Overcharged XR but not really?

Lia

Today got turned on it's head because SOMEONE wanted to be the centre of attention today.

TLDR:

Nothing was wrong, taking the board apart down to removing the battery and re-assembling resolved the issue. assuming charge buildup somewhere that was freaking out the balance lines.

Planned a quick ride on the one day it was going to be nice this week while @cheppy44 was here and Slushy; the drama queen that she is decided to announce to us after taking me UP a hill that she was overcharged.

Even after a minute or two of freewheeling her to try drain it (which she let us do straight after turning on) she still reported 100% and overcharged even with a total pack voltage of 61v. After which the usual Captain Morgan ensued and then nothing but mounts of shame till a power cycle.

We'd ridden in the wet the day before and I'd been careless as usual with my puddle riding. I saw no condensation in the lights which I check now after rides so I didn't think it was water damage.
Regardless I wasn't taking chances so we decided to take her apart.

...Although she put up a fight >.>

With enough oil and me finding the extra Ugga Dugga setting on my drill the stuck bolts came loose :3

Sitting feeling proud of herself stealing away the day and precious sunlight >:(

After taking her apart and checking everything nothing visually seemed wrong. Bone dry, no magic smoke, no damage and all cell voltages read correctly.

So... fearing we'd been duped I barely assembled the board and low and behold... no overcurrent warning >>>:(

Literally did nothing but unplug, probe and reconnect stuff leading me to believe she had some stray static charge lingering somewhere that dissipated when I took her apart and held the pieces.

After barely re-assembling to test ride around the flat to see if the issue was solved I re-applied the badgering and will see tomorrow if the issue re-occurs. Hopefully not since I need to do shopping :(

Anyone else had this? Never seen anything like it on a Onewheel (have in Laptops). After 4 years with this board and over 1000 days streaked she's never pulled a stunt like this.

Lemur

@lia I was going to suggest the little M8t mosfets, but your cell group voltages are even, if you had one cell group high and the adjacent cell group low, then the bms will cut off charging with the false high.

NotSure

@lia its stuck.

Lia

@lemur That's what I thought, like all of them were identical (which shocked me honestly).
I rode her twice today and not a single error so I assume maybe it was just static then since power cycling prior to disassembly didn't help.

Weird one, defo spooked me for a bit.

Lia

I think the same thing has happened again although in a much stranger way. Someone's jealous I have a GT, Pint and 2 XR controllers on the bench I guess.

Story time ^-^
Going to the shops and I'm 5 minutes into a ride where the total elevation change nets to nothing. About 2 minutes after a mild downhill I get a regen alarm!

App reports I have 99% in the tank while my voltage readout gives me 86%. App even confirms the battery is at 59.5v so I'm not going crazy.

To make matters even more confusing the diagnostics tab reports the BMS has recorded a usage of nearly 1AH while only regenning 0.1Ah. The battery percentage is a gas gauge calculation based on that data so I'm stumped how it has the data but the wrong output.

Then as if by magic since the alarm went off the percentage starts ticking down again like it should but offset by whatever it missed before giving the alarm.

I rode a bit more since I needed to finish my shopping trip while being very careful as to not nosedive due to a faulty gas gauge reading.

I'm at a loss how the board can keep track of the data it uses to calculate the battery percentage but not present it. It's almost like the board hung and didn't calculate battery percentage then decided mid ride to start again.

Currently Slush is on charge to try reset the percentage before I can go try again and see if the issue presents itself. If not then I guess I'll have to be more observant whereas if it does I might try swapping the BMS for one of the few I have laying around. I'm sceptical that is the issue if the controller was aware of the correct usage values but this seems beyond making educated guesses.

I'll update the post after I get back assuming I don't encounter a false OV cutoff and barrel into A&E for the evening.

Edit:
Everything back to normal. I can only assume I managed to stumble on an edge case where the BMS/Controller failed to process certain data. Legit have no idea otherwise how it happened.

Anyone else had similar?

TheAdman

@lia Not OW but I've had batteries register as fully charged on the work gear, and then they run out quickly. Put them in the charger which says half full. An hour later the lights red and the battery is hot AF. Always the old batteries.
Edited. I was at the pub.