Isolator’s good still no house charge

[racefan]

2017 Sprinter 3500 Thor Freedom Elite FE24. The Sprinter isn’t charging the house battery.
I got to the battery isolator today and here’s what I found. House battery voltage is 12.3 unplugged from shore power with the store/use switch off 12.1 with switch in the use (on) position, this was with the engine running at idle (I waited 30 seconds before testing)
Next was the chassis battery. 13.9 volts engine running at idle. (Didn’t check it with the engine off)
Last was battery isolator. 12.6 volts engine off. 13.9 volts engine at idle. The blue wire on the isolator read 13.5 engine running 0 volts engine off.
Also the fuse holder on the chassis battery checked out good (same voltage on each side of it (30 amp blade fuse)
So if the isolator is good why is the house battery only reading 12.1/12.3 volts?

[16ACE27]

I don't think Mercedes allows connecting another battery system to the chassis system? Maybe the other way around?

In any case, the "Isolator" you refer to is just a relay and controlled by other circuitry; either a BIRD or IRD. See this thread:

https://www.thorforums.com/forums/f8...ues-30501.html

[racefan]

Mercedes won’t allow the house to charge the chassis battery but Sprinter should charge the house battery.

[racefan]

I fixed my problem. With some further testing and some help from someone smarter than me (pretty easy to find) I replaced the isolator with a Cole Hersee 24213 and the house battery is charging from the Sprinter now👍

[16ACE27]

Originally Posted by racefan

I fixed my problem. With some further testing and some help from someone smarter than me (pretty easy to find) I replaced the isolator with a Cole Hersee 24213 and the house battery is charging from the Sprinter now👍

But you said it was good? Can't help you with bad information.

[racefan]

Yes it was totally my fault, I’m not trying to suggest that any help wasn’t useful

[Pillbox]

Sounds like a normally closed isolator instead of normally open. Just a guess.
Terry

[racefan]

I cut the old one open and this is what the contacts looked like. No wonder it may have been a little hit and miss

[Pillbox]

My bad normally not worky type. I forget adout those…..
Terry