Panbo

More Gizmo 2011, the solar panel project

... written for Panbo by Ben Ellison and posted on Jul 7, 2011
Gizmo_solar_panel_plan.jpg

So maybe this is an all-about-Gizmo week. Given her multitude of electronics partly described on Monday, and the fact that the boat rarely sees shore power, plus how helpful readers were in spec'n out the ChartTable21 discussed yesterday (and yet more strain on the 12v bank), I'm keen to add some solar panels and I again seek advice. Oh, and while Gizmo does have a 6 kW generator, I don't like running it, and would enjoy removing it altogether. I created the drawing above (PDF here) in an effort to explain to a solar salesman in Arizona what I was up to, but I haven't purchased anything yet...

The heart of the system is a pair of 135 Watt Kyocera KD135SX-UPU 12 volt panels that will be wired in parallel. This is about the most wattage I can fit on that aft cabin top and a conservative choice as Kyoceras are in use on many boats, including a harbor neighbor who raves about their output and reliability. He's also in full agreement about my desire to have a fore and aft tilt mechanism as our boats both lay at mooring floats that are aligned close to north/south and tilt means a lot at our high latitude.
   I also like the idea of being able to access that aft deck. I doubt I'll ever lift the little inflatable that came with Gizmo onto that high perch again, but I do still have it, and it seems wrong to remove the well installed teak chocks. Plus if I get the frame right, it could also serve as a crutch for those rare occasions when I lower the antenna mast. But it took me a year to realize that I could use the mast's existing tackle and winch to tilt the panels appropriately to the season rather than coming up with some sort of adjustable legs. And the old sailor in me likes that; who wouldn't want to sing out "Sun's aft, laddies, time to hoist the panels!"
   At any rate, I'm thinking of starting with off-the-shelf Unirac SolarMount panel rack components because they seem well designed, they're inexpensive, and, geez, it is July already. They're also anondized aluminum, which fits my desire to keep this system light, except for the flanged stand-offs which I plan to use as hinges. They're zinc-plated steel and could be a problem, but it would be easy to have them duplicated in aluminum at a later date.
   As for a charge controller, I don't think I need much in the way of monitoring -- Gizmo is already loaded with shunts, current sensors, displays etc. -- but I am pretty much persuaded that MPPT (maximum power point tracking) is worth a few extra dollars. Thus I'm thinking about a unit like the Blue Sky 1524iX, seen below as tricked out by eMarine for easy boat installation. So what do you think, Panbots, does this system look right for quietly helping me run electronics and even refrigeration at will?

e30_new__25341_zoom.jpg

Comments

I've had 3 Kyocera panels (3 120's, one of which got replaced with a 130) for the last 10 years, and a Bluesky MPPT that went in maybe 5 years ago. I'm quite content with the system and its output. (Photos of the mounts on the "projects" page on our website).

My first thought is that you're likely to see a lot of shadowing from your upper steering station/bimini and boom. Somehow the wind (at anchor) is always coming from the direction of the sun, SE in the morning, SW in the afternoon, but maybe that's a local phenomenon. Given that one cell shadowed at 60% cuts the output of a whole panel by 50%, I would expect you'll be disappointed by your output from the rear deck.

I'd suggest that you look at moving the panels to the top of the bimini.

Good luck.

Posted by: Larry Shick at July 8, 2011 6:30 AM | Reply

Larry is right on, the shading will be significant. You'd be better off to build a rigid Bimini top and put all the wattage you can fit, up there.

That is what I have done. I have 1.2kw (8 panels) on my hardtop in 2 banks, one with a Blue Sky MPPT, the other with a Morningstar Tristar MPPT. These are flat mounted I've seen midday current as high as 39 amps @ 24 volts.

Good luck

Posted by: Bill at July 8, 2011 7:28 AM | Reply

I am curious how many watts you hope to actually get out of the system, also how and what type of battery system/invertor do you use now.

Posted by: Chet at July 8, 2011 7:34 AM | Reply

Thanks, Larry. The thing about Gizmo's situation is that when she's on her home float, her stern is pointing nearly due South. So putting panels on the bimini would mean they were shadowed by the upper mast and radomes in the middle of the day. Also, when we're cruising, we're often running a 150 amp alternator when underway, so it's the home port time that's harder to cover with refrigeration and electronics juice.

