Solar Help
I have an older Class B motorhome and have been thinking about solar. I can boondock now for 2 days before I have to recharge my 125ah battery. The only thing that draws power is the 12V fridge whic...
Forum Discussion
The panel with VMP 26 is what is called "24V nominal". Mostly, 24V nominal panels have VMP around 30, so 26V is an odd number. For your purposes consider it a "24V panel", i.e. the one that requires expensive MPPT controller.
Using PWM controller with this panel will result in too much loss of power. It will simply clip the voltage down to 14V that battery requires, and because the Imp of this panel is already low, you will lose the power. OTH, MPPT controller will convert the excessive volts into more amps, making 14.8A @ 14V out of 7.9A @26V. With panels that are not 12V nominal, you have no choice but use MPPT.
I have to retract my statement about 190W 12V nominal panel - the biggest panel that is still 12V nominal, is probably 150W-160W.
Using PWM controller with this panel will result in too much loss of power. It will simply clip the voltage down to 14V that battery requires, and because the Imp of this panel is already low, you will lose the power. OTH, MPPT controller will convert the excessive volts into more amps, making 14.8A @ 14V out of 7.9A @26V. With panels that are not 12V nominal, you have no choice but use MPPT.
I have to retract my statement about 190W 12V nominal panel - the biggest panel that is still 12V nominal, is probably 150W-160W.
