Dead batteries after new ones put in

[jbz400]

So I got a new set of batteries about a month ago. Everything has been good until I let it set 5 days and they were both drained completely. When I opened to door the miles on the dash were flashing on and off and also a red light on dash was flashing on and off. No doors were cracked, no lights were left on. Thanks Jeremy.

 

[Prairie Dog]

Check the batteries voltage individually - this means you'll have to disconnect at least one.
A few years ago I bought two new batteries, got them home and figured out one was shorted internally.
So even if they're young they can be junk.

 

[p-Bar]

Yes important to have "matched " batteries either in series or parallel. I bought 2 trojan 6v for my trailer and I asked if I could put my digital meter on the batch he had to match them up. May want to have them load tested but they should have a full charge

 

[puller]

I had that same problem and after spending great hands full of money and many days at the dealer it turned out to be the ECM. Poor excuse for techs at the dealer.

puller

 

[puller]

I forgot to add while all this was going on I installed 2 battery cutoffs on the neg side of the batteries. After installing the cutoffs the batteries did not go dead it was inconvenient to reset the radio every day.

puller

 

[sag2]

You most likely have an ignition off draw. You can check for it by using a multimeter and measuring amps draw with everything off, doors closed and key out of ignition. If you are not familiar with basic automotive electrical troubleshooting and DVOM use do not attempt this procedure. You could injure yourself or ruin some very expensive parts.
Start by setting your meter to 10amp setting. Disconnect driver side battery positive post. Open windows, close doors, all lights off, key out of ignition. Attach a jumper wire (should have inline fuse rated at 10 amps for protection of circuits) from the cable end to battery post. If the fuse blows, STOP as you have a serious problem. Consult with a qualified auto electrical technician.
Place meter leads on battery post and battery cable clamp. Polarity does not really matter, the meter will read + or - amps. Double check your meter leads and meter setting. Remove the jumper wire leaving the meter leads. The meter will now be carrying the current instead of the fused jumper wire and will now show current in amps. If you connect the jumper wire and then disconnect it within a few seconds you will normally see about 3 to 6 amp draw that gradually drops to about 30 milliamps within a couple of minutes. Most normal late model vehicles will act similar. You want to wait a few more minutes and watch the amp draw. It may be normal for the amps to jump up slightly then reduce again. This is just from modules waking up and going back to sleep. If the draw goes down below about 50-30 milliamps and stays there for 10 or 20 minutes the fault is not there.
A vehicle with a problem may start to ramp down but jump back up over and over, or may ramp down some but never drop below an amp or two. If the amps stay up for a while (10-20 minutes) start pulling fuses one at a time until the amps drop below 30 milliamps. Wait a bit between fuse pulls for any modules to start going back to sleep.
If the amps stay low indicating the problem is still not there, reach inside and turn on the flashers for a second. That will wake up the BUS and amps will jump up, then ramp back down again if problem is still not there. If not it will stay up above an amp or more, then start pulling fuses. This procedure takes some patience as some faults may not be there for long periods of time. You just have to keep trying it.

 

[MLee]

There have been reports of Alternators having an internal short when the key is off, thus pulling the batteries down. Some people have had the alternator checked and it was found to be OK, according to the place it was check at. but further checking as pointed out by Sag2, the short was found in the alternator.
Sag, could he just undo the alternator connections to check out this possibility?

Doing a search on here for this problem, I found a few as above, mentioned.

 

[sag2]

Yes you could disconnect it, but unless you can see the draw before you pull the wire you do not know it is broken or not.

 

[MLee]

sag2 thats what I'm saying see if it can be checked and then verify it, by a disconnecting it. Makes sence to me.

 

[jbz400]

So I had just a little bit of time to try some things. Last night I stated truck and let it run for a little bit. Pulled it in garage and undid neg post on both batteries. Checked volts on both batteries. Both were 12.95. Went out this morning and both were 12.55. I put my 10a multimeter on neg post and other on cable and am showing 1.30a

Sag2. I know you said put on pos side, but will the neg side work just as well.

So is 1.30a to much, and do I need to start pulling fuses.
Thanks

 

[p-Bar]

That's a fair amount of current. Neg side is fine start pulling fuses

 

[Prairie Dog]

Yes, that's way too much draw but I just have to ask you this, was the under hood light on?
Not trying to be a smart ars - I can see my self doing this!

Scott

 

[jbz400]

Prairie dog. Hood light was unplugged.


I'm going to start unplugging in the morning.

 

[jbz400]

So now I'm showing 2.54 milliampes. Does that sound like its normal.

 

[p-Bar]

Sure that's not amps? Still too high start pulling fuses

 

[jbz400]

Well I 99% sure it's milliamperes. I talked to the electrician at work and he explained it to me. So basically i put the meter on ma and it reads 2.54. I did this on the neg side. Pulled all fuses and still the same. I then tried the same thing but this time on the pos side on both batteries. I went as far as undoing the cable to starter and alternator. I got it down to I think 2places. On the driver side pos cable there is a lead going to the ECM that is reading 2.54 and that is with it disconected. Then that same reading at the fuse box where the cable goes into the box.

Some things throwing me off are when I'm doing the reading is that I can open the door or plug in the hood light and it stays at 2.54

 

[sag2]

You are doing something wrong if you are stuck at 2mA. Start on the 10 amp scale. As soon as you connect the leads with the cables off the battery it should be about 4 to 6 amps. Within 30 seconds or so it should go down to an amp or two, then within about another minute it should be below one amp, and stop at 10 to 50mA. Depending on your meter it may not read accurate enough on the 10 amp scale once it gets below 100 to 200mA. In that case if it is staying below .1 to .2A or 100 to 200mA you are still fine. At 200mA it would take several days (maybe up to 10) to kill the batteries.

 

[Bob4x4]

So now I'm showing 2.54 milliampes. Does that sound like its normal.

If the IOD is over thirty-five milliamperes, the problem must be found and corrected before replacing a battery. In most cases, the battery can be charged and returned to service after the excessive IOD condition has been corrected.

 

[LFalconer]

Sure that's not amps? Still too high start pulling fuses

sag2, I suggest removing the negative terminal of the battery for this test. The current flow is from neg to pos. Once the neg term is removed, there is no current path to neg in the event of a dropped or misplaced multimeter probe. I agree this method will work as well as the positive terminal removal, just safer given the instantaneous current flow possible from the parallel batteries. Also both pos or neg batt terminals must be removed to have this test read correctly.

Just a suggestion from 40+ years in the electronics field...

Luke