: Best/biggest aftermarket battery for 2001 STS - need venting?



ocgltd
05-12-12, 09:27 PM
I'm about to buy my 3rd battery in 3 years - the prior Delco's all failed. Not too impressed, and considering switching brands. (there's a prorated credit on the battery but I'm not sure I want to go back to delco)

Since the battery in my 2001 STS is under the seat, I'm concerned about gas venting. If I stick with Delco I can reconnect the vent tubes, but aftermarket that won't be possible.

Are there compatible aftermarket batteries with the same vent tube connections? If not, is a completely sealed battery safe (does such a thing exist)?

If so...what's the biggest capacity / best battery I can fit into this car?

Thanks!

JimD
05-12-12, 10:49 PM
I'm about to buy my 3rd battery in 3 years - the prior Delco's all failed.
Any idea why the failures? That would be worth investigating. There are many possible reasons for "battery failure" that have nothing to do with the quality of the battery.

Since the battery in my 2001 STS is under the seat, I'm concerned about gas venting. If I stick with Delco I can reconnect the vent tubes, but aftermarket that won't be possible.Any aftermarket battery identified as Group 79 will have provisions for venting.

....If not, is a completely sealed battery safe (does such a thing exist)?
I'm not aware of a sealed battery that meets the dimensions specifications of a Group 79 battery. Battery case height is of course the critical battery case dimension for your car.

....what's the biggest capacity / best battery I can fit into this car?
Any brand of battery that meets Group 79 specifications is the ONLY way to go.

ocgltd
05-12-12, 10:53 PM
I can't explain why they go bad. Symptomatically I suspect intermittent cell.

I drive 15k KM per year, on smooth roads, so I can't see wear / vibration as the cause. I don't run accessories with engine off...so doubt that's it. I'm in Canada so it does get cold in the winters.

What type of causes might be at the root of this? (Assuming the problem is outside the battery).

JimD
05-12-12, 11:49 PM
....I drive 15k KM per year, on smooth roads, so I can't see wear / vibration as the cause.Metric is not my first language but that should translate to 9,320 miles per year or 25 miles per day if you drive the car every day. Short trips with frequent engine restarts can leave a battery in a less than fully charged condition which is a battery death sentence in freezing temperatures.

Your situation might be as simple as - you are not running the engine long enough to allow the alternator to fully charge the battery following the last engine start cycle.

What type of causes might be at the root of this? (Assuming the problem is outside the battery).Parasitic drain is the first thing I would investigate. And that requires some skills with electrical test equipment.

ocgltd
05-13-12, 07:00 AM
I tested for parasitic drain, and found that once RAP turned off the car drew less than 250ma. Of course if the cause of parasitic drain were intermittent then it may be way higher but I can't predict when that would happen. I did find a flat battery 1 day over past year suggesting something drew a lot of current over night, but no idea what and it didn't happen again.

In the event that there is some occasional parasitic drain (and I can't find it), I thought an AGM battery like the yellowtop Optima would be ideal - but they don't make one the right size...I don't think

JimD
05-13-12, 09:07 AM
I tested for parasitic drain, and found that once RAP turned off the car drew less than 250ma.
Whoa. I would expect to see much less than that. I measured my '98 model several times and consistently showed a 30ma draw after RAP timeout.

Several times that car was parked for 10 to 14 days and the battery cranked and fired the engine as usual.

Submariner409
05-15-12, 09:05 AM
Yeah, that ^^^ My 2002 STS draws about 18 mA after a day or so, and it will start consistently after a two week layup, no problem, AC Delco Group 79 battery, 4 years old. (almost 5.........)

ocgltd
05-15-12, 10:33 AM
Looks like my memory served me wrong...I think it was 28ma or 18ma...either way it seemed ok.

I realize I make a lot of short trips, so the battery may not be getting a full charge. However, shouldn't GM have designed for this? In other words, are customers expected to put a charger on their car nightly if they do short trips? Are all customers who do mostly short trips experiencing the same thing?

I'm really stretching here...but could this be a charging problem? A ground problem?

JimD
05-15-12, 05:44 PM
Looks like my memory served me wrong...I think it was 28ma or 18ma...either way it seemed ok.It would be worth the effort to connect your ammeter again and determine the actual number. It's too important to guess at.

I realize I make a lot of short trips, so the battery may not be getting a full charge. However, shouldn't GM have designed for this?....GM did take into account the starting load on the battery plus the electrical energy needed to simply operate all the vehicle's systems with the engine at idle. The alternator design and pulley size are such that the alternator can supply all the energy needed to operate the systems and still produce enough energy to begin to recharge the battery at engine idle.

In other words, are customers expected to put a charger on their car nightly if they do short trips?No more than customers are expected to be certain there is fuel in the tank and oil in the crankcase and coolant in the cooling system.

Are all customers who do mostly short trips experiencing the same thing?Who can know?


I'm really stretching here...but could this be a charging problem?That can be tested by a competent starter/generator specialty shop.
A ground problem?You would be having many other electrical problems if that were the case.

ocgltd
05-15-12, 05:54 PM
Well I got the battery test done today and it's defective...so I put a new Delco in today.

I start some diagnostics slowly and update the thread if I find something new...thanks