switched over to 14+ constant
volts at a fraction of the weight, dissed the special 14V charger, and
never looked back.
See Ya.....John Wayland
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What economy/country/state are you in:
Lubbock Texas USA - Agriculture/oil and gas/medical
How much does petrol cost in US$ per USgallon or litre:
$2.85 per Gal. on 8-22-06
How much does electricity cost US$/kWh:
$0.073 /kWh for my house in July 2006
How much does an Exide Orbital cost:
unknown
How much does a Trojan T-105 cost:
unknown
What/if any economic incentives and what are they worth:
I received a one time tax credit from the federal government on my
2005 taxes for the purchase of the car. About $350.
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I think I agree with you about the quality of the pot in the PB-6
although I don't have much experience with them. However, I wonder
about having the exact same failure mode on two pots in short order.
It makes me think there may be some other factor in the system
causing the failures - perhaps in the controller??? Or maybe it's a
manufacturing glitch. I have a call in to the Curtis engineering
dept to pose this question...
One thing I have seen is this:
In applications with little stiction (mostly those that don't use a
throttle cable) the shaking of the throttle pedal wears the element
out at the cruise condition.
On my 914 I replace the pot element about once a year due to this.
It's almost due again since it's getting rough. Probably I'll just
switch to the Hall effect pedal once I build a test bench for the
Hairballs.
Stronger return springs and some friction in the system can reduce
the pedal bounce and therefore reduce the wear.
hth,
--
-Otmar-
914 EV, California Poppy,
http://evcl.com/914/
http://www.CafeElectric.com/
The Zilla factory has moved to Corvallis Oregon.
Now accepting resumes. Please see:
http://www.cafeelectric.com/jobs.html
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I wrote about how after 5 day's on non use , one of the batteries on my
mower was falling way behind the others , but buy the end of the day and
many charges ( 15 maybe ) the battery had shown good progress and could cut
a whole lawn on one charge . Each day I've seen kind of the same cycle . No4
is weak on the first charge , but each day not as weak as the day before
and after a few charges it comes back quite a bit . Well before going to
work Monday I'm thinking , a $100 battery , if it gives 400 charges , that's
just 25 cents a charge , and I'm going to fool with this one battery , maybe
it might get better , maybe not . I put another battery on the truck , any
problems and this stinker is out ! First yard is a big one , 2 charges
usually ,. Stinker hits 11.0 v while others are 11.9 , so back to the truck
for a charge (200 amp) while I do the trimming , 2nd 1/2 and the stinker is
looking better. By the end of the day at the end of the last yard which I
cut on one charge the voltage on the stinker while under a 75 amp load was
11.5 and the others where 11.7. , very good , .
From: "Charles Whalen"
By the way, Steve, speaking of you, if ya got your ears on, I just read your
post about that one weak battery on your rider-mower, and I think someone
responded by saying that's a good reason to put regs on them. Well, what's
with that? I thought you had Rudman Regs on them, at least you did several
months ago when I was up there and you showed me the Regs blinking on those
batts on the mower near the end of the charge. So what happened -- did you
take them off?
Rudman Regs are still on there , and I have a 10 position switch that I can
look around at each battey . That's how I found the stinker . I stopped
using the pfc 50 to charge the mower when I found the dump charging worked
good . Got the pfc50 charging the truck now and a pfc 20 for the lawn mower
when I get home.. . Fast charging is what made the mower workable for my
business. Where people can argue where Ev's are cost eff , the lawn mower's
gas engine is a far worst deal that a car engine , 1000 hours ( what would
be 50,k miles ) is allot on one , and air filters need replacing each week ,
lots of oil changing and an expensive oil filter is what they take .
Engine cost to so if I had to get new batteries today It still would have
been a good deal , but I want to get as must time out as possible, I'll see
how the stinker dose the rest of the week . The rest of the pack looks good.
Steve Clunn
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Wonder what voltage range it takes:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=130019950443
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Ot,
I was looking at the Toyota Camry Hybrid my buddy just bought and I noticed a
HEPA that looked eerily exactly like mine. Same
OEM? I like the pedal, neat and concise. How secure is your supply on those?
Can it be used with any other (less expensive) controllers in case I want to
have a spare "limp around" or "project" controller on
the shelf? Otherwise, at a minimum, what would having a spare Hairball run me?
Mike,
Anchorage, Ak.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Otmar
> Sent: Tuesday, August 22, 2006 8:59 PM
> To: [email protected]
> Subject: Re: Potbox problems
>
>
> > I think I agree with you about the quality of the pot in the PB-6
> >although I don't have much experience with them. However, I wonder
> >about having the exact same failure mode on two pots in short order.
> >It makes me think there may be some other factor in the system
> >causing the failures - perhaps in the controller??? Or maybe it's a
> >manufacturing glitch. I have a call in to the Curtis engineering
> >dept to pose this question...
>
> One thing I have seen is this:
> In applications with little stiction (mostly those that don't use a
> throttle cable) the shaking of the throttle pedal wears the element
> out at the cruise condition.
>
> On my 914 I replace the pot element about once a year due to this.
