LeoDJ

My planned approach is using a P-FET with a RC network at its gate so it does the pre-charging over a few 100ms in its linear region. What do you think? I've simulated it in LTSpice and it seems to work ok and stay in the safe operating area of the given MOSFET. (I've chosen a similar FET in LTSpice for a good model)

@thunfisch@chaos.social Ye, that big tube thingy is the contactor. A Gigavac GV200, 500A 800V DC contactor to be exact. It will conduct the main current between battery + and motor controller +. But because motor controllers have quite beefy and low ESR input capacitors, if the contactor would simply make the connection when the input caps are empty, there would be many kiloamps flowing through not-quite-mated switch contacts, trying to charge the caps rapidly.

@jakob@mastodon.chaosfield.at Thanks ^^ Yeah, at that voltage I wouldn't want to rely on semiconductors that like to fail short either :D I also thought about a second relay + resistor but opted to go for this solution first ^^

That's where the FETs come in. They pre-charge the input caps slowly and only then the contactor will be engaged. The MCU is there to oversee that process. I.e. not engaging the contactor when it still senses a voltage difference that's too great, etc.

@Westfuchs@mastodon.social Vermutlich immer noch schneller als mitm Zug :P

@rightsprung Oohhh, that's amazing! With a cable that long, how early do you have to give control inputs to bring the bucket to a stop at the right location? Or how long does it take to correct for sudden gusts of wind? Or is stuff like this already engraved in your muscle memory and you don't even really think about it?

@aleksorsist@mastodon.social Huge congrats for the perseverance!

@forelioned@mastodon.online It's no car stereo, but I've got this: https://chaos.social/@LeoDJ/109832677947895279 :P

@poleguy@mastodon.social Haha, cool solution :D I *could*, yeah. But I wanted to go for this solution ^^ Mainly so I can leave the battery in, if I want to, because the plan is to have cable lugs screwed to the battery's contacts (it's meant for screwed connections). Connectors for 500A get expensive and large *quick* :D And also to have a switch that completely powers off the whole system should anything happen.