New to Solar, Some Questons?
Added a 100 watt panel to my MH with a 10 amp controller. Daily checks with meter show charging under varying conditions of 18 to 19 volts. This :Kit" came with minimal instructions so need some help ...
Forum Discussion
BFL if that really matters to you look at Unisolars. My 68w panel is rated at Voc 23.1v yet Isc is 5.1. A lot more Isc per watt than you generally see.
It's not really a low Voc that gets you good PWM current, it is a low Vmpp - one that is close to but above the battery voltage you want. Vmpp on these units at standard test conditions is 16.5v. Vmpp is pretty much the last voltage where you make decent amps. Go much higher in voltage and amps collapse very quickly on the IV curve.
As actual (under real conditions of temperature, light intensity, light angle, and atmosphere passed through - not the STC ratings) Vmpp approaches the battery voltage under charge, PWM approaches or even passes MPPT yield. The further real Vmpp is from the current battery charging voltage, the farther the PWM voltage is from the current panel max energy output, and the more benefit MPPT gives.
Jim
It's not really a low Voc that gets you good PWM current, it is a low Vmpp - one that is close to but above the battery voltage you want. Vmpp on these units at standard test conditions is 16.5v. Vmpp is pretty much the last voltage where you make decent amps. Go much higher in voltage and amps collapse very quickly on the IV curve.
As actual (under real conditions of temperature, light intensity, light angle, and atmosphere passed through - not the STC ratings) Vmpp approaches the battery voltage under charge, PWM approaches or even passes MPPT yield. The further real Vmpp is from the current battery charging voltage, the farther the PWM voltage is from the current panel max energy output, and the more benefit MPPT gives.
Jim
