So I am certain I have a parasitic drain, but I have no idea where to start. The batteries are fully charged from my battery tender but if I leave terminals attached, the truck goes dead after a few hours. I haven`t noticed anything not working because of it, and the truck operates fine.

Any help would be appreciated!

Also, this is my first post, but I have read many threads and tuts on here. Great place!

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Actually ive posted before, but forgot. Also, could a mod moved this thread? I accidentally posted it in the wrong section

 

Hi, I also have a problem with my batteries. I have a 2007 Freightliner with a 2006 Detroit series 60 engine. Today I noticed that my voltage meter was reading low. I took the truck into a shop and it was determined there was no problem with my alternator but two of my four batteries were bad. I had 4 900 cca batteries. The shop didn't have 900 cca so we installed two 1000 cca batteries. The meter showed 12.5v (it is usually at the 14.0 mark. Was told 12.5 was good. I couldn't hang about anymore as I needed to get to my pickup appointment. I don't seem to be holding at 12.5v. Is it possible that because I have mixed the batteries that I am draining too much? I have stopped for the night and am running my APU in the hope that I can start the engine in the morning. ANy suggestions would be greatly appreciated. Thank you

 

You guys need a small volt meter. Hook it between positive cable and battery post after you remove cable. (Completely remove all positive cables) after you hook up you should see some voltage flowing across meter. Remove fuses onecatva time till volts drop to zero. This will help you identify draw. And for ladybrit99 I'm sure you are correct, should read about 14 volts charging. 12.5 is just running on battery. You may have other issue than alternator but if you can check at post on alt with engine running you should be able to tell if its working.

 

12.5 is good for a battery not receiving charge and acceptable charge rate is 13.4-14V at idle or 1200 RPM, one easy way to tell if your alternator is charging is to find the field wire and either a test light or volt meter will tell you if its is charging, if not then you have a bad alternator. If its charging check your battery connections since most of the Big Rigs have multiple leads going into one battery and most of the time their is insulation on the one of the leads make sure you have a good connection on all your Battery leads. Also make sure all your leads are connected to the correct lead also. Hope this helps you, dont want a truck to go down tomarrow. As for the check for Persitic Draw and just start pulling fuses one at a time.

 

I have multimeter and an edge insight cs. My batteries read 12.8v and 13.9- 14.1 when the truck is on, so I'm.sure the alternator is charging. I used an amp meter too, and it's well over a 10 amp draw while off.A

 

Pop a fuse one at a time till your 10 amp draw goes away! . . That's the bad circuit. Then you have to determine what's wrong. . . Keep us informed. .