Solar panel trickle charger for sailboat batteries

[Sea Hunt Video]

John:

Wow Thank you very much. Your post is very helpful. I have many questions but I will post only one for now.

You wrote: "I wanted to be able to remove the solar panel when necessary. So, I needed a deck fitting that allowed me to disconnect the panel's 10' cable from a deck connector fitting."

My thought was that I would strap the solar panel to the cabin roof with the wires running from the batteries to the charge controller and then a new set of wires running from charge controller to the solar panel. When I wanted to store the solar panel I would just pick up the solar panel and wiring and put them in the port side cockpit locker (batteries are in port side locker).

With the Hella Marine deck connector it looks like I have to drill a hole in the deck (or cabin roof). If possible I would like to avoid that.

Thoughts

[John Stone]

Roberto,
Sure. I suppose you could do that. You need to be able to employ the panel without damaging the power supply cable though. So think it through. Lots of different ways to solve the problem. Figure what the endstate is first. Then figure out the different options to achieve that endstate. Determine the pros/cons for the different options. Pick the option that best meets your needs and then execute.

[Paul D.]

Roberto,

If you go with a deck connector, I recommend putting that in as out of the way place on deck as possible, difficult on our narrower boats! I ended up changing to a through deck connection instead of a plug in. This was after coming back to the boat and finding the deck connection unplugged when friends had use the boat. Possibly us and our kids accidentally kicked it while unloading stuff at times too.

Now I realize friends/kids using the boat is another factor, but my panel charges the house bank safely and steadily when we are away from the boat and after I found a low house bank a couple times, I solved that problem by eliminating that connection. This may not work for you if you wish to remove the panel. However, you could rig a quick connector at the panel perhaps. That may make an easier set up and take down, as you plan to stuff the thing in your locker.

I really love solar, if one can keep their power needs moderate, you can have a good, yet modern life powered only by the sun and a few dilithium crystals. Oh wait, those are for warp drive. Wrong voyaging reality...sorry.

The panel starts charging even at 1 bell in the morning watch. This shot was taken in Sikiwit Bay on passage leaving Isle Royal National Park for the Apostles.

[John Stone]

You raise a good point Paul. And I failed to mention that in my hurried post. For several reasons, I placed the deck connector under the upturned dinghy on the cabin top. One reason was to make it less likely that it would be tripped over. But, the deck connector I use also screws in so it can't be "pulled" out. Not everyone needs or wants to be able to easily unplug their solar panel. I did.

[Steve Laume]

One more thing to keep in mind with solar panels and deck connections is that the solar panel will be hot if the sun is shining. Most deck connectors are made to feed power away from the source. The solar panel is doing just the opposite, so the male ends will be hot. You might not want that kicking around in a cockpit locker without some sort of protection.

I was taught a similar lesson a very long time ago while looking at a solar electric fence charger. Who knew the florescent lights in the store were enough to power the thing, Steve.

[Jim Walsh]

I was taught a similar lesson a very long time ago while looking at a solar electric fence charger. Who knew the florescent lights in the store were enough to power the thing, Steve.

That's just too funny

[Sea Hunt Video]

The more research I do on this the more I am coming around to the idea suggested by John S.

Unfortunately, I am not the sharpest knife in the drawer so I have some concerns/questions, etc., about installing the Hella Water Resistant Chrome Brass Plug & Socket suggested by John.

Am I correct in understanding that the wiring from the charger controller would be connected to the Hella's socket portion and then the wiring from the solar panel would be connected to the Hell's plug. When the plug is connected to the socket "we got juice"

As with most holes drilled in a boat, I am assuming that I would drill a 1" or larger hole in the cabin roof (or wherever I plan to install the plug and socket) and then clear out the balsa core around the hole and then fill it all with epoxy to prevent water intrusion. Then drill a small hole just large enough for the wiring to come up from the charge controller, thru the coach roof and then to the socket. Does this sound about right

At this early planning stage I am thinking of installing the Hella Water Resistant Chrome Brass Plug & Socket on the port side near the aft end of the coach roof. On the Cape Dory 25Ds there is a handrail there that I can use to tie off the solar panel to keep it from flying away in windy conditions while on her mooring or at anchor. This would also minimize the wire run from the batteries to the charge controller to the solar panel since the batteries (2) are located on a platform inside the port side cockpit locker.

For those that have a Cape Dory 25D, 27 or 28 (I think the coach roofs, etc. are similar in design and configuration) is this a reasonable location for the Hella Water Resistant Chrome Brass Plug & Socket and solar panel or have you found a better

Thanks to ALL for the many suggestions, recommendations, advise, encouragement, etc. It is much appreciated.

