MacGregorSailors.com

I keep my 26M in a boat house, sometimes for weeks at a time, and would like to put a solar panel on the roof of the boat house
to keep the batteries "topped up" and help them to hold on through cold weather (Pacific NW). My research has suggested that
a Sunforce 15 Watt, 1 amp Panel, run thru a Sunforce 7 amp charge controller would do the job. Where can I "plug in" to the
boat's electrical system to charge both the house and starter batteries? If any one has done this successfully I would like to learn from
your experiences.

Bill Drury\WhiskeyTango

If it was me, I would install a 12V outlet and plug the solar panel into it. Just make sure you turn off all of the other loads when you are trying to trickle charge the batteries.

I'd put the charge controller in the boat and if you have a switch with the "both" on it I'd wire it to that switch so that you could charge "both" or one or the other. Now if you later want to take a trip and have the panel with you the charge controller is there.

You should put a fuse between the charge controller and the switch.

While you are at it maybe think about some different panel and controller. I googled the panel and it looks to me like they might be about $100. If so I might suggest a different panel. We have bought all of our panels, 200 watts for the Mac and 480 watts worth for the Endeavour, from Solar Blvd and have been happy with their pricing and service.

They have a 20 watt for $29.00 ....

http://www.solarblvd.com/Solar-Panels-& ... _info.html

a 40 watt for $58.00 ....

http://www.solarblvd.com/Solar-Panels-& ... _info.html

You don't need 40 watts to keep the battery topped off, but the extra will not hurt a thing and like I said you might want to put a mount on the boat at some time and take it with you.

Also they have a charge controller that we used with our first 40 watt panel for $25.00....

http://www.solarblvd.com/Charge-Control ... _info.html

So for about $85 you could have the 40 watt panel and the controller. Don't worry that you will over charge the battery, you won't the controller will see to that. Our boat has been sitting there with 200 watts hooked up with no problems at all.

I'd keep the wiring simple and get a 25 foot #14 wire size extension cord. Cut it about 6 feet or whatever works from the female end and wire that end through a fuse to the switch in the boat. Take the male end and wire it to the panel on the roof. Run it down to the boat and plug it in. When not in use put a female plug (no wires) on the one that goes to the panel. If you end up over 25 feet and more than 20 watts I'd go to a number 12 wire if you want maximum efficiency.

Good luck,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

Those are nice panels an good products I also like this place http://www.sunelec.com/ they answer any questions just make sure to calculate shipping before you buy to get the best deal. In the future I sort of want to make a bimini type T-top out of 100 watt panels to possibly help support a Air conditioning system but I have to crunch some numbers and save up some boat bucks, happy sailing

You shouldn't need a controller for a panel 20 watts or less
I have a 20 watt panel on my boat for some time charging two batteries with no ill effect

Allan

Nautek wrote:You shouldn't need a controller for a panel 20 watts or less
I have a 20 watt panel on my boat for some time charging two batteries with no ill effecte

Allan

Concur. A 15 watt panel doesn't have the electromotive force to damage a group 24 marine battery. You can literally just connect it and be done.

Nautek wrote:You shouldn't need a controller for a panel 20 watts or less
I have a 20 watt panel on my boat for some time charging two batteries with no ill effect

Allan

I disagree you will need a regulator irrespective of battery type but more so for wet cell probably as suggested use a 7.5 amp regulator so it will cover any future solar input on the water personally I use a 20 amp (cost $115 au) and it's keeping the boats two batteries charged from a 10w unit that came with our 120w fold out camping unit, wouldn't even consider using even the 10w unit without a regulator and it only gets sun for probably 4 hr's max a day and the batteries are on float.

Boblee wrote:I disagree you will need a regulator irrespective of battery type

Do you have a source for that? I doubt a 15 watt panel could power a charge controller and have anything left for the battery. I've been trickle charging batteries for years without a regulator, and had nary a problem.

http://www.westmarine.com/webapp/wcs/st ... EqXJKTyZHA

States that if a solar panel delivers <1.5% of a battery's rated power, a charge controller is not necessary.

