voltage drop when not in use.
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Cruising
Joined: Dec 2016
Posts: 13
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voltage drop when not in use.
My 03 battery looses voltage when not in use. In 3 days it drops to about 8 volts. As far as I can tell everything is turned off. No voltage loss if battery is disconnected.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,500
Likes: 3,999
From: Cape Coral, Florida
If your battery keeps discharging like that even if you find the cause of the parasitic draw you’ll most likely have to replace that battery !!…don’t know if you have any electrical skills and maybe own a DVOM but maybe this video may help !!..and I’d get your battery tested also…it may not be holding a charge and a battery less than 11.90 volts is dead.
Last edited by C5 Diag; Nov 15, 2021 at 02:43 PM.
Racer
Joined: Apr 2021
Posts: 289
Likes: 102
From: Texas
If you don't have a meter, and you can let the car go while you try things, you can pull fuses and see if it stops, that would tell you which things to look at.
So, for example, when I have had to do this in the past on a car with a mysterious draw, I pull about half the fuses. Then check the battery to see if it's holding. If it's not holding, I at least know it's the half that is left, so I put the original half of the fuses back, and then pull half of the half that was left to see if I have narrowed it down further. Basically, just keep taking out half until you narrow it down to the one or two left.
In my case, it was really obvious once I found it, the cigarette lighter was always on, and I had my charger plugged into it and it was drawing all the time. I rewired that to an ignition only fuse and that fixed my issue.
But the above it quite good if you have a meter and some time as well.
So, for example, when I have had to do this in the past on a car with a mysterious draw, I pull about half the fuses. Then check the battery to see if it's holding. If it's not holding, I at least know it's the half that is left, so I put the original half of the fuses back, and then pull half of the half that was left to see if I have narrowed it down further. Basically, just keep taking out half until you narrow it down to the one or two left.
In my case, it was really obvious once I found it, the cigarette lighter was always on, and I had my charger plugged into it and it was drawing all the time. I rewired that to an ignition only fuse and that fixed my issue.
But the above it quite good if you have a meter and some time as well.