[Sea Hunt Video]

I forgot another question.

The Jamestown website for the Hella plugs and sockets lists 2, 3 and 4 prong. Which prong # is appropriate for my set up I am assuming 2 prongs but I am not sure.

Thanks,

[John Stone]

Roberto,
Essentially that's correct. I am tied up for a couple hours but I'll see if I can find some time tonight to describe how I installed the plug. I may also have some pictures.

[Sea Hunt Video]

John S.

Thanks. But please do NOT go to any special time effort. I have not yet bought the solar panel, charger controller, etc. I plan to drive up to Ft. Laud. (EMarine) either Tues or Wed. It will then be 2-3 days of playing around with positioning, etc. before I even consider drilling a hole. When I had my CD Ty Weekender I wanted to install small cam cleats for the jib sheets. It took me about 1 month to sit and think and get up the courage to drill four (4) small holes in the coach roof of my little Ty Weekender.

When you do post, if you have photos, that would be helpful. I am a visual person.

Thanks

[John Stone]

Roberto,
If you go with the gantz 30 watt semi-flex panel, same as mine, then you want the two prong plug.

I looked for photos but can't find them which is odd since I shot photos of everything. So, I'll do my best to describe what I did.

On my boat, I located the plug over the top of the brass saloon table stanchion that I installed when I built my table. I ended up running the cord down the brass stanchion so it can't be seen. You don't have anything like that in your boat so you will need to think carefully about where the cable needs to penetrate the deck. If you drill a hole through the cabin top (I assume you have a headliner) you will have to account for a way to hide the power cord that runs to the solar controller. So think about where that needs to be.

Also, I recommend you locate the plug near some obstruction so that the plug is less likely to get stepped on--such as near a dorade or grab rail or coaming, etc.

Before I started the project I took the hella base with me to Fastenal to purchase some round head machine screws that would fit through the three small holes in the base of the connector. These are very small screws--like # 6-32 or something. While there I purchased a tap that corresponded with the machine screws that fit through the hole. It is a very small tap. Make sure your tap handle will fit such a small tap.

1. Once I decided where I wanted the hole I drilled down through the upper skin with a fostner bit. But I did not penetrate the bottom skin.

2. I dug out the balsa core from all around the edge of the hole. I placed the hella deck connector over the hole and made sure there would be solid epoxy under where the three little fasteners go to secure the base to the deck of the boat.

3.Once I was sure I had a big enough hole I filled it with unthickened epoxy. If it's hot out be careful not to pour too much at one time (multiple pours) or it can start to overheat. Or, mix in slow hardener. Either way works.

4. I then drilled a hole though the epoxy plug to accommodate the duplex electric cable that will connect to the bottom of the hella connector and run to the solar controller.

5. I placed the hella base on the deck (you can remove the electrical connector in the center) and drilled holes for the fasteners then tapped them with the corresponding tap. I test fit the fasteners and made sure everything fit snug.

6. I stripped the wires for power cord from the solar connector plug and the same for the electrical cable that connects to the base and will run to the solar controller. Be very careful regarding the base. Do NOT over tighten these little screws and do NOT back them all the way out. By the way, you will need a very small flat head screw driver--I mean small. Test all this in your shop before you do it on the boat.

7. Connect the electrical cable and then install the fitting. I used a little butyl rubber but you could use some 3M 4000. It will only take a small mount. Tighten the little screws down.

8. You will need some way to ensure the weight of the electric cable that runs from the base to the solar controller is not "hanging" or pulling on the connection. You can use a wire tie or whatever (there are many ways to solve this problem) to keep tension off the wires where they fit into the base.

9. Use appropriate wire ties along the cable running to the controller.

By the way, I used ancor red/yellow 12v duplex marine copper tinned wire. I don't remember the guage. Read what the controller says and check the guage size of the wire coming off the gantz panel. I think it's 12 gauge but I am not certain. I can get to the boat if you need me to check. But, just check everything in your shop or at your work station before you do any of this on your boat. It's not hard. You just want to work through all the steps before you do down to the boat and try to do it.

Let me know if you need more info.

[Steve Laume]

I hope to install a larger solar array in the near future. I installed my current panel with that in mind. What I have now is a 20 or 30 watt (I forget) rigid panel with a dedicated controller.

I bolted rubber feet onto the bottom of the panel frame and eye bolts on the sides. I can now lash the thing just about anywhere I want. Most of the time it lives on the spray hood. I tie it onto the bundled up, blow up boat when I am traveling off shore. Sometimes I will move it into the cockpit. Since I don't expect this to be my final solar set up, I just routed the wire out through the top of the companion way hatch. I wire tie to the hand rail, just inside and to the panel itself so there is no pull on the connections. There is plenty of room for the wire, even when the boat is closed up tight. It never gets unpluged. I do have the controller wired through a breaker so it can be turned off.

