wstuart Posted February 22, 2022 Share Posted February 22, 2022 So I just bought a used inmotion v10f that only has 3 miles on it (but 2 years old). I wanna figure out if the battery is still in good condition. It charged to 84.2 volts (I can see the voltage on my ewheels charger). Also the inmotion diagnostic says the wheel is in good condition. I weigh 220lbs. I rode around for 15 miles on flat ground and the battery went down to 66% . The battery dropped to 93% in the first mile. Also, every time I accelarated the battery would drop almost 20%, but them come back up once I stopped accelerating. Is this normal? I am concerned that I have a bad cell in the pack. (BTW, I am observing this in the inmotion app) I know a little bit about lithium batteries and I understand that voltage drops under load, I just don't know if 20-30% drops are normal. I am just concerned that if I try to ride around at 30%, the battery will drop to levels that make the wheel cut out. Quote Link to comment Share on other sites More sharing options...
Tawpie Posted February 22, 2022 Share Posted February 22, 2022 I think you want to run a few charge+balance cycles on it... don't ride too aggressively until it proves itself. Spending 2 years in disuse is first off, a horrible way to treat a wheel and makes my heart weep, but it also gives the battery pack a long time for its individual cells to drift around. A few balance cycles should sort everything out. Pay attention to the battery voltage, not the % state of charge. You want it to charge to 84V, under acceleration it'll drop a volt or 3 conditions depending. Quote Link to comment Share on other sites More sharing options...
Denny Paul Posted February 22, 2022 Share Posted February 22, 2022 15 minutes ago, wstuart said: I weigh 220lbs. I rode around for 15 miles on flat ground and the battery went down to 66% . The battery dropped to 93% in the first mile. Also, every time I accelarated the battery would drop almost 20%, but them come back up once I stopped accelerating. Is this normal? I am concerned that I have a bad cell in the pack. (BTW, I am observing this in the inmotion app) I know a little bit about lithium batteries and I understand that voltage drops under load, I just don't know if 20-30% drops are normal. I am just concerned that if I try to ride around at 30%, the battery will drop to levels that make the wheel cut out. Yes this is normal. It's called voltage sage around here. Voltage sag increases with a) heavier loads ie: increased rider weight or increased demand on the motor and b) size of the battery (specifically how many groups are run in parallel) Your values are completely within the expected norm. Don't be afraid. The fact that your wheel charges above 84 volts is a very good sign. For inmotions, you really only have to worry if they fail to charge above about 82v or so, and if that's the case it's often the charger's fault. If your wheel is failing to charge beyond [wheel's max voltage] - 4.2 volts, then you've got a cause to be concerned, as this is indicative of a dead cell. For 84 volt systems, like your v10f, this would be at 80-81v. 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted February 23, 2022 Share Posted February 23, 2022 Denny Paul is on point. V10F uses four LG MH1 (10A) cells in parallell to produce it's current. That's a decent 40A. It's not extremely high and the cells aren't high current (they're medium). So it results in more voltage sag and heat being produced. Specially for heavy riders or those that like to accelerate/brake quickly. Just to put in perspective. An RS and an EX.N have basically the same components, but one has a 1800Wh pack and the other a 2700Wh pack. The 2700Wh pack wheel is noticeably faster, basically because it can deliver more current and less voltage sag. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted February 23, 2022 Share Posted February 23, 2022 As long as your wheel charges to 84.0v and stays at 84.0v a couple of hours after you've disconnected the charger, it's likely (not guaranteed) in good condition. The voltage reported can't really be trusted in its absolute value but you can use it for repeatability. You can't trust that 84.0v really is 84v and not 83v or 85v in real life. But, if you after years of ownership still reach the same voltage reported again and again, then that pack is almost definitely in good condition. It's when you see the values change over time, that it's a bad sign. Like charging time being cut in half, or max voltage not being reached, or your range shrinks in a short period of time. Those are great signs of concern. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted February 23, 2022 Share Posted February 23, 2022 (The "EUC World" app can usually display the pack voltage.) Quote Link to comment Share on other sites More sharing options...
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