Solar fuseing, confuseing
Were installing a Renogy 400 watt solar system on our fith wheel. We stay on our property about two months in the summer up near Canada in Washington.Anyway this is the kit I bought. Mind you I'm comp...
Forum Discussion
BFL13 wrote:
I get so confused reading all this stuff. ISTR reading at one point that the tracking circuit in Absorb just did not track MPP anymore, but found the voltage (higher below the knee) that "met the demand" for the buck converter. The buck converter stays "in balance."
If you ran some extra 12v things while in Float, the solar amps, via buck converter, would crank up to meet the demand, but the controller will remain in Float. I have seen that with my MPPT in the afternoon when the batts are nearly full and I run something 12v.
For the amps to crank up with the output watts the same, the voltage must go back down--back up the IV curve towards the knee. So did the "tracker" do that change in voltage to meet the demand or what did? I have no clue. It is all magic black box stuff it might be better not to ask about :)
It gets even more confusing. An email answer from Roger Carrol at AMSolar.com stated:
" Good question: Does the SB3000i use a PWM tapering strategy during absorption and/or float operation? The answer is basically, no. There is no change in basic MPPT operation during all phases of bulk/absorption/float. It still continues to dictate the input voltage throughout all the charge modes. "
This is in direct conflict with what tech support at Morningstate said.
I am holding off eating crow until this question of MPPT using PWM gets fully resolved.