Please give some thought to the idea of having a two prong plug on your panel wire. That will provide 17 volts of power the to prongs, which are only a fraction of an inch apart, any time light hits the panel. So when you are coiling up the wire and the prongs hit the panel frame you are creating a direct short. Toss it in the cockpit locker and it gets banged around a bit to the point that it touches some metal and maybe it's okay until someone opens the locker and some light hits it. You get the idea. You never want male prongs on the hot side of a circuit.

This just isn't that hard, Steve.

[John Stone]

Steve, You are right about the two prong plug on the hot side. There is a potential problem there. I understand you are not supposed to allow light to strike a solar panel if it's not plugged in as it can damage the photo electric cells. I have a sunbrella slip cover for my panel that I insert the panel onto before I unplug it. Which means the panel should not be able to generate any electricity.

But, it's still something to think about. I'll muse on that for a while and see if I can up up with a solution that protects the prongs. Regarding "it's not that hard," actually there are few if any waterproof non plastic deck connectors on the market. Having a wire dangling in the companionway is not something I want. Hard wiring is an option for most sailor's but not one I want at the moment though I have considered it on occasion. I always reject it as a loss of flexibility.

I have been so happy with the set up we have I have considered adding another 30 watt gantz panel with a second deck connector I'd run the second panel through a second duplicate MPPT controller. That way, the shade on one panel would not interfere with the electricity generating output of the other panel. I could tie the panels side by side or one on one side of the boat and the second panel on the other side. But I would not want this set up hard wired. The deck connectors leave a nice clean sealed protected attachment point. In the mean time one panel serves us extraordinarily well.

Nonetheless, it's a good point you bring up.

[Steve Laume]

I never realized that if you were running two panels into one controller that shading one would effect both. I do know my home system is made up of three groups of ten and if any one of the ten is shaded it will affect them all in that group but not in the entire array. I would like to be able to run a 10 watt controller and then have the option of one large or two smaller panels. My thinking was that two smaller would be better in case one was shaded but now I have to re think that.

The wire running into the cabin doesn't really dangle. It is held in place pretty well with the wire tie and I even have a little pad eye just outside that I can tie it with if I feel the need. It then goes up alongside the spray hood and under the traveler so it is very much out of the way. I will probably do a thru the deck installation once I install a permanent system but will go with a Blue Sea clam and not a connector. It seems like it would be fairly easy to make up a rubber or plastic cover to insulate the prongs. Have you ever put a meter on the panel when it has it's cover on?

I think my panel is safer when tied in place then it would be in my cockpit locker, Steve.

[John Stone]

I use a Blue Sea through deck watertight deck gland for the AIS antenna which is mounted on the aft most stanchion right at the fantail.

I have not metered the panel when it's in its slip cover but I intend to in the near future. Now I am curious! I'll come up with a plug at some point. I don't store the slip covered solar panel in a locker but under the bunk cushion.

I don't recall offhand how the shaded panels affect other panels in the array (is it down stream or up stream) but it doesn't matter to me. I would want both panels to be able to operate independently without ever affecting the other panel. And I want to be able to operate with just one panel when that's all I need which is most of the time.

With modest requirements, small panels that can be moved around can meet one's needs saving big bucks on hardware and mounting cost. You can simply keep them in direct sunlight, while fixed panels are shaded. Even with one 30 watt panel we managed to charge a lap top, iPad, cell phone, Bose recharable speaker, two clip on 12v fans, multiple iPods, and a Davis portable clip on auto on/off LED anchor light on the rare occasion when I use it instead of our kerosene anchorlight. I charged a 12 v drill once. And we have a 12v vacuum we also rely on. We can operate perfectly without any of that stuff however. Not a small thing as we have no engine driven alternator. It's solar or bust for us.

Small portable systems are easier to repair and usually less expensive to replace. Plus, for me, on this boat, extraneous hardware (insiden or outside) looks like clutter and detracts from the beauty. That is not to say that I won't change my mind someday or if I had a different kind of boat I would not add a solar arch and refrigeration. This whole topic is about choices. Compromises. What is beauty and what is not--a very personal thing as so eloquently stated by the famous English Bard.

I have a great friend with a 35' steel gaffer he built himself. It's a pretty simple boat but has all the comforts. I love his boat and how it so perfectly meets his needs. But, I would not want those complex systems on the Far Reach. Thankfully, unlike the Europeans, we don't have much interference from big brother telling us how our boats have to be equipped.