Lowest OCV An MPPT Is "Worth It"?
There has to be some experience here on this forum to share. When I look at the MPPT manufacturer's data specs, the incredo-hyperbole gives me diarrhea.
Forum Discussion
Mex, you have to be careful with percentage gain and absolute gain as to what is worth it.
So if you got 20amps at high noon with PWM you would get 22amps with MPPT. Earlier and later when amps are lower it is still 2 more amps but the percentage gain goes UP. 2 over 10 is 20% (battery voltage is also lower earlier in the day which gets you more for MPPT so it is still 2 amps)
The percentages sound terrific, but it is still only 2 amps more for the day of say 8 hours--16AH. Do you even notice 16AH out of your day? I don't.
It makes no difference in MPPT if you have 12v panels in series to get 24v or one 24v panel except when you start looking at things like controller Voc input limits. A BIG DEAL!
There are all sorts of other factors to do with physical panel size and weight, controller read-outs and adjustable set points etc.
A factor often ignored is that you can mix and match by having more than one controller on a bank. I can have PWM 12v and 24v MPPT on the same bank and that is no different in daily AH from if I had matched panels and a very expensive bigger controller.
The limitation there is my PWM controller cannot do the 24 panel and I can't put the 12 and 24 on the same controller. I could if that one 24 panel were two 12s though. 12s give you more options for set-ups.
So if you got 20amps at high noon with PWM you would get 22amps with MPPT. Earlier and later when amps are lower it is still 2 more amps but the percentage gain goes UP. 2 over 10 is 20% (battery voltage is also lower earlier in the day which gets you more for MPPT so it is still 2 amps)
The percentages sound terrific, but it is still only 2 amps more for the day of say 8 hours--16AH. Do you even notice 16AH out of your day? I don't.
It makes no difference in MPPT if you have 12v panels in series to get 24v or one 24v panel except when you start looking at things like controller Voc input limits. A BIG DEAL!
There are all sorts of other factors to do with physical panel size and weight, controller read-outs and adjustable set points etc.
A factor often ignored is that you can mix and match by having more than one controller on a bank. I can have PWM 12v and 24v MPPT on the same bank and that is no different in daily AH from if I had matched panels and a very expensive bigger controller.
The limitation there is my PWM controller cannot do the 24 panel and I can't put the 12 and 24 on the same controller. I could if that one 24 panel were two 12s though. 12s give you more options for set-ups.
