This is my 40 Amp PWM solar controller/regulator, DIY home built project. It’s based on the LM339 quad ic and 4ea- IRF1104 100A MOSFET’s. It also has LM7812 and LM7805 regulators for the bias supplies. The circuit board is hand wired and mounted as a daughter board to the main pass transistors on the heatsink. It runs cool all day at full load without a cooling fan.
I built it on a bread board, migrated it to vector board and mounted the whole thing to 1/2 inch plywood. It has 2ea- 30A andersons in parrallel for the input with 10GA wires. Same on the output, 2ea- 30A andersons with 10GA wire in parrallel. The andersons let me “Quick Disconnect” if I need to service the unit. There’s a 60A circuit breaker on the input and dual 30A fuses on the output. Every MOSFET is wired with 10GA on the Source and Drain and so are the 75A Schottky Diodes. All components have Mica insulators with thermal compound on each side.
I found a surplus heatsink and removed the old TO-3 transistors and mounted modern 100A MOSFET’s in their place. Then cut down the heatsink to fit the circuit board. Bruce McCaskie N6THN
