Charging and heat

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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #32
    Re: Charging and heat
    boB wrote: »
    120 Hz half sine current ripple is exactly what I would expect to see at your battery shunt with a PFC charger.
    It tries to draw a sine wave of current from the AC input.

    It's certainly hard to tell what the waveform is without a scope, but I'll try anyway.

    I will assume PF=1 and no time-shifting of power.

    If voltage were constant, we would get a squared sine wave for current. For this curve, the avargare current would be 0.5 of maximum current.

    If voltage had full amplitude, we would get sine wave. The average current would be 0.7 of maximum current.

    In this specific situation, voltages varies about 12%. So, the ratio of average to maximum would be somewhere around 0.53.

    The measured value is (90A/200A) 0.45. Which means that somewhere during the cycle power is not taken and current is zero.

    We can get an approximate estimate of PF = 0.45/0.53 = 0.81. The specs say 0.98.
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