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
I did observe an ~11+% improvement in Amps when when I switched from PWM to MPPT with a pair of 85W 18.3VMP panels. I have since used the panels with both series and parallel.
Before switching to MPPT, I observed 9+A. After switching I observed 10+A, for about a 1A gain. This was in Summer with temps near 100F.
I also had a so-called 12V nominal panel. It was 130W and 19.6VMP. I say it wasted ~5V+ with my PWM controller during bulk charging because it had a lower ISC. It was a poor fit for PWM. An MPPT would have exploited that 5V.
Today and for a PWM solution, I would look for a lower and more PWM friendly VMP around 17V because the panel would have a higher ISC for the same Wattage.
With PWM, you shop for the best cost/ISC.
With MPPT, you shop for the best cost/Watt.
HTH;
John
Before switching to MPPT, I observed 9+A. After switching I observed 10+A, for about a 1A gain. This was in Summer with temps near 100F.
I also had a so-called 12V nominal panel. It was 130W and 19.6VMP. I say it wasted ~5V+ with my PWM controller during bulk charging because it had a lower ISC. It was a poor fit for PWM. An MPPT would have exploited that 5V.
Today and for a PWM solution, I would look for a lower and more PWM friendly VMP around 17V because the panel would have a higher ISC for the same Wattage.
With PWM, you shop for the best cost/ISC.
With MPPT, you shop for the best cost/Watt.
HTH;
John
