Sent: Friday, September 20, 2002 11:46 AM
Subject: Re: Real Battery Life (Newbie question)
> Paul G wrote:
> > In the world of lead acid batteries I don't think anyone (at least in
> > modern times) had managed to get a pack in an on-road vehicle (car or
> > Pickup) to last much more than about 30k miles.
>
Hi All;
Hadta jump in on THIS one. Did 22k on a set of old, used T-105's in my
Rabbit, when I forst got it up an' running wioth a Contactor controller,
about 4 yearz ago. Pretty well beat them to death over that year, with
numerous running down till the car would hardly move. Easy to do with a
contactor controller, running off a juicy acc. battery.
> It all depends on the batteries you choose. Let's say we have a
> long-range EV with about half its weight in batteries, like the Red
> Beastie pickup, which can go 100 miles on a charge:
Running T-145' s now, I THINK I could do 100 miles on a charge, if I
did litely on the go pedal' Did do 80 several weeks ago, at 45-50 Mph, and
kept it below 150 amps on launches. Havent run the T-145's DEAD, have over 6
k on 'em now, were still honeymooning! Never ran then below 90 volts, with a
120 volt system, when tired They always sprang back to 120 v at rest. So I
think they are in the prime of their lives, and should gine me, say, maybe
another 25k or so? Treating them nice, like that.?
>
> Consider AGMs, like Hawkers or Optimas. Life at a 1C discharge rate is
> generally around 250 cycles at 80% depth of discharge, or 400 cycles at
> 50% DOD. Cycles x DOD is the same for both, so the pack will last 250
> cycles x 80% x 100 miles = 20,000 miles.
>
> Now consider 6v golf cart batteries. Using the data Martin Jackson just
> posted, the greatest total mileage occurs at 560 cycles and 40% depth of
> discharge. The pack will last 1400 cycles x 40% DOD x 100 miles = 56,000
> miles.
>
> Then there are *really* long life lead-acids, as used in forklifts and
> other industrial vehicles. Oldham tubular plate flooded lead-acid cells
> are rated at 6500 cycles to 10% DOD, 2400 cycles to 50%, and 1350 cycles
> to 75% DOD. Best life is at 50% DOD, where the pack will last 2400
> cycles x 50% x 100 miles = 120,000 miles! (To satisfy the skeptics, Eric
> Sandell of Sweden put a set of *used* Oldhams in his Nissan Micra EV
> conversion. Last I heard, he has over 50,000 miles on them and they are
> still going!)
>
> But the drawback is that maximizing life also increases internal
> resistance and Peukert effects. Thsi means the lower the battery life,
> the less peak power you can get out of it. The AGMs give you fast
> accelleration and high top speed, but short life. The Oldhams give you
> great life, but sluggish accelleration and low top speed.
>
I LIKE this thinking, below.Like the Hawkers, John Wayland an' the
Racers use. Don't know WHERE I could put them in the Rabbit. Glove
compartment, maybe? A couple? Anybody done this concept?
> What I think is an interesting concept is to combine the two types into
> a single "hybrid" battery pack. Use the AGMs for fast accelleration,
> then recharge them from the floodeds. The AGMs depth of discharge is
> very low, for long life. Conversely, the AGMs shield the floodeds from
> the high peak currents; they can deliver power smoothly and continuously
> to minimize losses from internal resistance and Peukert effects.
> --
Bob Rice
> Lee A. Hart Ring the bells that still can ring
> 814 8th Ave. N. Forget your perfect offering
> Sartell, MN 56377 USA There is a crack in everything
> leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
>
