Good money after bad - Solar upgrade time

Author	Message
oreo Senior Member Joined: 11/12/2020 Location: Canada Posts: 138	Posted: 05:51pm 08 Aug 2026         Solar Mike said   Most likely it is a voltage spike thats killing them, 72v battery voltage, you need really 150v mosfets Thanks for the input Mike!  Can you tell me how you arrived at me needing 150v Mosfets?  I just linearly scaled up the 80v mosfets everyone else uses in the Wiseguy 48v inverter. (see calculations below)   Solar Mike said   Moving to compound die mosfets doubles the charge currents needed to switch them on in the shortest time, having 4 paralleled places a lot of extra stress on the mosfet driver and its bias supply, if the bias supply sags and cannot supply the required driver current then that will also blow them up, if you go for dual die versions, then a 2watt psu for the bias would be needed. While the gate capacitance of the HY5012 is higher than the HY5608, it does not seem to be that much different. (to me)  I show the numbers below.  I have checked the bias voltages in the past and will double check them again with the new FETs in there. Edited 2026-08-09 03:54 by oreo