They're all about 12/20mph in a 26" wheel whether 36v or 48v. Only the torque is different. There's no advantage of the 48v one that I can think of unless you don't have the skills to solder the shunt up to 20A for the 36v one. Obviously, if you run the 36v one at 48v, it goes faster. I ran my 36v one with 12S (about 48v) for a while, which made it 20% faster. No problems with the 36v controller at that voltage. It's possible that the latest controllers are dual voltage with an internal jumper. I haven't looked inside yet. The previous version was tricky to put back together because of the clamp-plates on the FETs, so I don't want to touch my new 48v unless I have to, so I can't confirm that.
2 Speed Xiongda hubmotor
- Thread starter d8veh
- Start date
menvert
100 W
hmm thanks cjh that makes it much clearer, and explains why there is such a variance in results on the thread.
The standard model they'd sell me in AU would be the Europe model (15.5mph).
So my 'custom' windings are actually a stock standard US 26"
Missed this earlier, others may have more experience here, but I think with 48v it's mainly higher weight and potentially less range per kWh depending on how you use it.
em3ev seem to be very well regarded, and although those bottle batteries have some space for a small controller I do not think it'll fit either XD controller and it is best that they have air-flow, mine gets really quite hot without airflow. I recently mounted mine under my rear rack.
The standard model they'd sell me in AU would be the Europe model (15.5mph).
So my 'custom' windings are actually a stock standard US 26"
I'd do the shunt except i don't think my battery will live long @20A (it's rated 15a cont.) maybe that's why my speed is not up to your level? but adding volts is doable, hopefully by this week...d8veh said:
lowspark said:
Missed this earlier, others may have more experience here, but I think with 48v it's mainly higher weight and potentially less range per kWh depending on how you use it.
em3ev seem to be very well regarded, and although those bottle batteries have some space for a small controller I do not think it'll fit either XD controller and it is best that they have air-flow, mine gets really quite hot without airflow. I recently mounted mine under my rear rack.
cwah
100 MW
d8veh said:
Would that work nicely with a 13s or 14s battery on a 36v controller? I don't want to blow that if i buy one.
You mentioned that it doesn't work so well overvolted, is it still the case?
Thanks for the responses guys. Previously I underestimated how much faster the motor would run in high over low. Although the info was here in the thread, somehow I distorted the numbers but I have a much better understanding now.
I am intrigued with the idea of a single speed bike even though I live in a very hilly area - maybe I am a bit of a contrarian - but it seems like that motor in low, in a 36V 15 (raised to 20?) or 48V 15 version should get me up just about anything, especially if I am willing to pedal. In my initial thoughts I figured I could climb in low at 12 mph and run in high at 16 mph and ride unassisted at 18 mph. But I like the correct values of 12 mph in low and 20 mph in high and being able to use the motor to take me a little faster, up to 20 on that single speed. 20 mph is plenty fast for me, riding mainly in town, although I definitely think those higher speed set ups some of you have built are very cool. Again I am willing to pedal through the range, I just want the motor to make it easier - especially on those hills. Alternatively I could mount the front hub version and put a three speed IGH on back, which has some advantages too. I'll have to think about that one a little more.
I am intrigued with the idea of a single speed bike even though I live in a very hilly area - maybe I am a bit of a contrarian - but it seems like that motor in low, in a 36V 15 (raised to 20?) or 48V 15 version should get me up just about anything, especially if I am willing to pedal. In my initial thoughts I figured I could climb in low at 12 mph and run in high at 16 mph and ride unassisted at 18 mph. But I like the correct values of 12 mph in low and 20 mph in high and being able to use the motor to take me a little faster, up to 20 on that single speed. 20 mph is plenty fast for me, riding mainly in town, although I definitely think those higher speed set ups some of you have built are very cool. Again I am willing to pedal through the range, I just want the motor to make it easier - especially on those hills. Alternatively I could mount the front hub version and put a three speed IGH on back, which has some advantages too. I'll have to think about that one a little more.
