> ... what is the 'mp' in Wmp?

I should havedefined it
Wmp or Wmpp is Watts at maximum power point. ie panel is irradiated at
std level (usually 1 kW/m^2 at 25C with light of AM1.5 spectrum*) and
then loaded so that Vx I product is maximised.
ie about as much as you will get out of it best case ever.

If you have a "12V" panel it will often have Vmp =3D 18V so a 180 Watt
panel will produce 18V x 10A at Wmp point. If you charge a lead acid
battery with a non energy-converting controller you get slightly more
than 10A (as Isc is > Imp (but not vastly so) and 12V load is between
Vmp and SC. So you immediately have a no more than about 1A x 12V =3D
129 Watt effective panel. Not a good start. MPPT controllers energy
convert and try to load the panel to Wmp and output at optimium for
system in use.



            Russell
--=20
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