Solar install on boat under cover...

J

jbdba01

New member
I debated to put this on here and figured the moderators can kill this thread if need be. I looked around the forum and found plenty of advise on panel sizes...but installs seemed to be few and far between.

I'm looking at installing a temporary solar charging system for the batteries on my boat that is 90% of the time under a cover. So basically when the boat is on the trailer it's charging - but the system is not connected when off the trailer. Coming clean here - this is a Glacier Bay 2670. It stays on trailer but under a cover in Tampa, FL. So crazy T storms and humidity is an every day event in the summer.

I pretty much get the concept of the panels, a controller, and wiring, but I'm struggling with the concept of water getting on the controller through condensation/humidity/rain. I think I have a couple dry spots to connect, but I have this vision of water tricking down the wire shorting something out and causing a fire.

With that in mind the best way to describe it is that the batteries are in the stern and are in individual compartments - so nothing is exposed to the elements.

I can picture putting a controller inside that compartment, but can it handle that humidity? So the wires that connect the panel to the controller would be under a gunnel (outside, under a gunnel but under a boat cover) and I would have to drill a hole for the panels wire to reach the controller inside the compartment. When not charging the panel comes off and stowed somewhere - truck/boat...

Hopefully that makes sense - basically I'm looking to see/hear how to mitigate fires/shorts. I'm sure I'm not the first encounter this, but apparently me google skills are failing me.

I don't think it makes any difference but the batteries are Optima Marine D31's. They are in separate compartments about 6' apart.
 
I have done this in S. Calif. and in Las Vegas, both places we're kept boats and a van --sometimes as long as 6 months between uses. Never done it in Pensacola--which is closer to conditions in Tampa.

I just used small panels, and I coated all of the edges with a marine silicone (dirty word on the boats, but this is a good application for it.) These are basically trickle chargers, and made to maintain lead acid batteries. These can be from 1.5 to 3 watts. They have a diode so there is no loss at night. The only issue is the rain, but if kept at an angle facing South, that is minimized. The cheapest are in the $20 range up to about $40--so one panel for each battery.

I had these on small light saw horses I made (weighted at bottom to avoid tipping over with wind).

No worry about rain water, you want a "sag" in the center of the wire, before it goes under the boat cover so any water drips off.

If you want big panels, I have a 200 watt flat mounted on the top of my RV--and it is now 5 years old--doing fine in the Florida sun/rain (we average about 65" of rain a year here). The controller is inside of the RV, and the wire is fed thru a fitting on the roof which is sealed. That was sized to run a household refrigerator during the daytime feeding from 6 golf carts..

Getting back to your Optima group 31's they will have very low self discharge, unless you are having some parasitic drain in the boat (some bilge pumps, memory on radio's, automatic charge relays etc.)

Now as for that Glacier Bay. It was high on my list when I bought the Tom Cat--but I wanted a better cruising interior. They do better going into chop, but not as good in beam and down wind/seas--good boats. Keep an eye on the hull to deck joints (not glassed fully as the Tom Cat).

You are right to want to top off batteries--since they often are not fully charged when just run from the engine charging systems.
 
Check out my photo album. Under electrical there is a sub-album for my solar panel. I used male "SNADS" attached to the cabin top and then added female snaps to the panel so that it snaps into place. It's a flexible 50W panel and has withstood greater than 75 mph winds. The connectors are a standard waterproof solar connector that allow easy removal of the panel for servicing or storage. You can find them on Google. The 10 AWG (oversized) wire is long enough so that there is a "drip loop" (just like on the service entry cable to a house) before it reaches any electrical connection.

Turns out that I have never removed it. I can charge my battery while towing.
Yesterday, I was getting ready for the Powell River event and loading the boat in the garage. I noticed that the solar charger was putting juice in the battery (just from the overhead florescent lights?)

Mark
 
The question is how much power do you need? Keep batteries topped off? Or running 6 to 7 amps a day? If the former--the trickle chargers are more than enough for an optima. If you are running some systems, then the units Foggy links to are going to be excellent at 10 to 20X the cost.
 
