US69 Posted April 22, 2018 Share Posted April 22, 2018 3 hours ago, Scouts Honor said: Is it true that the upcoming Z wheels from Ninebot are all low voltage wheels? Could that negatively affect their hill performance? the Z wheel is a 59v max wheel! In theorie that says nothing about its power. Practically my personal opinion is that is in now way as powerfull as GWs or KS latest 18 inch wheel. time will tell.... Link to comment Share on other sites More sharing options...
meepmeepmayer Posted April 22, 2018 Share Posted April 22, 2018 8 hours ago, Scouts Honor said: On a long incline with a relatively small battery, unless that battery is full, the battery can drain down below 20% or 0% if under load for too long on an incline. Taking foot off the gas/whatever you want to call it and removing all load from the battery for a second or two can boost the battery levels back up again. ... When my battery is only 50%, I get low battery beeps and my battery bars go down from 2 to 0, on big hills, until I de-load the battery for a second or two and It goes back up to 2 battery bars again. Oh, you mean the voltage drop under load that shows as lower battery %? That's normal. I've never heard of it increasing over time during high load, though. Are you sure this happens, or do you just see the increasing voltage drop during acceleration, and stop before it reaches some equillibrium? Does it really increase constantly until you hear beeps? What does an app (Wheellog does 1% steps) say? Link to comment Share on other sites More sharing options...
Keith Posted April 22, 2018 Share Posted April 22, 2018 12 hours ago, Scouts Honor said: Is it true that the upcoming Z wheels from Ninebot are all low voltage wheels? Could that negatively affect their hill performance? As @US69 has said power is Volts times Amps. Using simple numbers for convenience: 40V at 80A is the same power as 80V at 40A in both cases 3200 Watts. The Kv of the motor equates to the motor speed (RPM/Volt) so a 100Kv motor max speed at 40V will be 40x100 = 4000RPM. A 50Kv motor at 80V will also be 80x50=4000RPM. the good news is that to get a higher Kv you need less turns of wire on the motor, less turns means there is room for thicker copper wires (or more usually more thin wires in parallel) so the higher kV motor can handle greater current. Bottom line is that there is no reason at all that a 40V set up shouldn’t have the same power and torque as a an 80V set up and, of course, a battery of half the voltage can have twice as many cells in parallel for the same physical weight and size battery so the battery will also have no problem handling twice the current. Where the real difference occurs is I squared R. Heat loss through any resistance is equal to the current squared times the resistance. Using thicker wires in the motor will lower the resistance somewhat but there will still tend to be greater resistive losses in a lower voltage set up because of the current being squared. For example supposing my mythical 3.2kW, 80V set up at a max current of 40 Amps had a total circuit resistance of just 0.1 Ohm, then power lost (as heat) in the circuit resistance at full power would be 40x40x0.1= 160 Watts. Now supposing we had a 3.2kW, 40V set-up so max current = 80Amps. Also suppose we had managed to half the total circuit resistance to just 0.05 Ohms then the power lost would be 80x80x0.05 = 320 Watts. Same power input but now twice as much power is lost with the low voltage set-up. In conclusion, where a higher voltage set up wins is in efficiency. Of course this is a bit of a simplification as you have design issues like max voltage, max current and heat dissipation in MOSFET’s etc, etc to balance out as well as manufacturing costs and safety. Link to comment Share on other sites More sharing options...
Sobaka Posted April 23, 2018 Author Share Posted April 23, 2018 Thanks to you all for the feedback! Please don't infer arrogance from my desire to cruise at 18mph up a hill on an EUC having not yet been on one at all. I know I have some learning (and likely some falling) ahead of he before I even feel comfortable at 8mph (or 2mph). Rather, I'm trying to anticipate my future preferences. Maybe that's not 18mph up the hill, but I reckon it's >10mph! Given everybody's advice, which I very much appreciate, I think I'll start out with the KS14D and just keep its limitations in mind. The hill climb is also along a bus route, so being able to get up there quickly on the EUC is a luxury rather than a necessity. If I want something bigger in a year, I can negotiate that with my wife at that point! Again--thanks for all of the insight. In particular, the way in which the battery is important beyond range was not intuitive to me, so the explanation is helpful! Link to comment Share on other sites More sharing options...
meepmeepmayer Posted April 23, 2018 Share Posted April 23, 2018 10mph isn't going to be a problem Link to comment Share on other sites More sharing options...
Marcglider Posted April 23, 2018 Share Posted April 23, 2018 6 minutes ago, Sobaka said: Thanks to you all for the feedback! Please don't infer arrogance from my desire to cruise at 18mph up a hill on an EUC having not yet been on one at all. I know I have some learning (and likely some falling) ahead of he before I even feel comfortable at 8mph (or 2mph). Rather, I'm trying to anticipate my future preferences. Maybe that's not 18mph up the hill, but I reckon it's >10mph! Given everybody's advice, which I very much appreciate, I think I'll start out with the KS14D and just keep its limitations in mind. The hill climb is also along a bus route, so being able to get up there quickly on the EUC is a luxury rather than a necessity. If I want something bigger in a year, I can negotiate that with my wife at that point! Again--thanks for all of the insight. In particular, the way in which the battery is important beyond range was not intuitive to me, so the explanation is helpful! My first wheel was a 14D... looking back I would have spent the extra money and got the 14S.... a couple of reasons are 1st the reduction in speed on the S is at 30% where the D is 50%... I was told to get the most life out of the battery, not to fully charge it (80%, I go to 90% usually). The double battery means longer distance. That being said I love the wheel, it is what I use to practice tricks and new things like learning to go backwards, curbs, etc. I have a 16S and an 18S also and my 14 gets the most use right now and is the most fun to throw around... good luck! Link to comment Share on other sites More sharing options...
Circuitmage Posted April 23, 2018 Share Posted April 23, 2018 About train riding; My KS16S fits perfectly on my commuter train. I do see that the KS18L will be a bit large to carry on. About speed; I had a few years experience with 2 wheel electric scooters before getting mine, and 8-12mph is definitely too slow. It took me about 2 hrs to realize I wanted something faster when I got my first EUC, and when I did (about 2 months later) it was probably less than a couple weeks before I started hitting my 21mph often. After a few months, 20mph was very nice. Now, I am considering something a bit faster. About hills; IMHO, if you have to deal with hills, you may want a bit more power. About commuting; I also do 2 miles to my train, and from my experience there is a significant difference between 14" and 16 inch coupled with a faster unit. I was doing 12-14 minutes for the 2 miles on my (slower) 14". I now do about 8 minutes (sometimes less) on my KS16S. Link to comment Share on other sites More sharing options...
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