Testing for battery drain

[mcsvt]

I'm having issues with the Durango. The battery will die overnight. Before I go buy a new battery I want to make sure it's just the battery. I can jump it let it charge up a bit and then drive it like normal. I can even stop for a bit, and come out and it will start right up. I checked the voltage at idle and the alternator is working.

How do I test if something is draining the battery or if the battery is just dead and can't hold a charge.

Suggestions welcome, I only really have a multi-meter to work with... :)

[turbovanman²]

You need to borrow or rent an ammeter. Remove the neg battery terminal then run the ammeter in series, this will show the draw.

[black86glhs]

Gary, I take the + cable off and put the multi-meter in series between the cable and batt terminal. Just make sure you don't have any doors open and the ignition is off nad key out. Start on the highest amp setting. If it is an auto ranging meter then just put it on amps. If it shows less than 1 amp, move it to milliamps and read the meter. You may have to wait a few minutes for stuff to turn off that stay on a little while after you shut off the ignition. GM specs were 50 mA or less is fine. I have heard of 100 mA is ok for some other manufacturers.

[2.216VTurbo]

Easier way, take a small 12 light (like a bulb from the instrument cluster) and solder 10" or so of wire on each wire going into the bulb. Then take the negative battery cable off and put the light from the cable end to the battery post. Does it light up? That's your drain. Now star pulling fueses on at a time till the light goes out, that's your culprit:thumb:

[black86glhs]

Now you have your choices Gary. The scientific or hillbilly way.:p Either way will work.:thumb:

BTW....forgot to add the part about pulling fuses one at a time if you have more than 100 mA draw. Sorry.:o

[mcsvt]

Ah good stuff guys, thanks :thumb: That will definitely get me started, thanks!

[2.216VTurbo]

Now you have your choices Gary. The scientific or hillbilly way.:p Either way will work.:thumb:

BTW....forgot to add the part about pulling fuses one at a time if you have more than 100 mA draw. Sorry.:o


Hillbilly way you don't have to run to the meter to read it every time you pull a fuse, a quick glance at the light while you are comfortably positioned at the fusebox within arms reach of your beer:p

[ekimdam]

With the testing procedures above, I'd start with the usual suspects:

Glovebox/underhood lights and car alarms

They are typical culprits for over night battery drain issues...

[mcsvt]

Good point, it has an aftermarket autostart system on it, it was my first suspect. It was a pretty clean install, so I need to track down the module and see how it's wired in.

[black86glhs]

Hillbilly way you don't have to run to the meter to read it every time you pull a fuse, a quick glance at the light while you are comfortably positioned at the fusebox within arms reach of your beer:p
:hail::hail::hail::hail::hail::hail::hail::hail: :hail::hail::hail::hail::hail::hail:

[mcsvt]

Yeah and I just realized I have a perfect bulb, but my soldering stuff is in NJ... I'll have to see if I can go super hillbilly, I'll involve duck tape somehow...

[2.216VTurbo]

Gary, if you can't solder using your kitchen stove for something like that, you're not the man I thought you were:p

[mcsvt]

Thanks for all the suggestions looks like it may be just the battery, even though the idiot light is green...

First I blew the fuse in my cheap multi-meter, neighbor lent me his (much nicer!) and with all fuses in and all interior lights off I had 68mA... I still checked each fuse circuit, but I'm going to have the battery load tested to make sure.

Started it up for a bit to recheck the charging system, still looks good. But discovered a new problem, looks like some heater valve is leaking, can't seem to find another on any of the parts sites though...

Guess that's what I get for buying somebody else's problems.

[mcsvt]

Zombie thread... as I need to use this info again, now on the van. Battery dies after a week or 2 of sitting. Going to pull the battery during winter storage anyway, but wouldn't mind fixing it before then.

[amx364]

Still same as above.

[Polygon]

I would like to add that sticking relays are also a common cause of this. I need to really check this on the GTC. Has the same issue and it's parasitic draw for sure. It's killed two batteries.