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Keith

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Keith last won the day on September 8 2016

Keith had the most liked content!

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About Keith

  • Rank
    Veteran Member
  • Birthday 07/04/1955

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  • Gender
    Male
  • Location
    Surrey, UK
  • Interests
    Radio Control aircraft, photography, Malta.

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  1. Keith

    battery pack rebuilds

    I’m fully in agreement with @esaj on this! Having been a very early adopter of electric power for model aircraft, I have a fair bit of experience of using NiMh and NiCad batteries in high power applications. The first VERY telling thing about the power available from NiMh is that, even with the advent of much more torque and power from Brushless motors the battery was half the total weight of the plane I.e. if the battery weighed 1lb then the airframe, radio, motor, etc had to be built at not much more than 1lb as well or the plane would hardly fly. Another significant issue (which was quite handy in the winter) was how hot the packs would get - A high power (for the time) plane could melt the hot glue used to assemble the packs. Flight times of as little as 3 minutes were often the case and more then 6 minutes was a real result. Lithium Polymer batteries totally transformed electric model flying and any plane built for a Nitro engine can easily be converted to electric and fly as at least as well. Power and or duration are easily tripled compared with NiMh and weight (and size) at least halved. It really is the power density of Lithium and efficiency and power of BLDC motors that have made electric vehicles of all types viable. Using NiMh would be a bit like going back to steam powered cars (IMHO🤓)
  2. I cannot help with your Mini Pro problem (although this post will at least bump the topic so others see it) but I just had to say I love that tennis ball seat suspension - a brilliantly simple idea - repurposing at its best 🤓👍.
  3. Keith

    Taking up the Unicycle at 67!

    @freebiker great fun first post. I too was over 60 when I learned to ride. The two things I can add to what you have written are: At the very least, wear wrist protectors - you won’t fall as gracefully as a twenty year old and you WILL put your hands out and sprain your wrists, which also won’t heal like a 20 year old either - boy do you find out who your friends are when you cannot use either hand for weeks! Obviously if you start getting a lot faster further protection, especially a helmet become very sensible. The use of a safety strap is much misunderstood and therefore often derided! It should be long enough to hold loosely so you do not try to pull on it to balance (it won’t help at all!). If you come off of the wheel you simply lift the thing off the ground, preventing it whacking into you or charging off and damaging something or someone else - particularly when you are first out in public. Protecting your shins as well is no bad idea - I just used stout walking boots.
  4. Keith

    Headache

    Well we sold our house, moved 240 miles North and the new one currently looks like below so we’re a bit tied up at the moment 🤓
  5. Absolute bollocks. That is a hangover from NiCad Cells. There is NO memory effect on Lithium Ion as @FreeRide has already said. All that will happen is the batteries will be aged faster if fully cycled. Fully discharging a pack also risks real damage to some cells if they are already lower than others, by taking them below their safe minimum voltage or even reverse charging them. The only thing preventing them being seriously damaged by being completely discharged is that the BMS idea of fully discharged is usually still with 10% or 20% or even more capacity left in the battery to prevent them actually fully discharging. i would love to see a copy of where in a Ninebot user guide it tells you that you must fully discharge the cells?
  6. It’s hidden, not deleted. New user using a spoofed email address from St. Helena, but posting from Ireland whilst hiding his location. Also hiding details on YouTube. We rely on trust on this forum as we have had some pretty awful behaviour (which is why new users cannot P.M. either) so your behaviour doesn’t give us any trust. Give us a real email address and location and I’ll unhide your post. Only Moderators see that email address. Or, of course you can stay anonymous and have every one of your posts moderated.
  7. You haven’t thought out properly how an EUC balances and works. This just is not possible without faceplanting the rider. To reiterate what has been said before: the primary function of an EUC is to balance and that is ALL the electronics are trying to do. That this causes you, if you lean forward, to accelerate is a happy byproduct of that function. Anything you do to “reduce power”, brake, or anything else, like restrict maximum speed, control traction, etc, etc, is fundamentally going to bugger up balancing. Not to mention that they still haven’t been able to completely eliminate such oscillations due to poor skills by the operator in much, much more mature technologies such as motorbikes and planes
  8. Keith

    Used Rockwheel

    There is no lead in Lithium Ion batteries - there is, unsurprisingly, Lithium. We wouldn’t be riding EUC’s if the battery technology hadn’t advanced beyond lead acid batteries! I did not say “it can only be stored at 40% to 60% power”. I said leaving it fully charged or fully discharged for long periods is harmful. The word “should” in the English language means something is advisable. Something as expensive as a Tesla car (which owners have paid very many thousands for the battery in) has systems and software that does its damnedest to prevent the user from abusing the battery and indeed doesn’t fully charge the battery if possible. EUC’s are still really at the early adopter phase and and the user needs to have something of an understanding of all the technologies involved to ride them safely.
  9. Now all you need to do is get sponsorship from all those companies and you’ll be able afford a ?Z10 or KS-18 ?
  10. That might just be because not a it a lot of riders crash and fall off anything like as much as your copious previous posts suggest you do. I’m surprised any part of you still works? Of course neither do a lot of riders ride around all the time at less than walking speed which must put a lot of strain on the hips as twisting the hips is the only way to balance riding that slowly ?
  11. Yeh, spoken by someone who has never faceplanted due to a sudden failure. We had a guy like you a couple of years ago, called us all wimps, “All you need to know is how fall!” then came off riding at speed along a lakeside beach wearing just shorts. He did at least have the decency to publish the photos of his injuries afterwards.
  12. Keith

    36er unicycling at CicLAvia 9.30.18

    Moved this to off topic. It fails to be an “Other non self balancing PEV” on EVERY level.
  13. Keith

    MSX 100v VS MSX 84v

    This can be soooo wrong for electric motors because you are completely ignoring efficiency. The losses in any electric power chain are I squared R losses I.e. the bit that ends up wasted as heat. It is current that generates heat, not voltage, that is why very high voltage power lines are used to deliver electricity over long distances, the power doesn’t get wasted heating up the wires. Assuming that at a given speed and weight rider on a given day and place (I.e. all things equal) then the EUC will require a certain power consumption and given that P=VI then a higher voltage will require correspondingly less current which means correspondingly less losses due to heat so the 100V machine ought to have better range from the same Wh size pack, even though it will have less Ah then the lower volt pack. However this is in an ideal world where the motor has been correctly wound to give its best efficiency at cruising speed - which Gotway may, or may not, have done? Because I don’t know the characteristics of the two motors used, another area of uncertainty is this cruising speed. Electric motors are at the most efficient running (at full power) at around 80% of there no load (or absolutely maximum) speed, efficiency falls off rapidly if run below 50% of no load at full power (say when speed is limited by going up a very steep hill for example) that loss of efficiency again manifests itself as heat. I know we never run at full power on EUC’s but the theory holds for example if you are using half power and going at less than 25% no load speed you are again in an area of poor efficiency. If the 100V and 84V EUC’s both use exactly the same motor with the same RPM/V (Kv) then, cruising at say 15MPH on both will see the 100V machine running at a much lower efficiency as it is running at a much lower percentage of its higher no load speed I.e. you would have to run it fast to get any efficiency out of it. However if it has a lower Kv motor such that it’s no load speed is no higher than the 84V machine then it will be more efficient as it will consume less current for a given power output at a given speed. This is a long winded way of saying that only a back to back test of both machines by the same rider (or two of the same weight and riding style) will really show which works better.
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