ANT BMS 'Abnormal Start' error - SOLVED!

cg_ebiker

100 mW
Joined
Mar 28, 2020
Messages
43
Just thought I'd post this here incase anyone else is having similar issues with an 'Abnormal start' error on an ANT BMS...

For context, I have a 24s ANT BMS protecting a 14s2p C020B cell pack and powering a SVMC72150 controller. The bike itself is going to be put through the UK MSVA scheme so it needs to have a 12v electrical system for the lights, dashboard, horn etc.

Everything worked fine with the BMS connected to the sabvoton however when I connected it to the buck converter to take 58v down to 12v, the BMS seemed to stutter and either modulate the power or somehow only provide about 1A of current. After about 5s it shut down completely and I got an error on the app saying 'Abnormal load'

I couldn't find any info about it so I bypassed the BMS to prove it wasn't that and ofc it worked fine. My instinct thought it was an overcurrent protection from the inrush to the capacitors, but then the sabvoton also has big capacitors so wasn't sure (might have a softstart of some kind?).3

In the end it turned out to be the short circuit protection that was tripping, so I increased the delay from 770ms to 1000ms and now it turns on just fine. You should try and keep this as low as possible without tripping the protection just in case there was a genuine fault.

Long way of saying increasing short circuit protection solved 'Abnormal start' for me!
 
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