Battery help
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 8,429
Likes: 3,913
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
Battery help
Ok, here's the deal. If my car sits for about a week the battery will be dead. This is in my garage without the alarm on. I can charge the battery back up and it will work fine, and as long as I drive the car every couple of days all is well. The battery will show 12.5 or so volts with the car off, and the voltage reads 14.1-14.3 with the car running. Any thoughts? I'm thinking the battery is on the way out and just isn't holding a charge for very long.
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 8,429
Likes: 3,913
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
Re: Battery help
That's kind of what I was thinking. Guess I'll head over to Wal-mart and get a new one. They definitely have the lowest prices around, I just replaced the battery for my Tahoe and paid $35 for one with 2 year free replacement (7 year total warranty).
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery help (EvanLT1)
Your battery could be ok. Remove the ground cable from the battery and put an ammeter (VOM) from the battery to the cable and wait for the courtesy lights to time out and then switch down the ammeter until you can read the leakage current. I measured my 87 last week and its 26 ma. Your battery should last a lot longer than a week with normal leakage current.
Safety Car
Joined: Jul 2001
Posts: 4,178
Likes: 2
From: Windermere FL
Re: Battery help (jfb)
Probably the battery. I'd just get a new Delco. The optima is fine but doesn't have any real advantages for a C4. They are best when located inside the cabin like in a C3 as they don't leak fumes.
Melting Slicks
Joined: Apr 2002
Posts: 2,620
Likes: 0
From: 20 forward gears to shift through in MD
Re: Battery help (EvanLT1)
12.5 V open circuit and 14.2 V, give or take, while running is actually about right for a good battery. A new fully charged battery Lead-Acid battery is about 2.2 V/cell (13.2 V fully charged). However, in your car there is always a drain for things that continuously require power and thus 12.5 V is probably about right. Given your description, I would have suggested pulling fuses one-by-one to see which one may be drawing a ~little~ too much (while looking at the battery voltage) as it may be something is soft shorted.
