Solar and Lithium batteries going dead

[HDLimitedGuy]

Last October we took delivery or a 2024 3901RK Legacy with 400 watt solar.

10 days later, we left MN to spend the winter in Fort Myers. The 1st night we spent in IA. It was 11:00 PM and 22 degrees. We ran the furnace, fresh water tank heater, 12v fridge and freezer, water pump, and slides. Everything still worked in the morning.

We drove all day. That evening at sunset, everything in and on our camper went dead. No lights of any kind and no slides worked. It was 32 degrees, that night so we slept in the pickup for heat. That next morning I spent 2 1/2 hours on the phone with Montana. They helped me find that little screwdriver switch on the blue box from the solar panels, and changed it from #2 to #7. As soon as I did that, the solar system started to charge, and the lights came back on. Our dealer upgraded our batteries and didn't know about the switch on the blue box. Thought my problem was fixed.

That evening (3rd night) night at sunset our camper went dead again while driving down the intestate. After 3 miles of no lights we hit the 1st exit and found a Walmart. As soon as the sunlight hit the solar panels the lights on the camper came back to life. Same thing happened the 4th night. Been hooked up to shore power every since.

Montana sent out a mobile tech. He found the solar panels where working properly. A few days ago I had a Retired Electrical Engineer here in the RV park check the batteries. They are good.

3 days ago I unplugged from shore power and at sunset the camper once again went dead. I read a few articles here, found one about a switch next to the fuse panel. Mine looks similar but not the same.

Sorry this is long winded, but I know how everyone needs the details to help solve our issues. Any great ideas?

Thanks in advance!!!

Tom from Minnesota
hdlimitedguy@gmail.com

[Foldbak]

Welcome to the MOC. Did they install lithium? How many amp hours? Do you have a residential fridge? How many hours of sun?
If lithium, they shut off charging at 32 degrees to prevent damaging the batteries. Do they have built in heaters? If not they the BMS will shut off charging at 32 degrees. If they do, the heaters may be turned off.

Do you have the Victron app? If not then you need to download it. It will allow you to set the charger to the required settings. It will also allow you to view your solar production. See the attached pictures.

[HDLimitedGuy]

Thanks Tony,

Yes, my dealer installed the batteries.
We have a 12 volt fridge and freezer.
Perfect bright sunny days driving to FL everyday
Only one night was below 32 degrees and that was the first night.
Yes, Montana had me download the Victron app had me send them some screen shots.

3 days ago I unplugged from shore power at 10:00 am, and the camper was totally dead at sunset. Sunny and 76 degrees. Had been plugged in since November 4th.

Could it be a bad ground? Is the shore power grounded separately?

Tom

[Our3231CK]

Does anyone know of a tutorial on what all the data means when looking at it? I haven't been able to find anything for advertisements for it

[Foldbak]

Originally Posted by HDLimitedGuy

Thanks Tony,

Yes, my dealer installed the batteries.
We have a 12 volt fridge and freezer.
Perfect bright sunny days driving to FL everyday
Only one night was below 32 degrees and that was the first night.
Yes, Montana had me download the Victron app had me send them some screen shots.

3 days ago I unplugged from shore power at 10:00 am, and the camper was totally dead at sunset. Sunny and 76 degrees. Had been plugged in since November 4th. Some batteries have built in battery management systems, some don't.

Could it be a bad ground? Is the shore power grounded separately?

Tom

If the batteries are dead you have a problem. You need to verify that your solar is charging. Send a screen shot of the Victron solar history. Should look like this. Also a picture of your battery charge history. A couple of important questions you didn't answer, what brand battery and how many amp hours?

[HDLimitedGuy]

I have 2 Dragonfly batteries, model HFT0110012H

[HDLimitedGuy]

Not sure how to add my screenshots?

[Foldbak]

Originally Posted by HDLimitedGuy

I have 2 Dragonfly batteries, model HFT0110012H

They have an internal heater. So cold charging isn't a problem. I'd call Dragonfly and talk to them. 775-622-3448 They can walk you through troubleshooting.

[Bill and Lisa]

Not sure the brand of fridge you have but on our furrion, there is an "off Grid" mode that uses less energy when you are boondocking/not connected to 120V power. It makes a big difference in power usage

[Pburger]

What brand of inverter do you have. When I got my new Montana I found that the Magnum inverter didn’t play nicely with lithium batteries. Directly says so in appendix A of the documentation. I negotiated that I wanted my 3-300 ah batteries from my old trailer. Turns out I had to replace the Magnum with a Victron inverter.

[Foldbak]

Originally Posted by Pburger

What brand of inverter do you have. When I got my new Montana I found that the Magnum inverter didn’t play nicely with lithium batteries. Directly says so in appendix A of the documentation. I negotiated that I wanted my 3-300 ah batteries from my old trailer. Turns out I had to replace the Magnum with a Victron inverter.

Humm...that's interesting...I have a Magnum inverter with lithium, works great. I read the manual and it says nothing about battery type. And welcome to the forums. Found this online. Not sure what Magnum you had.

Magnum Energy brand pure sine wave inverter/chargers now provide greater ease of use for installers and end users with built-in battery presets for Lithium Iron Phosphate (LFP) battery types. The LFP profile joins existing profiles for Gel, Flooded, AGM1, and AGM2 battery presets.

[HDLimitedGuy]

After a bunch of ideas and testing, it came down to a bad ground on my pickup. I never would have thought that it would be the truck. But it makes sense.

[Ozzie66]

Thanks for the update. Where and how did you find the bad ground on your truck. I have similar problem with our 2024 3123RL.

[HDLimitedGuy]

I had to replace the 7 way / 4 way oval shaped plug in the rear bumper. Simple fix for $40. Was positive it had to be the camper. But a bad/no ground can cause a lot off goofy issues.