Boondocking & Battery Life

Lets get the easy part out of the way: the worst NuCamp battery combination was the "stock" 80 amp battery (with 40 amp hours "usable") and the two way fridge. Back when the fridges were the "3 way" fridge, where the fridge on propane "sipped" amp hours, that battery and a simple solar setup was pretty much easy to deal with. But: the 2 way fridges require more battery…or maybe a lot of good solar. The 2 way fridge can use 25-35 amp hours per day. The solar during the day can support the battery as the fridge cycles on and off…but then then sun goes down. The fridge will continue to draw power until the sun comes up the next morning. So now, the solar has to recharge the battery, and at the same time the fridge is running (it does cycle on and off). This constant race between solar input trying to recover the battery power used up overnight, while the fridge is still running, and the fan needs to be on….you get the idea. It is a constant race to try to keep the battery charged, and the 40 amp hours of "usable" power from your 80 amp hour battery is simply not enough.

Luckily for RV owners, lithium batteries showed up with much larger amp hour capacities, and portable solar became easier for everyone. 2 way fridges are much easier to manage with even a 100 amp hour lithium (about 90 amp hours available) and portable solar. There is much more of a cushion with 90 amp hours of battery capacity compared to 40.

For your battery: how old is it? If it is the original battery from 2022, it may simply have reached its end of life. The next thing to look over would be the History page of your solar controller. This will tell you what the status of your battery (roughly) when you pulled into your campsite and found your battery not working.

On your Victron readouts: The voltages you are showing in the screen shots are all "positive" values, so this appears to be the status of the battery while it was being charged. The battery voltage (13.6 or so) is also what any lead acid batteries will show while being charged. You are on the right track with getting readouts of power usage by using the Victron. The way to do this would be to turn the "Charger off" on the Settings page of the App. (It is just a toggle saying "Charger enabled". Just toggle that switch off.) With no charging coming in, turn everything off in the trailer (battery switch on). You will see in the "Current" section of the battery status a negative voltage number. That negative number is your "parasitic drain", the background power use that cannot be turned off: things like the carbon monoxide detector, the Jensens, etc. On my 2017, that draw is about -0.24, or about 1/4 of an amp per hour…about 6 amp hours per day. Now, with the solar off, and knowing the "base" draw of your trailer, you can turn those devices on one at a time and get a good handle of how much power the use. (You would subtract the base draw from each voltage number you get for each device).

Things to remember: your two way fridge (and I hope we are talking about a 2 way fridge!) will use more power when trying to cool down a warm fridge. It will cycle on and off when the compressor calls for cooling. So, your fridge will not always use the number you see when the compressor is running all the time. "Generally", your amp hour use for the fridge will be 50 percent of the number you see on your Victron, since the fridge might run 50 percent of the time. The pump will only draw power when the pump is actually pumping.

The other thing you will notice is the drop in the voltage number on your lead acid battery. I mentioned how the 13.6 voltage number indicates a lead acid battery being charged. Depending on the amount of draw from the battery as you test, you will see that battery voltage drop pretty dramatically. Both of these voltage readings , charged and being discharged, are "false capacity" readings of a lead acid battery. The only way to get a stable battery readout for a lead acid battery would be with the trailer battery switch off, and no power coming into the trailer.

So, good for you for working on this, it will be a very useful project. Tell us how old the battery is. Have a look at the history page for the day or so when you pulled into the campsite.