While it's not for me, I do like the idea of putting solar panels on a bimini. The space is usually unusable and it seems right to be collecting juice from rays that might otherwise have been damaging your skin. And I hear that Gemini Marine -- a local company I'm fan of -- is working on some hardware for this purpose: http://goo.gl/lImZv

A bimini install might also benefit from the super thin and slightly bendable Ganz Marine Panels I mentioned in an earlier solar entry: http://goo.gl/wnu7q

Posted by: Ben at July 8, 2011 8:30 AM | Reply

Chet, Gizmo's main bank is a pair of Deka 8A8DM AGM batteries with a 20 hour amp hour capacity of 245 each. I found this out with much help from Panbo readers when I got badly confused by a bogus amp hour deficit number on the boat's Link 1000: http://goo.gl/4vyZu

This Spring I had the alternator rebuilt and installed a Balmar MC-614H smart regulator: http://goo.gl/V6tof

It seems to be working fine on its default settings, but my "systems guy" Alden Cole hasn't done the final tune up because we're still waiting for alternator and battery temp sensors to arrive (I need to get on that).

At any rate, the bank seems to be in fair condition, holding a charge of about 12.6v and taking in as much as 120 amps once the Balmar ramps up. The charger/inverter is a Xantrex Freedom 25, but it hasn't been used since leaving the boatyard marina in mid May. Then again, I've only got about 100 miles on the boat so far this season due to multiple projects (for shame!) and I'm not yet running the refrigeration.

Posted by: Ben in reply to Chet at July 8, 2011 8:56 AM | Reply

Incidentally, I had lunch with Dan Corcoran yesterday, and he's working on ideas and hopefully some testing on how to plan ahead systems-wise for the time when high current lithium or thin plate batteries become a realistic option financially. We never did get around to talking about my panel plans, and I hope he'll add his two cents, but then again he is enjoying a cruise Down East.

Posted by: Ben at July 8, 2011 9:02 AM | Reply

I keep looking at solar power, I have a houseboat and a great southern exsposure.

One option is Grid-tie but my marina is a bit nervous about it.

I still like the idea of something that would work at the dock AND out on the water.

Could I get 200 or 300 watts at 120Volts for any decent length of time?

I also am liking the current 30% tax break on solar at the moment as well!

Posted by: Chet at July 8, 2011 9:15 AM | Reply

Ben,
I installed three of these panels last winter, with Blue Sky, tilting, and quick removal for hurricane stripping if required.

Four observations.
405 watts (with all the variability for clouds, shade, pollen, bird droppings, etc) completely meets our demand April through October on the Chesapeake anchored or underway (excepting AC) -- 40 foot sail boat with usual modcons, 660AH Lifeline bank.

The new panels you describe have internal blocking diodes and shading is far less of an issue than it was with the previous generation of Kyocera 135s.

The Blue Sky appears to get a bit confused by high current alternator output or the same with a charger. It's a subtle effect, but from time to time we see it reporting bulk charge when current is 0. This resets in five to fifteen minutes. Our shunt is collocated with the Ample and Link shunts and zero-ed. Even so, while amp readings match closely, accumulated AH can be significantly different when in accumulate and float. I have a VM directly wired to the batteries, and when comparing all three, I find the Blue Sky A & AH to match their predicted profile, compared with battery volts, better than the Link.

Tilting is a mixed bag. It definitely works , but more tilt is required than you may expect. You will get some sail area out of tilted panels. When titled they need to be secured against moving UP as well as DOWN. And when tilted they need to be protected from twisting. (it's not so much a glass or cell issue as it is a sealant issue.)

Posted by: Christopher at July 8, 2011 10:20 AM | Reply

Ben,

Long time reader and big fan.

Similar to your proposed installation, we rely on 510 amp-hr of 12V AGM batteries, 2 x 180 Watt panels and a BlueSky 3024iL MPPT controller. Even though our east-west main sail boom orientation often shades 50% of the panels in the slip, we have no problem keeping up with the 12 volt refrigeration load here in New York. Don't know your refrigeration load, but would expect your system would be able to easily maintain your batteries near 100% on the mooring.