You got that pretty well figured except the real life speeds. 12/20 mph is the maximum speed that the motor will spin. When climbing a steep hill, speed will be 8 mph or less. It helps to have a bike with triple chainwheels on the front so that you can gear right down for the very steep hills if you want to keep a high cadence. I can do hills about 20% incline with my 42T chainring. For the 31% one I had to use the granny ring (22T). Speed was down to about 4mph or less. On the flat with medium pedalling, my cruising speed is about 18mph using the PAS. With throttle, it goes a tiny bit faster. Note that this is the old non-sinewave controller. I have to build a 48v battery before I can try my new sine-wave one.
There is no 15.5 mph version for the European market. I've never heard of anybody reporting that speed. If you want to be legal in Europe, you set the speed limit to 25km/h in the LCD.
To answer Cwah's question: The problem with over-volting is that the automatic gear-change happens at a proportionally higher speed. You can still use the manual gear-change to keep it in the right gear though. I don't really see the point of overvolting it. In high gear it has about the same power and speed as 250 rpm Bafang SWX. With 12S, it'll have enough torque to get a light-weight guy like you up most hills in high gear, so you might as well get a single-speed motor. Although a bit heavier, the Bafang BPM is a lot torquier, stronger and faster. The Q128H is about the same weight as the Xiongda. I've got a feeling it's a hidden gem, but nobody has tried it yet. The main advantage of the Xiongda is that it can drag heavy, weak or lazy people up hills with minimal power. When you want to use more power, there's better options.
There is no 15.5 mph version for the European market. I've never heard of anybody reporting that speed. If you want to be legal in Europe, you set the speed limit to 25km/h in the LCD.
To answer Cwah's question: The problem with over-volting is that the automatic gear-change happens at a proportionally higher speed. You can still use the manual gear-change to keep it in the right gear though. I don't really see the point of overvolting it. In high gear it has about the same power and speed as 250 rpm Bafang SWX. With 12S, it'll have enough torque to get a light-weight guy like you up most hills in high gear, so you might as well get a single-speed motor. Although a bit heavier, the Bafang BPM is a lot torquier, stronger and faster. The Q128H is about the same weight as the Xiongda. I've got a feeling it's a hidden gem, but nobody has tried it yet. The main advantage of the Xiongda is that it can drag heavy, weak or lazy people up hills with minimal power. When you want to use more power, there's better options.
menvert
100 W
I haven't seen that table for 48v if that's what you mean, That would be useful as it's not clear how the windings are on the 48v (could be wound for the same max rpm as a 36v or could be set faster as seems to be the case with some on this thread)lowspark said:
Regarding your other comment - I think It'll probably be hard to get a good single speed setup as the speed range is huge, I'd seriously consider front motor and IGH, 3 speed chain-wheel sounds like a good plan too but you'd then still need derailleur/tensioner, so depends why you want single speed? is it for the stealth simplistic build?
I believe the windings for the 48V are the same as for 36V.
When I ordered one for a 700c wheel, I've been told that it wound for 270 RPM.
I asked for 280 since I wanted to get to about 35 km/h on flat w/ pedal assist.
As far as the battery goes, I've ordered
http://www.victpower.cn/product/2002749789-214365529/For_E_bike_QT_battery_48v_11_6ah_lithium_ion_pack.html
Motor and battery are still on it's way (I hope), so I can't say much more.
-Ed
When I ordered one for a 700c wheel, I've been told that it wound for 270 RPM.
I asked for 280 since I wanted to get to about 35 km/h on flat w/ pedal assist.
As far as the battery goes, I've ordered
http://www.victpower.cn/product/2002749789-214365529/For_E_bike_QT_battery_48v_11_6ah_lithium_ion_pack.html
Motor and battery are still on it's way (I hope), so I can't say much more.
-Ed
menvert
100 W
Ah cool, I did wonder as I'd seen suggestions that XD say the 48v goes faster, what did they charge for the battery?ktmede said:
By the way menvert - that is a nice bike that you built up.menvert said:
Yes you are correct, I am interested in comparing the 48V table to the 36V to get a better understanding of the difference between the two. On the one hand I hear the 48V has more power, on the other hand I hear that they have similar top speed but if more power means more low speed torque that is useful for my purposes.
