20Ah sounds pretty good. I'm getting about 25-27Ah out of my
batteries. I got them in December of '99. I had to replace a few bad
apples recently and my pack is much better since then. I have an '87
CRX. I don't know how the weight compares to the fiero but I get about
22 miles out of my batteries (at 192 volts).
-Jeremy
On Monday, October 14, 2002, at 12:42 PM, Peter VanDerWal wrote:
> My first thought was that your YTs are simply worn out, after all they
> are 3
> years old. But then I started adding up the numbers you posted.
>
> 20Ah from 3 yr old YTs is still fairly respectable, getting only 9
> miles
> from 20Ah on a 192V pack is not. That's about 400 watt hour per mile,
> about
> twice what it should be.
> Normally this would indicate that either you are driving with a lead
> foot,
> driving way too fast, or that you have a mechanical problem.
> Then I noticed the 750ft elevation change. The rule of thumb is that
> every
> 100ft of elevation change is roughly the same as driving 1 extra mile
> at
> 55mph. However I can't tell from your post if you mean 9 miles range
> on
> flat ground or 9 miles while climbing 750'. Even if it is, that's
> still to
> much energy.
>
> 20Ah from your pack is about 3400-3500 watt hours. I drive about 9.5
> miles
> to work with approx 600-700 ft of elevation change. I only use about
> 2900
> whs and that's in a pickup.
>
> I don't know how fast you are driving but if it's more than 55mph, try
> slowing down. The energy needed to overcome air resistance goes up as
> the
> square of your speed. It takes almost 50% more power to go 65 than it
> does
> to go 55.
> Accelerate slowly and watch the stop lights way before you get to
> them. If
> you are a 1/2 mile away and it turns red, slow down so that it will
> turn
> green before you get to it. That way you can carry some speed through
> the
> light rather than wasting energy stoping and starting.
>
> Depending on how you drive, 3 years sounds about right for battery
> life. If
> you drive 5 days a week, that's 250+ cycles a year for a total of 750
> cycles. Getting 750 cycles from YTs is pretty good.
> Unless you are willing to spring $20,000 for NiMH you aren't going to
> do any
> better, and there isn't enough data yet to say whether the NiMH will
> last
> significantly longer. NiCads will last for 25 years or more, but they
> need
> to be watered frequently. You can, however, buy watering systems for
> them.
> Still it's an expensive option (probably $10-15,000 with the watering
> system) at least in the short term. Long term, the nicads will be
> cheaper
> than YTs but who can say what kind of batteries will be available in 10
> years?
>
> Short term, I'd try replacing the three batteries that are giving you
> the
> most problems and try the tips above. One other thing, if the
> batteries
> aren't insulated, add some. If you keep the packs temperature up
> around
> 80-100 degrees(f) you'll get much better performance out of them. If
> they
> get down to 60-70 degrees expect to see much less useable capacity,
> below 60
> your capacity might only be 1/2.
>
> FWIW, Lead-Acid batteries are probably the most recycled product on the
> planet. Even with all the ones dumped in odd places (inside cars) 97%
> of
> them get recycled. So while generating a pallet of dead batteries
> every few
> years is expensive, it's not hurting the enviroment anywhere near as
> bad as
> burning dead dinosaurs.
>
>> I'm an experienced electronics tech, but new to EVs.
>> Recently I bought a 1991 MR2 conversion with a 196V
>> system. The batteries are Optima YTs of 1999 vintage.
>> My controller is a Griz and the motor is an Advanced
>> DC. The charger is a Manzanita with a home-brew
>> regulator box set to bypass current around any battery
>> showing more than 14.8 volts. The previous owner
>> claimed a 45 mile max range, I'd be happy if it could
>> make 25 miles. Sadly, the batteries in their present
>> state are pretty much dead at 9 miles. My experience
>> has been that the car cannot even get me to work (~10
>> miles freeway 750' higher elevation than my home).
>> This is NOT what I had in mind, nor even plausibly
>> related to what the previous owner claimed. The pack
>> is only capable of providing 20-22 Ah or so before
>> getting really soft. At that time, if I put a 2A load
>> on the bank, three of them dip to about 5-8V while the
>> others are around 10.5V. In a 5A static load test,
>> similar voltages appear at the 4.5 hour mark. Is this
>> typical aging YT behavior, or is my pack limp for some
>> other (possibly correctable) reason? If it really is
>> dying this soon, what would I have to do to get the
>> range I want out of a longer lived battery technology
>> (Evercel, etc)? My whole point in driving an EV is to
>> be less polluting. Generating a pallet of dead
>> batteries every 3 years is out of the question! BTW,
>> there are batteries in the tunnel, so sealed
>> technology is a requirement. At least conventional LA
>> is out.
>>
>> Thanks,
>>
>> Andrew
>>
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