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Scatcat

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Scatcat last won the day on October 14 2017

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About Scatcat

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  • Birthday 10/04/1966

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    Male
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    Gothenburg, Sweden
  • Interests
    Computers, Sci-fi reading, EUC, Vaping

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  1. Scatcat

    Rehab1´s accident(s)

    I've had three real falls, and each time my muscles were sore as h-ll afterwards. No permanent damage, just overstressed. Your pads saved you from worse, but those elbow pads just don't cut it, you should get some that sit tight in place. My POCs are just slide on, but have a velcro tape on the end that stops the tendency to slide - something like that might do it.
  2. Scatcat

    100V MSuper X ... check it out!

    Just a note on 18650 max amps. There is no "boolean" hard limit on any 18650 without a protection circuit. Even a cell rated at 10A can put out 40A or more for a very short period of time, and cells rated at 20A CDR can actually put out as much as 80A for half a second or so without taking permanent damage. The effect of "pulse power", that is discharging well over the CDR limit of course taxes the cells and shortens the life span. It heats them up pretty fast, faster the higher you go. To put it in a practical context, as I'm a vaper in love with my mech mods: My typical coil is 0.2Ω and I use two of those in parallel. That means I use my single 18650 with a resistor of 0.1Ω, which means a theoretical max amp draw of 42A. There are no cells on the market that can give that kind of juice continuously, the ones I use are rated ~20-25A CDR. I mostly use Samsung INR20R or Sony VTC5A, both of them with INR chemistry. Samsung are the only ones who've dared to actually publish figures for how long high pulses can be sustained, and those figures go up to 100A (less than half a second at that power ). In reality, with voltage drop, the true figure for my amps should be somewhere around ~35-38A. I can stress the cell for up to 6-7 seconds at that amperage without any undue risks, as long as I allow some cooling down in between. I can even do it twice or three times if I allow the cell to cool down afterwards. It DOES affect battery longevity, and I can't hope to use a cell for more than a year or so before noticing a serious degradation of capacity. When my 2500mAh goes down to 1500-1800mAh it is time to retire the cell. The Sanyos and Pioneers we use in our EUCs are a bit more volatile than the Samsungs and Sonys I use for vaping. They have a higher capacity but lower CDR. Mostly they should not be pushed beyond 10A draw continuously, but can peak at much higher powers. When my GT16 transients at 45A, that is from four parallel packs, meaning each cell is required to give ~11-12A. That number are well within the bounds of what the cells can take for such short transients. You could actually double the number for very short periods of time, and those transients are seldom longer than fractions of a second. Sure, it will affect the lifespan of the packs, but not that badly. So seen just from the battery perspective, 90A from 4p would stress the cells, but not dangerously so. The number is probably wrong anyway as @Marty Backe and @esaj both say above. Still and all, my speculation was that Gotway could do a lot more to handle those transients in a way that are safer for the board.
  3. Scatcat

    Ninebot One Z : Z6-Z8-Z10

    The pull is pretty easy to explain. I experienced it when I got a slow leak. When you lean a bit, the tyre gives, which amplifies the effect of leaning, which amplifies the give in the tyre and so on.
  4. Scatcat

    100V MSuper X ... check it out!

    It seems though that there have been some reports from Chinese customers that the 100V is less dependable. Some boards have fried when stressed. I don't have a source for this yet. Just something said when talking with a distributor that was a bit concerned. I have no idea if this is a prevalent problem, or just something in some pre-production wheels out in the wild. I'm considering the 84V version myself, mostly for the extra range, but also because it has been well received in the internal market of China. Note: Actually I have somewhat of a theory about that... please give me feedback if you think I'm on to something - or not. It seems from the reported amperage of Gotway wheels that there is a lot of transients going on. @Marty Backe for instance has a 90A alarm set. When I compare to my GT16 which also has a 2000W motor, the transients I get are almost never higher than 45A - which rhymes rather well with the motor max power. My theory is that the firm-ware programmers of Gotway hasn't implemented a truly working transient control. The firmware should stop asking the batteries for more juice when they reach such levels, and that should happen fairly quickly like microsecond-quickly. There are no reasons to ask for more anyway, since the motor can't really do anything with the extra juice. The only effects you get are overheating and the risk of fried electronics. When you up the voltage, these spikes remain, but now at a higher voltage - meaning more watts, meaning higher risk for failure. You can compensate by going for more resilient components (To-247 and such), which alleviates the problem, but doesn't negate it. Suppose you have a ~90A spike at ~84V, then you get a total of ~7500W in the spike. Up that to ~100V and the same spike is now ~9000W. At some point the spike is more than the board can handle. So going up, you have to control the transients better or get more problems. Feel free to prove me an idiot
  5. Scatcat

    Rehab1´s accident(s)

    Sorry about the shitty quality in the second part, the GoPro don't have zoom. I'll have to find a better camera with zoom and a better angle where you see the braking from the side rather than from the front. It looks almost lazy in the video, but it is pretty amazing that you can go from 35+ kph to 0 in 15 meters or so without actual brakes. The ride mode is hard (which on the GT16 means stone hard), so it looks very undramatic. The angle you have to push in hard mode is much less than in softer modes. Also interesting was trying the V8. Talk about different ride feeling! It felt both more and less stable. The much more narrow stance and rather high pads made it feel almost stiff when turning, until I put my feet further out on the pedals. The GT16 pads are less "dominant" in their effect on the balance. I can see however, why the owners like it so much, it oozes quality.
  6. Scatcat

    Rehab1´s accident(s)

    Native languages and all that But I think @Unventor will be a bit leery of a repeat performance, so I suppose it DID fail the test.
  7. Scatcat

    Rehab1´s accident(s)

    If I knew you'd take flight, I sure would have documented the evolution of man to bird... or is that chicken?
  8. Scatcat

    Rehab1´s accident(s)

    That is probably what happened. As @Unventor said, he landed pretty flat on his backpack, and slid forward a feet or two. But I have to give it to him, there was exactly one big rock on the road, trust @Unventor to find it... I stod there absolutely sure he saw it, then I started a stillborn shout as I saw him hit it dead on. I was maybe 25 yards away and the wheel got almost halfway to me before stopping. I’m going to see if the clip we recorded came out good, then you can all see the rock for yourselves... 😬
  9. Scatcat

    100V MSuper X ... check it out!

