ajayd

1998 993 needs a new battery. Can I go to any Costco and get one or do I have buy from the dealer? Your help is appreciated.

IXLR8

A group 48 or group 91 both fit.

They both have the same L x W dimensions. The group 48 is a half-inch taller than the group 91.
Quite a few here use the Interstate. I installed an East Penn 648MF.

Here is a battery list I put together ages ago...

NC TRACKRAT

Nice list, Alex! You may wish to add the DURACELL Group 48 from Sam's Club made by East Penn. Same as the 648MF, I believe.

IXLR8

Actually, I have a pic of it on my battery page...just uploaded a new list.

Here they are for the original poster...

ajayd

Thanks Guys appreciate. What do these typically run for?

NC TRACKRAT

I believe the DURACELLat Sam's is something on the order of $89.95. The AGM's will cost upwards of $150 or so.

IXLR8

To the OP, note that just because an AGM is more expensive, it does not mean you are getting a better, longer lasting battery.

AGM batteries have their advantages, but they have their disadvantages as well, and the latter are more important to us as users.

shellback

Stopped by WM last night and picked up a Everstart Maxx H6.
Once I got home, it had 2 small vent holes on each side and I couldn't find a way to attach the 993's single hose to these 2 vents. Back it went...

NC TRACKRAT

There's a vent hole at each end for multiple vehicle applications.. There should've been a plug for one end. Just use the one most convenient to location of your vent tube.

IXLR8

They usually come with an elbow for the vent hose to attach to and a plug that goes into the vent hole in the battery that you are not using.

s2racer

I've always used Optima batteries, but they aren't really supposed to fit our cars. Any suggestions for a gel-cel type battery? I've always worried (probably incorrectly) about issues with battery acid doing nasty things to the tray, and that's why I like the sealed batteries. Any thoughts/suggestions?

Thanks

Marc

IXLR8

So called sealed batteries (AGM or GEL) aren't really sealed.

s2racer

Hi Alex...quite true. What are your thoughts on the gel-cel batteries?

IXLR8

GEL batteries, like AGM batteries, have their place (just not in my vehicles) and advantages.

One major disadvantage to them is they should never be overcharged (because you can't top them up), so you better make sure the voltage regulator in your alternator is picked for the correct end voltage and is temperature compensating.

Here are a couple of charging charts out East Penn's technical manual.



Looking at the above charge voltage vs temperature, chances are good your alternator's voltage is too high. Mine is 14.0 to 14.2V at about 80F.




Quite the difference in charging voltages for the two types.

s2racer

interesting....I assume that with regular batteries, the vent hose (properly installed) alleviates concerns about acid damage (or do you use a mat underneath).