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Post by peterboat on Nov 27, 2017 13:23:20 GMT
Because of my MPPT controller i have about 100 volts feeding into it this allows more of the usable power to be used in low light levels. A PWM controller cuts off all the voltage it doesnt need and throws it away, an MPPT controller converts all the voltage to usable energy, so as the ad says its up to 30% more efficient. The bathtub is going to have about 2 kilowatts of panels on it which on a sunny day will allow me to cruise for free. You will probably find that on a boat, it's much more efficient to run the panels in parallel not series and keep the input to MPPT at about 30v (presuming you're on a 12v system). What solar controller do you have? I have nine panels it works as follows x 3 in series 3 times then back to the controller in parallel I have a Midnight controller and that is their recommended method of wiring back to the fuseboard before the controller. even in very poor light the controller is still putting power into the batteries
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Post by markhez on Nov 27, 2017 13:26:52 GMT
You will probably find that on a boat, it's much more efficient to run the panels in parallel not series and keep the input to MPPT at about 30v (presuming you're on a 12v system). What solar controller do you have? I have nine panels it works as follows x 3 in series 3 times then back to the controller in parallel I have a Midnight controller and that is their recommended method of wiring back to the fuseboard before the controller. even in very poor light the controller is still putting power into the batteries Thats the best way of wiring if the installation is fixed and not shaded at all, with boats that move around to various environments, if one of the panels in a series string is even partially shaded, it will seriously decrease the output from the other 2 in the string.
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Post by peterboat on Nov 27, 2017 13:40:59 GMT
I have nine panels it works as follows x 3 in series 3 times then back to the controller in parallel I have a Midnight controller and that is their recommended method of wiring back to the fuseboard before the controller. even in very poor light the controller is still putting power into the batteries Thats the best way of wiring if the installation is fixed and not shaded at all, with boats that move around to various environments, if one of the panels in a series string is even partially shaded, it will seriously decrease the output from the other 2 in the string. I get you but it isnt an issue for me as I have 1500 ah of full traction batteries so can go days without sun and at moorings they have good light with out shading
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Post by Mr Stabby on Nov 27, 2017 19:14:05 GMT
Because of my MPPT controller i have about 100 volts feeding into it this allows more of the usable power to be used in low light levels. A PWM controller cuts off all the voltage it doesnt need and throws it away, an MPPT controller converts all the voltage to usable energy, so as the ad says its up to 30% more efficient. The bathtub is going to have about 2 kilowatts of panels on it which on a sunny day will allow me to cruise for free. Oh and by the way mr stabby put solar panels on your boat you miser. Yes, I intend to when I get the time although I don't know when that will be as I'm working as many hours as my tachograph allows at the moment, anticipating work will drop off sharply after Christmas, I'll probably get around to it then firstly because I'll have more time and secondly because a fellow boater who has said he will do the install with me had ankle surgery this week and will be out of action until then.
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Post by Deleted on Nov 27, 2017 19:37:35 GMT
I like solar and I've had solar panels since 1998 when it was shockingly expensive. The only thing I would say is that as Mr Stabby apparently uses his boat for cruising during the "boating season" and leaves it on a mooring for winter it would be prudent to look at the actual requirements because covering the roof in solar can be a bit annoying on a cruising boat and the engine will be putting power in anyway. I don't personally believe that you can provide winter power requirements with solar in this country. Might be doable on a big wide beam but on a small narrow boat there is not much roof space and in my experience of 12 years cruising around the canal system in a 55ft narrow boat I was glad to have some roof to walk on as well as a small amount of solar. I suppose you could cover the roof in cheap solar and store it during the brighter months when cruising. I definitely wouldn't want it on the roof in summer unless stuck on a mooring with no electric. My 2p
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Post by Mr Stabby on Nov 27, 2017 19:55:07 GMT
I like solar and I've had solar panels since 1998 when it was shockingly expensive. The only thing I would say is that as Mr Stabby apparently uses his boat for cruising during the "boating season" and leaves it on a mooring for winter it would be prudent to look at the actual requirements because covering the roof in solar can be a bit annoying on a cruising boat and the engine will be putting power in anyway. I don't personally believe that you can provide winter power requirements with solar in this country. Might be doable on a big wide beam but on a small narrow boat there is not much roof space and in my experience of 12 years cruising around the canal system in a 55ft narrow boat I was glad to have some roof to walk on as well as a small amount of solar. I suppose you could cover the roof in cheap solar and store it during the brighter months when cruising. I definitely wouldn't want it on the roof in summer unless stuck on a mooring with no electric. My 2p I completely agree, it hasn't been a priority because when I'm out cruising in the Summer I generally move every day, for at least three hours and more usually six or seven, and when I moor up for the Winter (normally in September) there isn't as much sunlight anyway. So although I think it will be helpful to a degree, it's not as important for me as for folk who tend to moor for extended periods. I'd be thinking of maybe two 200w panels forward of the centre line cleat maybe?
