Solar Charge Controller - Power to Coach in Storage

[Highlander-cMac]

Wondering if anyone else has/had a similar situation. We are mainly weekenders. We keep our 321 RSTS in storage and I like to completely kill power to the coach when it's not being used. I installed a real battery cutoff switch for my LiFePO batteries this year. Yes, the factory battery cutoff only kills power to select components like slides, lights, etc. If you have a DC refrigerator, it likely remains powered with the factory battery cutoff switch off too. So again for this reason we installed a real battery cutoff switch in the battery compartment.

We noticed though that even with the coach powered down completely from the new battery cutoff, we still had 12v from the Solar MPPT. We power down the DC refrigerator from the front panel on the door. I also use the setting in the BMPro to turn off solar. This stops power to the coach. However, the next day when the sun rises, the coach powers up again and the DC refrigerator powers up, doors wide open to ventilate. Not a good situation to discover the refrigerator running for hours with the doors open. Or worse, if you have cloudy day you may not generate enough power from solar to drive 12v to the power the refrigerator. The refrigerator cycling on/off as the the sun maybe peaked out was again not a great situation.

In the BMPro there is a setting Solar setting for Default On at Power Up. That's the magic setting we needed to keep the solar from waking up everyday. So when we park the rig in storage, I make sure both Solar is off and Default On at Power Up is off.

I don't want nor need solar topping off my batteries when the coach is not used for a few weeks.

 

[Tadsher]

Just a reminder, the Solar MPPT must be connected to the battery before connecting the solar panels to the Solar MPPT. If you don't connect the Solar MPPT in that order you risk destroying the Solar MPPT and/or over volting the camper 12 volt system and causing huge expenses for you when you get the Campers low volt system repaired. The Solar MPPT uses the battery volts to set the MPPT's output voltage to the correct volts. The MPPT can output 12, 24, 36, and/or 48 volts.

 

[Tadsher]

Second comment. The lifepo4 battery will self discharge 3% or more per month and if the voltage in the battery is allowed to get below about 10.6 volts that very expensive battery will be irreparably damaged and need to be replaced. It is best to allow the MPPT to manage the battery's state of charge and not disconnect it.