    Ahhh, just when I thought I had decided on an 84V MSuperX, and now this! I'm really curious how it will differ from my Rw GT16 though. Bigger and heavier, wider tyre and more stability and all that...
  10. It has progressed from 35kph when I started to 40kph now. The wheel has a theoretical max close to 30mph/48kph (not that I would want to go anywhere near it). However, if you run at the hard mode, which I prefer, you have to push bloody hard when you go past 40kph to accelerate further - much like Marty going uphill when wheel-testing. The kind of rigid stance that entails, is not something I really like, it feels like any pot-hole or crack would make me shatter my teeth if my legs cant stay relaxed while riding... Also, as @Marty Backe noted, the stability at really high speeds isn't the GT16 forte. It is still a 16"-wheel, and I suspect slightly more unstable than the Tesla at higher speeds. Going 40kph on a smooth road ain't no biggie, but add some cracks, gravel and bumps to the mix and I'd rather slow down to, let's say, 36kph... I have a stretch close to work, the last 800m or so, that's newly fixed up with silk smooth asphalt. When I ride that stretch, is when I most often get speed alarms and tilt-back. You're basically accelerating past 40kph before you know it, and it feels like going 30-35kph on older asphalt. Lastly, I've recently tried to measure braking performance, which is not a simple thing to estimate. But there IS a big difference between stopping from 35kph and 40kph. While the motor is perfectly capable of applying some monstrous braking power (while 80%-beeping like crazy), the lag when you push the wheel before you and until braking starts is the same. But you travel further before you brake, and the braking takes longer. I can go from 35kph to a speed where I can put my foot down within 1.5 - 2 seconds, 15 - 20m, after braking starts. But you have to add another 0.5 - 1s to that from need to brake to braking start, which is basically another 10m or so. When I'm testing, I realise that the 15-25 meters where I go from 35-40kph to stop isn't really realistic, since I know beforehand that I'm going to brake and so prepare for it with allt the time in the world to spare. A more realistic braking distance when the need comes from nowhere, is probably 25-35m from such speeds. Which just goes to show that if you run fast, and suddenly need to brake, the odds that you go pancake is not very fun to ponder. So while it feels like someone grabs me from behind by the jacket while I'm braking, I'm afraid that it won't matter if I go to fast. So I run a lot more carefully if I'm not absolutely certain of my surroundings.
  11. Scatcat

    100V Monster water intrusion vulnerabilities

    Maybe there IS conformal coating. But obviously it didn't stop the capacitors from shorting (if that was what happened). A filter like in your post would probably solve the whole problem. Ideally it would still let air through, but stop water droplets. My guess would be it wouldn't be that hard to make such a solution, and that it would be pretty effective. Even a bloody impregnated paper mounted and curved correctly and fastened with some 3M double tape would probably do the trick quite handsomely...
  12. Scatcat

    Ninebot One Z : Z6-Z8-Z10

    I always read your walls of text with pleasure This is by far the most eloquent and clear explanation of the advantages/disadvantages of higher voltage. For me it pointed out a couple of things I had not thought about, the difference in resistance between parts rated for different currents, and the step down circuitry problem. Higher voltage solutions to the power problem require more expensive parts. But given a good design, it has the potential of higher usable power with a lower power loss. That part seems pretty clear. I tend to think that in the end, the manufacturer that accepts the extra costs of high grade parts. The manufacturer that do their homework in electrical safety and thermal solutions, will earn back the extra costs and research in no time flat. Consider a Gotway that made a 100V Monster where the thermal solution would easily, and with a temp margin, carry it to the top of Backes "Overheat Hill"... Consider that at the same time it had margins of mechanical and electrical error (shafts, shims, wires and so on), as well as good internal design providing resistance to water and general ruggedness. Even if they had to charge $3000 for it, it would probably sell pretty well. Or to not deviate from the NBZ too much, consider a 100V NbZ10, with the parts and quality to match. That would be something.
  13. There were two holes missing in my shell too. QC anyone? I drilled the holes with a 0.8mm drill, worked like a charm. Add the grip tape, that is my recommendation. Before you know it you'll do tight turns at high speed, and you DON'T want to slip with the bottom foot when you do. My own alarms are set to: 40/42/44 kph with tilt-back at 44kph. At lower charges I sometimes get 80% warnings. And there is tilt-back there too if you try to ignore them...
  14. Scatcat

    100V Monster water intrusion vulnerabilities

    I suspected that was it. I'd say it should be fairly simple to waterproof. But at the same time there is a geometry problem with the card just below and behind, with fans that may catch water droplets and blow them towards the board... I'd spray some conformal coating on the board. That is not fool-proof, but will at least serve to make sure 99% of the moisture hitting the card wont do any damage. I'd also consider something as simple as a plastic wafer as a shield between the board and the cable port, preferably long enough to cover most of the side of the card towards the port. That way any drops getting through anyway may not get sucked into the fans. You could probably use the wires to anchor such a plastic wafer securely enough. I'd have to say though, that Gotway hasn't really thought the geometry through in terms of water-proofing. Compare with the MSuper X, where they actually though about a labyrinth trap for the air inlet...
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