So what optima yellow top battery do I need for my cobalt? Since optimas aren't listed anywhere for cobalts I'm not sure which specific one to get. Thanks.

 

34/78

 

would a d75/25 be better or worse?

 

its a smaller battery then the 34/78. it wouldn't push up the carpet as much if you installed it normally (vs on the side)

 

i don't buy optima for Cobalts due to the need (as I understand it) for the battery to be able to 'breath' and be ventilated by fresh air in addition to being a 'taller' battery. AC Delco in the trunk FTW

 

would a 34/78 work in terms of amp cranking power I mean. Like it fits electrically?

 

you realize the ac delco is a sealed battery right? and the only reason for the vent tube is for the one in a million chance that some retard charges their battery to 20v and it explodes

 

the 34/78 is just a slightly bigger batty then the d75/25. its also by far much more common. the 34/78 has 20 ah more and like 100cca or something more as well.

 

so would a 72/25 work fine?

 

ya dont see why not

 

ok sounds good, the 34 one is a bit more expensive

 

So I got me a 34/78 yellow top like you suggested. Now I have a volts gauge. For a while it read normal as usual 15 volts. Then I swapped my zzp 2.5 dp back to stock so I could pass inspection. I've now noticed that the volt meter starts at at 15 as usual then slowly falls to 13 or now recently its falling to 14 steady which is ok I suppose. But why is it doing this? I thought maybe cause I have my wideband bung disconnected so I pulled the power wire to the gauge and nothing still does the same. Is it possible that I might have damaged the rear o2 sensor? Would that cause that? Or is it strangly possible that my alternator is going? 16800 3 year old car.

Pic: http://i642.photobucket.com/albums/u...8/IMAG0287.jpg

 

you have 1.6 million miles on the car?

what kind of volt guage is it? trustworthy? connections solid?

 

What? 16877 exactly. I have autometer C2 and yup connections are good. I guess its trustworthy its always been right.

 

My voltmeter goes from 13 to 15 all the time. One day it'll read 13, next day it'll read 15. I never understood it. Ive checked all my connections to, I just ignore it. Mine is a glowshift.

 

ya idk what to tell you. 15v is a tad high but 13 is a tad low. if its rounding up or down then depending on how it works its normal

 

This car is strange. Now its back to being normal @ 15 steady. Well whatever as long as it's not dipping under 13 then Maybe since the battery replace, the car had to relearn total voltage in a certain # of start cycles or some crap with the built in batt management system. Eh who knows


Now my drivers side headlight halos are out FML. Always something with this damn car lmao

 

our cars normally start at 14.4 then drop down to 13.8 after 30 seconds

 

it's maintenance free but it is not a sealed unit. it will spill acid if its laid on its side for some reason. the vent tube is because of the heavy gassing of a lead acid battery during charging. i had a 34/78 in my car for quite some time until i gave it to my mom. it worked great and i don't remember it pushing up the carpet at all?

 

Sounds like his gauge rounds.. or he is. ***Just saw picture... scratch that comment****

How much draw do you have on the battery? The voltage may drop if you come to a stop and have your radio cranked... alternator wouldn't put out enough power at low rpm to keep the battery 100% charged.

 

hmm i thought it was sealed. my bad

 

i got a yellow top 34/78 but the carpet is pushed up.....how did you guys fix this

 

try to lay the battery on its side