question

H Cronje avatar image
H Cronje asked

MPPT 250/100

So I decided to test the amperage on my MPPT. Stuck multimeter probes on the positive and negative for PV In and got a spark and a bang.

Now my MPPT no longer charges my batteries and the voltage reaches about the battery voltage and no more. I have about 200V coming in from my panel array but the MPPT shows 53V / 54V, just a bit more than my battery bank Voltage.

Also, if the system is off I test the 200V coming in on my PV disconnect breaker but if it is on it seems to equalise with the 53V / 54V the MPPT is stuck on and my multimeter gives a 53V / 54V reading on my PV disconnect MCB.

What have I done?

MPPT Controllersbattery chargingLithium Battery
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2 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

You mean, you used an Ampere Meter between the two PV contacts?


They are not shortcircuit proof (happen to accidentaly some years ago) which is wired, because an INPUT should be short circuit proof.


Do you have batteries connected?

53/54V look like the Battery Voltage

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Alexandra avatar image
Alexandra answered ·

To blow that it would have had to have exceeded the 70A short circuit of the MPPT. (Tech specs). And yes sounds like you succeeded in that.

Some mosfets would have lost their faces there.

Best way to test amps is a clamp meter.

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