Summner,
I have a built in 10amp battery charger that charges my twin group 29 house batteries and my group 24 starting battery (all deep cycle).
I am going to purchase two 40 watt panels and instead of a regulator cut a extension cord and plug the female end in my alread set up below deck for charging from 110 that I am now useing. I would think my charger would cut off any excess voltage and replace the controller. I also have a diode Yanda that keeps house from starting seperate. My concern is running it thru the charger with voltage/amps loss but would make it a easy set up as it iliminates another controler and posible problems.
Whats you take of this?
Dave

Sumner wrote: they have a charge controller that we used with our first 40 watt panel for $25.00....

http://www.solarblvd.com/Charge-Control ... _info.html

So for about $85 you could have the 40 watt panel and the controller. Don't worry that you will over charge the battery, you won't the controller will see to that. Our boat has been sitting there with 200 watts hooked up with no problems at all.

I'd keep the wiring simple and get a 25 foot #14 wire size extension cord. Cut it about 6 feet or whatever works from the female end and wire that end through a fuse to the switch in the boat. Take the male end and wire it to the panel on the roof. Run it down to the boat and plug it in. When not in use put a female plug (no wires) on the one that goes to the panel. If you end up over 25 feet and more than 20 watts I'd go to a number 12 wire if you want maximum efficiency.

Good luck,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links


Also they have a charge controller that we used with our first 40 watt panel for $25.00....

http://www.solarblvd.com/Charge-Control ... _info.html

So for about $85 you could have the 40 watt panel and the controller. Don't worry that you will over charge the battery, you won't the controller will see to that. Our boat has been sitting there with 200 watts hooked up with no problems at all.

I'd keep the wiring simple and get a 25 foot #14 wire size extension cord. Cut it about 6 feet or whatever works from the female end and wire that end through a fuse to the switch in the boat. Take the male end and wire it to the panel on the roof. Run it down to the boat and plug it in. When not in use put a female plug (no wires) on the one that goes to the panel. If you end up over 25 feet and more than 20 watts I'd go to a number 12 wire if you want maximum efficiency.

Good luck,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

Good info, thanks

DaveB wrote:Summner,
I have a built in 10amp battery charger that charges my twin group 29 house batteries and my group 24 starting battery (all deep cycle).
I am going to purchase two 40 watt panels and instead of a regulator cut a extension cord and plug the female end in my alread set up below deck for charging from 110 that I am now useing. I would think my charger would cut off any excess voltage and replace the controller. I also have a diode Yanda that keeps house from starting seperate. My concern is running it thru the charger with voltage/amps loss but would make it a easy set up as it iliminates another controler and posible problems.
Whats you take of this?
Dave...

Hi Dave, are you asking if the charger you have now will work as a charge controller for the 2 40 watt panels? If it is a 110 volt charger I don't see how it could. You need to get a charge controller made to work with the panels. The one I posted would be inexpensive and is made by a respected company in the field.

http://www.solarblvd.com/Charge-Control ... _info.html

Besides controlling the charge state it will also protect the battery from being discharged at night back through the panel. Only one caution with it and that is it is rated to 4.5 amps. 80 watts might be right at its max input. Instead of 2 40 watt panels have you considered a single 80 watt...

http://www.solarblvd.com/Solar-Panels-& ... _info.html

...the one above is the same price as 2 40 watt panels from them...

http://www.solarblvd.com/Solar-Panels-& ... _info.html

...but the wiring would be simpler and if later you wanted to mount it on the boat the mount would be simpler also. I doubt that the panel would ever put out the full amperage, but if you go with 80 watts maybe considered moving up to a little larger controller...

http://www.solarblvd.com/Charge-Control ... _info.html

...that would also allow for some expansion in the future.

Hope this answered the question,

Sum

mastreb wrote:Do you have a source for that? I doubt a 15 watt panel could power a charge controller and have anything left for the battery. I've been trickle charging batteries for years without a regulator, and had nary a problem.

I'm no expert here. Sumner might chime in as he's my solar go-to guy.

Trickle chargers as I understand them will cut off power at 13.8 volts (or whatever they are set for) and stop charging. They are regulated. Solar panels put out up to 17volts or more at peak and don't stop charging when the batteries are full. They will keep pumping into the batts until the battery reaches 17volts. Hence the need for the controller. At night, I believe they have the potential to discharge through the panel if connected directly.

Now 15 watts may not be enough to cook a battery, I don't know, but I'd use a controller anyway to be safe. They are cheap enough ($16).

I've never had a lick of trouble from my 80w panel and controller. It's my primary charging system.

