Sizing MOSFET Heat Sink

Just make sure you put an anti-parallel diode across your load since I'm guessing your load will have an inductive component.

Switching NPN low side.

670282 JAMECO part number for the MOSFETS.

FOD3180 Fairchild optocoupler.

1% 1-watt resistors, and 100 volt electrolytic, and 40 volt tantalum caps used throughout. I am taking no chances.

Actually I am going to be using 169 ampere National Semiconductor MOSFETS, and driving them with an enhanced (newer model) opto coupler with a 2000 ma output @ 9 volts.

Part numbers for those parts please? I still don't see your explanation of how you're going to generate the gate voltage if it's N-channel and you're switching the high side. Any concern about the reverse body diode?

Wuwee. Daughter four granddaughters and myself Mexican citizens.

México is no longer inexpensive.

When I stop learning, I start dying...I have watched far too many old people wither in front of a television. THAT I refuse to do. Returned to rental house in Baja. Need to get moved to border area and let the maniacs start cutting.

You must really love where you live, and all the projects keeping you busy, Mex... I'm sure it's not for love of the country, just the cost of living? What'n the heck ever happened to KISS?

And rig. When it gets ultra hot, I retreat into the rig. But I will be @#$%^&! if I will cook in here.

A few smaller of the same type of MOSFET relays are for the rig. Eliminates the need to switch off the water pump at a switch. Telephone wire is large enough for the Opto Coupler.

I think Mex is talking about his off-grid house.

WOW and thanks for the explanation, I didn't realize your disconnect was that far from the rig and the level of storms to which you are exposed. Certainly makes sense now....a lot different that our somewhat pedestrian camping trips up here....

Nice spot down there on the coast, are you far enough from Mexico City that you're out of the gang business?

Sorry if I went OT, I know you are looking for technical advice.

BurbMan, may I compliment you on your gentleman's style approach to puzzlement :) Heavy on Style...

This is a DIRECT CURRENT disconnect.

3:00AM. KA-BOOM! I wake up to a thunderclap and slashing of rain on the patio roof. It doesn't "rain" down here, the water gets into a contest with air molecules to see which one can crowd out 90% of the other. Bad? Even in daylight the rain is so heavy a person simply cannot see the ground. The platter and spatter bounces upward three feet. At night it is dangerous even with a powerful light. I have to make it (200') to the shed and back and cut off the power. No way Joser. The inverter gets cut off, 12" from the output. I have run ground ionization feeders downstream (12 gauge wire running to a ground stake). The electrodes parallel the lugs at a .050" distance. A ground path for a lightning strike. With 1K 10 watt resistors. Sure there's a chance the bolt will fry the MOSFETS. But it won't get to the inverter. Fuses help. And I have a manual switch disconnect on the house end, plus another ion path ground stake.

Thunderstorms EVERY DAY in the summer.

When I leave to go on a trip, I do not have to hike, unlock and re-lock the generator/battery/inverter shed door. Click, it all goes off.

One neighbor had a bolt blow a 20" hole through cinder block. The branches went into the kitchen and fried every connected appliance. The lightning traced INSIDE the house parallel to buried wiring. One went into the bedroom and blew the huge mirror over the dresser into tiny shards. Another caught a Puebla rug on fire.

On top of the hill another storm. A bolt hit the henhouse and killed a few dozen birds. Nothing like the mega aroma of Kentucky Fried Feathers.

If the motion detector light goes on, and I think something's wrong, "click!" another channel. 350 watts of LED lighting turns an a half hectaria into a futbol stadium.

Wanna suck all the flying insects away from the door before I exit. "Click!" and 10 watts of UV LED on the far end of the patio goes on for 3 minutes. Timed via a 555 single shot timer. Geckos await their evening snack.

The driveway is a pain. Not.....any.....more

Low voltage 10 watt LED's line the twists and switchback now, like an airport runway. Also on a timer. Click!.

But mostly, I do not like getting sopping wet at quarter to three.

While you guys discuss the technical specs, I am still struggling with the WHY of what a remote control shore power disconnect will solve?