Solar Panels & MPPT: Series vs Parallel

[Kedishen]

So I have decided that 100w is not enough for living in winter. I will be adding another 100w, maybe 120w depending on price and panel size.

There is 0% chance of shading because I pick where I park.

My research is inconclusive - should I connect in series or parallel...?

I am swaying towards in series. The wiring is easier, the wiring and regulator handles less current, there is less current loss from the diodes. Only problem is if one panel suffers failure, both panels stop working.. but hay ho I just disconnect the dead panel.

Whats your opinions?

[Altransit]

To double the power, you connect in parallel Connecting in series doubles the voltage, or am I missing something

[Kedishen]

You are right, PWM controllers only operate this way. But MPPT controllers converts voltage into current/power at the controller.

PWM controllers are basically a straight through to battery with a few special circuits (to control voltage spikes and charging etc) so solar panels can only operate at battery voltage.

MPPT are completely electronic. Batteries are completely seperate from the solar panel, so whilst battery can operate up to 14+volts, solar panels can be put in series up to 150V on some controllers, only 100v on mine. However, on 12v systems, banks of 24v panels are apparently most effective.

[Altransit]

Ah ok, with higher voltage, the power losses are smaller, and you don't need thicker cables to carry the higher current

[Kedishen]

Sounds good, but good old mechanical switches live on for years... bet my old charge controller will still work just fine after this electronic chinese thing has given up the ghost.

[ake]

Most solar PV panels are connected in series