XR+ bms issues
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Hello, I've been having some issues with my XR+. I've ruled out it being a battery problem with checking cell voltages and trying a new battery. It rides fine until at some seemingly random time it reports low battery and shuts off. Upon inspection of the BMS that I replaced last week to get it running I noticed this.
It looks like an inductor to me, but not actually sure. Does anyone know what part this is and if it could be causing this problem?
Thanks for you time! -
@cheesej Hiya :) That's a 270uH power inductor. If there's actual damage to the windings on it that could cause issues.
The only time I've seen similar when the battery was fine is dodgy caps on the balance IC.
Cell voltages can report incorrectly if any of the caps around the balance chip at the other end of the pcb are slightly detached or faulty. Common to do when unplugging the XT60 and bumping one.Might be worth giving this post a lookover to see if your board is doing similar if the inductor doesn't solve the issue.
https://owforum.co.uk/topic/403/xr-overcharged-cell-that-isn-t-after-battery-upgrade-repaired -
@lia Thanks so much for the info! I will check those caps again. I have a newer firmware version so the cell voltages won't actually populate on the app. It makes it a little harder to check what the cell voltages are reporting on the BMS. I'm going to go ahead and replace the inductor and see if it fixes it, and then go from there.
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Update: I replaced the power inductor with one that I reclaimed off of a dead BMS I had laying around, checked again for other visible issues with the caps and saw nothing obvious. I then put it back together and rode for about 7 miles, no issues. It was reading predictable percentages unlike before and coming down at an expected rate. I will continue riding and update again if it gets me stranded somewhere again.
(first time working on circuit boards, and boy was it tricky reclaiming that power inductor. Ended up getting it with a heat rework gun.)
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@cheesej Great work getting that fixed! Surprised that damage was enough to break the inductor.
Thanks for sharing your process :) -
@lia Update: It is indeed NOT fixed. After 2 half charges, the symptoms returned. I have noticed that it happens when going uphill. Going to do some testing on the BMS and see if I can track down any faulty parts.
