Battery Drain - Need Advice!
Thread Starter
Racer
Joined: Aug 2008
Posts: 388
Likes: 116
From: Jackson Michigan
Battery Drain - Need Advice!
I’ve had my 95 in the garage working on installing a new stereo. After it was done, I went to start the car, and the battery was too low to crank it. So, I charged it up overnight, and all is well. However, there didn’t seem to be a reason for the battery to be so low, so quickly (it’s a 2019 battery). I decided to try to figure out where the drain was, so I put my VOM I’m live with the disconnected negative cable, and it registers a steady 3.7 amp draw. This seems excessive, and certainly enough to drain the battery in a few weeks. I waited several minutes with the doors closed, to make sure it wasn’t something needing to ‘time out’. The draw stayed the same. So, I disconnected every fuse, in all three fuse panels, one by one, and the draw never changed. What am I doing wrong? Somebody with some electrical skills please help me out!
Thanks,
John
Thanks,
John
Instructor
Joined: Aug 2016
Posts: 240
Likes: 51
From: Putnam County NY
I have the same issue on both of my cars, both 1995 model year. I've seen other posts where owners have tried to track down the source of this parasitic current draw with different limited results. Some say it's the hood lights staying on due to the mercury switches, some say it's the security system or proximity system. I've stopped searching for the exact reason... during the season I usually run my cars enough to keep the battery charged and in the winter I keep them both on a battery maintainer. Hope you have better luck than I had. 
Advanced
Joined: Nov 2021
Posts: 67
Likes: 15
From: NC
I've heard of a bad diode in the alternator draining the battery. Here's a quote from this web site: https://itstillruns.com/can-alternat...y-7605315.html
Check for current flow between the battery and alternator with key off.
"Bad Diode
A malfunctioning diode in the alternator can create a parasitic drain on a car's battery. Diodes should allow current to pass in only one direction, but a bad diode will keep the charging circuit open even when the engine in not running, allowing the battery to go dead. This often happens overnight."Check for current flow between the battery and alternator with key off.
Advanced
Joined: Nov 2021
Posts: 67
Likes: 15
From: NC
Thread Starter
Racer
Joined: Aug 2008
Posts: 388
Likes: 116
From: Jackson Michigan
Actually, Jim, I’ve determined that I’m an idiot… I had my meter cables plugged into the wrong place for measuring amps. When I switched it, I only have about 25 milliamps draw at the battery with everything off. I guess I need to double check my battery to make sure it’s not low on water, or some other reason why it doesn’t seem to be holding a charge very long. Thanks to all for trying to help me solve an issue I didn’t have…
John
John
Advanced
Joined: Nov 2021
Posts: 67
Likes: 15
From: NC
Actually, Jim, I’ve determined that I’m an idiot… I had my meter cables plugged into the wrong place for measuring amps. When I switched it, I only have about 25 milliamps draw at the battery with everything off. I guess I need to double check my battery to make sure it’s not low on water, or some other reason why it doesn’t seem to be holding a charge very long. Thanks to all for trying to help me solve an issue I didn’t have…
John
John
