Solar panel trickle chargers for boat

Hey guys, I searched the boards here and have noticed people have been using these to re-charge batteries on their hoists, but has anyone used on on their boat?
I am thinking of the days at the sandbar, turn the music up and bring your cooler to shore. I have a Perko, but, does anyone know if a solar panel would keep the battery charged more to keep the stereo and amps running a little longer?

if you have installed one - have you found any fairly small ones? I was thinking of mounting two on the boat. One on each side of the boat, just in front of the windshield -just behind the base of the tower.

Here are examples:
http://www.sunforceproducts.com/english/results.asp?catid=3
http://www.ase-supply.com/product_p/pt-735x302.htm

they would not help if you were trying to keep your battery charged while listening to the stereo. They only produce an output of 2 watts.
your stereo draws way more. It would be good to maintain a battery.

I've thought about setting something like this up on the boat for when it's moored & not in use. Probably would just lay it on the bimini with the cords running under the cover. Seems like it would be a bit of a PITA to setup but might increase the battery life.

I have been looking for one of these myself. I just need it to keep the battery topped off between uses and makeup for the daily drain of things like the clock(s), XM tuner, etc.

What do you think 5 watter or the 2 watt version?

I'm thinking 2 watts should be more than plenty, but more is better.

These things work well with Optima's right?

I have one that I used on my last boat. Bill's thoughts are really the best use of the product as you will not notice anything if its plugged in during stereo use.

Bill its actually super easy to hook up. They come with a bunch of different battery connectors such as a ciggerette plug, alligator clips or wires for direct battery connect. I had mine connected to the battery all the time. When I put the boat away I pulled the cord out from under the seat and out from under the cover. Just let it lay on top of my mooring cover and it worked great.

Harbor Freight has a 5W panel on sale for $40 right now.

...or a 15W for $80. A couple of those might actually slow the drain from a stereo noticeably, unless you were really cranking it.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96418

Nice. Guess I have a trip to HF in my future.

So is there any need for some kind of protection against over charging the batteries when using a solar panel? And how should a direct connect be setup on two batteries?

Thanks

I think they do sell as an extra part that prevents overcharging. I never worried about it, because I used my boat a couple times during the week.

I have the Sunsei model its roughly 14x14 I paid $89 at West Marine, Probably better deals elsewhere.

I have a 3 watt. I keep it plugged in so I dont have to worry about the bilge pump running while the boat is moored for weeks on end. Damn boat always leaks.