What watt power solar panel to buy

[Heckler]

I think there are two ways to go. Either buy really good ones or really cheap ones. I went the latter way. This allowed me to get 2x50W on my coachroof for £100 and £150 - the cheap one from A.N.Ebayer and the more expensive from Photonic Universe. I didn't expect them to last long, and indeed the cheap one died last summer and I have just replaced it. The replacement cost £60. If I had bought really good ones I'd have paid.

The high quality alternative would have been 2x30W (shape constraints) for around £350 each. I'm happy to put up with occasional replacement because (a) the total cost of ownership is similar and (b) price per W is coming down - not only could I replace a £100 panel with a £60 one, my £150 panel now costs £100 from Photonic Universe.

Of course other might have different priorities - if I was crossing oceans I would go for higher quality and if I had room for solid panels I'd use the best I could afford there too. For me, though, semi-flexibles are a consumable, almost.

For what its worth, I put cheap 100 watt solid alu panel ones on swivels on my guard rails, I replaced the removeable wire with 25mm ss. They swivel up when in use with a simple notched 2x1 stick, plus one 50 watter on the coach roof. At anchor in Portugal I was self sufficient. Be aware that you have to divide the wattage by 20 tp get the max amps, they put out 20 ish volts on open circuit. 4 amps ish for my fridge, 4 amps ish for the rest, the auto pilot and instruments are looked after on passage.
LEDs all round by the way. They make a heck of a difference on the nav lights
Stu

 

[PaulRainbow]

I left the 2x30w, 1988 panels on the coachroof and fitted a pair of quality 100w rigid panels on an arch at the stern, coupled to a Victron controller. At the moment, in the UK, i'm self sufficient with some to spare.

 

[JumbleDuck]

For what its worth, I put cheap 100 watt solid alu panel ones on swivels on my guard rails, I replaced the removeable wire with 25mm ss. They swivel up when in use with a simple notched 2x1 stick, plus one 50 watter on the coach roof. At anchor in Portugal I was self sufficient. Be aware that you have to divide the wattage by 20 tp get the max amps, they put out 20 ish volts on open circuit. 4 amps ish for my fridge, 4 amps ish for the rest, the auto pilot and instruments are looked after on passage.
LEDs all round by the way. They make a heck of a difference on the nav lights

My boat being both smaller and pointier at both ends than yours I am rather constrained in where I can put the things ... some people mount them across rear pulpit but it makes access to the stern very hard and I have a windvane there. So for the moment 2x50W it is, and when they are both working that's fine. I have pretty low power requirements and, as you say, going all-LED for lighting, inside and out, made a HUGE difference.

What I'd really like to do next is go from lead-acid to Li-ion batteries. Room is tight and I can only fit low-rise batteries, which means I am constrained to 2 x 60W without major surgery. If I could go to 2 x 60W Li-ion I would effectively have doubled capacity, and I'd like to go higher than that. However, decent Li-ion batteries are still hella expensive, and even allowing for the fact that you can discharge them twice as much they are still several times the price of lead acid. When they are only double for practical Ah (ie four times for maximum Ah) I'll start planning ...