Solar Choices

[Nicholson58]

I'm not going to re-hash the points made above. I did find this guy's site held a wealth of good advice no matter what you choose. He lives off the grid in the SW, is an electrical engineer and has probably seen every problem you can imagine. Its a long read but well worth it. It may save you $$ and headaches.

HandyBob's Blog « Making off grid RV electrical systems work

[GILow]

Originally Posted by Nicholson58

I'm not going to re-hash the points made above. I did find this guy's site held a wealth of good advice no matter what you choose. He lives off the grid in the SW, is an electrical engineer and has probably seen every problem you can imagine. Its a long read but well worth it. It may save you $$ and headaches.

HandyBob's Blog « Making off grid RV electrical systems work

Yes that's a very useful link.

[CarinaPDX]

Yes, good info but served up with heaps of attitude which makes the unnecessarily long articles a hard slog. He starts out by saying that the main article is long but it is necessary, and if anyone can tell him how to make it shorter without losing the info he would do it. Simple: get rid of all of the bad attitude and stick to the main points and supporting arguments and recommendations. Then it would be a highly recommended read; as it is I'm not sure I wish the experience on anyone else even though his points are generally spot on.

Greg

[GILow]

Yeah, but it is a blog, and I reckon blogs are just a form of therapy for some poeple. Think what he saved in professional therapy fees.

Matt

[COLINFLTENG]

Good points

Sent from my SGH-I547C using Cruisers Sailing Forum mobile app

[COLINFLTENG]

Long read needs to shorten

Sent from my SGH-I547C using Cruisers Sailing Forum mobile app

[CarlF]

This has been a great thread. I'm still confused by the "one Genasun controller per large panel" configuration.

If partial shading occurs (and it seems likely on most sailboats), isn't it always better to wire panels in series to a single MPPT controller to keep partially shaded panels from "dropping out" completely? (e.g. the shaded panel's voltage has dropped below 16v but it still has current)?

Or will a single MPPT controller try to average the resistance setting for the shaded and unshaded panels making them both perform poorly?

What am I not understanding?

[COLINFLTENG]

I wired my pannels in parrel works good one MPPT controller upgrading from 160 watt to 500 watts 24 volt pannels

Sent from my SGH-I547C using Cruisers Sailing Forum mobile app

[Siege]

My panels are also wired in parallel into one MPPT controller. If one or more is shaded the ones that are still in the sun are putting out their full power. It might not be as efficient as series but it's much more effective for me. I have a small ketch with a forest of wires and, consequently, shadows. If I wired in series my output would almost always be less than optimal.

Too bad I had to go with small panels. I have six Canadian Solar 245w panels that I got for a cabin project that fell through. Still have them but they're almost bigger than my boat. They cost the same as the 80w panels I just installed.

[COLINFLTENG]

Same same replaceing 80watts with 250 watts and yes need parallel due to shade sun is one side at a time I got room on my 40CS

Sent from my SGH-I547C using Cruisers Sailing Forum mobile app

[s/v Jedi]

Originally Posted by Siege

My panels are also wired in parallel into one MPPT controller. If one or more is shaded the ones that are still in the sun are putting out their full power. It might not be as efficient as series but it's much more effective for me. I have a small ketch with a forest of wires and, consequently, shadows. If I wired in series my output would almost always be less than optimal.

Too bad I had to go with small panels. I have six Canadian Solar 245w panels that I got for a cabin project that fell through. Still have them but they're almost bigger than my boat. They cost the same as the 80w panels I just installed.

I bet you never tried series. Every panel with partial shade is totally put out of production in your setup, while it could still deliver partial output with series connection.

[Siege]

Jedi, when I installed the panels I did try series as well as parallel. I seem to get better numbers overall with my current parallel setup. I will admit though that I have not had enough time to really test and compare over time or while sailing.

You may very well be right that wiring in series will be better. But so far my limited experience with my boat's solar array has shown otherwise. I think everyone should try both and see which is more effective for their install and application. I for one definitely plan to do more testing as soon as I can get off this tugboat...

[s/v Jedi]

Originally Posted by Siege

Jedi, when I installed the panels I did try series as well as parallel. I seem to get better numbers overall with my current parallel setup. I will admit though that I have not had enough time to really test and compare over time or while sailing.

You may very well be right that wiring in series will be better. But so far my limited experience with my boat's solar array has shown otherwise. I think everyone should try both and see which is more effective for their install and application. I for one definitely plan to do more testing as soon as I can get off this tugboat...

Wiring in series requires the bypass diodes to be functional and an MPPT controller that can handle the high input voltage. Next is the measurements which needs to measure the energy delivered from the array, in Wh or kWh. Some controllers can record this, as well as some battery monitors.

Many boats can have a couple of big panels on an arch on the stern, as well as winged on the lifelines and on top of a bimini. We may soon have much more options with new technology coming on the market.

[sparrowhawk1]

Jedi. I've been reading reading reading. have you tested or know of any tests that compare 2 12 volt panels with one panel shaded. 1 set parallel 1 set series? Total of four panels needed for test. same controllers, same batteries, same wires. Thanks..... should have posted this on the series or parallel thred

[s/v Jedi]

Originally Posted by sparrowhawk1

Jedi. I've been reading reading reading. have you tested or know of any tests that compare 2 12 volt panels with one panel shaded. 1 set parallel 1 set series? Total of four panels needed for test. same controllers, same batteries, same wires. Thanks..... should have posted this on the series or parallel thred

No need to test, as theory is solid on that:

1. Parallel wins power generation because shaded panels do not impact unshaded.
2. Series wins power transport from array to controller because wire losses are much reduced.

These two factors will cancel each other out mostly for an actual boat installation.

But the comparison is one to make parallel look better; I mean, it is not a fair one. You should also test unshaded, where series with MPPT will show superiority and then test with partial shading a panel so that unshaded sections still generate power for series connection while this kills all panel output on parallel connection.

Most if not all installations will experience each of those three situations, which is why they must all be considered.