mark321 Posted March 5, 2016 Share Posted March 5, 2016 It looks like the kingsong 18" is available soon in the US as 800W 840Wh. I'm tempted to upgrade since my 14" (800W 680Wh) isn't as stable on rough pavement as I'd like, but I'm curious about the variations I keep reading about, possibly with 1100W motor and/or 1360 Wh batteries. Generally more is better, but does anyone know what the practical difference is between 800W and 1100W? I'd expect the top speed is already approaching unsafe levels at 800W. Would it be more efficient at cruising speed, or produce less heat? Link to comment Share on other sites More sharing options...
checho Posted March 5, 2016 Share Posted March 5, 2016 800w vs 1100w, when traveling in general the 1100w motor will be under less stress than the 800w, less stress means less heat for the motor, this is most important to avoid a faceplant when going over a pot hole, or going on steep hills, or both a pot hole while going up a steep hill. The general rule is that the more powerful the motor the safer it is due to the extra torque it provides, not only that but you will be able to accelerate fast. I personally I am a slow driver but like to be able to accelerate fast and a bigger motor gives you a better margin of safety.if you are a heavy rider the 1100w is a much better choice. The 1100 can go 40km/h vs 30km/h for the 800w. The 1100 motor will draw a little more power on average, and under stress conditions like a hill 1100/800 which is a ratio of 1.4 means it will draw a lot more power, for that reason the larger battery pack is needed, and even if you drive slow in the city with frequent stops, the fact that you have better acceleration will get you a better average speed vs the 800w motor. If you are light and drive mostly on flat surfaces they are equally good, but if you ride offroad and are a heavy rider the 1100w it is a better choice. The fact that more torque provides better safety is not specific to king song it applies to all wheels. How much extra torque is unknown by me since that would depend on motor windings, but someone that has both the 800w and the 1100w could probably better answer that. But if we assume similar motor winding the 1100w would provide a lot more torque, and torque means safety on a unicycle. As far as efficiency the 800w motor will use less energy, I would recommend the 1100w. Link to comment Share on other sites More sharing options...
Keith Posted March 5, 2016 Share Posted March 5, 2016 @checho, I would like to physically see the difference between the 800 and 1100W versions before drawing the conclusions you come to above. Everything you say above is perfectly correct providing the 1100W motor is physically larger than the 800W motor. I.e. The assumption is that KingSong have designed two significantly different motors for the same wheel and not just rewound it for higher wattage. If, as surely is likely, this is not the case then we have two motors with the same physical space for the copper windings. Clearly, since voltage is the same, the 1100W version must consume more current. That can only happen if the cross sectional area of the windings is greater in the 1100W motor and THAT can only happen if the 1100W motor has less turns to each winding. In other words it is entirely possible, without any proof to the contrary, that the 1100W version has a higher kV (RPM/volt) due to a lower turns count. The result of increased current by less turns of thicker wire (or more likely lots more thin wires in parallel) would be a higher no load maximum speed, I.e. the wheel would have a theoretical higher maximum speed, however this would be at the cost of lower torque and higher current consumption at lower speeds. Link to comment Share on other sites More sharing options...
checho Posted March 5, 2016 Share Posted March 5, 2016 There is a post by zlymex showing that the motor is physically thicker, that would indique a wider stator, which implies a stronger motor. In regards the windings I have not seen any information posted, in a few weeks once I get better at the wheel I will try some very steep off road hills and it will give me a rough idea about the torque. In regards a theoretical maximum speed I did the lift test ( test of Max speed with no load) and got 55km/h acording to the android app. Link to comment Share on other sites More sharing options...
sylvere Posted March 5, 2016 Share Posted March 5, 2016 The good part of the KS-18 800W 680w compare to KS-18 1100W 1360wh it's more managable since its lighter and also brake faster. This is my personal opinion after i drive both Link to comment Share on other sites More sharing options...
mark321 Posted March 6, 2016 Author Share Posted March 6, 2016 Thanks. I like both the theoretical discussion and the rider-experience reports. I'm still not sure which direction to go, so I guess I'll wait for now and keep browsing the discussions as more people get them. Surely the 30kph vs 40kph isn't a true top speed though, is it? According to my phone's gps-speedometer I can reach ~35kph on my KS14 800W. I know top speed would vary with conditions, but am I right to expect the KS18 800W would have a higher max speed than the KS14 800W? Link to comment Share on other sites More sharing options...
Keith Posted March 6, 2016 Share Posted March 6, 2016 10 minutes ago, mark321 said: Surely the 30kph vs 40kph isn't a true top speed though, is it? According to my phone's gps-speedometer I can reach ~35kph on my KS14 800W. I know top speed would vary with conditions, but am I right to expect the KS18 800W would have a higher max speed than the KS14 800W? There is no reason that it should be higher on the 18" as top speed is limited by software (tilt back) in order to ensure there is still enough torque available to balance the rider, I can't see that, at 800W, size of the wheel would make a big difference. Early 800W KS-14C's did have a higher software limited top speed than later models, if I've understood correctly I think it went down from 35 to 30kph. Mark321 said: "I'm tempted to upgrade since my 14" (800W 680Wh) isn't as stable on rough pavement as I'd like," How rough?, I've only got the 340Wh, 500W model and I have no problem using unmade bridleways, but I am limited to fixed 25kph max speed. If you are trying to go fast over rough roads then the 18" would certainly handle it better. Have you tried different ride settings as well? Link to comment Share on other sites More sharing options...
sylvere Posted March 6, 2016 Share Posted March 6, 2016 The calculation speed was a little wrong on the KS-18, i guess the fix it for the next shoot ? The KS-14C goes a little faster i will say a real 27km/h on the KS-18 800W 35 km/h for the KS-18 1100W Link to comment Share on other sites More sharing options...
OliverH Posted March 6, 2016 Share Posted March 6, 2016 If your EU struggle under you it's a different to jump of from a normal EU like the KS14 or a tall one like the KS18. You're more connected with your legs. Link to comment Share on other sites More sharing options...
mark321 Posted March 7, 2016 Author Share Posted March 7, 2016 As far as rough pavement on my KS14, I played a little with my ride settings initially but haven't recently. I guess I could take another look. Another avenue I hadn't thought about: does anybody know how wide a tire we can put in a KS14 (or KS18 for that matter)? It looks like mine has a 14x2.125" tire. And guesstimating I don't really feel like there's much room in there to go wider than that. I'm surprised it doesn't allow more flexibility there, as that would seem like an easy way to get more rough-terrain handling ability. I also like the idea of the KS18 being tall enough to trolley without a special handle. But I think it's still a few inches too short for that to really be convenient. Link to comment Share on other sites More sharing options...
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