Slaughthammer

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Slaughthammer last won the day on January 31

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  1. There has never been any problem concerning high currents on the battery side in any high powered wheel that I know of. That's only a problem on low powered wheels with max. two parallel cells in the battery. On the other hand, there have been quite a few problems with high currents on the motor side, especially in the Gotway 84V wheels. So why are we debating the benefits of higher voltage for the battery side of the wheel? I don't get this....
  2. Finally we can agree upon this! That's only possible if you assume 4,2V/cell during discharge. Optimistically (or as others say it, nominally) calculated, you get a max capacity of 3,7V*3Ah*80=888Wh edit: ooops, wasn't you who didn't believe my numbers, it was @meepmeepmayer
  3. The same motor! Each motor has it's own force factor (torque per current), so different motors can perform under different voltages quite similarly. On the other hand, the motor doesn't care about the battery voltage, it only cares how much current is pushed through. So, yes, more amps = more torque is true as long as it's always the same motor.
  4. This is clearly not true. Less voltage, higher torque, how should that work out? What drives the amps through the motor? Yes, it's the volts that do that. The higher voltage you have at your disposal, the more amps you can push through the motor. The more amps you push through those coils, the more torque you get. The faster the motor turns, the more voltage you need to push the same amps through the motor. Now, if you use the same motor with different voltages, like Gotway does with the 67/84V wheels, you get more power and higher speed from higher voltage. However, if you compare two different motors designed for different voltages, there is no way to tell by the voltage, which motor will perform better in which discipline. It all depends on how the motor is set up, how the controller is configured, how much current the batteries can supply etc...
  5. That's only possible if you assume 4,2V/cell during discharge. Optimistically (or as others say it, nominally) calculated, you get a max capacity of 3,7V*3Ah*80=888Wh, conservatively calculated you go to http://www.dampfakkus.de/akkutest.php?id=586 and see that the actual measured capacity for discharge at 3A from 4,2V down to 3V is 9,223Wh, so 80 of that give you realistically 738Wh. However, if they use the 35E (http://www.dampfakkus.de/akkutest.php?id=577) instead, they would get a nominal capacity of 3,7V*3,5Ah*80=1036Wh, so that's what I'd assume is done here. But consider, the 35E has an internal resistance of 28mOhms, compared to 18mOhms of the 30Q, therefore the usable capacity for high drain usage is not significantly higher. Again, for 3A discharge you'll get 10,695Wh out of a cell, so the packs give you 856Wh, or just shy of 16% more than the 30Q. Which actually matches with the specification quite well: 3Ah to 3,5Ah is a 16,7% increase. If you take the measured results for a 5A discharge, this difference melts down to 7,4%. The price for the higher capacity is a battery that will create significantly more voltage sag under heavy load, especially in the lower half of a charge cycle. There is a reason I used the 30Q to boost my own wheels battery. In my opinion the best bang for your buck cell right now.
  6. I know that loudspeaker repair guys use masking tape and cardboard to clean the magnetic gap of a loudspeaker. Fold the masking tape sticky side out over the piece of cardboard (business card e.g.) and drag that through the gap until nothing sticks to the tape.... can be seen in this video (15:30 onward):
  7. I can only agree. Especially for a Zero, the battery would become way to large to fit in. Additionally, I wouldn't trust this contraption to guarantee a good connection under all circumstances. OK for an e-bike, where battery failure means pedaling home, but not for en EUC, where battery failure equals faceplant.
  8. No, at least not for EUC applications. You can solder to the cells, but for that you really need to know what you're doing, and an appropriate soldering iron. The other, better option is spot welding nickel strips to the poles.
  9. Do you have someone who deals with RC models? They usually have quite a bit expertise about batteries, maybe get some help there?
  10. 0,9V sounds plausible.... when the cells are discharged that far, imbalances tend to stand out extremely. However, I'd try to charge the extremely low cells individually, but you need a special charger for that. If you don't know exactly what you're doing, better leave it to someone who does.
  11. Did you check the individual voltages through the balancing wires? The cells used in the IPS 340Wh batteries should be these: https://eu.nkon.nl/rechargeable/18650-size/panasonic-ncr18650pf-3-7v-2900mah.html (by the way one of the best online shops for 18650s in Europe)
  12. Es ging mir in erster Linie um die Akkulaufzeit, die bei über 20 km/h doch deutlich weniger Strecke zulässt.
  13. 24 km hatte ich gesehen, und bei 15 km/h ist das für mein Rad gut zu schaffen. Wenn eher mit 20 km/h im Schnitt gefahren wird, würde das doch arg knapp werden. Danke für die Info!
  14. And that's why I used 0,3*10mm nickel strips for my custom battery extension. just shy of 4 times bigger cross section, and my wheel is not a particularly powerful one...
  15. Moin Patrick, Willkommen auch von mir! Da ich auch aus dem Großraum Hannover komme, fände ich das sehr interessant, in die Gruppe aufgenommen zu werden. Wie organisiert ihr euch? Die Skate by Night Hannover kannte ich noch gar nicht, hört sich interessant an! Wie schnell ist der Zug so im mittel unterwegs?