First, figure where you are going to place the panels and then how to mount them. The 130 +- watt panels are about as large as you can mount on a life line/stern pulpit rail. Surface mounting on deck
, etc can use larger but will take up more realestate. I'd be very leery about mounting a panel where you'll be walking as a miss step could shatter a panel.
Panels wired in Series need smaller gauge wire to run to the battery(ies) but are more severely affected by shading of even a small portion of the panel(s). If you can't find a place to locate panels where they won't be shaded, you'll need to figure on the large wire sizes necessary for low loss transmission
with panels wired in parallel. In other words, lower the voltage output of the panels, the larger wire size you'll need. We aren't talking about 14 gauge vice 12, but 2, 4 vice 10 gauge so wire cost of wire gets to be an issue.
Once you've figured out how many panels you can mount and their size, you can start looking for panels and a charge controller. I've got 2 Kyocera
130 watt panels mounted on the Pushpit. They run through a BZ Products MPPT
controller. The panels are going on 10 years old and still going strong. Other panels may be cheaper but will they last in a marine environment
?? It's a decision you'll have to make between proven reliability
vice up front cost. You can buy controllers from less than $50 to more than $400. MPPT
are the most efficient in ideal conditions but you many not be able to take full advantage of that efficiency on a boat. Personally would go for a controller from one of the US manufacturers though you could buy 3-4 of the Chinese variety for the same price
and just swap them out when/if they fail.
Good luck with your installation
. Sure is a blessing not to have to run the engine or a generator
to charge the batteries. Did a 15 day TransPac from SF to Hawaii
and only used the engine to power into harbor at the end of the voyage.