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Can someone help me understand why I've burned up a DRV8302 in less than 10 seconds?

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shimdidly
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Joined: 2017-10-01 19:38
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Can someone help me understand why I've burned up a DRV8302 in less than 10 seconds?

Newly purchased VESC placed on an ebike with a brushless motor rated 170Kv, 10S Lipo battery (42V). BLDC mode (not FOC), twisted throttle once while sitting on the bike and now all I get are FAULT_CODE_DRV errors.

My configuration xml files are here: http://citrio.us/VESC/

shimdidly
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Last seen: 2 years 12 months ago
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Follow up: I had this configuration running fine with a 6S battery (25V). I added a 10S and retained the same configuration. The motor spun normally when lifted off the ground. The first time it was under load I got an abrupt cutoff (the DRV fault) and was not able to get any motion on the motor after that point. DRV faults are persistent.

From some research this evening, I am wondering if running BLDC motor detection again is necessary since I've changed the voltage. Could this have damaged the DRV8302? Should I lower the switching frequency?

RSR
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Joined: 2017-05-24 12:46
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Where did you purchase your VESC?   Combination of high voltage and FOC killed many VESC 4.xx:    http://vedder.se/forums/viewtopic.php?t=145

I do not know what was the root cause of the DRV8302 faults.

shimdidly
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Last seen: 2 years 12 months ago
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Thanks for referencing that thread, there is a lot of useful information there. I purchased 2 VESCs from diyelectricskateboard. The first one stopped working after switching to FOC mode. The 2nd one is this story.

After unintentionally melting off other components on my first SMD repair project I finally got the old DRV off and a new one fitted. There is no reason it should actually work but for some reason this repair attempt was successful. Since then, I changed a few things and so far the repaired board has not burned up. I am not sure what the best practices are to protect the DRV but here are the changes:

1. Shortened cable length from battery to VESC by removing 1ft long extension.

2. Raised default ramp up/down times to 2 seconds each.

3. Lowered max amps from 160A to 120A for battery and motor.

4. Changed "current" control to "duty cycle".