solar hookup

[berwick]

Hi, I am installing some more solar panels on our sailboat. Presently I have a Blue Sky2512 charge controller running 290 watts of solar panels (2-65w and 2-80w all in parallel). The 80w panels are prone to shading due to them being mounted on the bimini. I am going to add two 140w panels on the davits. I am looking for the best way (most efficient, esp with shading) way to hook up all these panels.
I think these are some of my options:
A) Use two MPPT controllers (so they can work together), have one controller hooked up to the two 80w panels in parallel that are subject to shading, and the other controller, to two sets of series/parallel panel configuration. In other words one controller will take a nominal 12v panel input and the other a 24v panel input. My thought is that the MPPT is more efficient with the higher voltages so I would series the two sets of panels. I had read that paralleling is better if prone to shading thus the idea of doing this to the 80w panels. All the voltages in the panels are very close to the same but of course the current isn’t thus I would not string them all together.
B) My other option is to parallel all 6 of them (larger wire) and run to one large controller. I guess if I am only using the nominal 12 voltages I could even go with a PWM controller instead of a MPPT as I am not gaining as much due to the nominal 12 volt system?

Am I gaining much more current/efficiency to the batteries by going the first route?
When you have two panels in series and you get a large shadow across one or both, do you loose mostly current from the cells and keep most of the voltage or do both decrease about the same? If it were mostly current then maybe two cells in series would work well with a MPPT controller which could still use the higher voltages?
Any better options I should look at?

Thank you

Richard

[Mike90250]

Any panels that will be shaded, should be wired in parallel.

If your panels are 18-20V nominal (max power) you can use PWM controllers to charge a 12V system. Most small panels are in this range.

Larger panels could be 19V or 29V or 49V or 65V, depending what was being built that day. More than 19V panels (not looking at the Voc spec, just the V Max Power spec) you will benefit from using a MPPT controller.

[berwick]

Ok sounds good, is there much to be gained by using two charge controllers as the voltages of the panel are the same but not the current, so would this throw off MPPT if I use just one?

Richard