The best photovoltaic solar panels
Thought I would share some information on what are rated as the best/most efficient panels available. Sanyo HIT Power N Series. The cells are hybrids of monocrystalline silicone, surrounded by ultr...
Forum Discussion
BFL13 wrote:
I found an error in the specs table I was using for the 230w panel, so forget that 7.29 earlier.
So for the 36v, 220w should be 6.1a
I am not getting it yet but perhaps almost. :( Maybe somebody can just clarify this part using Vmp and Imp: Thanks.
220w panel (39v, 5.65a ) vs
220w panel (36v, 6.1a)
Put a 30amp (so no clipping-can go full out for amps) MPPT on each of them.
Which will do more amps to the battery at 13v and why?
The input to the controller will be identical. The battery current will be set by the battery voltage, because the watts will be held constant. The only differences in two panels making the same actual watts out will come from the internal efficiency curve of the MPPT controller. Is this particular controller more efficient at 39v or 36v? Only a look at the curve will tell you. In reality they would be very close to identical.
Think of MPPT as a magical box that converts watts (at any voltage or current), to real charging amps at the battery. Watts are watts to an MPPT controller, no matter the voltage nor current. All it cares about are the real, this moment maximum Vmp and Imp (not theoretical).
Not if it is hot out and one panel degrades to 200w and the other to 180w at that surface temp, of course the higher real world wattage will win. Or if it's cloudy, of if it is low angle...etc.
But if 2 panels are actually making the same real world watts, their amps out to the battery will be very close unless they are on radically different parts of the efficiency curve for that MPPT controller because of very different voltages.
Jim
