XR shutting off at 25% after trying the milk crate thing when it cut at 15%

  • The onewheel app is telling me I need more juice at 25% now. This is after it shut down at 15% a few weeks ago and I did the milk crate thing + recharging for multiple days. I seem to be getting the right mileage at around 15-20 miles depending on hills. I checked my battery with the OWCE app and all cells look the same. The app is effectively useless like this. Is there a way to make it detect the proper charge or a better app?

    OWCE image

  • Next time you run it down to the point it can go no further take a screenie. Curious what each cell reports when it dies at the 15-25% mark.

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  • @Lia I got it just after it died now at 22% and then after I ran it down a bit more to hit 1%. It dropped to 1% within minutes after when I was running it down by hand.

    22% power 1% power

  • Thanks @Madroxkran
    3v is the low voltage cutoff for the cells so that makes sense why it's stopping at 22%. My board does pretty similar, cuts out at around 20%-25% these days and it's just down to wear and tear and not an actual fault with the board. I'm actually impressed how even the wear is on your cells!

    TLDR of what is happening is the BMS measures current leaving the pack to tell you what it thinks should be leftover. This method is known as "Gas Guage". Over time the current storage of a cell degrades so although it goes between the voltages of 4.2v and 3v normally the actual available current at those voltage ranges is decreased. Eventually this manifests in the board thinking it's used X% when it actually no longer has that leftover because the true capacity is now lower.

    On the plus side the board and moreover BMS are perfectly fine so you've got a few options to get the board back up and running like new.

    1. Ask FM to replace the battery. They'll be able to quote you on a new pack but will usually require you to ship the board to them. This gets costly rather quickly but it's done by them so you've got that peace of mind.
    2. Some Onewheel focused 3rd parties have been developing their own battery packs with increased range over a new stock pack. One company that seems to be quiet popular is Chi Battery Systems which have some pretty happy customers and you can fit the pack yourself to save time and money.

    No harm in looking around and getting some quotes from the various 3rd parties and FM themselves.

  • @Lia said in XR shutting off at 25% after trying the milk crate thing when it cut at 15%:

    Ask FM to replace the battery.

    @Madroxkran My batteries went out around 1900 miles on my XR and I had FM replace them (Tho I'm in CA, so shipping wasn't TOO bad). Still, it was costly and I was hoping I would get more than 1900 miles out of the new pack. Sure enough, I'm just over 6000 miles now on the board and keeping my fingers crossed. Problem is, it just takes one bad cell to ruin the whole pack, so part of it is luck. Once this new pack dies, I may go with @Lia's second option and try out the Chi pack.

    Good luck!

  • How many miles are the batteries actually supposed to last for?

  • @Madroxkran So many variables . . . I'd say anywhere from 10 to 5000+ miles! :D

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