Testing battery drain on Diesel

[tlcruiser66]

Okay the past 2 mornings I've come out to a dead battery in the truck and I'm gonna head out in a few minutes to test for a draw but not sure if I need to disconnect both batteries (since it's a diesel) or just the positive off one.

It's a 2003 GMC Duramax and I'm hoping someone will be able to let me know soon so I don't end up getting a bad result.

Thanks,

Kevin

 

[crash2]

Duramax--no idea :redneck:


Disconnect both batteries and use on for testing for a paracitic drain. Typicly you want to be below 20mA

 

[tlcruiser66]

Awesome, thanks Mike

 

[tlcruiser66]

So I may have just figured out what the problem is, I went to remove the positive cable fro the passengers side battery and the whole terminal came out instead...

Think I should bother with the test still or would this explain it?

 

[crash2]

I would go ahead and just double check it kevin. But sounds like that might be the culprit. You are loosing voltage internally and bypassing it when you throw jumper cables on it. Seen it happen a few times...

 

[tlcruiser66]

Came back with .012 A draw so It looks like it's the battery, thanks Mike for all your help.

 

[crash2]

Not a problem :awesomework:

 

[tlcruiser66]

So I'm having a related issue again with my truck.

This morning I came out to a set of flat batteries in the truck, jumped it and started to drive off only to notice that the voltage was sitting at 13.5 and wasn't getting any higher so I drove it back home, parked it and took the girlfriends car instead.

I get home and dive right in only to find that yet again I have 2 flat batteries again, I grab my multi-meter only to find out that I have not one but 2 blown fuses so checking draw with that is out. I've searched and searched but cannot find any common issues and was hoping that maybe someone here has a suggestion on where to start looking?

I know there's a serious draw since when I disconnect the negative and touch it to the neg post it has a pretty serious spark but there are like 100 fuses and I don't feel like fumbling around into the night trying to disconnect each one until the spark goes away/gets smaller.

 

[ceb0217]

I had 1 bad battery and it would drain the good one in about 3 hours. I ended up finding it by charging both of them up and then disconnecting both and letting them sit over night and using a battery tester.I had to replace a 6 month old battery that went bad.

I also did the unhook them check and got a good sized spark I think its normal.

my truck is a 2002 dmax

 

[skinny_pedal]

Start pulling fuses:flipoff: But with that big of a spark Id look more towards your high draw items. Starter, alt.

 

[tlcruiser66]

Okay so I borrowed a neighbors multimeter and it's only drawing .03ma so I guess it's probably the batteries again. I'll take them both back to Firestone and get them to figure out which is toast and replace it then I'll check back and let you guys know what the verdict is.

 

[tlcruiser66]

That battery musta had a serious short in it, I replaced it and now it's charging at 14.4.

Crossing my fingers that when I go out in the morning to head off to work it'll start.

Thanks for the tips guys.