I’ve recently started using the focbox on my ebike with 12s battery. I read a lot of threads about how lots of people killed their vesc with 12s and foc.
On my ebike though, erpm is lower than what most of you guys use. Four pole pairs and peak rpm around 9000. On the road I am usually at less than 7000 so less than 28k erpm. Also I don’t use regen so I can’t overspeed and fry anything while coasting down a hill.
Do you reckon this usage will be ok for the esc long term?
Wow 14s is 58.8 at full charge. Even though I have no need for smooth regen braking I bought one to play with as I have heard lots of (mostly) good things about it over the past couple of years. I also need sensorless and on many ebike controllers the sensorless implementation is not that good.
I’ve tested the focbox up to 110krpm… and I believe blasto and Johnny have done the same. If not higher…
My 13s calculated erpm is 73k. It’s the noise on older hardware designs that leads to failures as line noise can cause improper readings, and over current at high duty cycles…noise and slower sample rates…which is why pretty much all new vesc designs use direct fets…
I’m actually gonna defer to @Blasto to answer @deucesdown as he will likely give a more thorough answer.
I’m starting to remember more, but IIRC it was something about the sampling rate of the DRV chip will only allow 1-2 samples per wave at higher ERPM, and a lot could happen between samples. Which makes me think it’s not related to FOC vs BLDC at all. But I barely know what I’m talking about.
Sorry, I failed at googling up where I read that. I think on vedder.se forum somewhere.
Hey @Deckoz , about 14s on FOCBOX, is the electronics-limitation specifically related to the on-board capacitors? And further, would an inline ripple filter (cap bank) mitigate the risk from regen? The bank I’m running is HUGE, 22 whole-farads (as opposed to uF). It’s rated for 12s but the company that makes it (EM performance) have a 24s 6F bank too… just curious
Keep them nice and happy/healthy!! I’m into overkill when it comes to hardware, and stumbled upon the pack while looking for “normal” sized cap banks. The others i found were similarly priced but with not even a fraction of the capacity, so I snagged it for $55 on eBay. It’s probably instant death for most as switches tho, even my asm150 connector sparks a little when plugging in. The esc’s stay on for about 30 seconds after unplugging them, lol