Using solar to maintain battery in storage

[bgermane]

Thinking about a small solar cell that I can sit in a window to maintain the batteries while in storage. Anyone have any experience/thoughts with this or any suggestions on equipment?

Thanks in advance

[Mustang65]

Trying to maintain a charge by having a small solar panel on the inside of the is a good idea, but it more than likely will not meet your expectations. The small solar panels (like any solar panel) need to be angled up toward the sun to capture as much of the sun's rays as possible just to keep the batteries topped off. By setting it in the window it has already lost most of the suns rays. Secondly, the windows are usually tinted so that will reduce the solar rays even more. For small systems you need to put the panel/controller as close to the batteries as possible.

You would probably get better performance if you were to place the solar panel in the bathroom shower skylight, which lets a LOT of sunlight in. The issue there is the distance between the panel/controller and the batteries.

If you decide to go with a small system that will only be used to keep a charge in your batteries, make sure it has a small solar charge controller. Some of the inexpensive units say to connect the panels directly to the batteries, you really do not want those.. as most of them do not even have a blocking diode in them and when the sun goes down the panel actually discharges the battery.

I am sure some of our members that have this setup will let you know what they use or what to stay away from.

Just my thoughts,

Don

[bgermane]

Thanks Don. You just confirmed several of my fears. Our motorhome is actually in covered, not enclosed, storage. But, the front of the motorhome sees sun for about 6 hours a day. I was thinking of fabbing something that could support the panels from the front bumper, but then there is the distance issue that you brought up. Is the distance from the cells to the controller a problem, or just from the controller to the batteries?

[Mustang65]

Originally Posted by bgermane

I was thinking of fabbing something that could support the panels from the front bumper, but then there is the distance issue that you brought up. Is the distance from the cells to the controller a problem, or just from the controller to the batteries?

You would want the longest distance between the panel(s) and the controller with the shortest distance between the controller and the batteries.The SOLAR panel will be producing the greater voltage, and the distance will create less of a voltage drop. Don't get me wrong, if you get a 100 watt panel, put it outside, it will be able to accomplish its task with no problems at all. With the panel being inside the RV, that is the issue.

Just my thoughts,
Don