> It's almost due again since it's getting rough. Probably I'll just
> switch to the Hall effect pedal once I build a test bench for the
> Hairballs.
>
> Stronger return springs and some friction in the system can reduce
> the pedal bounce and therefore reduce the wear.
>
> hth,
> --
> -Otmar-
> 914 EV, California Poppy,
> http://evcl.com/914/
>
> http://www.CafeElectric.com/
> The Zilla factory has moved to Corvallis Oregon.
> Now accepting resumes. Please see:
> http://www.cafeelectric.com/jobs.html
>
>
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HI,
It is somewhat dangerous to have a dc dc with common ground. I have one in
my vehicle, its a 72 volt system. So far, no elctric shocks. Just remember
when working on the car to disconnect the high voltage pack.
You could add in a relay that connects the common ground connection together
when the ignition is turned on and then when the relay is off, the ground
connection is cut.
Cheers
On 23/08/06, elaine chiu <[EMAIL PROTECTED]> wrote:
I was rewiring things in my citicar and noticed that the Astron dc/dc
converter I am using has a common ground. It came with two black
wires, but it turns out they are spliced together.
isn't this dangerous to have my pack voltage grounded to chassis?
thanks to all that corrected my mis-wiring with the dc/dc after the
main contactor. it's moved back to before the contactor and things
work again. I just have to remember to unplug the dc/dc if the
truck's sitting for awhile without charging.
I found one of those silver canister solenoids for 12v. Can I use
that to switch the dc/dc converter on with the ignition?
elaine c.
berkeley, CA
76 citicar
86 converted pickup
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Hi All,
Don Crohan of the Triangle Electric Auto Association initiated and
produced a very successful Electric and Alternative Fuels Expo that was
followed by a showing of "Who Killed the Electric Car?". After the
show, Chris Paine, the Director, and a handful of experts on Electric
and Alternative Fuels were there to take audience questions. This was
obviously a first for Chris and some of the questions were definitely
related to issues in the Research Triangle Park area of North Carolina.
Our event was written up in the local paper that has wide circulation in
the area. A copy can be found here:
http://www.newsobserver.com/102/story/477783.html
Way to go Don!!
Peter Eckhoff
Triangle Electric Auto Association
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> I hope your friend runs on level ground. Adding even one tooth can cause
> overheating on hills. I have thought about an Ego but they go too fast on
> level ground. They should be registered as a moped.
Moped here in NM is up to 30MPH regulated speed.
Top (level) speed on an eGo with 200 lb. rider is around 23 MPH.
> They also don't
> climb
> hills well with heavy riders. I bet if you slowed the top speed down to
> 20mph(using a bigger rear sprocket) it would be an awsome hill climber.
I had noticed real heat problems only once, with hard riding.
I have thought about increasing the gear ratio (speed), but
if I do, I will certainly install a little 24v muffin fan in
front of the motor.
I climb the worst hills (15-16% grade) at 17-19 MPH depending
on SoC. My worst hills only have that nasty grade for
a few tens of meters though.
It can hold that on more typical 6-10% hills for a long time.
> Lawrence Rhodes....
> ----- Original Message -----
> From: "Dale Curren" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Sunday, August 20, 2006 6:01 AM
> Subject: Re: Ego Scooters. Battery replacement.
>
>
>> ** Reply to message from "Lawrence Rhodes" <[EMAIL PROTECTED]>
>> on
> Sat,
>> 19 Aug 2006 16:46:52 -0700
>>
>> > Anybody happy with an Ego and
>> > their batteries. What works well? Lawrence Rhodes........
I'm getting above reported range, but I have a PowerCheq.
Only 300 miles on it so far though.
--
Aaron Birenboim | I have an inferiority complex
Albuquerque, NM | ... but its not a very
aaron_at_birenboim.com | good one.
>http://aaron.boim.com |
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On Tue, 22 Aug 2006 21:24:33 -0400, you wrote:
>At this point I'm considering making replacement cables, at least for
>the misbehaved ones, but I'd need to get a source of nickel parts.
>
>
>* The ideal lug: nickel or nickel plated battery lugs to crimp on 4
>gauge copper welding cable, closed on one end (shaped like MagnaLugs) so
>when heat shrink tubing is added no copper is exposed.
>
SNIP
> you're better off using nickel or nickel-plated hardware.
Go to a chrome shop. The second layer is nickel. They should be
able to nickel plate your terminals for just a few bucks?
R. Matt Milliron
http://www.austinev.org/evalbum/702
My daughter named it, "Pikachu". It's yellow and black,
electric and contains Japanese parts, so I went with it.
1981 Jet Electrica.
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This thread
http://www.visforvoltage.com/forums/index.php?act=ST&f=31&t=4325&s=71612a004543b13cb5673077c0e2711a
has some discussion of the effects of lithium fires. Craig Ucheda is a
particularly extreme EV scooter enthusiast. Apparently the Fire Marshall
isn't so thrilled by his hobby...
Of course, gasoline burns pretty well too...
http://www.youtube.com/watch?v=rdCsbZf1_Ng&NR
Mark
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