2021 3791RD Battery Storage Question 4 Batteries

[Bryan T]

We recently bought a new 2021 3791RD and had the dealer add an additional 2 batteries for a total of 4. We have acquired an indoor storage space here in Minnesota, that I believe has a 20 amp receptacle but when I dropped the camper off it wasn't working. I saw an electrician there at the time so I'm assuming he had the breaker turned off because he was working on it. I'm heading there today to check. A couple questions:

Would you plug in the shore power cable from the camper to the outlet and call it good? If so, would you leave both disconnects off (the dial one in the battery compartment showing green and the red disconnect key in the water connections compartment left with the key in like for normal use and not "disconnected")

OR

Would you engage both disconnects and hook a trickle charger to the battery bank? And if you did that, how would you connect the charger? Would it be connected to the negative on the 1st battery in the bank and the positive on the battery at the other end (4th battery)? I really don't know how the 4 batteries are connected, whether they are all 4 in parallel together in the same bank or if it's 2 banks of 2 batteries each or what. I guess I never looked at the batteries closely before I put it in storage. IF I went this route might I need multiple chargers?

If the electric does not work from that receptacle in the storage area, would I need to install a disconnect on the negative terminal of just one of the batteries in the bank or all 4 of them?

Sorry to ask a question that may have been answered already somewhere here, but I did take the time to do a search and really couldn't get all those questions answered and don't know if having 4 batteries makes a difference in process for winter storage. Thanks in advance for any help!

[AZ Traveler]

Bryan,

My recommendation is to full charge your battery bank and then disconnect them by unhooking the negative terminal on the battery that is connected to ground.

Your 4 batteries should be connected in parallel so you may have more than one battery connected to ground.

Several folks leave the batteries on a charger without an issue. The potential downside of that answer is the power going off or the charger overcharging and boiling batteries.

[twindman]

I am thinking you have a residential frig - hence the 2nd battery. If so you would have to disconnect both battery banks from ground. If the battery is fully charged they can withstand very cold temps but I think I saw recently at 50% they can freeze at zero. here in AZ I don't worry about freezing and mine are fine after 6-8 months of sitting in storage.

[rames14]

You are fine hooking it to power and leaving the disconnects “on”, at least in the convenience center. That shuts off your charger if it’s off. Your charger will not over charge your batteries on the newer units. As Zack said, you can also remove your ground to the RV if you are fully charged. Either way will work.

Since it wasn’t working, I would err on the side of caution and disconnect the ground. We lost 4 six volt batteries because the dealer doing service let the batteries discharge and freeze.

[mlh]

I leave my camper hook to shore power and never disconnect the batteries. I had 2 6 volt batteries and had to add water about every 2 years. The thing you don’t wont to do is let them go dead. That will ruin them.
Lynwood

[Carl n Susan]

The easiest and safest solution is to disconnect the ground of the battery (after it has been fully charged).

Alternatively, plug it in to the 20 amp circuit and make sure the Red disconnect switch in the convenience center is in the position where it *CAN NOT* be removed. That ensures the converter is charging your batteries. The Montana converter is a 4-stage charger and will not over charge your batteries. The only downside if is the 20 amp power goes out for an extended period, the parasitic electrical draws (even if the Red Disconnect switch is removed it doesn't stop current draws) will drain, and ruin, the batteries.

I store my RV at home and with power always on. But I know if the power goes out and I have to take steps to disconnect the batteries. Like MLH, I add water once a year on my flooded cell six 6V Golf Cart batteries.

[Bryan T]

Thanks to all who replied! I'm going to head there today, top off the charge with my generator if the electric isn't working in the storage unit, and unhook the negative terminals with grounds.

This group is awesome and the help is much appreciated!

[RMcNeal]

To make it easier in the future, you may want to install a disconnect switch on the negative terminal of your last battery. Here's the one I put on mine...
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1