Folks I’ve found back the break chopper circuit made by Sawyer !! @Sawyer93 is it you by chance ?
Short word it is the end of HVC cut-off (like if you coast downhill and want to regen brake while battery is full, well you can still go at it).
We’d need to replace the halogen bulbs he uses to dry the excessive power by something more discrete IMHO. A big shunt or something similar ? A rack of high power LEDs to give it post-apocalyptic look?
Anybody is able to decipher it better than I do ? @b264@Deckoz what do you guys say ?
And a video of how it works / what it does (see the gauges in left corner) :
I dunno - were not talking about instantaneously dumping all the kinetic energy of the traveler. This guy uses a 225W array of bulbs to dump the excess current, and i doubt he’s shedding the maximum load that array can emit.
It’s my opinion that this should be handled by the BMS and not an add-on circuit. The balancing circuitry in the BMS would be best suited for this, maybe have a place for a large resistor or energy sink to hook up. @SimosMCmuffin
Thank s for the replies guys. Yep à BMS managing this would be killer (was thinking of the FLEXIBMS) ; still would be nice to get a spare pcb to simply hook up to your battery?
Heh, I just googled this and ended up right back here. There’s also some info on their website.
I’d be interested to see this, all the big resistors (1000w range) I came across were huge, as in the size of my forearm. Anyone pulled apart a Mellow board?
edit… Nevermind they have a rundown on their site too.
I’m not suggesting that a 100w resistor could effectively bring you to a dead stop. I watched the video, and based on that use case (light, short braking) a 100w resistor would be fine.
I know how hot they can get. We used to use them to make heated beds for repraps back in the day.
I suppose it could be done on the Switch-module. I don’t see any real reason it couldn’t. Might be actually possible to just use the BQ76200’s Charge FET output to directly control a N-channel FET going to a brake resistor. Heat dissipation might be the real problem, as you need to dissipate all that extra power somewhere else than the battery.
If you want to hook up an external dissipator though, it’d be interesting if the BMS had a spot for it. Maybe even a power resistor bolted to the truck hanger or something, dissipate heat on that…
I was about to ask about the type of resistor you’re thinking to use. My first thought was something located on the switch PCBs itself, but you seem to be thinking of a completely external resistor. I suppose the easiest could be to just leave wire hookup points available on the board.
