VESC bat regen settings with a discharge BMS

ESK8 Electronics
1

Here is my problem. I changed the 6355 sealed Maytech motors with 6374 sealed Maytech on my Evo. Both motors are supposed to be 190kv but I am not so sure if this is the case. Now the board has weak high speed brakes, low speed is fine. VESC settings: Motor Current Max Brake:-50A Battery Current Max Regen:-10A

Normally I would increase the Battery Current Max Regen to something like -20A but since I use a discharge BMS in this board I am afraid it will trigger the BMS protection. The BMS is the Besttech HCX-D223V1 and the Maximal continuous charging current is 20A so I am already at the limit.

Do any of you guys have any suggestions? (apart from bypassing the BMS of course).

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2

Weird cause my 6374s had significantly stronger braking than my 6355s both 190kv

I would raise it to -12 battery amps and try it out. Usually when braking it’s for a short amount of time so it would be an amp spike not a constant so even the BMS should be able to handle it.

What battery are you using?

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3

Yeah, I can’t figure out why. I use a 12S5P 30Q so handling more current for a short time is not a problem, it is the BMS I am worried about. On my other board with a charge only BMS I have the batt regen around -30A .

4

Wtf… How heavy are you :rofl:and dual or single?

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78kg, maybe close to 90kg with gear and backpack. Dual, however it is pretty steep where I live.

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-30a per vesc?

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Yes. 10 char.

8

Hmmmm… Alright than :sweat_smile:

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Just curious. What vesc version and brand do you have? Also, what firmware?

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Focboxes, FW 3.51.

The other board (the one with the bypassed BMS) has VESC6.

11

did you re-do motor detection? you should be able to go to -12 on max regen without issue, i mean try it out to make sure, but you should be ok. That’s my minimum, and that is really soft brakes IMHO.

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I did motor detection after I changed motors. Everything is working great apart from the high speed braking which is kind of weird since I did not have any problem with the 6355s. I am just afraid that if I go over the BMS’s maximum charge current it may at some point shut down and I am left without brakes.

At this point I am thinking that bypassing the BMS may be the only solution.

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13

I would bypass the BMS, I’ve had too many issues with Charge/Discharge BMS’s including e-switch failures, random cutouts on brakes (even at really low amps). To be clear 90% of the BMS’s Ive used in charge/discharge have been fine, but the bad 10% have me gun shy now.

Depending on you rBMS you may be able to direct swap the balance lead connector making the change out to a charge only BMS pretty fast and easy. The BesTech D140 is pretty great, I’ve used 10 or 12 and have only had 1 bad BMS.

If you have a BT module you can pad up and test the brakes at different levels to see if it cuts out at -12a per vesc, my feeling is that it wont, assuming the BMS is not faulty.

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