Location for a Small "Non Marine" 20W Solar Panel

[rardiH36]

I'm looking for forum input about the following project.

I've just purchased a 20w solar panel for the purpose of maintaining charge to my deep cycle batteries, and to replace the small current draws of listening to the stereo at berth between sailing outings. (I happen to have two solar charge controllers. I think I'll dedicate one to each battery). Size of the panel is 16" x 17" and weight is only about 4 lbs. I didn't obtain from a marine distributor, but it looks boat-suitable enough: Well contstructed with tempered glass, adequate strength anodized aluminum frame joined together by SS fasteners, and it has cauking sealant at all joint/frame interfaces and all around the junction box.

- I'm planning to mount the panel aft-side of the stern railing (opposite side of where the life-sling is) at the height of the upper-most bar. This is about 4.5-5.0' above the water line. My boat's transome is outward sloping. And at the water line the transome edge is beyond where the outward-most edge of the solar panel will be. In my year on SF Bay I've never had a wave strike in this area that even splashed above the cockpit coaming level. Putting the panel in this location will make it unlikely that it can be damaged by dropping something or stepping on it. QUESTION: GOOD LOCATION OR NOT?

- While the overall construction of the panel looks robust/sealed enough for the purpose, the underside is exposed. It would be easy enough to attach to the bottom side of the the aluminum frame a thin 16x17" sheet of plexiglass (or some other material) to protect the bottom from salt spray or a more significant splash from a breaking wave. I would leave a few gaps so condesation could weep out. QUESTION: IS THIS ADDED PROTECTION NECESSARY?

Thanks in advance for opinions.

 

[kendall]

as I understand

Solar panels should have ventilation so they don't overheat. Most manufacturers installation notes rocommend mounting panels on standoffs not directly to a surface. So you'd need to mount the new backer plate with enough room for airflow. A half inch off the panel, with good gaps around the edges should be enough to provide protection from waves etc hitting the back, and still provide adequate airflow. Try to mount them so any re-enforcements run vertically so they don't inpeded airflow

The connections are the only thing I'd realy be concerned with getting wet, and if you make sure they are tight then seal with varnish, or 'glue' a small box over them they should be good to go.

Ken.

 

[Ross]

If I had doubts concerning the weather proof

ability of a panel like this I would consider troweling a thin layer of marine grade caulk over the entire underside, sealing the underside against water and salt spray and salt intrusion.

 

[Dave Groshong]

phone number

206-651-2022

 

[rardiH36]

Kendall & [ un] - Solar Panels/Temp and Layer of Marine Caulk

Good considerations, both of you. Thanks

Kendall - Several years ago when I was researching before adding solar to my house, I recall several items affecting the arrays output calculation. The ones that still come to mind are: latitude, altitude (i.e. Denver vs Sacramento), slope angle and orientation of the array, % sunny days, shade issues, and AVERAGE DAY-TIME TEMPERATURE. The formula showed that efficiency went way up as temperature falls. On a sunny cold day, much more output than unders same but warmer. I subsequently noticed this myself. On days when rain/clouds have kept the panels cool during mid-day, and suddenly the sun pops out between the clouds, the system's meter shows virtually full rated output (1.8 kw in my case) before the panels begin to heat up under the sun. But for the same time of day when its been sunny and the panels are very warm, usually the best I see is 1.2-1.3 kw.

regards,
rardi

 

[Ed Schenck]

Solar on the H36.

Be nice to see some pictures of the installation Rardi. Will the angle be adjustable or fixed? That area is not available on my H37C, the outboard hangs there. And as you point out the other side has the life ring.

I am thinking on top of the bimini. But first I will replace the lightweight aluminum with heavier stainless. And now it is a folder with straps. I'll make the new frame rigid. Is it worth it to make it adjustable for angle?

A friend has panels over the arch of his 44DS and they are fixed. But then there are two and they are huge. It would be nice to not have to use shorepower when I am away from the boat for so long. But I have no other charging system and worry about no power for the bilge pumps.

 

[Taylor]

Location

I have my solar panel in the same spot you describe, starboard side, top rail cantilevered out over the reverse transom, and its been a good spot - rarely seems to get in they. Another alternative is poll mount it up higher. Best place is probably on a radar arch or above a set of stern mounted davits. I used some rail mount clamps and some stainless tubing for struts. With a smaller panel than I have you may be able to get away with just rail mount clamps.

 

[rardiH36]

Ed - Sure I will post a pic .... but .....

Ed:

I will be pleased to post a pic or two and a description when done.... but the installation will still be a few weeks off.

This because just finished several days to repair/reconfigure/rebed the leaking anchor roller and windless, which a PO from the past hadn't done too well. This stuff is crammed up against the last forward-most few inches of the narrow bow. A real bear to get a socket wrench in that spot from underneath. Lots of sore muscles and a few bruises.

So intend now to enjoy some fall sailing for a couple of weeks ... a break from repairs/upgrades.

regards,
rardi

 

[shorty]

This 20 watter sits nicely

on the companionway hatch cover. Flexible, not supposed to step on but not bad if you do. Has worked very well (so far) 2 seasons. Does a great job maintaining 2 each group 27 Lifeline AGM's. And yes, regulated.

 

[Mark Price]

Ed- Here is what I did on my H37c

All of the pannels are flex/thin film. Not real efficent but I do not live aboard and so the House (4 group 27s) and Start banks (1 group 27) are always topped off. Last week spent 3 days with an other couple and we had anchor lights, 3 fans, inverter (350 Watt) and CPAP machine running all night. During the day the pannels caught back up with the draw (we were on the hook and not using the motor). Very happy with set-up and did not cost any deck space.

Mark Price
S/V Illusion