Solar on 39i

[mthackray]

I would like to add solar panels to my 2007 Jeanneau 39i. I sail in the Pacific NW in Puget Sound and up into Canada. My current electrical setup is three 105aH AGM house batteries with a new ProNautic 40A charger and the original 80A internally regulated alternator. I have no inverter. My biggest user of electricity at anchor is the refrigerator. I plan to add two panels on the canvas bimini, on the order of 150-175W each. This should give me enough power, along with the batteries, to be at anchor for 2-3 days without running the engine.

I understand that connecting two panels in parallel, may give better performance when one panel is partially shaded. On my boat, the bimini is completely behind the boom, so I question how big an issue this is? It would seem that the mast and boom could shade the panels in some orientations, but not all.

Here are my questions:

• How do I mount the panels on the bimini canvas? Snaps, zippers, velcro? I have seen people recently using very strong ceramic magnets which seems attractive.
  
• Should I wire the panels in series or parallel?
• How do I get the wires inside the boat?
• Where is the solar controller mounted?
  

Any comments, learnings and experience would be appreciated. Pictures are often helpful.

[sitara]

Hi,

I mounted two semi-flexible solar panels on my bimini, about 100 watts each. I secured each panel to the bimini with Loxx fasteners, with no problems at all. There was some wear on the bimini fabric caused by the edges of the panels after a few years but some rubbing strips fixed this. Others have used velcro or zips. In the case of zips the zip fabric must be protected from UV damage. I know of a boat that lost both Solbian panels (expensive) when the fabric failed in a blow. I ran the wires down outside of the bimini frame and into the port pushpit upright which has a hollow threaded section through the deck on my 36i. The controller is mounted close to the batteries, one controller for each panel may be a good idea especially if the panels can be partially shaded.

[Charlie-Bravo]

I am sure a 39i owner will pop along soon with good info for you, but until then ......

The set up you are thinking about should easily keep the beer cool in the fridge.

As you have already identified, there are choices to be made with multi panel set ups, series connection of panels doubles the input voltage, this gives extra scope on cable lengths and voltage drops, as losing one or two volts out of 28  or more ,is less damaging than when starting off with less,  and gives you a longer charging period before dropping to a voltage where no charge goes to your batteries.

Shading of panels, this can be a bit of an issue, better panels are kinda split into joined smaller panel areas with diodes, and the shading effect , although not doing any set up any favours, can be reduced, most of these panels however are rigid, glass fronted, and more tricky to mount,  the cheaper panels lose a lot of voltage partly shaded, flexi panels are easier to fit, you can stand on many of them, and they do work ..... just not performing quite as well as the rigid glass mono crystalline variety, but easier to mount, bimini etc.

You can run 2 panels via two mppt controlers , making them completely independent, which keeps things charging well even if only one panel is in full sun, and the other in shade,  at the cost of reduced voltage of not being in series, so running multi panels through one mppt isn't always best, perhaps 4 panels as two independent sets of two  in series would work well.

At the outset, it seems there is a lot of information out there ...... but without a difinative best solution, and can be confusing, been there myself so understand your questions, there is always a choice of solutions.

I started with one tiny panel, and turned the fridge off at night, not perfect but kept the beer coolish, then had an arch and mounted two large 200w panels in series and didn't have to turn the fridge off at night, and made more power than I used, lost that boat , and on the next I was back to a tiny 25w, now mounted a 120 w on the hatch garage coachroof, ... under the boom, ( not ideal but it's out of the way) but got a glass fronted super duper panel, not a floating power station, but does keep instruments and the fridge going for a week away.

Being able to tilt a panel toward the sun will help a lot, but the sun keeps moving ...... and so does the boat, so what value that has ?
Some clever set ups have used panels as spray dodgers, which they flip up once anchored , for livaboard this is probably a good solution.

The real things are , how much you need v what space is available, ..... and of course funds available, and then make your choices to suit.

Hope the above gives food for thought, and sure a 39i owner will say what they have found works best on your model.

last tip, if the fridge is full of cold beer / food, it seems to stay cold using slightly less electricity than if only half full.
CB

[zaphod]

On our 39i we initially experimented with a single 160w Ronogy panel on the bimini. It provided enough power to offset our loads during the day, and it was able to replace the power used overnight. We did start to go into deficit when we got a few overcast days. Shade management was a bit of a nuisance, particularly when swinging on the hook.

After that experiment I decided to buy a second Renogy pan and mount them on the bimini. We decided to mount the panels on a piece of sunbrella which is then zippered onto the bimini. We did this to minimize the potential for chaffe damage to the bimini, and to make the panels easily removeable. We don't leave the panels on all the time, we only put them on when we are going on a trip and we need to be off grid.

