Challenges with Solar on boats

[witzgall]

HI all,

I am doing a bit of research for a project. If you are currently using solar on your boat, I would like to ask what issues you have run into with your installation. I am specifically looking for issues with wiring, regulation and charging of your batteries.

This is your chance to re-invent the wheel. If you could snap your fingers, and a new product would appear that is just what you wanted, what would it be like?

Thanks in advance,
Chris

[Cotemar]

Solar Panel wiring issues are always:

1) Do I use Parallel wiring

2) Do I use Serial wiring

3) Do I use Parallel / Serial wiring

4) Do I use 1 controller for all solar panels or 1 controller for each solar panel.

[softdown]

Oh boy......gaining competence with solar is often a very large undertaking. You might also try: Off Grid Solar & Battery Systems — northernarizona-windandsun

I believe the best system for significant solar production is solar racking built off of the stern. Good example is youtuber SVDelos. They used to use four 150 watt panels. Now they use three 330 watt panels. With five people and a lot of video editing and uploading, they are pretty heavy energy consumers. Not to mention the small fridges and freezers on a 53' boat. I think they recently added an icemaker for daytime production.

Some get by with 100 watts of solar panels, SVDelos has ~1000 watts. Only you can guess how much may be needed. Then add to that. Wind generators suffer from noise and moving parts = breakdowns. People seem to prefer solar on their boats.

Panels are cheap now, good time to invest. Golf cart batteries (GC2's) make good, tough, affordable solar batteries.

[Kenomac]

Install separate controllers for each panel to eliminate as many shading issues as possible.

[witzgall]

I am aware of the single vs. multi controller question, as well as the P vs S panel connection question. I am just putting out an open question as to what, perhaps smaller issues you have with installation, inefficiencies or the like. For instance, the connections on the panel are often mc3, mc4 or bare wire. Which ones to you prefer, and why? Do you have issues with other charging sources playing nicely with solar? I am trying to stretch, and think of the perhaps little things that are often overlooked that make a difference to you.

Chris

[john61ct]

Where the panel vendor supplies custom length/gauge wire, optional **quality** MC4 termination.

Granular blocking diodes on internal strings against shading issues, or even better

using the new embedded "MPPT on each cell string" ICs from Maxim.

Looking for US suppliers of Jinko "Eagle MX" is one line, others mentioned on Maxim's site are Trinapeak, and "ET COM"?

Also Zerun SunLoam "turnkey junction-box solution" incorporates the Maxim chips, not sure how that would work away from the panel itself.

[softdown]

MC3 connectors were no longer made with panels several years ago. I use them on some older panels though I supplemented the connections with MC3 to MC3 boots...of sorts. Can't remember the official name.

MC4s have completely taken over. Still not fool proof but much closer than the MC3s. MC3s are just way to easy to disconnect.

Replacing MC3s with MC4s involves a lot of small parts. It would make a decent sobriety test.

Lots of new technology. As for me, I like to see a track record rather than being a guinea pig.

Shade on one panel in a series is a big problem as you know.

[Flyingriki]

Was discussing solar with an engineer this evening and he reminded me of the recent leaps in panel tech. Wonder now on boats I'm looking at how "ancient" their panels are!
Guess there are other improvements to follow on this thread.

[DavidLGCrawford]

Last year we installed 4 new 265 watt panels, and kept a slightly older 250 watt panel, on Sail Quest for a total of 1310 watts.

We have two controllers, simply because finding a controller for 1300 watts is hard to find.

The 250 watt panel is connected to the same controller as our Rutland 1200 wind gen. This wind gen is nearly silent. How quiet is it? Well the only noise from it is a growl that sounds like a small electric motor. The blades are nearly always silent. Most times that we hear blades spinning in the wind we go outside to see what is wrong and find it's not our wind gen, but one on another boat in the anchorage or 1/2 way across the marina.

The 4 new panels are connected in a 2x2 series/parallel configuration. Those 4 feed into our Outback Power FlexMax 80 controller. These 4 panels typically bring in about 3 KwH per day. Even with the side-by-side fridge/freezer, 3 laptops, 2 PS4's, 2 TVs, and numerous other electrical items our batteries are usually fully charged by noon.

Each panel can put out up to 30 volts and 8 amps. So two in series produces 60 volts, 8 amps. Two banks of those in parallel produce 60 volts 16 amps. It's pretty simple math, if they are in series you add the voltages. In parallel, you add their amps together.

The charge controller then adjusts that from 60 volts down to the 12-14 you need to charge, and increases the output amperage along with it. As an example, assume a perfect sunny day with 60 volts and 16 amps coming in for a gain of 960 watts (60 x 16). The output at 12 volts would be 80 amps (960 / 12), and at 14.4 volts would be 66 amps (960/14.4).

The math is volts x amps = watts. Which is also watts / volts = amps, and watts / amps = volts.

As for wire sizing, there are many books on the subject, as well as online sizing calculators. Just run your numbers through a few calculators to see what they come up with, and if there is any question, go larger.

