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How can I calculate my charging amps coming out of my MPPT

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jbourne84
New Member

Posts: 5

How can I calculate my charging amps coming out of my MPPT Apr 12, 2017 10:21:37 GMT -8

Post by jbourne84 on Apr 12, 2017 10:21:37 GMT -8

two 100w panels in series
Tracer 20 amp mppt controller
MT-5 Meter

I used a friends meter to short circuit read my panels and got about 5 amps in pretty good sun, I regularly get a reading of about 40 volts from the two panels.

(Not accounting for conversion losses here) If the charging voltage is 13.6, can I just do the math straightforward and say:

40Vx5 = 200w

200/13.6 = 14.7 amps

Also, can I short circuit measure the +/- coming from the charge controller the same way I did the panels to get this reading?

rabird
Solar Fanatic

Posts: 552

How can I calculate my charging amps coming out of my MPPT Apr 12, 2017 16:21:24 GMT -8

Post by rabird on Apr 12, 2017 16:21:24 GMT -8

What's the meter for if it does not display charging amps?
Your math is correct, add some inefficiency like 90%, 14.7A x .9 = 13A

No, you can not sort the controller.

If you have a digital volt meter (CVM) that can measure amps ya put in in line to measure amps.

first ya set the meter to measure amps, 20A setting (easy to blow a meter fuse!), ya disconnect one panel wire, then disconnect either the + or - from the controller
Put the DVM inline with the wire that is disconnected and then connect the panel to read charging amps.