Solar Panel for charging batteries

[BUB1988]

I have been looking for a few months and have not found any topics for just wanting to keep the batteries on my RV charged while in storage. I have 4-12V batteries, 2 chassis, 2 coach. I believe the only drain is phantom power, radio, carbon dioxide tester, etc. I at first thought I would need a 100W system until I downloaded the solar sizing spreadsheet and took out everything except the phantom load. It appears I only need a very small panel, maybe a 60W panel with a dual controller/charger. With the 4 batteries it seems like I should be able to get away with one that size. My plan is to mount the panel on the ladder and disconnect it when we use the RV. We live in Central Florida and use the RV at least one weekend a month.
Any help is appreciated.

[BUB1988]

Yo Heap64
I'll tell my better half you said we should be fine putting holes in the roof.:B
Can I have her call you:)
I did look at the flex panels from renogy, but was concerned they were to flimsy and could break easier.

Thanks for the reply

[Heap64]

Another option might be the newer lightweight flexible panels. Especially if you want to put them up and take them down. I was interested in them, but decided I didn't want to glue them to my roof after reading one review where similar ones had cupped some due to heat buildup when glued down.

Renogy Semi Flexible Kit

With these you could lay them up on the roof and possibly bungee cord them to your roof rack? Just an idea.

If the traditional panels are installed with the right roof sealant you should have no issues with leaks. I put 20 holes in my roof, you only need 4 😉

[BUB1988]

Thanks for all of the replies and I will try and answer all of the questions.
Living in Central Florida I don't think we have to worry about days of overcast:)
We have had problems with roof leaks, so the better half has said 'NO' holes in the roof. So I opted for ladder install.
The parasitic draw should be correct, but only time will tell.
Currently I unhook all of the negative cables from the batteries, which is a real pain in my neck. I actual park the RV in our very nice neighbors side yard and is the reason for no available power. We are unable to get the RV into our backyard and the only deed restriction we have is: No RV's in side or front yard, bummer.

I have gotten a quote from Renogy for their 100W panel, wiring, dual charger/controller, and cabling. I went with 12 gauge due to the short runs I need for the wiring.

The DelTran seems a little small and I would worry about dead batteries and the price is only $100 less than the Renogy kit. But, it is really portable that would be nicer, than moving the panel up and down the ladder.

With all your help I at least feel good about the sizing. All of the looking I have been doing all I could find was boondocking and long term dry camping usage. I was getting pretty frustrated.
Thanks again to all.

[D_E_Bishop]

Here is what I have, CLICKY

The DelTran 120 volt input battery tender used to be the way to keep a fully charged disconnected battery fresh and happy. Now they have their solar equivalent and it gets "poo poo'ed" by most folks.

Don't know why, all I know is mine keeps the batteries up to snuff.

Mine is hooked up to the house batteries, I have nothing going to the chassis battery. I am at storage at least once a month to exercise the Onan and figure if the chassis battery goes down, I can start from the house batteries.

I disconnect the panel and store it in the OEM box in my garage if we are going on the road. If I am taking the RV home to work on it, I use the converter. I just installed a new pedestal box in my garage that has a 20 amp panel mounted outlet, 30 amp panel mounted RV outlet and a standard "F" connector in case I want the cable hooked up too.

The DelTran fits across one half of the windshield and rests on the dash. The only thing I would change is that the charge indicator light is only visible thru the windshield. I can't see it when the sun shines on the panel, it's too high to see, very directional and very dim. I would like a indicator on the back so I can see it.

[austinjenna]

My setup is a 120 watt panel mounted on the roof just for keeping my batteries topped off while my fiver is in the storage lot. I also put in a battery cutoff switch to take care of the phantom loads. On the last fiver I would take the batteries out and hook them up at home to a battery minder. My new fiver has the batteries up front so kind of a pain in the back to put in and remove. I was just trying to make it simpler for me and it has worked out great.

[Heap64]

Why wouldn't you want to just mount it and forget it is there? Renogy has some very inexpensive 100w kits including a basic controller that should take care of your needs. I have 5 of their 100w panels and I'm very happy with their construction.

[mena661]

Price between 60 and 100 is minimal. Go with the 100.

[KendallP]

Do you need to keep the banks connected to the coach & chassis?

If your parasitic draw audit is accurate, then go with that. Sometimes those draws can be pretty high.

Otherwise, 1 60W panel should even be a little overkill... unless the location is subject to many continual days of overcast skies.

[RoyB]

If you start out with a fully charged battery setup only a small wattage panel should be all you need. If you ever behind the charge curve of course the small wattage panel will not be of much use for you...

Roy ken