I wired the panels in parallel to prevent voltage loss due to partial shading. That would be less of a problem with panels equipped with bypass diodes, but the panels I bought are much cheaper.

I did the wiring in AWG10 wire to minimize voltage drop. The wires run aft down the centre of the bimini, then down to the transom where they penetrate using Scanstrut wire glands, and then forward to the battery compartment where the Victron MPPT 100/30 charge controller resides.

We were off grid for 3 weeks last summer and we never dropped below 80% even with a few overcast days. We even splurged and used the inverter to power the toaster at breakfast some mornings, and even on those days the solar had the batteries topped up and floating by early afternoon.

[mthackray]

All, thanks for the comments, information and pictures.  It is helpful information.  I am going up to the boat next week with some cardboard templates to scope out the layout before pushing the "add to cart" button.  I am getting close.

[vasko]

Always way better more fixed panel then flex - remember - dies not mean that you can flex them constantly - you just can mount them a bit bended.. always go for SunPower cells , fir you boat minimum 530-700 watts and better use EPVER MPPT

[zaphod]

Mar 27, 2022 18:59:38 GMT vasko said:

Always way better more fixed panel then flex - remember - dies not mean that you can flex them constantly - you just can mount them a bit bended.. always go for SunPower cells , fir you boat minimum 530-700 watts and better use EPVER MPPT

The op states that their main load is refrigeration so it is clearly not a power hungry boat. Even 500w is way overkill for his purposes!

[dbostrom]

If you'd like to cram in a little more, the hatch garage on the 39i nicely takes a notionally 100W Renogy or similar semi-flexible panel. Unless you have very young and/or very short crew members, there is little footfall on this area. Our panel in that location has survived without damage for some years. 

The panel is fastened down w/ an "industrial strength" 3M ball-and-socket style Velcro-like product. Conductors pass through a cable gland tucked close to aft end of hatch garage.

Note that in order to complete this neatly, you'll need to drop headliner, run cable forward, down through mast compression post, back to electrical bus connection at panel. In practice this is not terribly difficult. 

The downside to this arrangement is that for the very neurotic (me, for instance) there will be obsessive traveler/mainsheet adjustments when on the hook.  

In practice, this additional notional 100W panel supplies an extra 50W or so in favorable conditions. More or less, depending on the neurosis of crew. 

[mthackray]

Again, thanks for all the replies.  After my trip up to the boat last week, it looks like the 175W flexible panels are a bit too large and would bend over the Bimini center bar.  Thus I am now considering 2 panels of about 100 to 125w.  Not as much wattage as originally envisioned, but still a reasonable add.  

I spent time crawling around the aft cabins looking for how to route the wires.

All of this is conceptually easy.  The hard part is the actual details of mounting, cable entry into the interior, and routing.

Mark

[so40gtb]

Sorry for missing this post when it wasn't stale. Voyageur, a SO40, has had 2x100W cheap Renogy panels since 2014. They are now inefficient due to weathering, with a dull film look over the cells where shiny clarity was the norm when they were acquired. Accordingly, they will be replaced, and I'll buy something likely to last longer.

When first installed, the panels would support us in sunny weather for 24 hours with no net AH loss. I had retrofitted into the icebox a Webasto Isotherm fridge cooler that uses a water-to-refrigerant heat exchanger, which is about 40% more efficient than the standard air-to-refrigerant exchanger. All lighting was converted to LED.

The solar panels are mounted atop the bimini, attached to aluminum strips which are, in turn, fastened directly to the bimini bows. When I renewed the dodger, I had the canvas shop put eyelets in the bimini along the front and center bows, to facilitate solar panel fastening. Cable ties were used for 6 seasons (ugh, but they worked), but I've reworked the scheme to use screws attached to hose clamps. The clamps go around the bimini bows and the screws stick up through the eyelets, with the aluminum straps (and therefore solar panels) firmly attached to the screws. Needless to say, this makes mounting and dismounting easier at the season ends.

As for the electrical considerations, I had a large eyelet put in the bimini for the wires to penetrate. They are tied to the middle bow and framing down to the deck, where I installed a Marinco trolling motor socket that's good for more current than any solar panel that will fit would ever produce. Off season or when the solar panels are off, a rubber plug keeps water out of the socket.

--Karl

[dbostrom]

May 22, 2022 23:39:23 GMT so40gtb said:

 I had retrofitted into the icebox a Webasto Isotherm fridge cooler that uses a water-to-refrigerant heat exchanger, which is about 40% more efficient than the standard air-to-refrigerant exchanger. 

--Karl

Karl, that's something I'm very much interested in doing w/our 39i. By any chance is there a thread or writeup here describing details of your conversion?