I'm currently set up with two 80 watt solar panels
and really need to add another 40-60 watts to my system (the 160W normally keeps up with my needs, but doesn't generate enough extra to top up the batteries after a couple of cloudy days). I'm trying to decide the best (most cost efficient) way to do this. Right now the 2 12V panels
are mounted on a stern arch of my 27' boat, running through an MPPT
charge controller, so I have the option of wiring
them in series or parallel. It seems like my options are:
1) replace the current panels
wither either one 200-240 watt panel or two 100-120 watt panels. I don't like the idea of a single
panel (single point of failure). Cost of the new panels would be under $250 and I could probably get $125 for the current
panels so the cost is reasonable, but I'd have to rework the mounts to hold the larger panels.
2) add another 40-60 watt panel to the mix. Probably the cheapest option, but it would mean running the panels in parallel instead of in series. Because of the geometry of my mounting arch it would be easist to use a long narrow panel, but most of the ones this shape that I'm finding are thin film, not chrystalline, with a Voc around 16V, vs. the 20 Voc of my current panels. I'm not sure if this is an issue or not.