Monitoring of our battery voltages indicate that they usually are getting topped off (i.e. 14+V) in the early morning, going into float (i.e. approx. 13.2V) mid-morning. Presumably the refrigerator is drawing the batteries down a little overnight.

Your BlueSky 1524i seems to be a good match to the Kyocera panels with the caveat that any future upgrade in panels will require a new larger capacity and/or higher voltage controller as well. Question how the eMarine packaging allows for ventilation of the BlueSky heat sink?

One other thought, use of the boom to suspend the solar panels at an angle may need some additional tethers under the panels to keep the panels from getting twisted or blown to a higher angle from wind gusts at the mooring.

Posted by: Steve Strait at July 8, 2011 10:20 AM | Reply

I've been toying with the idea of polished aluminum or silvered mylar covers that would protect the panels from weather, and adjust their opening angle to reflect more light onto the PVs.

In my case they need to hinge at all four sides with a gimbal frame, and lock with friction clamps. I envy your mast. (Don't take that the wrong way.)

Posted by: Sandy Daugherty at July 8, 2011 10:24 AM | Reply

Thanks, Steve & Christopher. I'm already planning -- and looking forward to tweaking -- a bridled panel rack downhaul to keep wind from flippin it up.

Christopher, I thought it was inadvisable to have more than one shunt on the same battery bank. But it's working for you? I'd love to see a diagram.

Similarly, I think I need a diagram to understand Sandy's mirror idea, though it sounds interesting. And no worries about the mast envy, Sandy; it's a cross I've learned to bear ;-)

By the way, I'd appreciate recommendations on knowledgable yet reasonable solar components suppliers. The salesman I'm dealing with is not impressive.

Posted by: Ben at July 8, 2011 10:42 AM | Reply

Ben,

I sit somewhere in the lower half of journeyman when it comes to electronics. I went to the "master" who originally (and beautifully) wired my boat both factory and aftermarket. It was his suggestion to collocate the shunts. His explanation was the currents involved would be negligible for a system as small as ours. He said when he wires shrimpers or other workboats with frequent large current input/output, he uses separate shunts but is mindful of matching length and gauge of wire runs to the shunts.

I went with his guidance and have seen no ill effect. Nothing in the system guidance warned against so I did it. Worst problem was tiny screws, big fingers and a deep bilge (oh my).

Suppliers. I got great help from Northern Arizona Wind & Sun -- Panels, Cables & Blue Sky plus good telephone support. They aslo cut me a deal on the "package." And don't forget to look into Solar tax credit for second home.

Finally make sure you buy the cable connector tool (and a spare). If you have to undo these cables, there's a high probability of connector damage without the proprietary tool.

Posted by: Christopher at July 8, 2011 11:03 AM | Reply

Here is a good tutorial on planning an installation, if you can make it all the way through. (not easy):

http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/

http://handybobsolar.wordpress.com/the-history-or-how-did-i-end-up-so-angry/

Though I DO NOT agree with his max voltages, (especially for AGM's!) and some other details, he makes many good points.
I'll second a recommendation for NAW&S, good prices and good service.

Posted by: John K at July 8, 2011 11:40 AM | Reply

Reflectors: be careful.

Domestic use solar panels are designed for the maximum solar energy they would encounter in passively irradiated use with a safety margin for incidental reflection.

Adding a reflector might never cause a problem in a sun-impoverished place. Doing so where the sun is bright but incidentally cloud shaded, etc, can result in too much solar energy being presented to the cells.

Possible results: overheating, warping, cell damage, blocking diode damage, and voiding that 25 year warranty.

Most solar arrays with reflectors have detectors to measure received solar energy at the cells and actively redirect reflectors to keep the energy level to a safe and design compliant level.


Posted by: Christopher at July 8, 2011 1:06 PM | Reply

I tried the Blue Sky 3024 in 2008 and it created so much electrical noise in the system that the shunts for the Mastervolt MICC would not work. I took it out of the system and the MICC worked fine. I ended up using Mastervolt controllers.

It's looks like other people are using the Blue Sky successully now so perhaps they've addressed the noise issues.

