Lithium pack with electric parking break

[InVision]

Testing a lithium pack with my carts electric parking brake. No issues until I get under 30%. The lith pack abruptly went down and the brake engaged at 20 mph. Pants check scare. Not sure what to do. Is it the BMS or the cart that engages break when power drops. Work around is to always charge at 40%. Anyone point me to info on this would be most appreciated.

M

[jasonojordan]

When you lose pack power the parking brake engages. Does not have anything to do with the BMS. FLA carts do the same thing.

[EcoChandler]

@jasonojordan (forgot to quote your thread)

The BMS has a ton to do with it. The BMS is what tells the battery to shut down a lot of the times. That's why buying a quality battery with a quality BMS and cells is even more essential when installing into a cart with an EMB and zero CAN comms between that battery and the controller.

[jasonojordan]

Originally Posted by EcoChandler

@jasonojordan (forgot to quote your thread)

The BMS has a ton to do with it. The BMS is what tells the battery to shut down a lot of the times. That's why buying a quality battery with a quality BMS and cells is even more essential when installing into a cart with an EMB and zero CAN comms between that battery and the controller.

I am aware of the function of the BMS. Just this is the 1st experience I have had with one that also has a CAN function that controls the charging vs other traditional systems.

[InVision]

Originally Posted by EcoChandler

@jasonojordan (forgot to quote your thread)

The BMS has a ton to do with it. The BMS is what tells the battery to shut down a lot of the times. That's why buying a quality battery with a quality BMS and cells is even more essential when installing into a cart with an EMB and zero CAN comms between that battery and the controller.

What info do I need on BMS that would be helpful?

Thank You

M

[InVision]

Thanks for the reply. I was thinking there was someway in the BMS not go from 50v to 9 volts instantly.

[TheCartBoy]

So is the reported 30% SOC actually 0%? Like the gauge needs a recalibration.

Or does the BMS behave differently at 30% SOC, like a reduced current draw limit? That would be atypical.
Perhaps what happened is you mashed the pedal and one of the cells voltage dropped and that triggered the protection fault.

I have some tuning info for the RXV about this. The undervoltage protection on your Curtis controller could be adjusted to work better with your battery.
https://www.buggiesgonewild.com/showthread.php?t=194038

[InVision]

Originally Posted by TheCartBoy

So is the reported 30% SOC actually 0%? Like the gauge needs a recalibration.

Or does the BMS behave differently at 30% SOC, like a reduced current draw limit? That would be atypical.
Perhaps what happened is you mashed the pedal and one of the cells voltage dropped and that triggered the protection fault.

I have some tuning info for the RXV about this. The undervoltage protection on your Curtis controller could be adjusted to work better with your battery.
https://www.buggiesgonewild.com/showthread.php?t=194038

Thank You CartBoy !! I am starting to look at this. Here is the only reading on my programmer that I found with undervoltage. *see photo.

FYI-The battery tech support re-calibrated my battery remotely.

This is the only undervoltage that I could find in the manual. *see photo

Should I use 97% for Undervoltage? 46.4v/ 48v

Should I use 115% for Overvoltage?

Thoughts?

M

[InVision]

Thanks for the info. Pretty sure it was not a fault as the battery reported 0% when it started to charge and charge normally from there. The battery came with a display. I was on my way home and the last I looked it was reporting ~30% or so. I was not hitting the go petal much because I was in a 15mph speed zone. clue in the data that can help. Have not seen any recal settings in interface. But you might be right that it need recalibration setting 30% as 0%.

Thank you Cart Boy !!. You have always been a huge help on this forum.

M

[TheCartBoy]

You are looking at monitor values on the handset, those are read-only statuses. It's the parameters page you want to change.

Underv 46.4v sounds like a good start point
Overv 58.4v would be my start point, essentially no regen allowed when at full capacity.