mppt or pwm An opinion from Victron
Hi all, Victron, which makes high quality equipment, has charge controllers. At the end of an overview they give their description of the differences between PWM and MPPT. They do not support it wi...
Forum Discussion
Salvo wrote:
Without measuring the panel output power, your time was wasted writing all that. :SBFL13 wrote:
A. 230w (two 115w) total Isc of 14.5a to battery, batt voltage 13.5 = 196w
230-196= 34w wasted or 34/230 = 14.8% wasted power with PWM all season
B. One 230w and MPPT 15.5a to battery, batt voltage 13.5 = 209w
230-209 = 21w wasted or 21/230 = 9% wasted power with MPPT at 16C ambient, 44C panel. (April)
C. 230w and MPPT 13.5a to battery, batt voltage 13.5 = 182w
230- 182 = 48w wasted or 41/230 = 21% wasted with MPPT at 25C ambient, 51C panel (July)
Salvo, I don't think so. It is not necessary to have exact figures to show that the panel does fewer watts than rated when hot. The definition of "wasted watts" may be at issue.
If the watts were never produced, were they "wasted" or just lost?
I do have the controller's output power as quoted above, so all I need is controller efficiency and there is the power at the controller intake. I also know that voltage is 29.3 at the panel and 29.0 at the controller for line loss. That voltage should be the Vmp selected by the controller at the time. Only thing not measured is Imp but it can be calculated from what is known.
If my controller is 93% efficient, much lower than its max efficiency, then when its output is 182w as seen in July, then input must have been 196w. (29.0 Vmp x 6.76 Imp)
Suppose I had a meter on Imp and it was indeed 6.76 while voltage at the controller's array terminals was 29.0. What more would that tell you than now? What more would you know if it were higher or lower other than give a different controller efficiency percentage?
