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View Full Version : Anyone know what kind of current their car draws while off?



Paul408Notch
06-03-2007, 10:37 PM
I was just wondering if anybody has ever measured their car's current draw while the car and all lights are off. I've been having problems with my Optima, so before I throw a new battery in my car, I want to make sure it's not being pulled down by my stereo/alarm/whatever.

I threw my meter across the power feed wire to my amps and it was only about 5mA, and the power feed to the rest of the car was only about 25mA with the alarm turned off. The battery drains whether or not I have the alarm turned on, so I don't think that's the problem.

30mA doesn't seem like a lot of current draw to me, and there's no reason that should drain my battery from a full charge to nothing in 3 or 4 days, so I'm just wondering if anybody else knows what their car draws.

ibstrokin
06-04-2007, 12:31 AM
I'm not sure what acceptable current draw would be, but I know a good way to isolate your source.

Disconnect your negative lead from the battery, place a test light between the neg post of the batt, and the neg batt cable. If the test light lights bright, then you have current draw. Start pulling fuses until the light either goes out, or very dim. When you see a drastic change in the light after pulling a fuse,chase that circuit. Remember there are a couple of circuits that come off of the starter solenoid.

Paul408Notch
06-04-2007, 12:44 AM
I'm not sure what acceptable current draw would be, but I know a good way to isolate your source.

Disconnect your negative lead from the battery, place a test light between the neg post of the batt, and the neg batt cable. If the test light lights bright, then you have current draw. Start pulling fuses until the light either goes out, or very dim. When you see a drastic change in the light after pulling a fuse,chase that circuit. Remember there are a couple of circuits that come off of the starter solenoid.

I have a really nice Fluke meter that I use for all of my electrical work, and it works well for stuff like this. I just don't know what normal draw should be.

That's an awesome method for somebody that doesn't want to drop the bucks on a meter though. I'll have to remember that for future reference. :bigthumb

ibstrokin
06-04-2007, 01:06 AM
I have a nice fluke meter also, this is the easiest way I've found for chasing current draw. A meter will work using the same method(flipped to the amp scale), but the test light is more visual, and easier to see while pulling fuses under the dash while watching the light under the hood. Hope this helps.

PaulFiveOh
06-04-2007, 02:21 AM
I cant imagine there would more than .1Ahr Because the only draw should be the bleed through ground.....shouldnt it?

Black Horse
06-04-2007, 03:25 PM
Check to make sure your trunk light or glove box light are not staying on.

You might have to go circuit by circuit through the fuse box to pinpoint the source. My '99 with the PATS system and Radar Dectector left on had less than 5ma.

chad393na
06-13-2007, 11:40 PM
Amp meter is the best way to find a drain. The test light may not light with a draw that will still kill the battery over time. Just recently, I had a mercedes at work with a draw that would kill the battery overnight. I tried using the test light and pulling the fuses to isolate the drain. I couldn't find it, so I put the meter on it and disconnected the alternator. The drain went away. The light wouldn't put enough load on the drain to use it up when the alt. was disconnected. The meter did. Most of the time the testlight works great, but if you can't find it, try the meter.

Dirtyd0g
06-14-2007, 08:56 AM
I always heard 2ma was acceptable limit, maybe you have a trunk light or glovebox light not shutting off. That stuff is common and can seriously wear you out. Most vehicles range at about.5ma stereos and stuff will quickly change that however.
Alan

dedpedal
06-14-2007, 09:24 AM
Paul, I had a similar issue a while back. It turned out that the makeup lights in the visor were on.

bangingears
06-14-2007, 09:29 AM
Paul, I had a similar issue a while back. It turned out that the makeup lights in the visor were on.

common problem that is easily overlooked

RACEME
06-14-2007, 09:43 AM
I have also been bitten by the visor light. I would pull the radio fuse and any amps that you have in there, and then see if it still has draw. If that doesn't work then you need to go fuse by fuse (i realize you know this)

I guess another way would be to just leave the battery unhooked for a couple days to see if it dies while unhooked.

Black92LX
06-14-2007, 10:42 AM
Paul have you had the Optima tested??
I was having the same problem. Couldn't find anything that was draining the car. But after some looking around I guess the way that Optimas are made that if they have a bad cell they will drain with even the smallest amount of current to them.
Mine was still under warranty so it was replaced for free and I have had no problems since.

Paul408Notch
06-14-2007, 12:46 PM
I figured the battery was bad, I just wanted to check what normal draw was before I got it switched out. I warrantied the battery on Saturday, and so far, it still has plenty of juice to start the car.

I'm sure I can find whatever the draw is if there really is excessive draw, but I just don't know if what I'm seeing is excessive or not. I don't think 30mA total is a lot, I just wondered if anybody else knew what their car pulls.

Black92LX
06-14-2007, 03:02 PM
doesn't seem like it.
i was in the same boat and couldn't figure out why the Optima would drain so fast just sitting. But for whatever reason it did got the new one and have had zero problems.