Sumner,
After I posted the question I relized the 110 amp charger and ordered a 6 amp controller as the one you sugested was maxed out on the two 40 watt panels.
I saw the 80 amp panel but decided two smaller ones would fit on the boat for storage. I will mainly use only one for a weekend ancorage and two of them for longer periods. Both of them will power my 65 quart refig./freezer during the day and add a little more charge to batteries.
At night the frig. runs much less and with my twin 29 group house batteries it won't discharge much even a 5 day anchorage without charging from engine.
I now don't have any panels and batteries would get down to 60% in 3 days, these two panels during 5 days should only drop the batteries down 10 % or less.
The Batteries should last a much longer time due to less deep draw from the batteries.
I keep my boat in my back yard. I will probably order the 80 watt as a full service to boat in the event of power outage during huricane season so I don't need a generator and we camp on boat, kind of like a bunker in mid states during tornado.Surge comes up, I float off the Trailer.
Thanks for the info.
Dave

Sumner wrote:

DaveB wrote:Summner,
I have a built in 10amp battery charger that charges my twin group 29 house batteries and my group 24 starting battery (all deep cycle).
I am going to purchase two 40 watt panels and instead of a regulator cut a extension cord and plug the female end in my alread set up below deck for charging from 110 that I am now useing. I would think my charger would cut off any excess voltage and replace the controller. I also have a diode Yanda that keeps house from starting seperate. My concern is running it thru the charger with voltage/amps loss but would make it a easy set up as it iliminates another controler and posible problems.
Whats you take of this?
Dave...

Hi Dave, are you asking if the charger you have now will work as a charge controller for the 2 40 watt panels? If it is a 110 volt charger I don't see how it could. You need to get a charge controller made to work with the panels. The one I posted would be inexpensive and is made by a respected company in the field.

http://www.solarblvd.com/Charge-Control ... _info.html

Besides controlling the charge state it will also protect the battery from being discharged at night back through the panel. Only one caution with it and that is it is rated to 4.5 amps. 80 watts might be right at its max input. Instead of 2 40 watt panels have you considered a single 80 watt...

http://www.solarblvd.com/Solar-Panels-& ... _info.html

...the one above is the same price as 2 40 watt panels from them...

http://www.solarblvd.com/Solar-Panels-& ... _info.html

...but the wiring would be simpler and if later you wanted to mount it on the boat the mount would be simpler also. I doubt that the panel would ever put out the full amperage, but if you go with 80 watts maybe considered moving up to a little larger controller...

http://www.solarblvd.com/Charge-Control ... _info.html

...that would also allow for some expansion in the future.

Hope this answered the question,

Sum

DaveB wrote:Sumner, After I posted the question I relized the 110 amp charger and ordered a 6 amp controller as the one you sugested was maxed out on the two 40 watt panels.
I saw the 80 amp panel but decided two smaller ones would fit on the boat for storage. I will mainly use only one for a weekend ancorage and two of them for longer periods. Both of them will power my 65 quart refig./freezer during the day and add a little more charge to batteries....

Sounds like you have a good plan .

When we were at the boatyard there was a small tornado about 6 miles away and we didn't even know it until a couple weeks after the fact,

Sum

===================================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida
Mac-Venture Links

Progress report on installation of "top off" solar charger on roof of boat house to maintain batteries when boat not run for extended periods:

Followed Sumners advice and went to solarblvd.com and ordered an 80 watt/12 volt panel (120 bucks) and a Morningstar Sunsaver
Duo with remote meter (about 150). Bolted panel to boathouse roof and connected 12 ga extension cord, leaving positive plug on
cord. In the Mac I mounted a single plug outlet from Home Depot wired to the remote meter, charge controller, and both
house and engine batteries (with 7 amp in line fuse for each batt) all connected with 12 ga multistranded copper wire.

After I figured out that the "house battery" is actually 2 6-volt batts wired together and got my wiring right, it all seemed to work fine,
producing at least 500 milliamps in weak light. While this is not enough to recharge a runout battery, it should work to "maintain"
the batteries by pushing a few electrons in the right direction every day. This set up also has the advantage of giving me a voltage
reading on both the house and starter batteries through the remote meter-- something I felt was lacking in the original set up.

Thanks to Sumner and all other posters.

Bill Drury--- WhiskeyTango