Lance 1181 solar install?

keefr wrote:
If you go with an MPPT controller, you can wire your panels in series for 24v to the controller (Actually will be about 34 volts), and the controller will drop it to the proper battery charging voltage without much loss. Higher voltage in the wire means less current, so thinner wire will work. EP Solar makes an MPPT controller that will take up to 100 volts in. You could have 4 panels in series and at 60 volts in, 300 watts would only need 5 amps - well within the capacity of 12 ga. wire.

I think this would be the way to go if it weren't for the issue of partial shading. You would have less loss of power at the higher voltage because the current to the charge controller would be reduced. (The loss on the wire is equal to the current times the resistance. So, if you can reduce the current OR the resistance you are going to reduce the loss.) (This is why they do such high voltage on the power grid transfer lines.....to reduce the loss. AC has much different characteristics than DC in this regard, however.)

I won't have the luxury of parking in full sun a lot of the time, and with the series connection any panel that is partially shaded reduces the output of all panels.....With parallel panels, the panels that aren't shaded still produce their full output, but you will be at the mercy of higher current to the charge controller and therefore more loss.....unless you increase the wire size.

Does anyone have any real life experience with this partial shading effect?