I'm responding to a simple solution for the poster's original statement and
concerns.

"I'm looking at installing a temporary solar charging system for the batteries
on my boat that is 90% of the time under a cover."

Cost is relative. Recreational costs are almost irrelative.

Aye.
Grandpa used to say, "You get what you pay for."
 
Below is basically the panel that I used. You can see the electrical connectors that come with the panel and allow it to be removed. Put the MPPT controller inside where you can read all of the information that a stand alone controller provides. All this for $110.

I would advise against the panels that supposedly have a solar controller on the panel for several reasons. First, it takes up panel space so a 50W size panel becomes a 45W panel. Second, you don't get a digital read out as to what the panel and your batteries are doing. Third, an efficient charge is based on battery temperature. If the solar controller is in the sun on the deck, you can't get maximum efficiency. Fourth, I've had the same flexible solar panel in daily use for 18 years. I've gone through 2 solar controllers in that time (at $10 each). That's actually okay with me because they have improved and now have digital read outs instead of just LED lights. But if the controller was part of the panel, I would have had to throw the panel out. Which brings me to #5. The panel with the integrated solar controller is $600. Ouch. Efficient, no. Convenient, maybe. Costly, yep.

When I first started using solar panels, I remember that $4 per watt was about the going rate if you shopped around. That has really come down. Don't worry about going bigger than just what's required for trickle charging. The controller will limit input if necessary.

I ended up buying a bigger solar controller for one of my installations. I could remove that flexible panel and face it directly at the sun. Turns out that doing that also got the reflection off of calm water. My 32W panel put out almost double it's supposed rating and blew out my little 4A controller. Now I spend a few $ more and get a controller that is at least 200% of panel rated output. Like a 10A controller for a 50W panel.

Mark

Panel:
http://www.ebay.com/itm/50W-18V-12V-Lig ... 2548.l4275

Solar controller:
https://www.amazon.com/Sun-YOBA-Solar-C ... ller&psc=1
 
My point is we don't know what the OP power demands are. That makes a huge difference as to the type and size of solar panels.
 
I am going through the same process right now of installing a system on my Tomcat so we can anchor out longer without starting the engine. We use a lot of electrical power stuff on our boat.

From what I understand, putting the controller as close to the batteries as possible and in the dry battery compartment is the right thing to do. Use good wire #10 or #12 and keep the run to the batteries as short as possible to reduce voltage drop. Also put a fuse that matches your controller output between the controller and the batteries. (20a controller...20amp fuse)

Since the panel generally only has short lengths of wire you will need to get a wire from the panel to the controller in the battery box. For this you will need a male and a female MC4 connector (Amazon or Ebay.) These are fairly waterproof so it will be an easy disconnect when not in use if you like.

If you are worried about rain coming down the wire make sure you use a good thru hull waterproof wire fitting for the extension from the panel to the controller. Also put a drip loop (Low hanging point) in the wire. If you buy the wire at a boat supply store they can give you some options. They also generally have a crimper and can help you attach the MC4 connectors.

Not sure how you are attaching the panel. There are some pretty clever ways so it can be removed, I am putting mine on my Bimini using outdoor Velcro on the top and bottom of the solar panel with Sunbrella that folds over to clamp the panel in between. (bottom and top Velcro). I have also decided to only put it in 4 places, and put some small 1/4 inch thick rubber window seal on the bottom in different places. This will hopefully let air and water that gets under it dry out. Also, I hope it will help keep the panel cooler and reduce any chaffing on the bimini.

I am finding that you cam get a 100w panel and 20 amp controller for about $200 give or take a few buck, however there is another $50 in other "stuff" you will need to buy to attach and install the system.
Keep in mind that I am learning this solar stuff from others like you so take anything I say as non expert advise.
Good luck,

PS Dr. Bob...you are right about how the Tomcat handles the following seas. This morning we found our selves surfing some surprise stand up 6 ft rollers across the Straights of Juan de Fuca and we never side slipped once. For me... a little scary but kind of fun.

mike
 
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