question

When I read "Connecting inverter with 4KW" I immediately thought that the Load Output mOSFET would not survive this.
In the first milliseconds, this is a few hundred Amps, no chance for that output MOSFET.

Short circuit MOSFET is most likely the problem.

This is an old thread, but I have experienced the same problem recently. Output MOSFET was fried after trying to switch ON a 350W (!) inverter.

The reason for the fried MOSFET is most likely not the high inrush current (as the output is advertised as short circuit proof!). It ist most likely the inductive voltage spike when switching OFF wehn the unit detects the high inrush current. There does not seem to be any supressor diode on the output! So even switching longer cables may destroy the output MOSFET.

After adding a 82V suppressor diode to the output, the second MPPT 100/20 is now happy switching the inverter ON and OFF repeatedly!

For me this is a real big issue with the load output on this device! Having short circuit protection without overvoltage protection is not enough! Perhaps one of the Victron people can shed some light into how the output is supposed to be used ....

Best regards, Jörg.

Hallo @Jörg Becker,

What type of diode is it exactly, and how is the polarisation?

Thanks in advance

(De: um welche diode handelt es sich - wie ist die typen bezeichnung und wie muß sie gepolt werden? Vielen dank im voraus )

I have used a P6KE82. This is available as unidirectional (P6KE82A) or bidirectional (P6KE82CA).

I would prefer the unidirectional type, cathode (white or silver ring) connected to plus.

The diode can be soldered directly to the pins of the output connector which can be seen between the radiator and PCB. Sorry, the unit is in use on in a hardly accessible space so I can't take pictures...