Do solar power panels realy work to keep batteries charged?

[Tom Foley]

I do not have a charger on my outboard used on my CD25. Will a solar charger work to keep batteries up? Please relate experiences.
Thanks
Tom Foley
Kennebunk



alewife house@mainecoast.net

[Mike Everett]

We use a Unisolar USF-11 (flexible panel) on our CD28. This does a great job keeping the batteries charged while we're not using the boat, and seems to keep up with normal use (e.g. depth sounder and radio) on a sunny day. It's nice to arrive at the boat and not have to run the engine just to charge the bank. I figure the solar panel saves us several hours of diesel time each year.
I don't think, though, that a solar panel would be adequate as a primary means of charging the batteries. Our panel is rated to produce a maximum of 3.7 amp-hours per day. Assuming this means one or two amp-hours in sub-arctic Maine, the charger would store enough juice to run only one or cabin lights for an hour per day.
Mike Everett
s/v Dr. Pepper



everett@megalink.net

[Tom]

I do not have a charger on my outboard used on my CD25. Will a solar charger work to keep batteries up? Please relate experiences.
Thanks
Tom Foley
Kennebunk

Tom, There's solar panels and there are solar panels. I'e got one of those one foot by four feet solid panels that puts out 2.2 amps per HOUR. It charges two group 27 batteries (large car type)and easily keeps them charged between times I'm on the boat. In fact you have to put a regulator in to keep it from frying the batteries. 90 percent of the time it's not even charging. Of course it's big and awkward on a small boat and cost about $ 500 plus $ 60 for a regulator. You can certainly get a solar panel to do it, but I think your real question is how big a one do you need for what you want to do and how big and expensive would it have to be. You can get a car or mototcycle battery pretty cheap and keep it on a trickle charger at home and bring it with you when you're going out.



TacCambria@thegrid.net

[Tim]

Tom, I use an Aerogen wind generator to charge my batteries during the times I'm not on the boat (I unplug the shorepower to prevent stray current problems) and it works great. It's low noise, has a good two bank regulator, and I have completely isolated my house bank from my starting battery. My house bank has 220 AH capacity and is always charged up (I use a Link 2000 meter to check) as well as the starting battery when I get to the boat, even with relatively slow S. California winds. It's mounted out of the way on my mizzen mast and has worked great for two seasons so far. But you'll spend more for a wind generator than solar panels, but it'll last longer the panels.



igassn@aol.com

[John]

I do not have a charger on my outboard used on my CD25. Will a solar charger work to keep batteries up? Please relate experiences.
Thanks
Tom Foley
Kennebunk

I like Tim also have a Aerogen wind generator on board our CD30 cutter and I also have a Sovionics flexible solar panel that is several years old now. The panel is mounted to the top of the bimini and it is rated at 2.5 amps (short circuit current) or 2.15 amps (battery charging point). I mention the two currents because if you do go out shopping make sure you are comparing apples to apples because as you can see there is more than one way to rate output of a solar panel.

Yes it will keep your batteries charged dependant on battery use but that is where you have to do your homework calculating your power usage and normal battery drain while away from the boat. Don't forget the importance of cloudy weather into your calculations. We don't have sun problems in Florida.

The panel has to be regulated because it will overcharge the batteries if left connected all the time, it will also discharge them just as fast if you do not have a blocking diode in line installed when wired direct. The hard panels with aluminum frames will hold up the best. I have a sun cover for our flexible Sovionics panel to add to its longterm life when its not being used so I don't have to remove the panel from the bimini. The flexible panels are far more susceptible to climatic damage. I've seen the hard panels mounted on bimini's as well but I'd probably mount a hard panel on the stern rail. I believe the best panels are made with sliced silicone wafers. I don't know if the Sovionics panels are still made. They were made by a company called McCoy Industries in Sarasota, Florida. They made all types and sizes of panels.

FYI...The Aerogen wind generator as Tim states in his message is a real nice generator and very compact. I have a Aerogen 3 mounted on a custom made stainless stern pole. It runs through the factory supplied regulator feeding two banks. The only complaint I have is that the glass filled nylon blade material deteriorated from UV exposure over time. I had to remove all the blades after four years and scraped and sanded them down and the coated them with two coats of West epoxy and primed and painted them with polyurethane. Aside from that the unit has always run just great and is extremely quiet. I honestly think the wind generator would be excessive for a CD25 because of its bulk and weight. The Aerogens are the smallest I've ever seen though and are good units.

[yves feder]

Wonder if anyone has ever used the 20 watt solar module, Solarex MSX20L. The flexible USF11 looks like it might be a good answer (very fine info, Mike) but looking at the Unisolar site, they have quite a few choices.

On our CD27, a good location might be on the lazarette hatch - short run to the batteries - hard to figure where else to mount a panel. Perhaps just forward of the main hatch, or on the hatch cover? It would be shaded by the furled main though.

Looks like 2 or 3 days of solar charging would be very beneficial -
we keep our CD27 on a mooring so it would be ideal.

All of these systems come with built in reverse diode setups to prevent battery discharge, right?

Thanks for any additional info!

Best,

Yves
Chief, Maintenance & Propulsion Plant Engineering Department
CD27 S/V "Alphee" Stonington CT



W1UX@tinyradio.com

[bob B]

I had a CD-27 which had an alternator go bad on it. I bought a 20amp pannel, the hard Seimens variety. It kept everything charged up. I would recommend two pannels if you used autopilot a lot. I could operate my radios and lights but not refrigeration and the autopilot would wear it down. I also had a two battery bank and would change over from one to the other. Mine were mounted on a wooden, home made bracket on the stern rail. It was out of the way and high enough not to get pooped from astern. It was just easier for me than installing wind gernerators on such a small craft.

Bob B

[Bob Pence]

I do not have a charger on my outboard used on my CD25. Will a solar charger work to keep batteries up? Please relate experiences.
Thanks
Tom Foley
Kennebunk

My 60 watt solar panel keeps 4 100amphour batteries fully charged here in Maryland.



sixpence@dmv.com