Onewheel V1 broken

  • My V1 bit the dust, it won't power up. I plugged in the charger and the board powered up, but the lights came on too. Charger showed green.
    The app showed everything except battery level (0%) and I can balance the board with the charger plugged in. I left the charger on for a couple of days, but still no joy.
    I tore the battery box apart and measured the cell voltages and they ranged from 3.47v to 3.50 v, so it seems the battery is fine.
    If I plug the battery directly into the controller, the board works fine. I assume the BMS is gone.
    I'll try to repair the BMS as I have identified some of the components. The two mosfets measured fine, but I think the mosfet driver (m1271) may be faulty, if I can source one, I'll try to solder it in.
    Anyone know who can repair a Onewheel bms?
    v1 bms.jpg

  • @lemur -- When my V1 BMS got water damaged I just bypassed it. But there are people who can take a BMS and repair it. Try StokeLifeService, or the Onewheel Facebook groups -- maybe especially the Onewheel DIY Squad.

  • @blkwalnutgrwr It’s pretty cool that the V1 can have the BMS entirely bypassed. Makes diagnosing stuff a little easier.

    From a safety standpoint it’s a bit iffy but theres nothing stopping you getting an off the shelf BMS to wire in between so you can retain some cell balancing and protection.

  • @blkwalnutgrwr
    Thanks for the leads. I'll try both.
    I was thinking of bms bypass and using a external xt60 connector with a matching male or female xt60 that has a wire loop to complete the circuit.
    Better than an on-off switch that can accidentally be shut off.

  • @lemur -- I did hear the story of someone who put the whole Onewheel battery in a backpack, then riding trails through the woods snagged the cable on a branch and was suddenly powerless.
    @Lia -- Several months in and more than a thousand miles later I must say I feel safer without interference from the BMS. The biggest downside is that I had to break the push button switch habit in my own neuro-circuitry.

  • @blkwalnutgrwr
    Good to hear that a bms bypass works for the long haul. Thanks.
    I just ordered some mosfets and mosfet drivers to try to repair the bms.
    They were under $15 for a whole bunch. If that doesn't work, then it's the bypass.
    I thought of a lithium ion bms, but the cut off voltage is too high for iron phosphate cells leading to early cut-off and crashing.

  • @lemur
    I've got a Plus on the way with 189 miles along with a two-x kit to be installed. During the installation the BMS is coming out. I've owned a number of Onewheels and EUC's and I'm done with the random errors and shutoffs from bms's.

  • @Senior-Coffee
    Sounds good. A bms seems to cause problems.
    Good thing all my Onewheels are "hackable" unlike newer ones with "married" battery, bms and controller.

  • @Lia
    That sounds doable with a generic 14s bms for charging and balancing but not for discharging. Discharging straight from the battery pack.

  • Update, I have nearly 400 miles on a couple Plus boards and a V1 without a bms. I call it quiet floating because lack of all error messages. Smooth as silk. More power as well. I thought the increase in power was in my head but it was recently confirmed by someone else who removed their bms and noticed a power increase. The batteries stray very little over time and in my opinion after seeing all of the problems with these boards I believe most of them are caused by a faulty bms. Ride On!

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