Advice Needed on Solar

[Islander]

I'm about to put solar on the boat and could use some advice.
For reasons of space, I'm thinking of using a single panel, maybe the Kyocera KD215GX-LPU, mounted on a 1" rail across the back of the davits.

I'll then run about 10 feet wire to a Blue Sky 3024il MPPT controller just beside the batteries.

Are there any "gotchas" I should be aware of? For example -

Are only some panels suitable for use on a boat?
Are there specific "marine" electrical connectors I need to buy, or does all this come with the panel?
Any good leads on places to get parts like mounts etc.?

Thanks for any suggestions and experiences.

Cheers.

[djmarchand]

I installed a 135 W Kyocera panel on my dinghy davits like you describe many years ago. That panel came with a junction box on the bottom of the panel that I wired to. Use a wire gland or clamshell fitting where the wire enters the boat.

That size panel really won't pay for a MPPT controller. You could save a boat buck or so by using an inexpensive controller. There is much debate about the power benefits of MPPT.

Wire it with at least 12 gauge wire and put a breaker or fuse on the battery side of the circuit.

David

[smurphny]

I use three panels mainly because they were bought at different times. They are my main power source(no wind/water). It certainly would be neater to have only one unit but I like the idea of redundancy. On a boat >1 is always better. It is also possible to stow one or two when not needed to minimize possibility of theft. One panel can be left pretty much out of sight in the cockpit if boat is left on a mooring for a few days just to keep batteries up to charge.

[marshmat]

Spec sheet on the Kyocera KD215GX-LPU: http://www.wholesalesolar.com/pdf.fo...D215GX-LPU.pdf

Originally Posted by Islander

Are only some panels suitable for use on a boat?

There are some out there that won't last very long. Look for sturdy tempered glass, two-part silicone edge seals (avoid butyl) and well-encapsulated cells. Take a good look at the warranty terms- good panels have 20+ year warranties that also include declining output over time; cheap ones have all sorts of "gotchas" in the fine print.

Are there specific "marine" electrical connectors I need to buy, or does all this come with the panel?

See what's available from your dealer. Some sell kits that include everything, others ship a bare panel.

Originally Posted by djmarchand

That size panel really won't pay for a MPPT controller. You could save a boat buck or so by using an inexpensive controller. There is much debate about the power benefits of MPPT.

With 215 watts, perhaps not. Depends on how much your MPPT costs relative to how much the panel costs.

With the 215GX and no MPPT, output will be down by about 10% at a bus voltage of 24 V and by 20% at 29 V, compared to its optimal operating point of 26.6 V.

Its output will be down by 25% at 50 celsius, and by 60 to 80% at 75 celsius (on a 26.6 V bus, relative to output at 25 celsius) if you omit the MPPT. To maintain anywhere near rated output at 50 celsius, you'd have to drop the bus voltage to ~24 V, at which point you're not charging the batteries at all.

There's a good reason why all competitive solar vehicles, and virtually all grid-tie solar installations, use MPPTs. When conditions are optimal (direct sun, mid-20s temperature) they make no difference, but when the bus voltage is down or the weather's acting up, they keep the panel cranking away in conditions where its output would otherwise drop dramatically.

[noelex 77]

Originally Posted by marshmat

Spec sheet on the Kyocera KD215GX-LPU: http://www.wholesalesolar.com/pdf.fo...D215GX-LPU.pdf


With 215 watts, perhaps not. Depends on how much your MPPT costs relative to how much the panel costs.

That solar panel can only be used with a MPPT controler.It is not a standard 12v or 24v solar panel.

[Olorin]

I recently installed two Kyocera KD235GX-LPB panels and four Shell SQ-75 panels on my boat.
I mounted them over my bimini and davits respectively using 1" aluminum channel and stainless steel U-bolts. Primitive but robust.
I have two Morningstar 45 Amp MPPT controllers: one for the Kyoceras in parallel and one for the Shells in series and parallel.

The only gottcha I encountered was the Kyocera panels had sealed connector box with these new MC4 connectors on the interconnection cables. The best way to connect to the panels is to buy an MC4 extension cable twice as long as the distance from the cables on the panel and your connection box. Then cut the new cable in half and use the male and female connectors and cable to make the cannection. If you cut the cable attached to your new panel the warrenty is voided.

I put in the appropriate fuses (50 and 60 amps) going into and out of the controllers.

The system is currently (pun intended) putting out 56 amps at 13.8 volts in the Bahamas sunshine.

[noelex 77]

Originally Posted by Olorin

I
The system is currently (pun intended) putting out 56 amps at 13.8 volts in the Bahamas sunshine.

There is something wrong with those figures .
From 770w of solar panels you are getting 56 x 13.8=772.8w of power.

This is not very likely. The panel ratings already assume you are using the maximum MPPT point, the cell temperature is 25c (it will be much higher) and there is no loss in the wiring or voltage conversion.

Some of the meters on solar regulators are very optimistic and this, or similar measurement error, is occurring here.

Still 770W of solar is impressive and will give you lots of power.

[marshmat]

It is possible, in the Bahamas, to get more than the standard 1.00 kW/m2 total insolation at high noon, which would increase the current (and thus power) well above the panels' nominal rating for a few hours. But that's countered by the high temperature of a dark silicon wafer in bright tropical sunshine; high temperature reduces voltage (and thus power).

