as long as I dont go over my max voltage cut-off by riding downhill and braking with a full charge I’m good right? Maybe I should up this limit a bit.
as long as I stay under the max erpm of the esc which would be my kv times voltage x 7 I’ll have brakes right?
Otherwise no brakes in the first situation or esc death in the second?
definitely thinking I feel safer with a kv that’s on the higher side for this reason. Couldn’t be worse than losing brakes going down a hill at full speed.
I go down steep busy hills with stop signs at the bottom. san francisco city. without brakes I’d be dead quickly
higher voltage allows you to increase your rpm and also the erpm.
but I still havent heard an answer. Looking for the speed limits for the vesc. I know it will cut the brakes off after the high voltage cut out, so going faster than the no-load speed based on the kv and voltage, but I forget anything else.
direct drive
90kv x 50 volts (full charge) is maybe 4500 rpm. x7 equals 31,500. so I’m good on keeping under the erpm but what about voltage spikes? If i get above my no-load speed going downhill and then brake I’ll have an even greater voltage spike than the 57v cut-off maybe?
I’m confused by the voltage spike. I thought the voltage sent from the motor was determined by the speed of the motor yet you can have a high voltage spike braking when youre going slowly
I believe voltage spikes only occur in the battery (don’t quote me on this). Keep in mind your hub motors should have higher erpm due to additional pole pairs.
The spike is actually beneficial in order to regen your batteries as anything lower than the current working voltage of your batteries would be lost as heat instead of regening.
If you’re working with 40 volts, you need to have a BEMF of 40+ volts in order to regen or the energy will be lost as heat.
ok. so it has to be higher than the battery, which makes sense, but how does it get higher as I thought the voltage was tied to the speed, just as it is when the motor is being used as a motor and not a generator?