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Old 04-02-2018, 07:43   #1
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I want more solar - where do I put it?

I bought my boat with 4x 18v 100w rigid solar panels. These feed into a MorningStar ProStar 30 PWM controller.

On a sunny day in the Med I see somewhere between 80-100 amps per day. This is ok, but would like more especially for shoulder months, and partially cloudy days.



Not sure the gains from switching to multiple MPPT controllers would be worth it given the low voltage per panel.

Been tempted by the LG 365w panels (21.1% efficiency), plus an MPPT controller, but at 36kg for two, it's a lot of weight, and I'm loathe to get rid of decent fully working panels.
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Old 04-02-2018, 08:43   #2
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Re: I want more solar - where do I put it?

You picture shows part of your problem--the shadows from your sails and masts.
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Old 04-02-2018, 08:48   #3
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Re: I want more solar - where do I put it?

If the panels moved backwards a bit you could probably fit another pair of 100w panels across ways

How about using some of the smaller MPPTs paired up with panels some panels in series to generate a higher voltage and enable the MPPTs to choose the best charging option.

Just about to buy another one of these to do just that and retire my second PWM regulator now the price of MPPTs has come down.

https://www.ebay.co.uk/itm/Victron-E...EcwbeIKjcCPq3Q
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Old 04-02-2018, 09:11   #4
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Re: I want more solar - where do I put it?

Quote:
Originally Posted by donradcliffe View Post
You picture shows part of your problem--the shadows from your sails and masts.
There's no problem so to speak, you're never going to eliminate all shadows at all points of sun. I think with the angle the panels are at, they do very well. I get about 13a/h on average with 16a/h being the max I've seen.

Obviously in my photo I'm up the mast and the line I'm climbing is on one of the panels, but otherwise the soft shadows from the lines on the stay sail have little to no noticeable effect. Perhaps that says more about the PWM wasting power than it does anything else.

The panels must be 4 years old, probably Chinese (at a guess), but I've been happy with them.

I don't have davits, nor an arch so placement is limited. I don't even have long enough rails to mount panels there (not that's want to due to windage).

I do have a cockpit tent that is permanently erected, but when at anchor I almost always put a shade over it.

Quote:
Originally Posted by Pete7 View Post
If the panels moved backwards a bit you could probably fit another pair of 100w panels across ways

How about using some of the smaller MPPTs paired up with panels some panels in series to generate a higher voltage and enable the MPPTs to choose the best charging option.

Just about to buy another one of these to do just that and retire my second PWM regulator now the price of MPPTs has come down.

https://www.ebay.co.uk/itm/Victron-E...EcwbeIKjcCPq3Q
Been looking at 100w flexible panels, but they tend to come in at around 120cm long which is too long to clear the raised centre of the coach roof. I'd need something more in the 96cm range.

I could try running alternating panels in series to two MPPT controllers. That's about, not sure if there will be much gain though.
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Old 04-02-2018, 16:34   #5
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I want more solar - where do I put it?

I cant see the aft end of your cat but an ideal location is having them extend outward from your aft cockpit. [ATTACH]163475]
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Old 05-02-2018, 00:11   #6
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Re: I want more solar - where do I put it?

I'm painting myself into a corner by going for mass centralisation. Hence no davits or arches. An extra 60kg on the stern wouldn't do me any good.
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Old 05-02-2018, 01:38   #7
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Re: I want more solar - where do I put it?

Quote:
Originally Posted by mikedefieslife View Post
Been looking at 100w flexible panels, but they tend to come in at around 120cm long which is too long to clear the raised centre of the coach roof. I'd need something more in the 96cm range.

I could try running alternating panels in series to two MPPT controllers. That's about, not sure if there will be much gain though.
These are a little more square in shape:

https://www.photonicuniverse.com/en/...lar-cells.html

The alternative as you say is to sell of the existing system and start again. If you are planning keeping the boat for some time there may be some merit in doing this and getting 10+ years worth of benefit from new panels and new MPPTs.

Certainly in the UK there is a very active second hand market for panels as I found out during the summer when I sold an old 80w panel for nearly the new price.

Pete
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