Pretty much. Controlled shorting of the leads using the fets.
The bms I mentioned has some decent heat sinks on the fets it also has a heat sensor and would shut down if over heated. I wouldnāt recommend braking a mile downhill with a full battery. My test was on a fairy short hill.
Yep confirmed, is seems maximum braking power is independent of maximum battery charging current limit. The excess energy must be wasted as heat like any other form of braking. Higher charge rate batteries are still the best way to go though, for better efficiency and to keep the motors cooler.
Letās say your settings are -50 A Motor min and -10 A Battery min.
When you do a full brake the VESC will try to achieve 50A brake power because with the remotes trigger you control the motor min value. Which means at half trigger the VESC will try to reach 25A brake power, at 3/4 trigger 32.5 A and at full trigger 50 A.
When you go full speed and brake full immediately then the duty cycle goes down. Because of back EMF which goes in the other direction but thatās to much details. So in reality the duty cycle drops to around 60% in this case.
At 60% 50A at the motor would be 30A (60% of 50A) at the battery. But battery min only allows -10. So the brakes wouldnāt be as strong as the trigger tells the VESC. It will only brake with 16.6A (10 A / 0.6) at the motor.
While you continue braking the wheels becomes slower and the duty cycle quickly drops. So at 40% duty cycle the VESC still wantās to reach 50 A brake power but that would mean 20A at the battery. But 10 A are the maximum so it will only brake with 25A at the motor.
At 20% duty cycle it is possible for the VESC to brake with 50A at the motor.
So it is good to have a high battery min value. I for example set the settings about 50% higher than the max charge of the battery would allow. With 4A max each cell in a 4P setup that would be 16A. But i set it to 24A because i think it doesnāt hurt the cell when you brake hard from time to time. And you reach these high amps only for like 2 or 3 seconds. And i try to brake gently at high speeds during my normal rides but want full brake power if i need it in a emergency scenario.
I think that charging the cells with a power supply at high amps damages the cells much more because it is a constant charge instead of a short pulse. But maybe i am wrong with my theory.
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Hi everyone, do you know how to setup the force of brake via vesc-tool, to make skateboard can stop complete when i push the throttle to maximum? thanks
Increase āmotor min regenā its usually at -40 some have it at -60 at most play with those values vesc has a smooth throttle you generally donāt want to stop completely at full break instantly asking for trouble thatās what ESCās are for if your into that stuff.
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So I have Racerstar motors that has max current is 46A. I have a 10s4p battery made of samsung 30q which has a discharge current of 15A and for a BMS i have a Bestech190 that has a max charge current of 10A. Iām running dual setup So for motor max and min it should be 46 and -46 and for battery min it should be -5?
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Are you bypassing the bms for discharge?
If soā¦ 4p* 20a = 80a/2 ESCā¦ or 60 if you wanna use the 15a rating.
40a bat max per esc
3ah*4p = (12ah * 2c charge)/2esc = -12 bat min.
For simplicity for the motorā¦ Motor max 46 Motor min -46
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Just correcting my comment from a few months ago. I was wrong. All braking is by regen.
The reason for a separate regen current setting and negative battery current settings is to do with braking efficiency at difference speeds. So low c rated batteries will break more poorly at higher speeds, but catch up with high rated batteries at lower braking speeds. The vesc designer guy explained it on his forum a few days ago.
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I guess I would be bypassing the bms for discharging because it is a 10a charging with no discharging. It was from the group buy the TGH did in novemebr
http://www.bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D190.html
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Thank you very much all of your help, I am trying it. thanks so much.