I am putting my front trunk in order and want to replace the current Interstate battery as it is too long and not clamped down (89 911 Cab). I prefer the properly sized battery so all that wiring and washer lines have proper clearance around the battery. I can't find anything on recommended batteries. Should I just go with a Bosch battery or a red top optima? Any thoughts.

 

Here's a recent thread with lots of opinions and perspectives. I personally am sold on Optimas, and use a mounting plate attached to the battery for mounting in a 911. Lot's of threads over on Pelican too if you care to make your own plate. Hope this helps.

https://rennlist.com/forums/showthre...ghlight=optima

Keith
'88 CE coupe

 

Check out some of the mounting kits from Rennline, a forum sponsor.

http://www.rennline.com/products.asp?dept=161

 

Interstate used to make a 1000 amp cold cranking battery that was the shiznit. Now, Delco is the only company making such heavy duty batteries.

I don't know about the Optima, but it seemed a little on the light side and too pricey, and I didn't want to fiddle with all of the little bits and stuff to get it to fit. So I bought a heavy duty Delco. All I can say is it will still be working 5+ years from now.

It's a good idea to clean your battery contacts, and replace your negative cable with a longer one. You may eventually have to cut off the positive battery clamp on a 3.2 911. They all seem to have a slight drain and if the clamps are not coated with some sealant, the vapors will leave corrosive buildup on the clamps. I replaced mine with a gold plated Monster Cable batt clamp. Still working fine after 8 years.

I just read the other battery thread. I should add that I have more than a few 800 watt amps as part of a stereo system. No way would a wheelchair battery work for me. If you have an alarm and use it, get a heavier battery. Look at the CCA rating, not just the warranty. The starter needs a big surge of power to kick out the solenoid and turn over the motor, which needs to spin fast enough to start. All the while you need at least 12 spare volts at each injector to fire them, as well as run the DME. Often this is after the car has sat for awhile. What good is light weight if you have to carry jumper cables and rely on the charity of others to give you a jump all the time?

 

+1 on optimas. I like them because they're sealed, so you don't have to worry about acid eating away at your baby. I welded in a threaded insert in the pan and used a piece of aluminum stock to bolt the battery down nice and snug in the factory location. It works like a charm.

 

I've had my 'smaller' interstate for about 7 years with no problems...

I monitor the water level and use a 'battery maintainer' in the winter months..

k