89 Dodge xplorer coach battery charge

[Dopefish]

Hello, I have an 89 Dodge xplorer camper van, new battery and this new deep cycle coach battery purchased in 2018, I also purchased a new sure power 120 amp 1202D Isolator in 2018, back in 2014 I purchased this alternator.

I took a trip in 2019 with the refrigerator set on 12v but when I got to my destination the coach battery was dead, I just tested the coach battery terminals with the engine on idle and it reads 14.4v, I did this both with the fridge on and off with the same results, I also tested directly on the isolator with the engine idling and it also read 14.4v, I tested every fuse I could find both in the glove box and in the rear across from the restroom and they all are good fuses, hopefully someone here can help me, I'm wondering if I maybe got the wrong alternator or just got a bad deep cycle battery or something.

Thank you

[hbn7hj]

You need to test the voltage at the refrigerator. If it is 13.7 or above with the refrigerator running on DC and engine running you have no problem. If it does not measure above 13.7 or so you will need to find out why.

From your post I expect it to measure 12.6 or less.

[Dopefish]

interesting, I tested from the fridge with the engine running and the fridge on DC and it reads 14.1v, there was definitely nothing else running when I was driving except maybe the stereo. I have no idea what the issue might be other than possibly a faulty battery, I always take my batteries out of the van and put them in a closet during the winter to keep them warm, the deep cycle battery was totally dead this year however I can't remember if I put it away dead or not, I don't usually do that.

[Dopefish]

Originally Posted by hbn7hj

You need to test the voltage at the refrigerator. If it is 13.7 or above with the refrigerator running on DC and engine running you have no problem. If it does not measure above 13.7 or so you will need to find out why.

From your post I expect it to measure 12.6 or less.

So I poked around with the refrigerator and did some wire tracing, I found a 2nd 12v wire not connected to anything, I tested it and no power to it, did some wire checks and found that one of the floor walk lights wire was pulled out, I reattached it and the light came back on and did a connectivity test to the new wire by the fridge and it was a match, I then traced it back to the center lug on the isolator marked "refrigerator", then I traced the other wire that was connected to the fridge and it had constant nonstop power from the coach battery even with the engine off, I swapped the wires around and capped the coach wire off.

I'm going to assume this was probably the issue for killing the coach battery?

Thank you.

[hbn7hj]

Originally Posted by Dopefish

I'm going to assume this was probably the issue for killing the coach battery?

Thank you.

Dunno. Tying the refrigerator to the center post of an isolator is certainly a unique way of powering the fridge. Power there should go to zero with engine off.

Does fridge work on propane with engine off?

[hbn7hj]

You would be a happier fellow if you put in a battery monitor.

There are several brands but this is one:
Battery Monitors - Bogart Engineering

[Dopefish]

Originally Posted by hbn7hj

Dunno. Tying the refrigerator to the center post of an isolator is certainly a unique way of powering the fridge. Power there should go to zero with engine off.

Does fridge work on propane with engine off?

Yup, propane works as its supposed to and now the fridge has no power with the engine off and has full power with the engine running, if i remember correctly my dad had a small cooling fan in with the old fridge (why im not sure) so that might explain the other wire connected to the coach battery if he ran it with the propane, the old fridge might have go too hot or just worried my dad if he wired it like that.

[Dopefish]

Originally Posted by hbn7hj

You would be a happier fellow if you put in a battery monitor.

yea, that's on my list, it has the stock one now with a light bar but i don't think its very accurate, usually the lights just flicker.

Thanks for your help!