I think Noelex77 is right; this is likely a case of a rather optimistic monitoring device. Even so, at ~7 kWh/m2/day total insolation (typical of the Bahamas), an array like Olorin's should be able to put a good 300 to 400 A.h per day into a 12V battery bank when it's sunny.

As for going without MPPTs on the Kyoceras: I'd strongly advise against it. It's not impossible to use them with an old-school regulator, but it'd be a waste of an expensive panel as it won't get along particularly well with either a 12 or 24 volt bus.

[Islander]

Thanks for all the info, very helpful, especially the heads up about the MC4 connectors and how to deal with them. Also, the redundancy issue bothers me as well (I have a catamaran so I know 2 is better than 1 ) - I think I might also get a small flexible panel if I need to leave the boat unattended for a while.

I've read the pro and con MPPT arguments, but I figure it's worth the extra if it can squeeze a little more out of the single panel, I don't want the weight of a second panel.

I'm in the Seattle area so there's not a lot of this stuff laying around to go look at. If anyone can suggest a local dealer I'd be obliged - shipping a panel in seems to cost 50% on top of the purchase price.

Thanks again,

Cheers.

[thinwater]

I would try Googling some blogs. Many have installed panels and written up their experience; perhaps one will be a close match and give you blow-by-blow what worked.

This was my experience:
Sail Delmarva: Solar Panels

Ultimately, if you are going to do much electrical work on your boat, you'll need to learn about wiring methods, circuit protection, and charging. It's not rocket science, but it is more than a 3 sentence answer. I would suggest a basic book on boat wiring first; it should answer all of these questions.

[Seahunter]

Anytime you add solar you need a MPPT, especially for high wattage panels. I think you're on the right track with your choices. Personally I like the Sanyo panels for their reliability and their technology as well as Outback MPPT's but I see no problem with your choices. As for mounting, flat mount is okay, but make sure it's bolted down good; you don't want to loose it in the 1st 30Knot blow.
Wiring is another thing; don't cheap out. Use #6 (min) from the panel(s). Heat shrink and or liquid tape all connections and use soldered fittings and dielectric silicone on all mechanical joins. Again don't let anybody talk you out of an MPPT as it is required, especially if you value your batteries. I would choose a programable one though being my choice as you can have a genset option as well as other alternative energy management included in one contoller. I use http://www.wholesalesolar.com/ Good Luck.

[noelex 77]

Originally Posted by Seahunter

Again don't let anybody talk you out of an MPPT as it is required, especially if you value your batteries. .

Battery management of MPPT controllers and non MPPT controllers should be the same. Unfortunately many medium priced MPPT controllers compromise battery algorithms to reduce cost so are actually worse.
Keeping your batteries charged always helps battery life, but there are many ways to achieve this.

[witzgall]

whatever size you get, make sure you can fit it down the companionway if needed. If a big storm comes, you want to be able to take it down and store it safely away down below.

Chris

[Seahunter]

Originally Posted by noelex 77

Battery management of MPPT controllers and non MPPT controllers should be the same. Unfortunately many medium priced MPPT controllers compromise battery algorithms to reduce cost so are actually worse.
Keeping your batteries charged always helps battery life, but there are many ways to achieve this.

This is in part true, the $55 controller from West Marine is going to be more detrimental than not, however it's important not to cheap out on an MPPT charge controller. Good ones start at around $300 and excellent ones are about $500. Considering a bank of batteries is at least a "G" note it's a good investment to take care of them. It's vital for battery life that the MPPT be adjusted and programmed to the specifications for each brand of battery (not good to mix brands/types if you're going solar or wind). There are many roads to Rome as well, but nothing works as well as a properly programed MPPT charge controller to maintain optimal battery charging, but to also squeeze as much as possible the total produced alternative energy to those very batteries. I've seen many "haywired" solar system, so I don't disagree with your observations, so do it right, or don't do it at all, has become my motto.

[Mark Johnson]

You might as well make it where you can tilt the panel toward the sun when it's low, and storm worthy as well.

In the photos...
This 110W panel on the back, was mounted to a 1" dia tubular SS frame, that had 3/8" rod gussets in the vertical and horizontal plane. It was strong enough for TWO people to swing from violently! I had the frame for the panel welded up out of 1.5 X 1.5 X 1/4" thick angle aluminum, with 4 athwartships pieces of aluminum flat bar across the back.

In the middle of the flat bar I mounted 4 "Starboard" hinged "rail clamps", with a thumb screw tensioner. (West Marine) With these I mounted the new frame with the panel inside, to the 1" SS crossbar frame. A tubular bar across your davits would work the same.

The 4 "Starboard" rail mounts provide enough tension for it to sit in what ever orientation I leave it, and for hurricanes, I have a pair of VERY thin Kevlar "for N aft" downlines on each side, that run 3' down to a cleat mounted on the aft side of the SS legs.

This is SO secure that it, along with the other three deck mounted panels, have weathered numerous hurricanes, up to cat 4, with 150 MPH gusts! (been on there 14 years now)...

I suggest Anchor brand, ROUND, #12... or preferably larger, double jacketed, tinned wire. Using through the deck rubber "wire grommet seals", ROUND wire is MUCH easier to get a good weather seal. Round wire is also a better seal on the rubber gland's entry into the panel's junction box. West M sells the round wire, but you may have to order it.

Pictured also is the 3 stage (& equalize capable) smart charge controler I chose for my application, and these are meant for standard low V panels, that tend to be rated around 18V, before regulation.

Hope this helps...

Mark