Solar Panel Recommendation

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casampson
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Solar Panel Recommendation

Post by casampson »

I have a trickle charger for my CD 25 but I think it is inadequate. I have the usual stuff on my boat: LED lights, radio, bilge pump, and a few gauges. I bought a controller last season that is rated for 10 amps. Any advice on solar panel make and output would be appreciated.
Carl Thunberg
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Re: Solar Panel Recommendation

Post by Carl Thunberg »

What leads you to the conclusion that your trickle charger is inadequate? What does the voltage read on your battery? Your demand loads are pretty modest.
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Megunticook
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Re: Solar Panel Recommendation

Post by Megunticook »

I got one of these portable panels that does the job. It fits nicely on the sliding companionway cover.

https://www.campingworld.com/nature-pow ... 90097.html
casampson
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Re: Solar Panel Recommendation

Post by casampson »

Thanks for the tip, Megunticook. As far as the trickle charger goes, I have no experience with these things. All of my previous boats have been non-electric. I suppose I am wondering if I go away for a weekend and use the lights etc. a lot on one night, will the trickle charger be able to refresh the battery enough so there will be ample juice for the second? Or do I need a panel that can recharge the battery in a matter of a few hours?
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barfwinkle
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Re: Solar Panel Recommendation

Post by barfwinkle »

GM

The pic below shows the 5 watt panel controlled by a Morningstar SunGuard 4.5 amp controller (see link below), that I used on Rhapsody for over a decade. Small, lite weight, and very effective. Rhapsody had all halogen lights at the time, and just "normal" electronics. The batteries were always charged and if I monitored my consumption with a Victron 600S. At the time I was still working and thus a "weekender" and was on the anchor a lot. Never had an issue for the panel not keeping up.

https://www.morningstarcorp.com/products/sunguard/

Fair winds
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Re: Solar Panel Recommendation

Post by Capt. Fritter »

When I bought Hard A Lee, also a 25, an electrical engineer had completely redone the wiring and box. It has 100 watts in two 50 watt panels with controller and two batteries. All lighting is LED. Anchor light stays on all the time since I’m in a mooring field. Also running is the fan for the compost toilet which draws maybe .3 amps. Other than charging phone and tablet I use little else so more than enough power. Even got room to add more panels on the custom dodger if I ever needed it. Helps to be in the Keys where there is plenty of sunshine.
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Tod Mills
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Re: Solar Panel Recommendation

Post by Tod Mills »

The You Tube channel "Pacific Yacht Systems" (https://www.youtube.com/user/PacificYachtSystems/videos) has a lot of info about electrical systems. You'd have to browse through the videos to find the ones relevant to you.

A charge controller he seems to like is a Genasun: https://sunforgellc.com/genasun/#gen_product_row They are very efficient and sealed solid state and inexpensive. On a sailboat, it is often best if each panel has its own charge controller.

If you want a charge controller that you can monitor from your smart phone (bluetooth), there is Victron: https://www.victronenergy.com/solar-charge-controllers Here is a video about one of their products: https://www.youtube.com/watch?v=oaRqOxULung

As for a panel, it depends upon whether you want a semi-flexible or a rigid, what size you want for your needs, and how you want to mount it. Here are some panels. https://www.renogy.com/products/solar-panels/ You'll want MC4 connectors.

Really, before you do anything, you should list your loads so you can properly size your system. A very small panel can shorten the life of some batteries (such as an agm battery). A "trickle charger" should not be used to charge a battery, only for maintaining a charged battery. For example, this agm battery requires a bulk charging current of at least 8 amps and less than 35 amps. That would mean at *least* a 100 watt panel to supply adequate current. After the bulk charging phase is completed, the battery accepts a lower current: https://www.vmaxtanks.com/SLR125-12Volt ... _p_38.html
Last edited by Tod Mills on May 29th, '19, 07:02, edited 1 time in total.
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Megunticook
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Re: Solar Panel Recommendation

Post by Megunticook »

Tod's right, you should take a few minutes to calculate your power requirements before buying anything.

Check how many amps each component draws (check the specs. on the nameplate or user manual), and then figure how many hours you might be using it. With a little math you can come up with a number of amp-hours that you might typically draw from your battery in a 24 hour period. Then figure on getting a panel that can reasonably be expected to replenish those amp-hours during the day.

I think you'll find that a 40 watt panel will easily take care of your needs, and given how cheap they are now, not sure there's much reason to go lower than that.

Which charge controller did you get?
casampson
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Re: Solar Panel Recommendation

Post by casampson »

Thanks for the advice. I ended up buying a 50-watt flexible panel from Sunpower for about $125. I am confident it will do the job. Here's the link:

https://www.wholesalesolar.com/9433675/ ... olar-panel

I have a nice 10-amp controller, but I can't recall the manufacturer. It's on my boat, which is in harbor...

My next question is what to do with the MC-4 connectors. I am not sure how to set up the connection from the panel to the controller, which accepts bare wire connections. I see that there are a variety of MC-4 connectors on line that might do the job, but any advice would be appreciated.

Thank you.

Chris
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Megunticook
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Re: Solar Panel Recommendation

Post by Megunticook »

Where's your charge controller mounted? And where do you plan to set the panel?
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Frenchy
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Re: Solar Panel Recommendation

Post by Frenchy »

Chris, I would suggest reading MaineSail's article on installing Mc-4 connectors and purchasing quality connectors from
his site, linked below. I put the connectors right at the solar panel so I could disconnect itl easily. I think I used 10-
gauge wire and the corresponding connectors. You want to minimize loss. Good luck - Jean




https://marinehowto.com/installing-solar-mc4-terminals/
Jean - 1983 CD 33 "Grace" moored in
Padanaram Harbor
Massachusetts
casampson
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Joined: Feb 8th, '12, 20:01
Location: CD 25 "Mahalo"

Re: Solar Panel Recommendation

Post by casampson »

I was thinking of mounting the solar panel on the non-sliding portion of the cabin roof. Can't step on it anyway because it is a little weak. The best place to mount the controller would probably be right next to the electrical panel, and then continue on to the battery.

Thanks for the tip, Frenchy. I will follow up on it.
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