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Post by peterboat on Nov 27, 2017 21:45:27 GMT
I like solar and I've had solar panels since 1998 when it was shockingly expensive. The only thing I would say is that as Mr Stabby apparently uses his boat for cruising during the "boating season" and leaves it on a mooring for winter it would be prudent to look at the actual requirements because covering the roof in solar can be a bit annoying on a cruising boat and the engine will be putting power in anyway. I don't personally believe that you can provide winter power requirements with solar in this country. Might be doable on a big wide beam but on a small narrow boat there is not much roof space and in my experience of 12 years cruising around the canal system in a 55ft narrow boat I was glad to have some roof to walk on as well as a small amount of solar. I suppose you could cover the roof in cheap solar and store it during the brighter months when cruising. I definitely wouldn't want it on the roof in summer unless stuck on a mooring with no electric. My 2p That is why I fitted stick down flexible panels which can be walked on it makes choices easier, and it does allow me to moor up somewhere nice for a week or two without worrying about lack of power in the batteries. Also it does make batteries last a lot longer as fully charged batteries last longer than discharged batteries
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Post by JohnV on Nov 28, 2017 8:30:01 GMT
I have 4 260w panels wired series parallel. at the moment (0815) with a bright sun at a very low angle and only one pair of panels in the sun (the others shaded by the first set) I am getting 2.2A ....not too bad ...... however I am drawing 37 amps out of the bank at the same time So I am about to fire up one of the generators to run the washing machine. even so, every little helps .... In full summer sun I can get over 50 amps charge but the system was designed purely for summer use, the plan being to be somewhere with shore power in the winter. just to add .... now an hour later and the angle is a bit better and the charge rate has gone up to 6.1A should add to all this that I have a 24 volt system
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Post by Jim on Nov 28, 2017 16:29:01 GMT
I fitted a 130w stick down flexible panel and mppt controller from photonic universe, around £400. No room for any more it's only a small boat. Works great running lights and radio, normal 12v stuff. The stick down panel had a sticky foam layer over the whole surface. I sealed the edges, just because, with polyurethane squidge. Just saying, because no one else has, all panels need to be the same size/watts.
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Post by bargemast on Nov 28, 2017 16:48:08 GMT
I like solar and I've had solar panels since 1998 when it was shockingly expensive. The only thing I would say is that as Mr Stabby apparently uses his boat for cruising during the "boating season" and leaves it on a mooring for winter it would be prudent to look at the actual requirements because covering the roof in solar can be a bit annoying on a cruising boat and the engine will be putting power in anyway. I don't personally believe that you can provide winter power requirements with solar in this country. Might be doable on a big wide beam but on a small narrow boat there is not much roof space and in my experience of 12 years cruising around the canal system in a 55ft narrow boat I was glad to have some roof to walk on as well as a small amount of solar. I suppose you could cover the roof in cheap solar and store it during the brighter months when cruising. I definitely wouldn't want it on the roof in summer unless stuck on a mooring with no electric. My 2p Not only are they a lot cheaper now, but (supposedly) their quality and power supply capacity have improved over the years. Peter.
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Post by Deleted on Nov 28, 2017 17:31:41 GMT
I believe that is correct but I would still want some space on a narrow boat roof to walk all around any solar so panel size would need looking at. I wouldn't want to walk on flexi panels as a matter of course as I don't think they have anti slip coatings. Maybe they do?
This is for a boat cruised on narrow canals at least every couple of days regardless of weather and dealt with by one person.
Its really handy to have roof space for walking on. I haven't really looked carefully but it seems to me that the cheap panels are the 36v "domestic" type (is the low price to do with the removal of PV power generation government subsidies or is it just a made in china thing?"
These 36v panels tend to be quite large.
I'd go for a couple of 75w panels in a line and a simple controller. And rely on beer shops for cold beer and milk (they have a fridge on all the time)
I am Luddite though to be fair.
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Post by Jim on Nov 28, 2017 18:02:58 GMT
my flexi panel has a slightly bobbly surface so its not smooth and slippery. It's best to tread on it gently. It does say it's not really meant to be walked on. as for no fridge - I lined a cupboard with foil insulation, except for the base, sitting above the bilge. it stays cool, we just buy milk in 2 pint bottles max. In really hot weather I've also used the old trick - put bottle in bowl of water, put j cloth or similar over bottle into water - evaporation cooling.
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Post by peterboat on Nov 28, 2017 20:01:03 GMT
My panels can be walked on and are anti slip I value the ease with which I can decide when and how long I can stop for not the batteries which is why they are on the roof
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Post by leo326 on Nov 28, 2017 21:08:54 GMT
Just saying, because no one else has, all panels need to be the same size/watts. I have 2x100w and 2x30w. They are all 12v panels and all connected in parallel. I added the 2x30w panels later and they produced a proportional increase in amps. I was warned that I shouldn't mix panel sizes but, in my case, it worked just fine. I later heard that provided the maximum voltages of all of the panels are pretty close to each other it works OK with parallel wiring.
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Post by Gone on Nov 28, 2017 22:37:02 GMT
Just saying, because no one else has, all panels need to be the same size/watts. I have 2x100w and 2x30w. They are all 12v panels and all connected in parallel. I added the 2x30w panels later and they produced a proportional increase in amps. I was warned that I shouldn't mix panel sizes but, in my case, it worked just fine. I later heard that provided the maximum voltages of all of the panels are pretty close to each other it works OK with parallel wiring. To avoid paralleling different size panels I put my 2 big panels in series into a MPPT controller and the older little panels now go to the battery via a cheap PWM controller, that way (so I hope) the MPPT can get to the sweet spot for the big panels, and anything from the old panels is a bonus.
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