Posted by: Russ at July 8, 2011 2:47 PM | Reply

Hi Ben,
I have koycera panels 6 x 40 watts in two banks port and starboard controlled by 2 x blue sky 2512i controllers and a Figoboat fridge. Batteries always charged and fridge on 24 7. Smaller panels reduce effect of shadows hopefully only effecting one. If you use thin skin panels remember that you will need more area for same amps. If using thin skinned screwed down ones, use the ones with 38 cells to overcome voltage drop when they get to hot. Blue sky and Koycera panels represent excellent value, $ to amps gained or in my case £ to amps.
Laurence

Posted by: Laurence Woodward at July 8, 2011 3:52 PM | Reply

Similar subject for another time.

I'm curious to know if anyone is doing solar hot water systems for marine. Tired of running the engine for an hour to heat the tank (sail on mooring), and looking for more that the small sun bladders.

Posted by: Paul at July 8, 2011 6:31 PM | Reply

Ben,

Another thought. The best I could tell, the cables from the panels contain untinned wire. I wrapped all connections in self-vulcanizing tape and splash protected all the junctions and the run down from panels to Blue Sky with loom and a drip loop. Loom is pierced at drip loop low spot just in case.

Posted by: Christopher at July 8, 2011 6:44 PM | Reply

Ben,
It's probably good practice to have a clear understanding of what the system will do before spending the money and then test that against your expectations. It would help to have a good idea on actual 24 hour energy consumption and then factor that against a realistic estimate of solar panel output.

The easiest way to determine the 24 hour energy use is to disconnect/turn off all charging sources, note the amp hours remaining in your battery bank and check it again the result 24 hours later. The difference is the consumption. Just use your boat as you normally would (including refrigeration).

At our latitude in Brisbane Australia, I count on about 60% output of the solar panels for say 6 hours a day - that is for panels lying flat on a roof. This is what we found on our Argus Boats project.

The two hours after sunrise and before sunset don't count for much. On that basis, I would expect about 70 amp-hours returned on a good sunny day for 260 watts of solar panel. You will need to add the extra obtained by setting the panels at an angle.

The amp-hours consumed minus the solar amp-hours generated will give you the deficit in energy that needs to be made up from other charging sources.

I suspect at the dock, you will still need to be plugged in to shore power unless your daily consumption is less than the solar output. I assume that you do have shore-power available? None the less, only you can put a value on using that much less coal (nuclear?) energy.

At anchor, 70 amp-hours of solar charging will probably translate to about 45 minutes less of engine run time based on a 100 amp charge acceptance rate of your batteries.

It will be interesting to see the measured result on daily consumption to get the total picture.

Posted by: outbackgary at July 8, 2011 8:34 PM | Reply

You are right about the impact of shadowing. Check out custommarineproducts.com. They have an interesting pole mounting system that may work for you.
Tom

Posted by: Tom in reply to Larry Shick at July 8, 2011 10:54 PM | Reply

Thanks, Gary, but I tend to look at it from the other side. My boat is almost never on shore power (it lives on a moored float) and I've always been pretty careful about power consumption because I don't like running the engine or generator when not underway.

I don't know what my two Sea Frost refrigeration units use, because their load is variable (and I haven't yet passed it through a watt hour meter), but it's not trivial and might even equate to that 70 amp hour per day figure. But I think my panels may do better than that when the boat is home because I do have a good angle on the daily solar path that I can tilt to.

And if I do get more juice than needed for the stuff I use when messing around at my mooring plus a constantly cool refrigerator, I have no doubt I can find a use for it! For instance, I'd like to have an always-on monitoring system with a shore connection. And it might be fun to put my underwater lights on a timer for a little flash, or turn the twin reefer boxes back into freezer/fridge mode.

My point is that amperage budgets are not constant. And they tend to grow, especially if the power doesn't cost in terms of noise or fuel. I also think there's a plus to the slow but long term nature of solar panel charging. I may be able to put some 70 amp blocks of charge into my batteries in 45 minutes of alternator time but certainly not the last block and maybe not the one before that.

