slightly different solar qx
Am looking at solar on a small class A. I currently have 3 group 27 batteries (rv/marine) for the house. (prior owners had just installed 2 new, and I had one from a trolling motor setup) they will...
Forum Discussion
FWC wrote:red31 wrote:
controller eff of mppt is a real loss of power via heat sink, esp cheaper models!
mismatched or in low power conditions.
While I can't speak to some of the off brand/cheaper models of MPPT controllers, for the reputable ones (think Victron, Morningstar) the conversion efficiency is really pretty good. In the figure below, the orange line is a Morningstar MPPT controller, they don't say which controller the blue line is. In either case the power lost to heat is much lower than the power gained by MPPT and reduced wire losses.
Victron's whitepaper and the graph 7.2 Absolute performance as a function of temperature (~page 10) convinces me with my various small 100w systems that mppt was a waste of my time locally in the heat. Their little blue shaded area is actually wider than they suggest!
7.2 Absolute performance as a function of temperature
https://www.victronenergy.com/upload/documents/Technical-Information-Which-solar-charge-controller-PWM-or-MPPT.pdf
graph assumes mppt has higher voltage to continue to 'buck'. :E
