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MunkPuppy · Posted: Fri Feb 20, 2004 8:58 am Post subject: battery size?

hey everyone
did some testing yesterday, and it seems that my battery may be hooped. I tried to charge my battery with a 2A/6A charger I bought last week, but the battery won't hold a charge.
SG (specifig Gravity) on the hydrometer varies between cells from 1.250 to 1.200, with one cell reading 1.150
I'm trying to do some shopping ahead, but can't seem to find any reference telling me what group-size battery the 924 uses. Can anyone help me with that? I'll bet Lizard has the answer

Thanks everyone!
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'80 931 FOR SALE

"It's a shame that stupidity isn't painful"
-Anton Szandor LaVey

Lizard · Posted: Fri Feb 20, 2004 9:14 am Post subject:

same size as a vw rabbit works.
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3 928s,

MunkPuppy · Posted: Fri Feb 20, 2004 9:19 am Post subject:

grrrrr Lizard!

Group number!!

I called a few places, and they all agree it's a group 41.

L- 11 1/2"
W- 6 7/8"
H- 6 7/8"
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'80 931 FOR SALE

"It's a shame that stupidity isn't painful"
-Anton Szandor LaVey

Smoothie · Posted: Fri Feb 20, 2004 11:18 am Post subject:

You are correct-sir.

I have a Diehard group 41, cca 650, ca 800 in mine.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

MunkPuppy · Posted: Thu Mar 18, 2004 12:05 pm Post subject:

update!

Yep, my battery is hoopski.
I replaced all of the electrolyte in each cell using some premixed acid you can get at Interstate Batteries outlets for about $4.00CDN per litre/quart. I made the mistake of buying 3 litres, then found out that my battery only holds about 1.5 litres. Oh well, I have more if I ever need it.

I still cannot get the battery to accept more than a 50% charge, and upon closer inspection saw that most of the lead plates have become calcified.

Lesson: keep your battery charged!
_________________
'80 931 FOR SALE

"It's a shame that stupidity isn't painful"
-Anton Szandor LaVey

Khal · Posted: Thu Mar 18, 2004 12:40 pm Post subject:

I bought one of those battery saver/charger units. It's pretty good -fully electronic/automatic. It was AU$69, so in the U.S. it's probably $1.50!

Worth the expense, I reckon. Especially if your car doesn't get driven for weeks at a time and sits in the garage with the alarm/immobiliser armed...
I paid about AU$130 for my current battery. Don't want it to die any time soon

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'80 924 Turbo

PopUpProject · Joined: 06 Aug 2025 Posts: 111 Location: NE Ohio

chuck21401 · Joined: 20 Feb 2005 Posts: 606 Location: Annapolis, MD

I'm running a Duracell 40R (T6), CCA 650, CA 800 in my car. Purchased at Sam's club.

The sticker on it says 12/2020...works just fine. Guess we'll see what happens when the cold weather arrives. Did a quick search to see what they cost these days....$139.88.
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1981 Porsche 931 w/S1 engine & euro g31 transaxle. Water-cooled intercooler