Posted by: Ben in reply to outbackgary at July 8, 2011 10:55 PM | Reply

Thanks Ben. I was thinking that you were living aboard Gizmo at the mooring for extended periods of time. If you were aboard for only a day or two at a time, then the 270 watts of solar (or much less) would amply charge the batteries while away. You would probably be dipping significantly into your house bank while aboard.

It would still be interesting to understand the amp-hour consumption for a 24 hour period of "live aboard".

Yes, solar panels are a great way of getting a set of batteries to that final charged level - provided that their output is greater than consumption.

Posted by: outbackgary at July 8, 2011 11:29 PM | Reply

Ben, I'd be surprised if those two panels will keep your system charged with the refers running.

Assume your refer load is 3-5 amps 33% of the time 24 hours a day winter, 50% of the time summer(x two systems?)somewhere around 100 amp hours/day. My system, 12v, consumes up to 125 amp hours/day in the tropics, and it is a single, small, well insulated, box.

Your panels will provide around 8 amps each for roughly 6 hours per day, even with tilting, so you have roughly 100 amp hours input.

Doesn't leave much for all the electronics, lights, stereo, etc. When you are not aboard, if you turn off some referigeration, and you have sunny weather, it might hold the batteries, but probably not while you are aboard at anchor or on your float.

Posted by: wingssail at July 9, 2011 3:16 AM | Reply

Ben,

I did extensive power modeling before I shelled out for the three 135s we now have. So we have spent a lot of time looking at performance vs our model.

We have Frigo-boat Reefer & Freezer and 11 cuft combined cold space. We keep them at 34 and 18 deg F respectively.

All lights aboard are LED. We listen to stereo perhaps 6 hrs a day, and watch TV perhaps 3 hrs (some of that is just weather radar display). Microwave gets used perhaps 30 mins a day.

We have 37 years of experience conserving water so those pumps don't run much.

7 fans don't pull an amp together.

Underway, we run radar, VHF, AIS, NAVTEX, AP, and instruments.

We have an 80 Amp Alternator with Nextstep and a Xantrex 3000 CH/INV with Link

All told, our five season average daily demand varied from 100 to 140 AH

Today at lat ~38 with the boat generally on an E-W axis and panels flat, we are at -40 to -60AH at sunrise. We see full battery charge between 11 am and 2 pm. We see no further deficits accumulate until about 2 hrs before sundown as the panels can service all of our loads once they have serviced the batteries.

Underway we have yet to see a deficit accumulate. However, the amount of time time takes to recharge is clearly impacted by how hard the AP has to work.

We have not used the Xantrex for charging since installing the panels. Alternator runs cooler now as it rarely runs above 30 amps for more than a few minutes.

Clearly every boat is different. Peoples usage patterns vary. Skies cloud. But for us, unless we run the AC, we have stopped needing fossil fuels for electricity (not counting what the alternator is providing for the short while it's in use.)

With two of these panels clearly there will be differences, but I think you are going to be very pleased in the long run. WIth current fuel costs and figuring the tax credit, we expect payback in 2.7 years.

Posted by: Christopher at July 9, 2011 4:25 AM | Reply

Paul,

I needed a diversion load for my solar 'array' and settled on a Seward water heater that I replaced the 120v element with a 24vDC heater element. They are available in 12vDC if that's your voltage. Links below.

http://www.seawardproducts.com/waterhtr.htm

http://www.survivalunlimited.com/diversionloads.htm

From my electrical guru: With full battery and max sun and 100% efficiency it takes 2.5 hours to heat 6 gal of 80°F water to 112°F and 9.9 hours to 212°F with a 185w panel.

Posted by: bosunj at July 9, 2011 5:07 AM | Reply

Thanks all! You guys are great, but I think some clarifications about my particular situation are in order ;-)

* Shading: I guess the images don't tell the story well, but horizontal panels on that aft deck will have a wide open sky view over about 300 degrees of horizon and the obstructions in the 60 degrees are fairly broken up. Check the header photo on the Forums and understand that the mast is about 4' forward of the panels and the bimini further. I actually don't think a hard top bimini (which I don't want to get into) would be much clearer (though it could accommodate more panels). It's a bonus that that the aft deck is aimed within about 20 degrees of true south when tied to her mooring, which is where I feel the power pinch the greatest (Bing has great photo maps of Camden now: http://goo.gl/8iZgs ).

