Sabvoton SVMC 72150 not working...

Archocell

1 mW
Joined
May 3, 2021
Messages
10
Hello everyone,

This is my Electric dirt bike spec:
Controller: Sabvoton 72150
Motor: QS273 8000w Hub motor
Battery 20s19p 72v 60.8ah Panasonic cells 150amp peak

The Sabvoton 72150 motor controller recently stopped working...
Everything was working fine until the controller sometimes starting shut off on me when I pulled full throttle. I usually had to turn it on again after it shut off and it worked fine. I originally thought it was the low voltage cut-off getting triggered at full throttle but I lowered the voltage cut-off setting to 55V and it was still shutting off. I had the max current cut off to 100amp to be safe and phase current to 200amp. But all of a sudden it shut off on me at full throttle again and now it won't turn on. When I hook the motor controller up to the power supply the voltage drops to near 0. When I opened it up I didn't see anything visually damaged or burned inside the controller. Is there a way I could fix the motor controller or diagnose what the issue can be? Also, I have no idea why it kept shutting down on me at full throttle... Please help!
 
It's probably not the controller; it's more likely to be the battery. A cell or cells in the battery are too low for safe operation, and when a load is placed on the BMS discharge port, it shuts down the output to protect the cells. Previously, it was just that the cell(s) were low when under a higher load, but now it's gotten bad enough the pack wont' operate at all.

If you check each battery cell group's voltages, starting at hte most negative and going to the most positive, and post them here, we can help you determine which, if any, groups are problematic.


If it is a controller issue, it would typically be either the LVPS that makes the 12v and 5v being dead (internally shorted at it's input), or FETs internally shorted on both the upper and lower halves of the same bridge, shorting out the battery input. Or a blown/shorted main capacitor. You'd probably read a short across the battery inputs with a multimeter, with no battery connected to them, if this is the case. If it is a normal non-shorted input, then you'll read a slowly rising resistance as the meter charges up the capacitors, eventually reaching some fairly high (tens of thousands or hundreds of thousands of ohms or more).

IT can also be a motor winding problem, or phase wire problem, where there is a high resistance short between phases, so it only happens when a high enough voltage / current is applied.
 
Thank you so much for all the information you have provided! Here are some updates on the troubleshooting process!

I originally considered the battery pack to be the issue. However, I knew a friend who has a power supply and we connected the motor controller directly to the power supply at 72v to see if it would power on. When we connected the power supply, the voltage dropped on the power supply to 0. Indicating that it's going into short circuit protection mode. This makes me believe that the motor controller has a short somewhere along with the input...

For the battery pack, I will be upgrading the BMS with a 300amp ANT BMS for me to monitor everything VIA Bluetooth. During the process, I will check the voltage level of each cell and post it on here.

Would this be enough evidence to consider the controller as the problem for sure? If so, how can I start troubleshooting the motor controller to repair it?
 
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