solar panel any good?

[LookingForCruiser]

Hi all,

This is my last electrical question. A Motopower solar panel was included with my boat. The battery sits in a lazarette locket, and the panel was velcro'd to the top of the lazarette hatch. The panel is connected to the battery with alligator clamps.

Now, I'm wondering:

a. The panel puts out 2.5v when I checked with a multimeter. It was a cloudy day though. It's got some weird discoloration on it though, like some permanent condensation inside on parts of it. Is the panel still good? Is this a normal amount of voltage out of a solar panel? It's about 2 square feet.

b. Is just connecting the panel to the battery with battery clips a good idea? Does there need to be a regulator?

[sailingdog]

Read the primer on Solar Power on Boats I wrote... the panel is probably shot if it is discolored and has permanent condensation inside the glass.

[lbdavis]

A panel that size doesn't necessarily *NEED* a regulator (though it's not a bad idea), but 2.5 volts is not a charge. Check it again when the sun is out, but if it's got "weird discoloration" and has moisture inside, it's likely shot.

There should be a tag/stamp on the panel telling you it's output.

Any pics?

[sailingdog]

btw, a good 12vdc system solar panel may put out as much as 18-22 vdc, depending on if it is a shade tolerant panel or not.

[nickmerc]

A solar cell will output a constant amount of voltage if it is exposed to light. This voltage is about 0.5VDC. Different voltages are achieved by wiring cells in series. If you measure 2.5VDC on a cloudy day (assuming all electrical connections are good in the panel) you will get 2.5VDC on a sunny day. The amount of light and the area of the silicon effect the amperage.

In short, your panel is not working properly and should probably be replaced.