* Power needs: I use Gizmo in many modes -- from floating test lab to live aboard cruising to possibly leaving her on a mooring down south for a month or two next winter -- and my power needs are quite elastic anyway. I spent much of two winters in the Bahamas without any refrigeration at all, and it was probably the healthiest time of my life (long term skin damage excluded).
I've already converted some of Gizmo's lighting to LED and plan more. I also added foam insulation to the freezer/reefer partition in Gizmo's large but heavily insulated top opening reefer box so I could more efficiently run the former freezer side as just a refrigerator. (If you've lived without refrigeration, it's really easy to live without a freezer.) And I put several five gallon jugs of water on the bottom of those boxes to act as cold sinks.

I'm not a hardcore environmentalist (I think Carlin has that pretty right: http://goo.gl/0fnd ) but I am willing to trade some 'comforts' for peace and quiet aboard. Then again I do like to work and keep in touch with the world from the boat -- best office ever -- and I do enjoy food kept fresh with refrigeration, pressurized water, etc. (I still can't get over the fact I have a boat with a real shower).
At any rate, I think I'll enjoy whatever Watts I can get out of the proposed aft deck system, and I very much doubt that it will be a failure and lots of folks are satisfied with similar installs. But maybe there's a better way to use the panel space I have. Alden Cole called yesterday and said he'll propose higher voltage panels installed serially with a charge controller that converts the results down to 12v charging currents. I don't see much out there about such systems, but he's up on this stuff...

Posted by: Ben at July 9, 2011 11:35 AM | Reply

Hi Ben,
I am sure your system will be just fine, the blue sky controllers are already dropping the panel voltage from 17 volts to something the batteries can handle without loss. Friends call it free energy, I guess Alden is talking about something similar but scaled up although I have not come across high voltage panels. I plan to have a solar hot water system at some stage at the moment is just a black container left on deck. As you say Kiss.
Laurence

Posted by: Laurence Woodward at July 9, 2011 4:26 PM | Reply

Do read Handy Bob and then read it again. I followed his advice and am very happy with my 4 x KD210 panels and Morningstar Tristar MPPT-60 controller. They are working great right now in the Thousand Islands and have performed great in The Bahamas as well.

The big thing I decided was that the number one reason solar installations perform less than expected is voltage drop. It is real easy with 12V (nominal) panels to not have enough left to charge batteries well. My 8 x L16HC trojans are spec'd at 14.8 volts and they are almost 50' away by the time the wiring gets from the pilothouse roof to below the waterline. That is why I decided on higher voltage (28V) at the panels which cuts the wiring voltage drop in half and ran 2 AWG cable after bringing each panels cables into the pilothouse. This does require an MPPT controller that can handle this. You could also wire the panels in series to achieve higher output voltage.

wayne
FLUKE KK48 Whaleback
flukeblog.blogspot.com

Posted by: wayne thomas at July 9, 2011 6:20 PM | Reply

Maybe this is too extreme, but what I would do in this case is mount the panels on the float and use that system as a "shore power" source. When cruising the engine alternator should suffice. When at a mooring down south, empty the reefer.

Posted by: norse at July 9, 2011 6:38 PM | Reply

Thanks, Wayne! Enjoyed your blog, too, and found an entry that seems to show your panel set up well:

http://flukeblog.blogspot.com/2011/06/waterford-way-west-on-erie-canal.html

Norse, my float is 6x30', I only own half of it (how we do it here), and panels would often be shaded by the boats tied to each side. But besides all that, why would it be better to put my panels there instead of on my aft cabin top, which is unused space with about 300 horizon degrees of unimpeded sun exposure?

