kintips Posted July 23 Share Posted July 23 7 hours ago, Mono said: The V8-series wheels have been sold in the order of 100,000 times, so it seems that many people "got lucky". That's quite a coincidence. What happened with the V5F after the factory reset? I have documented it all on my youtube channel incase people don't believe me. Yes total V5F 260km dead (misbalanced cells) i did a reset on it and it did let me ride for about 1km before a please repair came on again. The v8F died at 250km, it got a please repair at 58% battery left, i had to roll it home manually with the walk of shame. V12HT misbalanced cells (the voltage difference on 1 pack gets too large it stops functioning normally), had to have inmotion recalibrate it, but it still has issues, if you hit the spin kill button the machine stops balancing totally till you charge it up fully again, again Walk of shame rolling it home manually (watch my review). then if you turn it off at any point it screws up again. there was a 1.7 volt difference, when it was recalibrated it was 0.4 difference. but it gets larger and larger again. So yeah i know first hand wrongway is right about it. Maybe it was just my luck but all 3 inmotion wheels have died on me. Quote Link to comment Share on other sites More sharing options...
Mono Posted July 23 Share Posted July 23 26 minutes ago, kintips said: Maybe it was just my luck but all 3 inmotion wheels have died on me. Which looks like a quite improbable concurrence of events. With my (9 years of) prior knowledge, I would have given it a chance of 1 : 100,000 or less, which relates to a 2% chance of an early battery failure (which still doesn't look particularly low to me). This lets me wonder whether there is some common cause for these failures that only applies to your case, but it's hard to see what that could be. Quote Link to comment Share on other sites More sharing options...
kintips Posted July 23 Share Posted July 23 Just now, Mono said: Which looks like a quite improbable concurrence of events. With my (9 years of) prior knowledge, I would have given it a chance of 1 : 100,000 or less, which relates to a 2% chance of an early battery failure (which still doesn't look particularly low to me). This lets me wonder whether there is some common cause for these failures that only applies to your case, but it's hard to see what that could be. Yeah its crazy it happened to me, you can watch the videos, the V12HT it happened at the end of filing then lugged it all the way home all 63lbs with no power to roll it. Same thing with the V8F no power rolling it home, which isn't too bad because its lighter. I was lucky with the V5F i was already home when it happened lol But i've noticed more recently on the forums in the inmotion forums V12 issues have been popping up a lot more now. It is possible the BMS on the V12 is too stringent and doesn't allow a bigger voltage difference (i read it somewhere). All of this could be remedied if inmotion gave classes on how to manually rebalance the cells or put in some sort of balancing. I read somewhere inmotion could also give a slightly higher voltage charger and that might fix the issues too, I'm not sure if that would work i'm not tech that would know these things. Quote Link to comment Share on other sites More sharing options...
Rotator Posted July 24 Share Posted July 24 On 7/12/2024 at 8:07 PM, RagingGrandpa said: Umm... here they are: No, these are not bleeding resistors. They are 1K resitors, and they are in series of two resistors. So actually, they are 2K resistors. Bleeding current would be 2 milliamps, which is not any balance current. And as I said, in my testing procedure, I couldn't even detect one milliamp of balance current (drain current of the overcharged cells). And regarding the remote recalibrating, it is not any than taking advantage of a software feature to make minor adjustments of any mismatches in the BMS monitoring system, to make believe the user that the voltage of the battery is ok, when really it is wrong. 1 Quote Link to comment Share on other sites More sharing options...
RagingGrandpa Posted July 24 Author Share Posted July 24 (edited) 9 hours ago, Rotator said: No, these are not bleeding resistors. What other purpose might they serve, then? (I think it will be obvious from studying the specification of the ASIC controlling them... and I expect they become connected to load individual cell groups, according to a cell voltage threshold. Do you have a BMS to teardown where you can find component labels of that ASIC? What's its part number?) Edited July 24 by RagingGrandpa Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 24 Share Posted July 24 3 hours ago, RagingGrandpa said: What other purpose might they serve, then? For sensing input RC filters are put infront - some "higher" resistor value with the parasitic capacitances could be enough. Or this resistor values are just according to the datasheet. If it is some ic like https://www.ti.com/document-viewer/BQ79616/datasheet with sensing and balancing at the same pin (9.2.1.2.1 Cell Sensing and Balancing Inputs) a "too high" resistor would be a way to disable balancing. 4 hours ago, RagingGrandpa said: I think it will be obvious from studying the specification of the ASIC controlling them +1 Quote Link to comment Share on other sites More sharing options...
Rotator Posted July 31 Share Posted July 31 On 7/24/2024 at 7:41 PM, RagingGrandpa said: Do you have a BMS to teardown where you can find component labels of that ASIC? What's its part number? Impossible to know, the label of the chips is factory removed. Hence, the only way I could think of, is to raise the voltage on one cells group and check if any drain current was generated. But not, there was not any drain current. I have added my own passive balancer to the battery and I have repeated the experiment. Now yes, about 70mA current it is drained for each cells group exceding 4.2v 1 Quote Link to comment Share on other sites More sharing options...
rcgldr Posted August 1 Share Posted August 1 (edited) On 7/24/2024 at 10:41 AM, RagingGrandpa said: What other purpose might they serve, then? 1000 ohm resistors translate into 0.0042 amps, too low of a current for normal balancing of a pack. My 18XLV2 uses 100 ohm resistors, 0.042 amps, and during balancing, shuts off charging most of the time with intermittent bursts of current of 0.25 amps every 5 seconds or so, in order for the average charge current to be less than the bleeding discharge current, so no cell group reaches over-voltage. Once the pack is balanced, the 18XLV2 will shut off charging with no intermittent bursts. KingSong states that EUCs should be left on charger for 2 to 3 hours after charger LED turns green, but by using the KingSong app to monitor the charge you can tell when it has balanced the pack and stopped charging rather than waiting the full 2 to 3 hours. The Inmotion BMS with 1000 ohm resistors would take 10 times as long to balance a pack using this method, but they don't. Instead one or more cell groups will reach some maximum voltage, and charging is shut off. On my V8F, after charge shut off, it slowly discharges the pack down to 82.5 volts over the next 8 hours before it reenables charging again. The slow discharge maybe due to just what is needed to keep the V8F "awake" and communicating with the app, and those 1000 ohm resistors may not be involved and there is no balancing. < other purpose? To be able to sense the voltage using a high resistance | low current load for each cell group in order to shut off charging if a cell group reaches over voltage. Edited August 1 by rcgldr Quote Link to comment Share on other sites More sharing options...
RagingGrandpa Posted August 12 Author Share Posted August 12 (edited) On 7/31/2024 at 2:45 AM, Rotator said: the label of the chips is factory removed No... Most EUC BMS PCBs are painted with conformal lacquer, which can make component markings difficult to see... but scrape the coating away, and the info is there. (Sherman Max BMS example below) Edited August 12 by RagingGrandpa Quote Link to comment Share on other sites More sharing options...
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