Battery isolator/separator breakdown

[RT170P]

Aloha all: 

I have a 2007 Roadtrek 170 (MJ 🙂), and I’ve recently encountered a not seen before problem. The vehicle battery stopped charging (well, wasn’t holding a charge), and as it was a few years old, I replaced it…still didn’t hold a charge, but the house battery was still charging while MJ was running. We replaced the alternator, but still didn’t charge MJ battery, so we put the old alternator back in then disconnected the house and vehicle battery from the battery isolator/separator and hooked the vehicle battery directly to the alternator, as it would be in a regular vehicle.

Result: vehicle battery charges fine, house battery does not charge while MJ is running (but still charges with the generator).

This leads me to believe that my battery  isolator/separator has crapped out. 👎🏼 Does that sound feasible/has anyone encountered this before? It just happened so I haven’t had a chance to look for a replacement isolator/separator. 

Any feedback would be VERY much appreciated. 

Mahalo

Mike

[RT170P]

Hello all:

A quick question; my alternator is rated at 145 amps, but can I use a 130 amp isolator? If I did, would it be dangerous, or just not charge as much?

mahalo

Mike

[Grit_dog]

I believe you have very likely diagnosed it correctly. 
To verify, I’d find your separator and re-create the old scenario and check power is or isn’t goin where it should. 
But it sounds like you’re right. 
if looking for a replacement, I have had a Blue Sea ACR in our boat since about 2010. It still works great. 

[RT170P]

Thanks Grit-dog. The person assisting me was an actual mechanic (my level of knowledge is looking for the giant "on/off" button 😁), and he tested everything, including every fuse in the near-by box... definitely the separator. And thanks for the replacement suggestions; I'll dig further to see what is recommended specifically for the Roadtrek, but what I've seen so far, a good, standard separator will work.

[SuperBus]

As with any component, it can certainly have a failure of some type.  Depending on the make and model of the isolator, I'd check with the manufacturer for troubleshooting instructions.  Intellitec has good guides on it's website, for example, if that happens to be who made yours.

[RT170P]

Thanks SuperBus, I had never encountered Intellitec before...great suggestions. 🤙