MPPT vs standard PWM?

[Jemplayer]

You almost got it right, but stated it incorrectly.

Power (watts) = Voltage x Current.

What you want to know is does Power Input = Power Output.

To do that that you need 3 pieces of information. Input Power, Output Current and Output Voltage.

OK so as an example you have 2600 watts input to the controller. On the output you measure at the same moment in time 58 volts @ 42.6 amps. What is the output power? 58 volts x 42.6 amps = 2471 watts. So with an Input of 2600 you have 2471 watts output. That is a conversion efficiency of [2471 / 2600] x 100 = 95% efficiency which is really good.

What I think you were doing to determine ouput wattage was using nominal battery voltage fixed at 48 volts which is an error. Under the same example 42.6 amps x 48 volts = 2046 watts which is incorrect.

Thank you very much for the explanation. I am going to note battery voltage as shown on the MPPT and multiply that by the amps shown, I should then get more or less the wattage shown at that time, minus the losses. So the wattage will be a bit higher than the calculation, correct? Due to 95% efficiency.

[Sunking]

Thank you very much for the explanation. I am going to note battery voltage as shown on the MPPT and multiply that by the amps shown, I should then get more or less the wattage shown at that time, minus the losses. So the wattage will be a bit higher than the calculation, correct? Due to 95% efficiency.

Like anything in life, output will always be lower than input. No such thing as 100% efficient. Note this will only work when the controller is in BULK mode charge. You will not see that in Absorb or Float mode at which point the controller switches to PWM.

[inetdog]

Like anything in life, output will always be lower than input. No such thing as 100% efficient. Note this will only work when the controller is in BULK mode charge. You will not see that in Absorb or Float mode at which point the controller switches to PWM.

An interesting point, which may vary from one CC design to another. Among the possibilities are:
1. The CC continues to deliver a regulated voltage, without direct PCM by shifting the input away from MPP until the continuous power from the panels is all that is needed to maintain the battery terminal voltage.
2. The CC delivers a PCM voltage to the output by shifting the input side between open and MPP in a PCM fashion.
3. Some other variation.

I do not know what any particular actual CC does. But the key thing is that in all cases the power taken from the panels will be less than PMPP while the peak voltage on the input, as measured with a peak catching DC meter, may be anywhere from below V_MP all the way up to V_OC.
Can anyone on the forum supply the definitive answer for their particular MPP CC?