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Everything posted by WI_Hedgehog

  1. EUC: "Basically a land torpedo." I like the idea of looping excess through the belt but not tying it...the rope ought to keep some pressure on the wheel, but not wreck your body. Some of that stuff is really funny: Black Nano Cord - 300 Feet Breakaway POP Barrel Connectors - Black Mini Carabiners - Black 20% Discount Coupon: WELCOME20 Total: $19.71
  2. You have King Songs, so attach a clothesline to the center of the handle. I wrapped my handle with auto masking tape, then cut about 10' off the neighbor's clothes line pole (a little foraging can go a long way). Tie a thumb knot in the end, then loop it around the handle, then another thumb knot around the rope forming a slip knot. Wrap the clothes line around your 4 fingers, holding them about chest high, then remove the loops from your hand. Unwind about 3 loops and slip the end through the loops, wrap the line around the bunch, then slip the end through the other end of loop
  3. 174Wh / 20W/mi x 80% usable = 7 miles, enough for learning, and it's so light it's probably not going to break, which help$. if you add a second pack it's 14 miles, which is a decent outing with a friend. I think the newer KS-14D battery is 210Wh ($170) making for (174 + 210)Wh / 20W/mi x 80% usable = 15 miles, about the range of a miniPRO hoverboard, so I'll call it reasonable for a beginner wheel (especially given the price). BUT, you could put KS-14S shells on for $80 and stick in (2) 14S 420Wh batteries ($295) for $700 total. (Then maybe sell off the 14D shells on eBay for a
  4. Electric Unicycle King Song KS 14M DEMO SALE eBay - metroorangeartinc (out of New York) I offered ~60% of list price as I thought that was a fair price for the wheel, and we agreed on ~65% (plus $45 S/H). I took the wheel apart and it's like new (I think it was 0 miles?--I'm not sure, but was not even any dust inside the shell and the molding hairs were still on the tire!), with OEM King Song battery and room for a second battery on the other side, so it was an awesome deal and I greatly thank the seller. On KS-14SMD I got the battery connections are in parallel, so just plug in a 2nd bat
  5. Unless modifying the BMS, I agree with @RagingGrandpa, other than thinking to charge in the garage, or basement if necessary (cement floors), with a smoke detector/alarm. Generally LiPo fires produce small flames, it's the EUC plastic & rubber tire gasses that are toxic and produce larger flames. I charged non-EUC LiPo stuff in a fire resistant bag, the charger having a temperature sensor that went in the bag too. Temperature sensors linked to cutout circuits are a huge safety gain
  6. It has little to nothing to do with throttle & brake being on the same hand, or brakes being both a pedal and leaver. Most motorcycle accidents happen because the driver has been drinking or they're hit by a car, or both. The third largest contributor is rate of speed (fast leads to a life past, slow is the way to go). There were far fewer crashes when the clutch was operated by the left foot, the gear change was a shifter lever operated by the left hand, and the spark advance was on the left grip, front brake and throttle on the right, rear brake on the right foot pedal. Crashes have
  7. I feel smarter. (I may not "be" smarter, but I "feel" smarter.) This is a great thread, thank you!
  8. The biggest problem seems to be lack of proper balancing (the 80% group largely neglecting balancing), however, there are plenty of reports of failed cell groups on the forum by 100% chargers. I want to learn how & why things work and maximize pack life, but that's just me. Maybe I'll build this out later, right now I need to finish the miniPRO Speed project. EUCs haven't been out long enough to age the cells to death, but we should start seeing that in a year or so. The other thing is early EUC adopters that ride 10,000 miles seem to buy several EUCs, so don't tend to notice if the b
  9. Then it's not a passive component like a resistor...maybe something more complex like a reverse-bias diode, or transistor, depending on how inexpensive a manufacturer wants to make it. My understanding is King Song started out as a BMS manufacturer, and therefore have solid BMS units. Electric Bike has a good BMS article. Example 4-cell balancer.
  10. Great point, I have a calibrated FLUKE meter. As the battery ages and hits the 80% capacity mark, one tends to use closer to 100% of its capacity, and it fails rapidly. It's like a cell phone battery, where every day you use 30% and it has 70% charge left at night when you plug it in. Then one week you notice it's in the low 60s, then 50s, then 30% charge left, and you know you'd better get a new phone. If a 100-ohm resistor were in parallel w/the cell it would constantly draw an average of 0.0385A (0.15W), not a huge draw, but the batteries would lose 3.5Wh a day in parasitic load..
