Small Solar Panel Chargers

[shade788]

Do small solar panel battery chargers really work?<br /><br />I noticed them in Northern Tool Supply and West Marine for around $30. They come with suction cups to put a on a windshield or mounting hardware for where ever.<br /><br />I thought while the boat was at the dock I could hook it up and get some free power from the sun. Rather than having to pull the battery out to charge it at home.<br /><br />Any information would be greatly appreciated.

 

[shade788]

Re: Small Solar Panel Chargers

Whoops I guess this should have went in "Electronics & Trolling Motors."<br /><br />Sorry

 

[gewf631]

Re: Small Solar Panel Chargers

I picked up one of these from Harbor Freight when it was on sale for $10<br />

<br /><br />It has a simple cigarette plug, and I rotate it between my boat, garden tractor, motorcycle, and my jump start battery (which also has an air compressor). Since it only puts out 1.5 watts, I figure it's a decent trickle charger.<br /><br />I've had it about a year, and it seems to work. I've used the battery/compressor a few times, and its status meter has always stayed in the green.<br /><br />I like it because it's small and completely portable (especially since I don't need an extension cord).

 

[briannh1234]

Re: Small Solar Panel Chargers

I have a different one than Ed F but with simular results. They are good at keeping a charged battery charged. (aka maintinence charge) What they are not good at is recharging a dead battery. (It takes too long). They don't seem to have enough watts to overcharge a battery either so you can leave it connected all the time.

 

[ED21]

Re: Small Solar Panel Chargers

I used a similar one for years to keep a battery on a sailboat topped off & seemed to do OK.<br /> <br />After learning a little more about battery charging recently, I checked the output voltage & found it to be about 21 volts. <br /> <br />At the small amps out, I don't know if it could damage the battery. Voltage regulators for solar chargers that small don't seem to be available.

 

[briannh1234]

Re: Small Solar Panel Chargers

Ed -<br /><br />21 volts open (not connected to the battery) is about right. If you connect it to the battery you will see that it drops to whatever voltage the battery is at. <br /><br />I have connected mine to a single AAA rechargable battery that read 1.1 volts. With the panel connected it was still 1.1 volts. Left for a few hours in the sun it went up to 1.3+ volts. (Charged for a AAA battery)<br /><br />Edit: I have also connected mine to a 12v Jump-n-carry battery that read 12.2 volts. (12.8 is charged for that battery). After two month's with some sunny days it read 12.3 volts. This is too slow for most people. Since then I have charged it with AC power and just use the solar panel for maintinence charges.

 

[ZmOz]

Re: Small Solar Panel Chargers

Just remember, about all it's good for is keeping the battery topped off. It would take weeks to actually "charge" a battery.