battery
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1st Gear
Joined: Feb 2017
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battery
When I Shut my car off, when all the lights are off and the doors closed, something runs my battery down. The battery is brand new. The only thing running is the security system. Any ideas???????
Burning Brakes
Joined: Jan 2019
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From: Park City, TN
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When looking for a drain I put an ammeter inline and then pull fuses one-by-one.
I then find when the drain drops to give me the circuit to look into.
You didn't say what car you have, but I would ask another to help by looking at the meter while you are inside with the doors closed. Also disconnect the hood lights if you have them.
I then find when the drain drops to give me the circuit to look into.
You didn't say what car you have, but I would ask another to help by looking at the meter while you are inside with the doors closed. Also disconnect the hood lights if you have them.
Le Mans Master
Joined: Feb 2000
Posts: 9,065
Likes: 215
From: Epping NH
Buy this and start checking for shorted circuit https://www.harborfreight.com/30-amp...ter-67724.html.
Short term disconnect the negative lead and put an voltmeter set on amps in between negative lead and negative battery post...car with doors shut and lights off shouldn't pull more the .003 (30mA) of power.
In the meantime disconnect your battery when not driving! A short is pulling current and current generates heat, in the wrong place this can cause a fire!
Short term disconnect the negative lead and put an voltmeter set on amps in between negative lead and negative battery post...car with doors shut and lights off shouldn't pull more the .003 (30mA) of power.
In the meantime disconnect your battery when not driving! A short is pulling current and current generates heat, in the wrong place this can cause a fire!
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Buy this and start checking for shorted circuit https://www.harborfreight.com/30-amp...ter-67724.html.
Short term disconnect the negative lead and put an voltmeter set on amps in between negative lead and negative battery post...car with doors shut and lights off shouldn't pull more the .003 (30mA) of power.
Short term disconnect the negative lead and put an voltmeter set on amps in between negative lead and negative battery post...car with doors shut and lights off shouldn't pull more the .003 (30mA) of power.
Next, that HF fuse tester can't measure less than 0.100 A ( 100 mA ), so it's useless for the residual current drain test. If you truely have a "short circuit", you'll probably draw more than 30 A, and therefore blow the fuse in the tester. So that's no different than blowing the fuse in your car, and you haven't learned anything.
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
First, let's get our facts straight. The residual current drain shouldn't exceed about 30 mA is correct, but that's 0.03 A, not 0.003 A. 0.003 A would be 3 mA.
Next, that HF fuse tester can't measure less than 0.100 A ( 100 mA ), so it's useless for the residual current drain test. If you truely have a "short circuit", you'll probably draw more than 30 A, and therefore blow the fuse in the tester. So that's no different than blowing the fuse in your car, and you haven't learned anything.
Next, that HF fuse tester can't measure less than 0.100 A ( 100 mA ), so it's useless for the residual current drain test. If you truely have a "short circuit", you'll probably draw more than 30 A, and therefore blow the fuse in the tester. So that's no different than blowing the fuse in your car, and you haven't learned anything.
...with a minor exception: after determining a parasitic draw above 100mA, which isn't that unusual for a problem draining the battery e.g., over nite, the HF meter is useful in isolating the problem circuit. (I have that HE meter, and I found in the majority of cases a true problem parasitic drain will register on my HF gadgit.
Last edited by Paul Workman; Jul 19, 2019 at 07:28 PM.
Le Mans Master
Joined: Feb 2000
Posts: 9,065
Likes: 215
From: Epping NH
...with a minor exception: after determining a parasitic draw above 100mA, which isn't that unusual for a problem draining the battery e.g., over nite, the HF meter is useful in isolating the problem circuit. (I have that HE meter, and I found in the majority of cases a true problem parasitic drain will register on my HF gadgit.Corvette Stories
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