The single speed range requirements may indeed be too great. I am trying to get a handle on unassisted climbing with a given weight of the bike and rider - the corresponding slope and speed. Ideally I could gear the bike and spin at a cadence of 90 and go 18 mph and spin at 60 and go 12 mph. but I would be okay with maybe knocking the speed down to 16 mph @ 90 and 10.7 mph @ 60 - on level ground, unassisted. What I am trying to figure out is what kind of slope that motor will get me up if I spin @ 60 without working too hard. I can ride up any hill in Seattle now unassisted but some of them are tough work and slow going and I don't like to be drenched with sweat if I am going to be walking into a meeting so I end up taking the bus or driving instead.
The infatuation with the single speed is partly what you suggest and partly curiosity. I think it would be very cool to have a simple drive train, no shifters (except for the 2 speed hub motor), no derailleurs, single chain ring. A pure simple single speed bicycle with a clean look, light enough to easily lift or carry but because of the electric assist, enable this aging cyclist to tackle most climbs in a very hilly city. Without electric assist I would never dream of getting a single speed in Seattle although I do see some who make that choice - perhaps they ride different routes or are much more fit.
I'll probably give it a go, and if it doesn't work out can add a front derailleur, another chain ring or two, a tensioner, switch to a chain more suited to flex etc. But if the numbers are not encouraging before I take the plunge I think I might try a 3 speed IGH and a front hub motor instead.
ktmede said:
ktmede - that battery looks very similar but more affordable (shipping?) than the one that I was looking at.
I know little about electric motors. If the windings are the same for the 36V and 48V motors, how would performance differ (sorry about the simple question and I have been pouring over info but seem to sometimes get conflicting info from knowledgable people.)? Would it be faster? Would it have more torque? If I order a motor for a lower speed will it have more torque than a higher speed motor or will torque be the same but speed is simply limited? Thank you.
menvert
100 W
lowspark said:
Yeah I hear ya, I was quite confused when I came to order mine (and in some ways I still am). In the end I ordered the specific RPM I wanted, although I overestimated the difference between loaded and unloaded max RPM, so it's a bit slower than I planned.
re: 36v or 48v, my understanding that I hope is more or less accurate;
If they are the same windings EG: 270rpm, then the 48v will have a better top speed in both gears, and I think it'll have better torque through the whole range too, because it's more watts.
If they are both setup for the same top speed (eg: 20mph unloaded) then they will each have different edit: [strike]RPM[/strike] Windings and on the 48v that will mean more torque and acceleration but same top speed...
Given what ktmede said I think we are dealing with case #1, however there are conflicting experiences, so you could confirm or order the specific winding to suit what you actually want - more torque (lower RPM) or more speed (higher RPM)
You can then calculate speed by using - tyre circumference (in meters) x RPM x 60 /1000 to get kmh, then convert to miles (there is probably another way to do it in imperial directly)
Though when I ordered mine, the default is 25kmh loaded (Because I am AU) Yona seemed to want to talk in terms of max loaded speed rather than RPM, maybe that would have been easier
Whilst I haven't dissected these motors, I can explain by way of a postulated example what the probable difference is between the 48v and 36v motors. The 36v with 16 turns of 6-strand wire and the 48v with 12 turns of 8-strand wire. Both motors would have 96 loops of the same diameter wire around the poles, so would be visually and dimensionally the same. They would rotate at the same maximum speed. The controllers would deliver the same maximum current, say 15A, so the 48v one would give 30% more power. As the speed is the same, that difference would be in the torque, so the 48v one would be able to give approximately 30% more torque for the same current. If you increase the current of the 36V one to 20A, the two motors would perform more or less the same.
menvert
100 W
Good luck with it, it was my other option, but this motor suited better as I can't maintain the 60-90 RPM cadence that the BBS's run efficiently at and being crank speed, you cant change it by different bike gears, though maybe you can get alternative rpm models, but it didn't seem so when I investigated (i mean you don't really need to cater for wheel sizes with a mid drive)lowspark said:
You can even go stealth-ish with an 8 speed IGH with them
I actually got my extra 3.7 volts added in for this mornings commute, so now hovering around 42volts @ medium load.
Now it runs like I expected! comfortably sitting on 20mph on flat no pedaling.
menvert - I am pleased to hear that the added volts provided the necessary boost to get the performance that you had hoped for.
