From the measurement I did when I had the wattmeter plugged in between the battery and the FVT ESC:
10-20 Ah when accelerating slowly and cruising (~250/500Wh) and 40Ah (900Wh) at peak (accelerating full throttle uphill)
On the VESC, initially I had configured motor max as 40A and then 50A but I had not enough power to accelerate strongly uphill (I weigh 95kg), after I changed it to 60A I never experienced cut-offs so I guess the max drain will be around 55A.
My question is, if I had a 12S setup then I could set motor max to 30-40A and not experience cut offs in theory isnt it?
To keep the mosfets (a.k.a. FETs) of the ESC cool.
They handle most of the current in the ESC, they switch and modulate the current from battery to motor (electrical side of the things, the main chip instead, the DRV in case of VESCs, sends low voltage pulses to them to control their output current)
yes, people put small heatsinks that have adhesive tape on them (like these) or thermal glue to keep them cool, or even a piece of metal so the dissipation surface is increased, also if you add more code to the VESC that does extra calculations is recommended to cool the main chip down as well.
Yes, these things apply to any ESC, every ESC has a chip that is the “brain” of the ESC, and does the calculation for draining and outputting the right current based on the receiver’s input, battery and motor status, and that chip, like the FETs, has to be kept cool as well.
I’ve been planning forever to pot my vescs since then they wouldn’t be suffering the physical abuse that they get otherwise and according to Chaka and Vedder the vesc’s fets are the only heat source that I’d need to worry about and shouldn’t be potted.
The brain doesn’t get that hot?
I have so much potting resin but am still afraid to do it. Wouldn’t need an enclose just glue it to the board with the potting resin.
How fragile are the fets? I planned to have them exposed and just covered with stick-on heatsinks.
nice effort! not sure if this worked though - had a weird result screen after submit. also I got a lot of suggestions since many things arent clear enough and allow various funky inputs:
gear ratio -> example of input in brackets (16/36, 1:2, …)
wheel size -> add unit (mm)
board weight -> add unit (kg)
rider weight -> add unit (kg)
battery voltage -> add “nominal”
battery capacity -> add unit (Ah)
C-Rating -> floating number with “,” or “.”?
imo: add “Continuous Current (A)” and calculate C-Rating and vice versa!
peak draw -> add unit (A) or power (W)
average draw -> add unit (A) or (W)
max speed -> add unit kph, mph or m/s
energy consumed -> add unit (Wh)
watt/hour per mile -> thats wrong, change to Wh/mile (I prefer Wh/km obviously)
Energy consumed -> add unit Wh
Hill Time -> add “in % of total ride”
Average incline -> add “in %”
the lower 4 entries are supposed to be what?
max wattage used -> max power used in units (W)
avg wattage used -> avg power used in units (W)
watt/hour -> not sure what that is supposed to be?
wat/hour per mile -> Wh/mile
imo, to the right of the entries should be an example template completely filled out so that people can at least see if their numbers make ANY sense at all. not everyone is firm with basic physics, units, etc!
also, please no unnecessary input:
from avg speed, distance and energy consumed, the script should calculate avg draw and Wh/mile on its own - no need for the user to calculate all that imo.
personally I would also add ESC & commutation mode (maybe as text like you did for motor), single/dual/quad config and belt/hub (which is probably halfway clear with gearing)!
not sure if this worked though - had a weird result screen after submit. also I got a lot of suggestions since many things arent clear enough and allow various funky inputs: