AGM battery replace - Roadtrek zion

[Goozer]

Hey folks.

I recently installed a new AGM battery (house battery) into my 2018 Roadtrek Zion. It works, but when i checked this morning, the voltage was 12.03 and the battery was at 74% (vs 92% the night before). Battery was disconnected. The circuitry/settings should be the same as before, but there's clearly something drawing off the battery. any ideas?

Thanks a bunch

[mumkin]

The first possible culprit to check is the inverter. Was the inverter accidentally left on after the installation?

Make sure that the switch on the inverter itself is off, as it should always be off.

[Goozer]

Thanks mumkin. I can confirm the inverter was (and is) off. The solar and engine will charge the battery, but I don't know what could be drawing from it.

[GeorgeRa]

Is battery fully disconnected? Check if solar charge controller is not directly connected to the battery bypassing the battery disconnect switch or relay. Solar charge controller will drain battery if solar panels have no light.

[Goozer]

Thanks George.

Yes, the battery is fully disconnected. From what I can assess, the solar charge controller is the only thing that is drawing a load off the battery. That said, I wouldn't expect it to drop significantly overnight (from full to 75%).

It's a challenge to diagnose, but I'll keep testing. Again, really appreciate the feedback.

[mumkin]

I can confirm that on Roadtreks the solar is always charging. I had their set-up on two rigs, and never shut off, and I never had to touch them.

If your battery disconnect is working... there is really nothing but the inverter that could be pulling power that I know of. (I'm not techy or mechanical... just based on how things worked for me on my two)

Was the battery fully charged when you got that high reading the night before... or was there still a surface charge from the solar? I always did my reading in the middle of the night when only the fridge was drawing.

[GeorgeRa]

Originally Posted by mumkin

I can confirm that on Roadtreks the solar is always charging. I had their set-up on two rigs, and never shut off, and I never had to touch them.

If your battery disconnect is working... there is really nothing but the inverter that could be pulling power that I know of. (I'm not techy or mechanical... just based on how things worked for me on my two)

Was the battery fully charged when you got that high reading the night before... or was there still a surface charge from the solar? I always did my reading in the middle of the night when only the fridge was drawing.

My Morningstar charge controller drains in idle about 250mA, so in 24 hrs. it would be about 6Ah or 42Ah in a week. I left my charge controller once for longer time at completely drain my batteries.

[mumkin]

Originally Posted by GeorgeRa

My Morningstar charge controller drains in idle about 250mA, so in 24 hrs. it would be about 6Ah or 42Ah in a week. I left my charge controller once for longer time at completely drain my batteries.

I think it means that there is no way his solar controller could have fully discharged his battery overnight??

But then, I just noted that his original post said that 12.03 was "74%" but 12.03 is less than 50%. I never think in percentages, but in actual voltage reading. So, perhaps there is a typo and it is actually 12.3. In that case, I would just do a few days of testing.

[D&C ERV2]

My 2018 Road Trek Adventurous only disconnects the house 12v with the battery disconnect switch. The solar chargers and the lithium batteries stay connected. I do have the ability to turn off charge and discharge on each of my lithium batteries but cannot disconnect the solar chargers. Given this type of system connection the AGM will be drained by the 2 solar chargers if not in daylight and if the lithium batteries are on and depleted, they will be trying to charge using AGM power.