[Stu Jackson]

Originally Posted by witzgall

>>>>>>>>>>>>>>
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Do you have issues with other charging sources playing nicely with solar? >>>>>>>>>>
>>>>>>>>>>>>>>

Chris,

Good basic question.

Asked and answered so many times by Maine Sail and others. Just arrange the setpoints of your alternator's regulator and your solar controllers to be a tad different. This avoids them "fighting" each other.

I have a small solar panel to avoid leaving my boat plugged in. But if I had a "working" solar farm and was a full time cruiser, I would set my boat's solar controller and alternator regulator up properly as recommended.

And I'd be able to tell you immediately what they were.

Since I don't, I can't.

But doing a tad of reading on a regular basis, and maybe even reading the electrical section of this forum and all its thousands of solar posts, would find it for anyone interested in the answer.

Just an example of the literally small amount of recurring questions that keep popping up. Usually from folks too lazy to do their own homework and research.

Not YOU you understand. I "get" your query.

Many times questions are so incredibly basic that many respondents suggest that the OP just buy a book and learn.

CHALLENGES:

Where do I put the panels on my boat to avoid shading?

Shoot, we get this one hourly!!!

Oh, then they forget to tell us what boat they have!

[edmundsteele]

Two years ago I purchased six of 100 watt semi-flexible panels from Budget Marine in Sint Maarten. They performed phenomenally for 12 months and then over the next 3 months, one by one they “died” until they were all useless. My boat is a Leopard power-cat and the flybridge roof seemed the perfect place to install them – near flat and unshaded. I didn’t want too much weight that high up, for obvious reasons, thus I went with the lighter semi-flexible panels. The problem “seems” to be that the terminal blocks on the panels were not marinized, as claimed. Unfortunately, to access the interior of the terminal blocks, you have to get to the back of the solar panel and they were “glued” to the flybridge roof with a bead of silicone sealant. I haven’t worked out a way to remove them without destroying the now non-working solar panels.

From a product standpoint, I am looking for replacement panels for my $3,000 investment (the supplier would / could not honor the warranty) that has access to the terminal blocks from the front of the panel and also has some form of installation option that would 1) keep the panels attached in bad weather and 2) enable the owner to easily replace a failing panel. Those fancy snap on connectors are worthless if you can’t get the bloody thing off!

[softdown]

Originally Posted by edmundsteele

Two years ago I purchased six of 100 watt semi-flexible panels from Budget Marine in Sint Maarten. They performed phenomenally for 12 months and then over the next 3 months, one by one they “died” until they were all useless. My boat is a Leopard power-cat and the flybridge roof seemed the perfect place to install them – near flat and unshaded. I didn’t want too much weight that high up, for obvious reasons, thus I went with the lighter semi-flexible panels. The problem “seems” to be that the terminal blocks on the panels were not marinized, as claimed. Unfortunately, to access the interior of the terminal blocks, you have to get to the back of the solar panel and they were “glued” to the flybridge roof with a bead of silicone sealant. I haven’t worked out a way to remove them without destroying the now non-working solar panels.

From a product standpoint, I am looking for replacement panels for my $3,000 investment (the supplier would / could not honor the warranty) that has access to the terminal blocks from the front of the panel and also has some form of installation option that would 1) keep the panels attached in bad weather and 2) enable the owner to easily replace a failing panel. Those fancy snap on connectors are worthless if you can’t get the bloody thing off!

I have yet to see a positive report on flexible panels from a longer time user. They...just...don't...last.

[edmundsteele]

Originally Posted by softdown

I have yet to see a positive report on flexible panels from a longer time user. They...just...don't...last.

You are absolutely correct in this. After the fact (!!!), I researched these panels and discovered they have been used extensively for RV’s, motor-homes and campers, as well as marketed to sailors. The suppliers have been sued in various parts of the world since they claim to be manufactured variously in “UK”, “Germany”, “Australia” and the websites and reviews all look genuine. In fact they are all made in China. Not a problem for me except for the premium price I paid for the so called high quality Euro manufacturing. Budget Marine was not able to contact their UK supplier, so I had my brother in the UK go over to the “factory”. He found a single room empty office and the fellow in the office next door said he hadn’t seen anyone there “in some time”.
Caveat emptor!

[barnakiel]

The only problem we ever encountered was very early on when we did not use a regulator. The panel dried the batteries prematurely.

If there is no regulator, either the panel must be very small, the battery very big or else you must use the battery on a very regular basis.

Basically, avoid unregulated solutions in the long run.

b.

[Ardbeg]

I installed 2 x Kyocera 240 W 5 years ago. One controller. I have never had a problem and never run out of juice. I have fridge & freezer on full time plus full set of navigation tools when moving. I have never done any maintenance and my batteries have lasted wonderfully. The only thing I was warned, make sure the shore power is turned off before engaging solar and vice versa. I probably do not plug in more than 5 days per season.