Pwm Charge controller question. C40

nobody928
nobody928 Solar Expert Posts: 62 ✭✭✭✭
in Solar Beginners Corner #1
I have a xantrex c40 charge controller. It is 40 amps. Im not sure how many panels I can put on this controller. Watt is the maximum amount of panels it can handle?

Can I over power the charge controller by a few watts?
I would like to put around 560 watts of panel to it @ 12 volts? Will this harm anything?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Pwm Charge controller question. C40

    On a 12 Volt system 40 Amps would be produced by about 700 Watts of panel. The math looks like this: 40 Amps * 17.5 Vmps (typical for '12 Volt' panels) = 700 Watts
    Remember that this is a PWM controller and can not down-convert Voltage: panels would all have to be at around 17-18 Vmp and all in parallel.

    That gets a bit tricky as it calls for some big wires and fuses per panel since most "12 Volt" panels are no more than 140 Watts: five to get 700 Watt array (7.9 Imp each * 5 = 39.5 Amps).
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