2nd alternator not charging house battery

[Mike R1]

I have a 2024 Thor Tranquility
House battery does not charge while engine is running

House battery does charge with shore power

Any help would be appreciated

 

[16ACE27]

We get reports of this on the Class Bs with the UHG about weekly - soooo - many threads. Mark may be along shortly to help but, in the meantime:

What batteries do you have?

 

[Mike R1]

I don’t know. It is very cold in OH, could that affect the 2nd alternator and charging? Shore power changes the lithium fine

 

[16ACE27]

I don’t know. It is very cold in OH, could that affect the 2nd alternator and charging? Shore power changes the lithium fine

Depends on what batteries you have. Unless they are heated, LFP batteries won't charge in freezing temperatures,

 

[Mark54]

I don’t know. It is very cold in OH, could that affect the 2nd alternator and charging? Shore power changes the lithium fine

Check MRBF fuses at B+ buss bar from UGH feed and atop each battery B+ post-
Also the UHG will not charge if battery mgmt system (BMS) has shut down due to cold temps- anything below 32° will do that- so if batteries are not heated, then no charge until they get above that temp. And if they are heated- same thing- gotta get up above 32°.
Also check regulator to be sure it's wired correctly. Mine had reverse polarity on the battery voltage sensor at the regualtor- was reversed. Temp sender needs to be checked to make sure it's on the regulator correctly as well. You need to find the batteries and let us know what you have- mine had ReLion RB100LT batteries (low temp, heated) now replaced with larger unheated LFP's and moved inside the coach.
Your master battery switch needs to be ON (or "USE") for UHG to charge. Shoreline will charge regardless of that.

 

[Goomba-THOR]

I have a 2024 Thor Tranquility
House battery does not charge while engine is running

House battery does charge with shore power

Any help would be appreciated

Mike, I have the same exact issue on my 2023 Sanctuary. I've had it in to 5 different service centers for warranty repair of this issue for almost half of the year and a half I've owned it. The best we've been able to do is find out that the 15A fuse that's just before the battery blows. When we replace it everything works fine for a couple of days and then the fuse blows again. Thor is trying to help, but hasn't figured it out yet. Right now it looks like we're going to have to start replacing parts (like the whole wiring harness) until we find something that works. It's definitely not cold temps as this happens in all weather conditions. If you figure anything out, please let us know. Joe

 

[pcgeek]

Could be a lot simpler - we just picked up a 2024 Sanctuary 24C and from-factory, the mastervolt controller configuration for the alternator was set for "standby".

If you scroll to the 3rd panel in the mastervolt control screen, check the alternator setting. Tapping the one on the right lets you change the setting to "active" which then started charging the batteries off of the alternator.

 

[Mark54]

Could be a lot simpler - we just picked up a 2024 Sanctuary 24C and from-factory, the mastervolt controller configuration for the alternator was set for "standby".

If you scroll to the 3rd panel in the mastervolt control screen, check the alternator setting. Tapping the one on the right lets you change the setting to "active" which then started charging the batteries off of the alternator.

Interesting! I have no issues, but never knew that about the MV display- can you post a picture of that?
(I'm SO glad Thor explains all these nuances... NOT.)
update- tried to find manual for 'Smart remote' only to not find anything!! I'll have to play with it when I get my rig back online...

 

[pcgeek]

On the 3rd panel of display settings, from the factory it looked like this:

If you tap on the right-side override box you can change it:

When it is enabled, both show "activated" (at least on mine):

I have no idea why there are separate state and override panels but mine wouldn't charge unless I set the override to activated (maybe there's supposed to be some automatic switchover logic?). I wondered why the battery level had dropped to 75% after I had idled with the AC running for a couple of hours, expecting it to have charged. Once I switched the toggle it finally started charging.

 

[Mark54]

On the 3rd panel of display settings, from the factory it looked like this:

View attachment 981394

If you tap on the right-side override box you can change it:

View attachment 981395

When it is enabled, both show "activated" (at least on mine):

View attachment 981396

I have no idea why there are separate state and override panels but mine wouldn't charge unless I set the override to activated (maybe there's supposed to be some automatic switchover logic?). I wondered why the battery level had dropped to 75% after I had idled with the AC running for a couple of hours, expecting it to have charged. Once I switched the toggle it finally started charging.

Nice- thanks!