If for some reaosn the RPM limiter doesn't do what you're after, then for an automated speed limiter you can use the Cycle Analyst from Grin; if you're not already using one.
flippy wrote: ↑
Mar 14, 2018 9:58 am
my slight worry is the motor. i do not know how it will like having shoved 80V into basically a 48V motor.
If it's a brushed motor, it'd have extra wear and tear on the brushes and commutator from this, and more waste heat out of the watts poured into it, heating it up more than you'd expect from the higher power level.
If it's brushless, it doesn't care what voltage you put thru it. It only matters the total wattage creating heat vs what it can shed.
There's various calculators to guesstimate what your watts at a specific speed might be, on flat roads. Then you can use a calculator (same one or different) to see what the watts would be at that speed on the worst slopes you have to deal with.
Then you can add in some percentage to deal with headwinds, etc.; whatever you know you'll encounter that will require more power to overcome and maintain the speed you're after.
Once you know what that wattage is, you can then guesstimate if your hubmotor is capable of doing that continuously. If it isn't, there's a number of threads about cooling hubmotors that might fix that; statorade (ferrofluid) and hubsinks are the simplest effective method of shedding heat that doesnt' require opening up the hub, or dealing with leaking oil or other fluids on your tires and brakes, etc.
Then, knowing the wattage its' going to take to maintain that speed, you can work backward thru your controller and battery to be sure they can also handle that kind of power, too. If they can't, you can replace the controller, and add more parallel cells to the battery, or rebuild it with new ones that are higher capability, or both.