Choosing a solar panel

PabloPicasso

PabloPicasso

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I'd like to fit a solar panel to keep two 70ah batteries topped up. The boats mainly used for club racing (and occasional cruising). so engine only on for short trip in and out of the harbour once or twice a week. Electric power for instruments, depth, speed, 5inch plotter, VHF, lights and there's no fridge. Any recommendations for panel size, type, and anything else in relation to fitting?
 
I assume you will want a semi flexible panel - something that can be mounted on deck rather than held in a permanent gantry or rolled up in between uses.

If that is the case, then I would first work out where they are to be mounted, including wiring runs. Then buy the panels that with give you the biggest wattage for the dimensions available. When I did this last year I was surprised at the range of sizes available for different wattages.
 
You also haven't mentioned how much you actually discharge your batteries and the time to recharge.

I have a 60w panel that puts in a consistent 3-3.5 a - about 20ah a day in the summer on the Hamble.

If you're discharging to 50% then a similar sized panel will replace your discharge in 4 days..
 
You are not going to want a big ugly gantry on a 26' boat, especially as you race. You are also not going to have much deck space for permanent deck mounting. Therefore I would suggest fully flexible that you can tie in place when you leave the boat & remove & throw down below when racing. Something like the Spectraflex 32 Watt is an excellent piece of kit, although expensive.
 
From what I have seen flexible panels die quite quickly if moved and flexed. 2 to 3 years.

Cheap Chinese rigid panels die too, usually because the metal connections turn to green goo., often n 18 months. If you go down this route pot the connections in epoxy or similar.

I have Kyocera marine panels that are 8+ years and still going strong. Bu the smallest panel they make is 140 watts [ I think ] and more than you need.

A rigid rectangular panel around 50 to 70 watts should do. Bungee on to the boom and it is safe from careless feet.
 
TQA said:
From what I have seen flexible panels die quite quickly if moved and flexed. 2 to 3 years.

Cheap Chinese rigid panels die too, usually because the metal connections turn to green goo., often n 18 months. If you go down this route pot the connections in epoxy or similar.

I have Kyocera marine panels that are 8+ years and still going strong. Bu the smallest panel they make is 140 watts [ I think ] and more than you need.

A rigid rectangular panel around 50 to 70 watts should do. Bungee on to the boom and it is safe from careless feet.
Click to expand...

That's not true , we had non marine panels for years , never a problem , everyone we know with panels are all non marine
 
I spent 400 euro on an 80 watt marine panel in Greece 8 years ago and another 100 euro on a quality Stecca regulator , the panel performed fine for the six years we had it in the boat , the Stecca began misbehaving after four years or so .We then sold the boat .Next boat I fitted a 100 watt eBay special rigid panel bought for £100 plus cheaply regulator for £20 , so far we have had these for three years and I can't fault either . 100 watt panel obviously will be too big for your boat so flexible looks your best route . Wondering myself how the cheapo flexible panels compare to a marine flexible panel .
 
I have 2 x 60Ah batteries - on a 26 footer - which are kept fully charged for all I need by two 50W semi flexible panels on the cabin roof. Or, rather, which were kept charged etc etc etc because one panel died last week. A replacement from eBay cost £60 and should be waiting for me at home. When I fitted the panels I decided to go cheap and expect to replace from time to time: "marine" panels would have cost me around six times more.

A word of caution. Lots of eBay sellers have aluminium-backed panels which they say are good for 30o of bend. They are not. They are good for 3% - I suspect that someone in China has confused "0o" and "%".
 
Semiflex is the way to go IMH and permanently mounted. You want them charging as much as possible - useful amps can be generated whilst sailing despite some shading, you get zero amps when the thing is in a locker!
Sounds like you should be able to get 2x50w which should keep up with your usage.
A decent PWM regulator will protect the batteries and optimise charging (£12 from China).
 
Hi! We have 2 boats and both of them have solar panels installed.
The first one is used for racing, she has 60Ah battery and 1 50W solar panel with PWM controller. We do not have fridge, electric water pumps, and windlass that consume lots of power. We only use instruments, lights, VHF and charge devices. We didnt connect to shore power since the panel was installed.

This is how the installation looks like: http://www.osa-30ft.dp.ua/blog/wp-content/uploads/2015/01/IMG_5338-620x465.jpg
When racing we usually detach the panel and put it in the locker.

The second boat is Beneteau First 36.7 which is used for cruising. She has 2*74 Ah house batteries, fridge, water pumps, cockpit shower, instruments, vhf, navigation, etc (everything you can find on big boat). We have installed 2 * 50W panels, Victron Energy MPPT controller and Victron battery monitor. During last week we were cruising along adriatic coast. The batteries were discharged every night (-20 - 50 Ah) and then charged to 100% by the middle of the day.

On the second boat we have the same installation on the pulpit.
 
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