Dreaded battery drain syndrome
04-12-2018, 02:24 PM
#1
Pro
Thread Starter
Dreaded battery drain syndrome
I read a lot of posts on this subject when I started having no start issues.
Thought I'd post what I went through to maybe save someone else some time.
For those that are working through a parasitic drain issue, here is another possibility I did not see in any of the researched threads I visited while trying to diagnose my starting issues. Here is what I did:
1) When it wouldn't start after 48 hours, jumped it and drive long enough for full charge, then checked that all lights in car were off (thought I might have hit the map light switch left of the steering wheel by accident). Left car for 48 hours, wouldn't start.
2) Jumped car and went to Autozone for battery/charging system check. Both checked out in the green with the full 600 CCA on the battery. 48 hours later, wouldn't start.
3) Jumped car and went to Batteries Plus who have a better meter. Same result.
4) Disconnected battery and put 10 amp meter between negative cable and negative battery post. Initially read 1.5 amps until all computers shut down and then settled at .025 amps (25 milliamps) which is a normal drain for these cars.
5) At this point, it started taking only 24 hours to not start. As the battery voltage was reading 9.5, I suspected it might be a bad cell that charges fine, but was dying faster and faster, so I drove the car to a full charge (about 40 miles) and disconnected the battery when I got home. The next morning, I put a meter on the battery before hooking it back up and it read 9.5. Bingo, bad cell in the battery.
The battery being roughly 2 volts down should have led me to a bad cell earlier (6 cell battery, 2 volts/cell), but I had read so many threads on parasitic drain on these cars, that I just didn't think it through properly.
Replaced the battery with an Interstate.
Hope this helps someone down the line.
Thought I'd post what I went through to maybe save someone else some time.
For those that are working through a parasitic drain issue, here is another possibility I did not see in any of the researched threads I visited while trying to diagnose my starting issues. Here is what I did:
1) When it wouldn't start after 48 hours, jumped it and drive long enough for full charge, then checked that all lights in car were off (thought I might have hit the map light switch left of the steering wheel by accident). Left car for 48 hours, wouldn't start.
2) Jumped car and went to Autozone for battery/charging system check. Both checked out in the green with the full 600 CCA on the battery. 48 hours later, wouldn't start.
3) Jumped car and went to Batteries Plus who have a better meter. Same result.
4) Disconnected battery and put 10 amp meter between negative cable and negative battery post. Initially read 1.5 amps until all computers shut down and then settled at .025 amps (25 milliamps) which is a normal drain for these cars.
5) At this point, it started taking only 24 hours to not start. As the battery voltage was reading 9.5, I suspected it might be a bad cell that charges fine, but was dying faster and faster, so I drove the car to a full charge (about 40 miles) and disconnected the battery when I got home. The next morning, I put a meter on the battery before hooking it back up and it read 9.5. Bingo, bad cell in the battery.
The battery being roughly 2 volts down should have led me to a bad cell earlier (6 cell battery, 2 volts/cell), but I had read so many threads on parasitic drain on these cars, that I just didn't think it through properly.
Replaced the battery with an Interstate.
Hope this helps someone down the line.
Last edited by RogerRamjet21; 04-12-2018 at 03:34 PM. Reason: Clarity
The following users liked this post:
EVRose (04-12-2018)
04-12-2018, 05:35 PM
#7
Race Director
I agree putting it on a real battery charger is the preferred way to charge it but why did his battery test good at 2 different places after only a jump start and drive over there however far it is?
04-12-2018, 10:56 PM
#8
Melting Slicks
Member Since: Jul 2010
Location: Tacoma, Wa/Surprise, Az
Posts: 2,849
Received 195 Likes
on
166 Posts
Of course it can, the only question is, how much will it recharge in a 40 mile run, and at what engine speed are you running at since the alternator output depends on RPM 's. It is more efficient to use a charger, but a good battery should have come up on charge enough to last 24 hours.
04-13-2018, 12:48 AM
#10
Race Director
Member Since: Sep 2007
Location: Peoria/Phoenix AZ
Posts: 16,555
Received 2,061 Likes
on
1,505 Posts
C6 of Year Finalist (performance mods) 2019
I must be real lucky, since I never had the DBS. Yes, I've had batteries that died, but usually get 3 years of good service first, which is average for the Phoenix heat. I've never used a battery maintainer either.
I'm currently using a 360 CCA Deka motorcycle battery. In Feb I quit driving the Vette for 4 weeks (medical), then hopped in and it started just like I had driven it everyday. I didn't expect the smaller battery would last long without running regularly.
So I suspect there must be something in common for all those with battery problems. Maybe someone should start a thread or poll question to find the commonality.
I'm currently using a 360 CCA Deka motorcycle battery. In Feb I quit driving the Vette for 4 weeks (medical), then hopped in and it started just like I had driven it everyday. I didn't expect the smaller battery would last long without running regularly.
So I suspect there must be something in common for all those with battery problems. Maybe someone should start a thread or poll question to find the commonality.