solar power battery maintenence

pianotuna wrote:
Hi,

For 9 years I had 30 watts of solar panels with a controller maintaining 210 amp-hours of battery bank.

If you wish to equalize the bare minimum is 60 watts per 100 amp-hours of bank.

With panels costing as low as 67 cents per watt, it may be cheaper to get 100 watts and a controller, rather than buying the "package" you suggest which has but 15 watts.

D.E.Bishop wrote:
Delray now has a solar Battery Tender, 15 watts and three step charging. Basically the same as the 120volt model but no need to plug it. I have one and it works fine if I start with charged batteries, but if not fully charged, it takes a long time to restore the charge.

It seems that the solar police insist on 100watts and a controller. That's okay too but if all you want to do is keep the batteries topped off, not necessary. Look into the 15watt tender at about $98.00 on line. By the way, my storage yard is 45 miles away and I don't have power or water there, just like most National Park Campgrounds.

Okay so I'm not as versed as some of you are in current pricing. Neither do I have any interest in putting anything else on the roof and we don't normally sit in one place very long so my alternator works great between sites for charging. I just know that the SP keep saying it isn't adequate for maintaining.

Your reply has been the first with any real facts and the post by bpounds is the first to be agreeable that 15watts is good for maintenance. There are as he suggest several rigs in our storage yard with the HF or Coleman or other 4"X10" panels and they seem happy with the results. I thought that maybe the extra cost for the Delray panel was worth it with the built in controller instead of just diodes to stop backfeed.

So thank you for your frank and outstanding response to the OP's question. Now he has a lot more information available on which to make a decision.