Regen braking fried my controller

[InvalidUsername]

Originally Posted by Volt_Ampere

I would go with an aftermarket controller like Alltrax. You can dial how much Regen you have with that.

His 1266 allows him to adjust regen quite well

[TheCartBoy]

Originally Posted by nejccesar

Well yeah, I did feel the regen braking kicking in. I changed from AGM batteries to Lifepo4, when I changed them it worked ok the first day when the Lifepo4 batteries were at 50% charged, I went downhill and up no problems with regen braking. The next day I charged the lifepo4 batteries to full charge, wen downhill and the controller fried.
Before when I had the AGM batteries going downhill sometimes generated 75V of electricity from the motor, looks like the BMS did not accept the voltage now and it stopped in controller.

I am now afraid If i purchase the 1266 controller it will fry it again if I still use regen braking. The hill is 15% incline so it is pretty steep.

Now we are getting the full story.
BMS shutdown because it couldn't take the regen current, so system voltage shoots through the roof and blows up the controller.

[TheCartBoy]

Invalid, I could look it up but am being lazy. What are the options for overvoltage protection on the 1266?

[InvalidUsername]

btw how long is the hill? 15% grade is not steep IMO (at least not with what I have to deal with)

[InvalidUsername]

Originally Posted by thecartboy

invalid, i could look it up but am being lazy. What are the options for overvoltage protection on the 1266?

@##.jpg

[InvalidUsername]

Plus there's the Overvoltage Beep parameter that can be turned on and off. An Overvoltage fault should beep the beeper at a fast rate and reduce armature and field currents until overvoltage condition clears

[Volt_Ampere]

If over voltage protection prevents regen, then that might work but if the BMS shuts down while you are driving, the only thing that will protect the controller is a flyback diode on the solenoid big terminals! This needs to be a beefy diode too!

[TheCartBoy]

Originally Posted by InvalidUsername

Attachment 245854

Perfect. He should set that number below the BMS shutdown voltage. I'd probably start around 53-54v and see how that works.

[InvalidUsername]

Originally Posted by Volt_Ampere

If over voltage protection prevents regen, then that might work but if the BMS shuts down while you are driving, the only thing that will protect the controller is a flyback diode on the solenoid big terminals! This needs to be a beefy diode too!

I think I'll get one. Can you point me in the right direction?

[nejccesar]

Wow, thank you for all the help :)

Would 250A 1600V diode be enough? They sell one on Aliexpress, find the image in attachments.