1992 Dodge 350 Roadtrek

[paisleyjr]

My engine battery drains if I don't disconnect the positive battery terminal cable. I had spent a fortune replacing the cabins generator and batteries. 
Does anyone have any ideas or a similar situation? How can I fix this issue?

 

[B and C]

How old is the battery and how long does it sit? A cheap two year battery may already be starting to go.

 

[paisleyjr]

If it sits for a week it dies....I bought s new battery in February...I charged the old battery at autozone several times before it stopped accepting the charge. I've had 5 batteries in 2 1/2 years. Also if I switch the refrigerator on electric and drive it wipes out my cabins power and I have to take it in to be charged. So I do not use it anymore. I'm afraid I've got an electrical nightmare.

 

[B and C]

I only switch the fridge to 12V power while driving as the alternator charges the house batteries. 

The only way to chase a battery drain is with a multimer (better yet, ammeter).  Disconnect the battery positive cable and place the positive lead on the battery and the negative on the battery cable.  Start pulling fuses until the voltage drops.  You found the circuit.  The fun begins with chasing the circuit.  The fuse panel should be labeled with what the fuse protects.  Disconnect wires at those devices one at a time until the voltage goes away again.  Remember that your radio probably has a very small drain all the time to keep the clock on time and radio presets, etc.  I would pull the radio fuse(s) first.  Mine has two.  This is where an ammeter shines as you can see a bigger load drop off while the small radio load is still there.  After you get that one circuit repaired, replace fuses one at a time to see if there is another parasitic load still present.

For this type of problem, a Dodge forum would be a better place to get this kind of help as this is specific to the vehicle and not what Roadtrek added (probably).


You kinda stated that your engine alternator does not charge your house battery(ies).  This leads me to believe that your battery isolator is bad, disconnected or not wired correctly.  I would start by chasing the engine battery positive cable to this isolator to find it and then see if any voltage is flowing at the isolator with the engine off and on with each cable disconnected.

 

[paisleyjr]

Thank you for the advice....I will try this.