  11. It has been 3 weeks, any updates from Gotway? Personally, I would not ride the MSP until someone opened it up and looked at all the connections and tested the internals. It did not suddenly fall asleep for "no reason," and will most likely do so again. There are many people here suffering from shoulder injuries from a sudden fall, even with protective gear, I would not want to risk being one of them...or fall into traffic, or have the wheel go to sleep and smash into someone's car, or fly into a person on the street...that will not be a good insurance claim: if someone is seriously hurt--
  12. HAS A POSSIBLE CAUSE OF PREMATURE CELL FAILURE JUST BEEN DISCOVERED? Charging to 80% and then balancing the cells, which requires balance leads, means a loss of 20% range per trip, but gain of 100% to 200% more battery charges. Say the EUC can safely go 30 miles on a charge: 30mi x 100% range = 30 mile trips (or less) 30 miles x 300 charges = 9,000 mile battery lifespan 30mi x 80% range = 24 mile trips (or less) 24 miles x 600 charges = 14,400 mile battery lifespan If you're fanatical and don't discharge below 20% battery capacity: 30mi x 60% range = 18 mile t
  13. The other item of concern is bearings...are the bearings in Wheel_X serviceable with moderate effort, like changing a tire's innertube?
  14. "Pictures or it didn't happen." (old forum rule --LOL) There's a whole series of misadventure threads by @Rehab1. He's the reason I am acquiring safety gear. (Credit to @Unventor also.)
  15. On one hand, for guys like myself who live in cold weather climates it's about battery longevity, so buying more battery than needed is not optimal. On the other hand, commuters like yourself are indeed the ones who have to look at how many charges per day they're doing. One full charge might mean replacing the batteries yearly. Two half-charges (to 4.2V) might mean you get an additional year of use due to shallower depth-of-discharge, so bringing a charger to work (or leaving a second one there) may have excellent Return On Investment. What voltage does the Battery Managem
  16. Sad to hear of your crash. It sounds like a bad connection that resulted in heating and an ongoing electrical arc over time, eventually resulting in burning up the connector and circuit failure. I've seen great riders run away from a crash, but all were standing. You shed insight on the risks of sitting.
  17. Charging "slower" creates less stress on the battery, so while a fast charge of 1C is safe, it tends to heat the battery and cook the chemicals inside, wearing it out sooner. 0.5C is generally the fastest I've seen suggested, with 0.1C being optimal. This seems to be why EUCs come with "slow" chargers. It's true slow chargers are cheaper, but when you're buying a $2,000 wheel the extra $10, $20, or $50 it would cost the manufacturer to upgrade the charger isn't a huge consideration...a much faster charger would be &$10 more, faster yet another $10... Slow chargers are present less risk of
  18. As a note, charging your battery to 80% instead of 100% (4.00V vs 4.20V) tends to double the life (batteries are usually rated at 500 full cycles, I'm hearing in EUCs they last about 300). Discharging to only 30% (3.77V) instead of 0% (3.27V) should also double thier life. That would take your battery life from 300 cycles to 1,200 cycles, although your trips would be about the distance you're tanking now. Remember that since the cells are in series and don't like to be over or under-charged, its good to balance charge them regularly. I've heard the figure "every third charge," and that
  19. Jason showed us inside King Song's new factory in good detail. KS does rigorous testing, and the quality matches what's inside my KS-14, which is to say well thought and very good. Maybe you're confusing King Song with Gotway? --Fragile plastic, soldered by a guy with Parkinson's, hot-glued by an epileptic...
  20. Veteran EUC: Tank no come wif steh-we-oh! NO STEHWEOH! You go home now.
  21. (do not add adhesive enhancer) E6000 is not hard to remove. Clean the surfaces and apply E6000, wait for it to cure overnight. If you want to peel it off later it requires a reasonable amount of force, but comes off cleanly and as a single piece. There is no need to pretend to be Gotway's Glue Gun Guy--just seal the void slightly and a little past the void for waterproofing and you're good--you do not need to act like an epileptic having a seizure.
  22. King Song: Wha you do? You make sound? From wheel??? ... We make sub-woofer--make better sound! Maybe add more lights too! Gotway: You no hear of earbud? Inmotion: King Song rip off our suspension idea!
  23. You could use E6000 flexible adhesive.
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