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alcatraz

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About alcatraz

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  • Location
    CN
  • EUC
    v8

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  1. Another possible reason for the runaway heat are the nickel strips. I've seen gotway packs use waayyyyyy too low crossectional area nickel strips. At the ends of the packs you have something like 4 negative poles connecting to 4 positive poles with a single nickel strip. At the center the peak currents are heating up the strip extremely hot. The shrinkwrap starts to melt. Both the outer wrap and possibly also the cells wrap. Because the tesla motor cells have been refurbished and rewrapped, maybe some refurbers used low melting point shrinkwrap so that common gotway pack temperatures actually melted it and caused outer casing short circuits. If replacement packs are slightly larger, that could indicate added cell casing protection between groups. It means that's likely what caused the fires.
  2. That coating looks good. Is it hard to do? Is it expensive? Is it impossible to take off? Do you get a lower board temperature reading after adding it? I like the idea of added moisture protection and temperature dissipation. @Aibolit66
  3. This is interesting. Other gotway wheels with the same battery + control board configuration and spacing don't exzibit overheating issues. Why these wheels? What's different between the affected wheel models and unaffected models?
  4. I unlocked my 10000km without incident V8 (with a stronger 20s3p battery) and the wheel cut out on me at 32km/h on a flat road warm weather and plenty of charge in the battery. I'm 65kg. As long as your pickup speed is 44km/h like on other V8, do not go faster than 30km/h. For heavy people even 30km/h is dangerous. The fall at 32km/h was enough to dislocate my shoulder and it still hurts 9 months later. No common protection would have prevented it. Always have a healthy margin between pickup speed and actual speed. 12km/h is TOO LOW!
  5. A wider tire allows lower pressure which in turns gives you more compliance/comfort on uneven surfaces at the cost of quick turning. The downside is easily manageable by simply learning how to control the euc, and is after a while even enjoyable for cruising as it's less nervous going in a straight line. Both my V8 came original with a 2.125in tire. Make sure that you center the tire properly. Many people rush the install and get an unbalanced tire rubbing etc. If you center it, not only do you get less rubbing but also nice high speed stability. Sometimes the rim itself isn't perfectly true so by offsetting the tire in the right direction you can deal with that. What tire width suits you depends on personal preference, weight, terrain. For a 60kg ridera 2.125in tire could be considered fairly wide but for a 100kg rider a 2.5in is too narrow. A lighter rider can ride with lower tire pressure and enjoy a relatively narrow tire more than a heavy rider. You want to have compliance but you don't want to bottom out and damage your rim which is a part of the motor, an expensive component. If you for any reason happen to dislike low tire pressures, there's basically no benefit of going wider.
  6. You know that the extra weight of the v10 probably is in the copper coils in the motor to get the higher power rating. And twice the battery size. How are you going to fit a v10 battery in a v8 shell? V10 uses chinese 2800mAh cells and V10F LG MH1 3200mAh cells (same as V8).
  7. Looking good! I did a simila mod with MH1 cells. I didn't get anywhere close to 70km but a good 50km was possible on a good day. That's an interesting idea to use a V10 control board. Do you really think the V8 motor can handle that power? If you get any benefit at all I'd be curious to know. Careful to overspeed on a weak motor. Always stay 15-20km/h below the pickup max speed.
  8. I'm guessing malfunctioning bms. Or a bms with weak balancing currents running a capacity of cells way over what its rated for. Running LG cells could help only by being better matched from the factory. After they age they will be in the same boat as the Tesla/Panasonic cells, and balancing currents will be inadequate aswell.
  9. Remember that you don't have to balance often. As long as you don't go under 2.8V or over 4.2V you're fine. You will get a hang of how long you can go between. If one group is 4.0v and the others 4.2v it's no big deal. Even if you deplete the pack to 3.4v that low group won't go under 2.8v. When the low groups start to get to 0.3-0.4v below the median then you should balance I think.
  10. If the battgo isn't connected to a power supply it can't top balance. You might end up with two sets of 8s cells at different levels. Also I think it will take an eternity. Check the balancing current it can supply. How much is it? I know attending it is annoying but you already have to take the euc cover off etc. Better to turn the juice up on those unbalanced cells and save you some time. If you are using a balancer with a power supply. Make sure they each have a separate supply and that they run off the mains. Any DC-DC power supply can't be used as it will short the pack. If I were you I'd buy one of those 8s balancers and 2-3 (how many you need?) single cell high amp chargers. The really useful thing about balancing without top balancing (power supplied balancer) is that you can balance at any charge level which is good. Otherwise you might only be able to balance at 100% which takes an eternity.
  11. You can add larger washers and threadlocker if you're worried about slippage.
  12. I did the bulk of the 10kkm at 30km/h always hitting the tiltback. I'd say it's 99% safe for her at that weight. It's on the very limit. Still a 14km/h margin to the lift speed isn't much and I wouldn't do that if I wanted 99.9999% safety at 65kg (my weight). I have a Gotway tesla for faster rides so I don't feel like pushing the V8 to its limits.
  13. The v8 tops out at 44km/h in a lift test. The default max speed of 30km/h is already closer to the lift max speed than other brands = very unsafe. I did 10000km on my v8 and thought it would never fail me so I unlocked it. Big mistake. Shoulder still hurts a year after. I'm 65kg commuting on flats, 10 degC with 4/5 bars on the battery.
  14. When the shell has an open dropout it's easier. On the tesla the led strip goes right under the dropout and pedal. You need to do something about the led strip to do that. Either cut it or reroute it somehow.
  15. Opened them both up and probed them. I had plans before the arrival of the 2nd wheel to rebuild one of the packs as a learning experiment. Go from 40 to 60 cells.
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