So when you have two solar panels(the same type), you have the option to connect them in series (like our two 6v batteries) or in parallel (negative to negative, positive tp positive). There is a lot of opinion out there as to which is best.
If the panels are in series, the voltages for each panel add be t the current is limited by the lowest current panel.
If they are in parallel, the voltage will be the highest of either panel, but thr current will be the sum of each panels current. Diodes are privided the nside each panel to prevent a higher voltage panel driving current into the lower voltage panel snd wasting energy.
I am sitting in the sun with my 200watt external panels wired in parallel, in good sun. The volage is 15.7v 6.3 solar amps (controller in trailer) 13.54 volts 6.9amps to battery.
My tab solar is in shade, the panels are in series. 19.92v 0.5Amps solar battery 13.36v 0.6Amps.
So heres my thoughts:
If you have a long run of wire to your solar panels it would be best to have the controller near the battery in any case to reduce current and hence cable energy losses which are proportional to current.
In this case the panels should be in series.
If the panels are in shade so that the voltage from them is too low to get the charger to function, must me 4-5v higher than required battery voltage, then in series the voltage could be enough to use what little energy there is.
However, since in series the current is limited by the panel with the smallest output, this is not the best solution when one of the panels is in the dark.
My panels seem to be more efficient in parallel. If they are in enough sun to wake up the charger.
So it seems that if you will not have access to the panels after installation, then series is a good compromise. But if they are external and you can chose then if its dull, or the panels are far away chose series, but if its a really bright day with both in sun, chose parallel.
So anyone got any other thoughts?