Interested in a small solar solution to keep 2 24 group batteries topped off while the RV is in storage. Right now I disconnect and haul the batteries to the house and charge them monthly. The RV is in full sun all day long in central FL. I'm guessing that 10-20 watts might be enough??? Of course the more I research solar, the more the plan grows. When these batteries die I will go up in size to at least 2 group 27 or possibly 2 golf cart batteries if they fit in the compartment.

How long does the trailer sit unused ?Mine sits for about 3 months.I throw the disc. switch in the coach and just let the E450 sit.I run the truck and gen every 30 days or so for about an half hour.That should be as effective as your method, only you don't have to remove the batteries.If you have AGM batteries, they can sit disconnected in place without attention for 3 months with no problem.....IF they are fully charged going in.

Sitting varies from 2 weeks to 2 months. After 1 week of sitting the batteries are down the 12.1 volts. There is no disconnect switch, which I found unusual.

It sounds as though you need the solar to not only keep up with battery self-discharge, but also powering parasitic loads in the RV. If your battery is running down to 40 or 50 percent capacity after a week of sitting, that's maybe 40 Ah of charge gone in a week, perhaps a little more, or about 6 Ah per day. 10W would definitely not be enough, and 20W likely also would not. I'd suggest somewhere around 50W minimum...but I'm very far from an expert on these things.

I have 4 golf cart batteries that I connect to a 30-watt solar panel and an appropriate charge controller. The trailer sits in storage for 6+ months and the batteries stay fully charged. I have a disconnect switch, but you can accomplish the same thing by just removing the positive or negative lead from your battery bank.

Solar for keeping batteries topped off. | Good Sam Community

33 Replies

DrewE
Explorer II
Dec 28, 2016
It sounds as though you need the solar to not only keep up with battery self-discharge, but also powering parasitic loads in the RV. If your battery is running down to 40 or 50 percent capacity after a week of sitting, that's maybe 40 Ah of charge gone in a week, perhaps a little more, or about 6 Ah per day. 10W would definitely not be enough, and 20W likely also would not. I'd suggest somewhere around 50W minimum...but I'm very far from an expert on these things.
Twain
Explorer
Dec 28, 2016
Sitting varies from 2 weeks to 2 months. After 1 week of sitting the batteries are down the 12.1 volts. There is no disconnect switch, which I found unusual.
Sam_Spade
Explorer
Dec 28, 2016
How long does the trailer sit unused ?

Mine sits for about 3 months.
I throw the disc. switch in the coach and just let the E450 sit.
I run the truck and gen every 30 days or so for about an half hour.
That should be as effective as your method, only you don't have to remove the batteries.

If you have AGM batteries, they can sit disconnected in place without attention for 3 months with no problem.....IF they are fully charged going in.

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Solar for keeping batteries topped off.

33 Replies

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