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Everything posted by Tadas

  1. Tadas

    18XL Tire pressure

    Those low pressure pictures really scared me. Experimented more with 3.6 bar, seems much better now: Now I think I will try to never go lower than 3.5 bar (50 PSI) for my total weight 130 kg (286 lb).
  2. Tadas

    18XL Tire pressure

    Rider+wheel weight: 130 kg (286 lb). KS18XL tire pressure: 3.1 bar (45 psi). Apparently much too low!!
  3. Assuming you have 15S pack on one side and 16S pack on the other.. 15S pack is constantly being overcharged, that will kill the pack eventually. 16S is never getting balancing, which will kill one cell eventually by letting it discharge too much. Long-term this setup is unsafe and unreliable. How dangerous is it? No one knows, but is it worth to risk a faceplant or a fire?
  4. At 39 km/h = 10.8 m/s it only takes 284 N of force to translate to 3070 W of power. (Power = speed * force). Heavy riders really need to go slower, a rider of 290 lb = 131 kg weight would have already overpowered the wheel.
  5. Just leave the wheel for ~8 hours, cells above 4.2 V will be discharged to 4.2 V. Lower voltage cells will not be discharged. That is how passive balancing works. Please correct me if I'm wrong.
  6. Lithium ion battery packs do not get fixed by discharging and charging again. From your description it seems you have a problem. The wheel could be unsafe (faceplant while riding or fire at home) and someone will need to open it for diagnosis. If it's under warranty, contact your seller, if not, then find someone who will repair it for you.
  7. So I received a new battery pack from Kingsong. Pretty happy with their service!
  8. I had a similar issue with 4V "missing". If your wheel has 2 battery packs, then one might have a dead cell. You could try opening the wheel up and trying to charge one pack at a time. Before connecting both packs together, make sure their voltage is the same.
  9. The long time is only for balancing the cells. The heating problem on one side you describe could be because of unbalanced cell pack, or not, very hard to say.
  10. Next step is get a 84 V charger and see if the battery charges fully.
  11. There should not be an imbalance then... But still I suggest you leave it plugged in once for 50 hours. After that 1-2 hours plugged in after each charge. If that doesn't help, you might have a faulty cell
  12. Ideally you'd have a 84 V charger, but balancing is being done by the BMS on a cell by cell basis. Even at 82 V battery pack you can have cells that are above 4.2 V, those cells will be drained by the BMS and the BMS will heat up. Let it balance for 50 hours, especially if you have never done it before.
  13. With Kingsong app on Android you can disable all speed warnings (maybe except the final 50 km/h one?) I only managed to silence "Bluetooth is connected" by decreasing volume via the app, but that disables the speakers completely.
  14. Perhaps it's just doing the balancing. Total BMS rebalancing might be putting out 3W of heat, that would heat up the BMS quite a lot. The battery pack stores incredible amounts of energy, let's say 800 Wh and is only being rebalanced by small bleed which heats the BMS by up to 3W power (19 cells each doing 0.16W). Keep full charge for ~50 hours, either always plugged in or plug in every 4-8 hours. It may take that long to rebalance the cell pack. Having a smoke detectors is always wise.
  15. So you're 180 cm tall, very interesting perspective , thank you! I'm still new and trying to figure it all out. I'm 190 cm and here's me standing on ks18xl. The wheel doesn't come close to my knees. I would actually prefer a taller wheel. Is it about leg length? Is ks18xl a short wheel?
  16. 42 mA balancing current, 3 cells in parallel each 3500 mAh, so that's 10500 mAh. 1% imbalance would be 105 mAh and take 2.5 hours to balance.
  17. They wouldn't, as been said, the charging ports are connected in parallel. Imbalance occurs naturally with charging/discharging, not because of chargers.
  18. The BMS does the balancing by passive bleeding off the highest voltage cells. It takes a long time (2.5 hours for my KS18XL to balance just 1% imbalance). Fast charging should be fine as long as people leave their wheels plugged in for 1 extra hour after charging. Or 20-30 hours fully charging each ~10 cycles? Most users probably don't do that, so they develop inbalance in the cells. I think people underestimate how much time it takes to balance through the tiny bleed current in the BMS. 2.5 hours to rebalance 1%. 25 hours to rebalance 10%.
  19. 80% charge would only be 4.0 V per cell. Or no? Balancing (for KS18XL passive bleed with small ~40 mA current, only 13 mA each cell) is only once the cell goes above 4.2 V.
  20. The batteries are at higher temperature after riding. It would be better to have the batteries cool off a bit before charging. Hard to say if it matters much. Cell balancing only starts around 100% charge (above 4.2 V per cell) and it takes a long time (2.5 hours to balance 1% for my KS18XL). Ideally, charge to 100%, leave it to balance for 1-3 hours, go ride, store at 30%-80% charge. Bad to store at 100% charge (20% battery degradation in 1 year).
  21. Very valuable post, thank you! For example in KS18XL, the balancing is only done via 100 ohm resistor, 42 mA current. It would take 2.5 hours to rebalance a 1% imbalance. 25 hours for 10% imbalance!
  22. When I was just starting I didn't notice any difference at all. Now after 800 km I notice a huge difference in the settings.
  23. I am 190 cm (6'3"), 90 kg (200 lb). 18XL is my first wheel, but it feels really really small to me. The wheel weight 25 kg (55 lb) is also not heavy. I was wondering if I was alone or not. I would really like a bigger wheel, but monster is the only option? Any suggestions, thoughts please? As it's my first wheel I would really love other's perspectives.
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