Opinions on 100W Solar System
I've done my reading and research and think I have a system figured out. Limited space on the roof of my 815 so plan on going with a single panel. Maximum space available is 52 x 25, but optimum...
Forum Discussion
In my opinion and many others pwm and mppt are quite close in performance when panel voltages are in the low 17's... If a panel is rated in the 18+ then you see some gains that can be quite significant. You are never going to get any more wattage out of a panel than it's spec... Watts = amps X volts...
A panel that has higher voltage 18+ and less amps and is rated at 100watts that is it, no more gain that the panel is spec'ed for. MPPT will convert that higher voltage and the lower amps into 100 watts.. There are losses so you will not actually see 100watts... Think Rogue specs about 97% or better.
A Pwm with the same panel will not give you 100 watts because it can only provide the current /amps the panel produces (Isc)... It only passes the current... thus the reduction of performance. MPPT wins.
That is the reason I said that these Renogy Panels with the higher Voltage would really work well with MPPT.. If you were to put a PWM controller with them you will only see the ISC amps of those panels MAX... Whereas a MPPT controller will utilize the higher voltage and produce more than the ISC amps... Probably 15%+... Like I said in my post above ...
Numbers are example only:
4.5 amps x 2 panels = 9 amps but I see 13.x+ . Because of the higher voltage..
A pwm controller will only provide 9 amps
As for heat.... Fairly close for each... I pay no attention.. My controller is mounted under the sink... out of sight out of mmd. It does have over temp protection.. I have felt it after a few hours of pumping 10 amps and it does not get hot.
This video does a good job of saying what I have said:
https://www.youtube.com/watch?v=K7NWpxxEB9o
Jim
A panel that has higher voltage 18+ and less amps and is rated at 100watts that is it, no more gain that the panel is spec'ed for. MPPT will convert that higher voltage and the lower amps into 100 watts.. There are losses so you will not actually see 100watts... Think Rogue specs about 97% or better.
A Pwm with the same panel will not give you 100 watts because it can only provide the current /amps the panel produces (Isc)... It only passes the current... thus the reduction of performance. MPPT wins.
That is the reason I said that these Renogy Panels with the higher Voltage would really work well with MPPT.. If you were to put a PWM controller with them you will only see the ISC amps of those panels MAX... Whereas a MPPT controller will utilize the higher voltage and produce more than the ISC amps... Probably 15%+... Like I said in my post above ...
Numbers are example only:
4.5 amps x 2 panels = 9 amps but I see 13.x+ . Because of the higher voltage..
A pwm controller will only provide 9 amps
As for heat.... Fairly close for each... I pay no attention.. My controller is mounted under the sink... out of sight out of mmd. It does have over temp protection.. I have felt it after a few hours of pumping 10 amps and it does not get hot.
This video does a good job of saying what I have said:
https://www.youtube.com/watch?v=K7NWpxxEB9o
Jim
