XR fully charged battery & rapid self-discharge/ voltage drop

  • If I fully change my board until the charger light goes green, then wait a few minutes and turn on the board it NEVER reads 63.0v like I would expect. It will at like 62.5 and slowly dropping. Next day it will be more like 61.5, still without any usage....

    Is this normal?

  • Not sure about the voltage, but I do notice this with the remaining battery percentage. When my board reaches 100%, I unplug it and set it down to ride only to look at the app and it suddenly reads 99%. Didn't even use it! How could it drop?

  • So I don't checked the voltage but I recognized the same. Fully loaded and turned on it "only" shows 99% and and that moment I put my foot on the sensors the reading drops to 98%
    So would be really interesting why this happens and now I know that others are also be affected.
    I've tried to fully discharge the battery. Was riding it til low battery pushback, turned off and on again an burned the battery down. Also a 48h charge doesn't mangaged this problem. Have had the same issue with my + but there it had worked with burning it to death and recharge overnight.

  • Thanks, it is nice to know this is typical. I guess their formula for calculating % full is a little off at the top end.

  • @suboba I got my Onewheel just a couple of days ago. Had the same experience after I charged it for the first time... . I thought it was because I didn't charge it long enough past the moment where the light on the charger switches from red to green.
    Does it even matter if I charge it past the green light? And is there any relation between this and the tip they're giving to periodically leave the charger attached to your Onewheel+ overnight to allow the battery pack to throughly balance? But they also say the charging automatically stops when the green light pops up, so how does that "throughly balance the battery pack"?

  • @Daaavy

    The pack is 15 cells and they can have small differences in voltage. So balancing the battery allows the BMS to go through the cells and get them all back to exactly the same voltage.

  • @Daaavy To preserve the battery's capacity, most battery nerds recommend avoiding a full 100% charge every time, and instead target like 80-95%, depending on how paranoid we want to be. Once every 5-10 rides, I charge all the way to green light and leave it on the charger a while, to make sure the cells are balanced.

  • @suboba Hi I just received my new XR and I have noticed exactly the same problem: when plugged, it fully charges to 100% on the app (and green led on the charger) but when unplugged and switched on, it then only reads 99%. Moreover as soon as I engage the onewheel and start to ride, the battery reads 98%.

    Was already owner of a +, never had this kind of problem. I've tried to charge for 48h+ and to fully drain the battery but it doesn't solve anything. It happens systematically since the first charge out of the box.
    Have you got any clues from FM? I've seen on an other thread of the forum that you sent yours back because of the shitty BT connection (I'm also touched, fu***ng rev.4208??)

  • @helmut002 There's nothing wrong with your board. Mine has done the same since day 1. They try to measure % capacity using voltage which is notoriously dicey. It is often mildly inaccurate, and sometimes persistently, wildly inaccurate. Try paying attention to "% Usage" in the lower right part of the main app screen instead. This measures amp-hours as power is consumed and thus is more accurate at estimating how much power you've used. It is offset by "% Regen" (also a measure of amp hours, the inverse direction) which you can subtract to give a picture of total remaining capacity. The only drawback is these values are reset whenever you disconnect or power down.

    Because of all this, the best way to be absolutely sure your battery has something comparable to "factory-new capacity" is run it to low battery pushback, note the trip mileage & compare your weight, terrain, and tire PSI against others vs what mileage people are getting. Typically most of us get at least 15 miles out of the XR, many get significantly more on flat pavement.

  • Thanks a lot for your answer.
    For my first long ride, I did 12 miles in delirium mode, it was mostly offroad with a lot of diffeference in height. I weigh 154 lbs. Gonna try with mission on flat pavement.

  • 12 miles. nice ride!

  • Back to the original topic - FYI the reason for this behavior (voltage drops >0.5v immediately after full charge) was a bad cell in my OEM battery pack.

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