Dominic Winsor Posted February 13, 2022 Share Posted February 13, 2022 Hi. I charge my V12 to 100%, then take it off charge. I notice that a few days later it is 99V or 98V… My Sherman does this too, actually. Is there an issue with phantom drain, or a deep power-save mode that I can enable? At the moment I only get to ride it once or twice a week so most of the time it is sitting dormant. Quote Link to comment Share on other sites More sharing options...
BlckRck2014 Posted February 13, 2022 Share Posted February 13, 2022 I think this normal and safe. 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted February 13, 2022 Share Posted February 13, 2022 3 hours ago, Dominic Winsor said: Hi. I charge my V12 to 100%, then take it off charge. I notice that a few days later it is 99V or 98V… My Sherman does this too, actually. How much volts does your v12 show after charged to 100%? And an hour after charged to 100%? You charge until the light on the charger changes to green? Monitor the daily drop of the battery voltage, too. 1 Quote Link to comment Share on other sites More sharing options...
Dominic Winsor Posted February 14, 2022 Author Share Posted February 14, 2022 9 hours ago, Chriull said: How much volts does your v12 show after charged to 100%? And an hour after charged to 100%? You charge until the light on the charger changes to green? Monitor the daily drop of the battery voltage, too. Yes. I always charge until green. I’ll record the voltage as reported by the wheel. I can try to measure the voltage at the charge pins with a voltmeter but idk if this works for the v12. Side note: My sherm gives a lower voltage at the pins than it does if I measure each battery (which are all balanced and consistent). Both my wheels have always done it to be fair - it’s just annoying. Quote Link to comment Share on other sites More sharing options...
Chriull Posted February 14, 2022 Share Posted February 14, 2022 37 minutes ago, Dominic Winsor said: Yes. I always charge until green. I’ll record the voltage as reported by the wheel. Great - so you should have them quite as balanced as possible and a history! 37 minutes ago, Dominic Winsor said: I can try to measure the voltage at the charge pins with a voltmeter but idk if this works for the v12. Should not be necessary - the wheels reported voltages should be enough, since the interesting point is the relative change - this drop after charging. Some drop is very normal. There are different possibilities: - immediate drop due to charge current stopping, as charge current does not go down to zero continously until charge stop. Should be quite low - some very roughly 50mA x 30mOhm ~ 1 mV per cell in Serie Just in case of elevated internal resistance or premature charge stop this could once be a reason. - A balance/bleeding resistor is enabled in parallel to every cell group exceeding 4.19-4.2V until _after_ charging the cell is discharged to this level again. As this thresholds underlie tolerance (typically some 50mV ~ 1%). Charger output voltage should have some comparable tolerance. So there could be some small (relative) "overcharge" beeing depleted after each charge cycle. - li ion cells tend to reach (very) slowly some equilibrium voltage after beeing charged. "Once the charge is terminated, the battery voltage begins to drop. This eases the voltage stress. Over time, the open circuit voltage will settle to between 3.70V and 3.90V/cell. Note that a Li-ion battery that has received a fully saturated charge will keep the voltage elevated for a longer than one that has not received a saturation charge." Cited from https://batteryuniversity.com/article/bu-409-charging-lithium-ion - Self discharge should be about not noticable within some days... - Your mentioned phantom drain was afair only reported for the Z10 and the KS16X/18XL did not turn off with some firmwares? Or even turn on and not off again after charging stopped? You could try if your V12 does somehow activate himself during/after charging. If bluetooth connection gets available even if it was turned off before? So the different voltages over time could be interesting to maybe find some reason. Drop from 100% to 99V could be about "nothing" - don't know the exact thresholds for the V12 but most/many wheels have a rather big 100% range which could still about include 99V. Sherman is afaik one excemption with no 100% range but strictly proportional battery voltage to charge % calculation. 1 Quote Link to comment Share on other sites More sharing options...
Dominic Winsor Posted February 14, 2022 Author Share Posted February 14, 2022 3 hours ago, Chriull said: You could try if your V12 does somehow activate himself during/after charging. If bluetooth connection gets available even if it was turned off before? I have a Vanmoof S3 bike which does this. You have to force quit the app on your phone otherwise it is always trying to connect from a long distance! Thank you for the info. I will do some investigation. Quote Link to comment Share on other sites More sharing options...
lagger Posted February 21, 2022 Share Posted February 21, 2022 (edited) But really charging to 100% all the time and leaving the wheel for days is not good for your battery life. At 100 % as Chriull said it will naturally drop by different long and short term mechanics. Anyway for longevity you should avoid charging the wheel right after some energetic drives or when the battery is hot e.g. due to sunshine. Its best to keep charge level around 30-85% if possible. I charge 85% most of the time and only charge to 100% before long rides. I am also basically never discharging bellow 20%. I also store the wheel for longer periods at 50-60 % SoC. Edited February 21, 2022 by lagger 1 Quote Link to comment Share on other sites More sharing options...
Dominic Winsor Posted February 22, 2022 Author Share Posted February 22, 2022 I'm aware of Li-Ion battery chemistry and behaviours to a reasonable state. I understand that deep discharge can be particularly damaging. I also understand that there is little issue with maintaining a full state of charge for a wheel receiving regular use. I'll see if I can find the reference but for high states of charge the reduction in capacity trends over an annual timescale and was barely noticeable. I'll see if I can find that. I agree with you though - I don't think any of my wheels have been below 40% actually! Storage hasn't been an issue as they're used at least weekly. My wheels are stored in an environment that is low moisture and at a temperature at 15ºC Quote Link to comment Share on other sites More sharing options...
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