Posted by: Ben at July 9, 2011 7:06 PM | Reply

I have just waded through Handy Bob's blog which is undoubtedly one of the better references I have come across - but it is very targeted at RV installations and possibly misleading in a few areas. As it was referenced here, I would like to add a few comments for marine:


  • Flooded cell batteries are a great choice for an RV where ventilation to atmosphere and access to check levels is not a problem. They are an accident waiting to happen in a boat so it is probably best to go Gel or AGM unless the installation is meticulously performed.
  • Bob notes that MPPT doesn't perform any better when the batteries are near full and that they are best when the batteries are at a lower voltage. That's true - it's when the batteries are in bulk charge mode that the MPPT's come to light and it is in this mode that we need the benefit. They are particularly good in overcast conditions. See http://en.wikipedia.org/wiki/Maximum_power_point_tracking
  • When using MPPT controllers, pick one that allows the panels to be connected in series (all panels must be identical) so that the array can be operated at a higher voltage with less current. This will minimise voltage drop.
  • Another benefit of an MPPT controller with panels connected in series is that one is not restricted to the native battery system voltage when it comes to panel selection. Given restricted spaces on boats for panel placement, a larger selection of physical size is a huge plus. The Outback Power Systems Flexmax MPPT regulator allows up to 140 volts (open circuit) for the panel array. The MPPT controller will step this down to the correct battery charging voltage.
  • Modern solar panels have bypass diodes which allow panel current to "bypass" strings of high impedance shaded cells. We have worked on very few vessels that don't suffer from masts, booms and other shade producing objects. That's the nature of boats. As seen here on the Argus E35 project, the radar tower is a shadow source but the bypass diodes and MPPT keep things in order, all be it with reduced power from the shaded strings. However bypass diodes will not help even with a thin shadow across all panels at once.

Posted by: outbackgary in reply to Ben at July 9, 2011 10:37 PM | Reply

HandyBob Solar leaves me with the message that PV is still only for geeks willing to dive into tech details.
http://handybobsolar.wordpress.com/

Regarding the idea of locating the panels on the float, this is only better if they would be unnecessary while cruising and a bother on the boat, and if both owners of the float agreed and gave it a clear south-end location. HandyBob stresses that certain components should be close to each other, so this idea may not be practical at all.

Posted by: norse in reply to Ben at July 10, 2011 4:27 PM | Reply

Hi Ben,
I would wire the panels in series rather than parallel. In parallel, if one panel gets partially shaded you will lose its entire output. In series, you will only lose the output of the shaded cells.
You will be slightly more efficient in series since the current in the wires and the controller switching circuits will be lower. The controller you picked will work either way.
I would also skip the tilting apparatus, and spend the money on bigger or more panels.
Good luck

Posted by: Tony at July 11, 2011 2:34 PM | Reply

Ben, I love your boat. Can you please tell me what make / model / year it is. I am considering moving from sail to power and I like the design lines of your boat. But don't know what it is. Thanks, Dan

Posted by: Dan at July 16, 2011 9:39 AM | Reply

Dan, She's a Duffy 37, hull #1 built in 1999 by Atlantic Boat Company in Brooklin, Maine, and designed by Spencer Lincoln, also of Brooklin:

http://www.atlanticboat.com/duffy37.html

However, you'll see that Gizmo's extended cabin top and other elements are unique, and that's because she was shipped as a bare hull, though maybe with engine and bulkheads, to Covey Island Boatyard in Nova Scotia for finishing. I suspect that the original owner was quite involved in the detailing, and I'd love to thank him. She was launched as Cardigan Bay in 2000.

Posted by: Ben in reply to Dan at July 16, 2011 9:59 AM | Reply

Hi Ben, We are about to order a Kyocera 140W solar panel and Genasun MPPT Boost 8a Controller for mounting on our davits. Before we did so, we thought we would run it by you in case you might say "God, no not that!". We appreciate any thoughts you or any of your loyal followers might have about that combination of products. Thanks, Jack

Posted by: Jack Moore at August 13, 2014 12:31 PM | Reply

Hi Jack,

A year after this entry I wrote about the system I actually installed, which is slightly different:

http://www.panbo.com/archives/2012/08/greening_gizmo_17_amps_of_solar_panel.html

I'm very pleased with the long term performance of two Kyocera 140 Watt KD140SX-UPU panels and a Blue Sky 2512i MPPT controller all purchased through eMarine. But I've heard good things about Genasun.

I don't know if you're working with Bruce Schwab, but he has become quite the expert marine solar source in our area:

http://www.bruceschwab.com/solar-power/

Posted by: Ben at August 13, 2014 5:04 PM | Reply

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