Battery question

[Team SSR]

Need to buy a new battery for the 944. How 'similar' does my new replacement battery need to be? Some of the gel 'automotive' batteries are very small.

[JoshS]

Instead of one of those racing batteries (Odyssey/Optima, for example), I got an AGM battery of the same group number as the original wet cell. Hard to believe there could be any concern about that.

[keycom]

Need to buy a new battery for the 944. How 'similar' does my new replacement battery need to be? Some of the gel 'automotive' batteries are very small.
[/b]

How is a gel battery even remotely "similar" to the wet cell that was O.E. on you car?

However, this is a "grey area" that I have NO expert knowledge or experience regarding.

[shwah]

e. Any ignition system which utilizes the original distributor for spark timing and distribution is permitted. Internal distributor components and distributor cap may be substituted. Crankfire ignition systems are prohibited unless fitted as original equipment. Any spark plugs and ignition wires may be used. Ignition timing is unrestricted. Batteries may be replaced with those of alternate manufacture provided they are of similar amp-hour capacity and weight and are fitted in the standard location. Additional battery hold-down devices may be used, and are strongly recommended. Cars originally equipped with two (2) 6-volt batteries may replace them with one (1) 12-volt battery installed in either of the original battery locations.

This is why it is fine.

[keycom]

I stand corrected then because I thought the reason one would chose a gel battery is for weight reduction.

Is there another reason?

[tom_sprecher]

Maybe because you'd be hard pressed to find a wet cell battery these days?

[shwah]

Gel batteries are much more durable in high vibration environments, and don't leak acid out when they get crunched....as much.

[Gary L]

Batteries may be replaced with those of alternate manufacture provided they are of similar amp-hour capacity and weight and are fitted in the standard location.[/b]

IMO, this rule is so grey it's silly.

The word "similar" is just too subjective to be meaningful in this context. If the original battery weighed 34 pounds, at precisely what point do you consider the replacement dissimilar? 32 pounds? 28 pounds? How about 15 pounds? Or, if you happen to admire the stock location of your battery (from a ballasting perspective), how about 58 pounds? Even at the two extremes mentioned, I can say they are "similar", because both batteries have mass of the same order of magnitude. And if it's the same size and shape as the original, mounted in the standard location, and has "similar" amp-hour capacity, seems to me you're good to go.

Just out of curiosity... has anyone ever seen a protest written for battery weight?

[JohnRW]

Just out of curiosity... has anyone ever seen a protest written for battery weight?
[/b]

Please refer to U.S. Supreme Court Justice Potter Stewart's definition of "pornography".

I sense another thread descending into the "color, texture & flavor" abyss.

[dj10]

I stand corrected then because I thought the reason one would chose a gel battery is for weight reduction.

Is there another reason? [/b]

Wouldn't a gel battery be less susceptible to explosion, fire and leakage? This sounds like a saftey factor that isn't being considered by the ITAC or CRB. This might be a good rule to change.

[AntonioGG]

From someone who bought a $90 Oddysey Battery for my SM (smaller than stock) and couldn't get myself to use it, I think my philosophy on this is that if I have to wonder if it's similar enough, it probably isn't.

[JoshS]

I recommend that people check out Deka batteries. They make AGM (Absorbed Glass Mat) batteries as direct-fit replacements for stock batteries (in some sizes). Same technology as an Optima, but in the stock form factor.

Deka automotive batteries

[mlytle]

just for reference in the bmw world of "similar" wet cell batteries that fit the stock battery hold downs..

stock bmw battery for e36 (made by douglas) = 42.6lbs 750cca
interstate mtp-91 replacement = 35.4lbs 700cca

[biovic]

I think that if it is a similar amp hour capacity +/- 25% (yes I know this a big range), then I would have not issues. I switched to an Odyssey last year in my Integra. One for some weight savings (30lb stock, ~15 lbs Odyssey). However, the main reason I switched is for saftey of the closed cell design, no leakage if upside down or gets crushed, and have experience to prove. I hit a barrier diagonally 3 years ago on the front bumper and knocked the battery loose, acid got everywhere. Last year I had a hard front impact, the Odyssey has a metal casing that got bent in 2 places, bent the tie down bracket, and the wires got cut = no leakage.
Victor

[JoshS]

How is something that's 50% of the weight of the original "similar weight"?

[mlytle]

How is something that's 50% of the weight of the original "similar weight"?
[/b]

it is not. i would say that one is not legal.

[tom91ita]

just as an fyi, i looked up the battery for my car at autozone:

http://www.autozone.com/servlet/UiBroker?U...UP%7C%7EBattery

they are as follows with regards to warranty period in years, weight and price and cold cranking amps

A. 6, 25.7, $49.99, 410
B. 7, 28.1, $54.99, 425
C. 8, 27.7, $79.99, 500

since they are all listed as Group 51 replacements for my car, i would say that they are "similar"

[Z3_GoCar]

Yes, but are any of those the optima style gel-cell and should gel-cell's not be allowed ( de-facto ) when they provide a clear safety benefit because they happen to be lighter? I know that as an ITE car i'm allowed more lattitude, but I run an optima group 52 in my car as there's not an optima that matches the stock style battery. Basically, it's close in size and shape but the battery posts are on the left side of the battery instead of the right side. I run the optima for two reasons, first my battery is in the trunk and I don't want acid or it's resedue back there, and secondly the optima is susposed to be more tollerant of vibration. As long as it close in size shouldn't it be legal? Anyone check out the add in Sportcar for the Carbon fiber battery's? How are you going to keep some one with more money than brains from doing something like spending several hundred on an ultralight battery because they think it'll give them 0.0002 seconds per lap? My Tirerack window banner's good for like about 0.5 seconds per lap If it looks like a normal battery size for the car, why worry about it?

James

[JoshS]

Interesting argument ... but there are ways to be both safe and legal. You just have to do a little more research. Sure, the "big two" -- Odyssey and Optima -- might not make batteries in the stock size and weight, but there ARE other companies that use these same technologies that do. I have an AGM (same as Optima) battery in my Z3 Coupe, that's exactly the same size as stock (Group 48), using the stock hold-downs. It's a couple of pounds heavier than stock. It's made by Deka (link above).

The additional weight is fine for me since it's in the right place and I'm ballasting up to minimum anyway. But even if someone wasn't in that situation, the point is, that if you want a non-wet-cell battery that's actually legal, they can be found.

BTW, I was forced into this battery by the rules. My stock battery location is inside the passenger compartment (in the floor of the hatch). It's exposed once you remove the trunk carpeting. The rules require a wet-cell battery that's in the passenger compartment to be in a marine-type container. But I could not find any marine-type container that could both fit a stock-sized battery AND still fit into the stock location. I bought and returned SEVEN different containers. So, I needed to find something that wasn't a wet cell, yet was of "similar" size and weight to stock. Naturally, I started with the big two, but came up empty ... it took a little research, but they're out there!

[dickita15]

http://www.autozone.com/servlet/UiBroker?U...UP%7C%7EBattery
[/b]

Well that is interesting. According to Autozone there are 7 or 8 I could use for my car. Wet cells range between 28.1 pounds and 44.8 pounds and the optima is 43.8 pounds. That is a pretty big spread.