battery drain

[RenegadeT]

My Ram wouldnt start this morning, nothing worked, it was like there was no batteries connected. Diagnosing it, I put the voltmeter on battery #1 (drivers side, connected to all the truck stuff, alt, grid heater, etc)...1.15V
The second battery is where I got surprised, I expected the same voltage, but got 12.14V. This battery has one cable grounded to the body and one to the other battery.
How is this possible? I thoguht both would read the same voltage. Both batteries are around 6months old Duralast Golds. My truck is far from perfect, I have some electrical gremlins. I have been pulling the IOD fuse for a while now, to prevent the battery drain, but forgot this time.

 

[burrellsjeep]

Can you measure voltage on the dead battery using the the frame or body for a ground and see if it reads 12+ voltage, it could be that the dead battery is not allowing a ground.

 

[transman731]

if one battery is good and the other dead, i would say there is an isolator somewhere. it may be that one side of the isolator is bad

 

[RenegadeT]

no isolator that I can see, both batteries have a separate ground cable from negative terminal to somewhere (I'll look closer, I think its the frame). The good battery positive terminal is linked directly to the positive terminal on the bad battery. The positive terminal on the bad battery not only has the cable to the other battery, it also has cables to the alternator, PDC, starter, grid heater, etc.

I'll look at the grounds, especially on that good battery. It doesnt make sense that they have different voltages when they are cabled together. Maybe the ground on the good battery is loose/bad, so basically its not even connected to the circuit.

 

[drkelly]

I'm pretty sure JT told me he had one of his Duralast Gold batteries take a fat on him during the first year. Azone replaced it under warranty I think.

 

[burrellsjeep]

My gold top Duralast died this year also, but it was six years old, and they still prorated the warranty, If its with in 3 years (No receipt necessary, Its listed in there system) of purchase they will replace it at no charge.

 

[braxton357]

Are you just probing the pos terminal to the neg terminal? Maybe you just didn't get a good reading on batt 1? What do you think is causing the batteries to drain in the first place? I had the same thinkg happening for a while and it turned out to be the glovebox light

 

[upnover]

I am thinking that if it's a diesel, and needs 24V to start it, and 12V to run everything else, then you probably do have an isolator. If it's a gasser then there should not be one unless the PO put one on. I had similar issues with my batteries in my hauler. Both tied together. My issue was corrosion on the cable ends.

 

[RenegadeT]

I'll have to charge the dead battery and see how its tests @AZ. If its bad, would I be OK replacing just one? I thought its best keeping them in pairs...I'm not even sure if AZ would replace both if one was bad.

I think my ignition switch is bad, but have been a huge slacker and done nothing. I put a meter betweenthe neg. terminal and cable, then started pulling fuses. When I go tto the IOD (igniion off draw) the drain stopped. So I've been pulling that fuse.

I double checked my readings, because it didnt make sense to me. I was just probing the terminals. The batteries were connected still while I was probing, I thought voltage should be the saem?

I'm no electrical geniuis, but I don't think its 24V...both batteries are hooked in parallel to double the CCA's at 12V. This truck is my '98 12-valve Cummins Ram 2500.

 

[drkelly]

I'll have to charge the dead battery and see how its tests @AZ. If its bad, would I be OK replacing just one? I thought its best keeping them in pairs...I'm not even sure if AZ would replace both if one was bad.

Call JT. I am pretty sure Azone replaced both of his batteries even though only one had taken a .

I think my ignition switch is bad, but have been a huge slacker and done nothing.

 

[braxton357]

You're right about the cummins being a 12v engine with parallel batts. Sounds like maybe you have a bad connection between the two causing the funny reading? What does the positive post at the fuse box say? And, the ign off circuit goes to a lot of things such as lights and the radio so don't be so sure it's the ign switch. And check the glovebox light to see if it's staying on, or any other interior light. Like I said, I chased the same shit for a while and it ended up being simple.

 

[RenegadeT]

You're right about the cummins being a 12v engine with parallel batts. Sounds like maybe you have a bad connection between the two causing the funny reading? What does the positive post at the fuse box say? And, the ign off circuit goes to a lot of things such as lights and the radio so don't be so sure it's the ign switch. And check the glovebox light to see if it's staying on, or any other interior light. Like I said, I chased the same shit for a while and it ended up being simple.

I know the IOD fuse goes to a lot...when I leave the fuse in, I can pull the key and still operate radio, wipers, HVAC fan...

Good stuff here, I'll dig in deeper tonight.

 

[Ron]

n/m

 

[RenegadeT]

started diagnosing tonight, found a "bad ground". The negative cable on the far battery was extremely loose, so it wasn't getting drained/charged.

n/m

thanks for the help

...check the glovebox light to see if it's staying on, or any other interior light. Like I said, I chased the same shit for a while and it ended up being simple.

holy crap, I checked the glovebox light...WTF is this contraption!? I think I kind of figured how it was supposed to work. The flat piece of plastic was laying in the glovebox, so obviously this concept has flaws. If I wiggled the light, it would go on.
I pulled the bulb, don't need no glovebox light. I still have electrical issues though, I doubt pulling the bulb will stop the drain.

 

[Ron]

thanks for the help

I started to explain the IOD bs and by the time I posted you had replied negating anything I had typed so I just deleted it...