smkettner wrote:
I would not even buy that for storage use only.
Get 80+ watts and a decent controller for best results.
...
FWIW, we have a 5W panel on the roof of our old mh and it is sufficient to keep 4 batteries charged over the from Sept to April in Ottawa, Ontario, Canada (i.e. there's snow from about Nov to Mar and while the wind will blow it off and sun melt it off, the panel is most certainly covered some days not to mention very short days).
You really don't need much to maintain batteries in storage if everything is off.
I use something similar to what the OP listed on our DP (6 batteries) which is stored in Florida and haven't had a problem with dead batteries with that one either (without the panel, I think my house batteries are low after about 2-3 weeks). However you should be able to get a much better price than that one (I don't think I paid more than $30 or $40).