I think that BBS02 option is very nice and would probably work out well - fortunately I think I can match the required cadence - but I am thinking the XD motor is the way I will go. The BBS02 would get me up the hills and would provide a higher top end, but that top speed is really not important to me and I know the energy required increases exponentially with speed as you get up in the 20s which leads to more battery needed, more weight if you really want to run at those speeds much. I prefer the simplicity of the hub motor set up but it takes a little more effort, it seems, to spec the appropriate set-up.
I like the idea of having a perfect chainline and never shifting (except for the two speeds of the XD and I suspect that I will operating in high most of the time). With my target of 18 mph @ a cadence of 90 I am going to spec a 44t chainring and 17t cog. I will probably investigate this further because if I go with a larger chainring and cog I can still hit my 18 mph @ 90 target and the the drive train will last longer. In any case, the drive train will last much much longer than with a BBS02.
I have taken a closer look at that 36V table and I am trying to see if i can interpret it and apply it to the real world - anyone please correct me if I am wrong. I am planning to build my bike with 650B rims and 38mm (or maybe 42mm tires). I have calculated the corresponding speed in mph for a given rpm of the motor for wheels and tires of that size. For example, when operating in low, near the peak efficiency value, the XD turns 116.6 rpm and puts out 151.9 W, operates at an efficiency of 82.9 and the corresponding speed on the bike would be 9.0 mph. Does that more or less mean that for the conditions of slope, wind, etc. if X watts are required to go 9.0 mph, I need to provide X-151.9 watts and the XD provides 151.9?
I think that BBS02 option is very nice and would probably work out well - fortunately I think I can match the required cadence - but I am thinking the XD motor is the way I will go. The BBS02 would get me up the hills and would provide a higher top end, but that top speed is really not important to me and I know the energy required increases exponentially with speed as you get up in the 20s which leads to more battery needed, more weight if you really want to run at those speeds much. I prefer the simplicity of the hub motor set up but it takes a little more effort, it seems, to spec the appropriate set-up.
I like the idea of having a perfect chainline and never shifting (except for the two speeds of the XD and I suspect that I will operating in high most of the time). With my target of 18 mph @ a cadence of 90 I am going to spec a 44t chainring and 17t cog. I will probably investigate this further because if I go with a larger chainring and cog I can still hit my 18 mph @ 90 target and the the drive train will last longer. In any case, the drive train will last much much longer than with a BBS02.
I have taken a closer look at that 36V table and I am trying to see if i can interpret it and apply it to the real world - anyone please correct me if I am wrong. I am planning to build my bike with 650B rims and 38mm (or maybe 42mm tires). I have calculated the corresponding speed in mph for a given rpm of the motor for wheels and tires of that size. For example, when operating in low, near the peak efficiency value, the XD turns 116.6 rpm and puts out 151.9 W, operates at an efficiency of 82.9 and the corresponding speed on the bike would be 9.0 mph. Does that more or less mean that for the conditions of slope, wind, etc. if X watts are required to go 9.0 mph, I need to provide X-151.9 watts and the XD provides 151.9?
menvert
100 W
The trouble with that table, is that it's unclear what load is being applied on any given row.
The row with 116.6 rpm is actually only 5A, so that's only drawing 1/3 power so I'd assume it's not very loaded, I usually see about 5A full throttle on flat
I don't believe it's as simple as double load needs double watts or amps, to maintain a particular rpm, maybe someone here knows the physics of it better?
To give you a real world example (on my normal 36v battery) On my steepest hill, I get about 15kmh in low, which is.... about 112 RPM and drawing about 12.5A/450w from the battery (the engine will see less based on efficiency)
The row with 116.6 rpm is actually only 5A, so that's only drawing 1/3 power so I'd assume it's not very loaded, I usually see about 5A full throttle on flat
I don't believe it's as simple as double load needs double watts or amps, to maintain a particular rpm, maybe someone here knows the physics of it better?
To give you a real world example (on my normal 36v battery) On my steepest hill, I get about 15kmh in low, which is.... about 112 RPM and drawing about 12.5A/450w from the battery (the engine will see less based on efficiency)
cwah
100 MW
d8veh said:
but my point is not to be able to go over hill, but to be more efficient under acceleration. On city commuting, my BBS02 is way more efficient than my BPM because I do a lot of start and stop. On my bbs I most of the time stay on low gear so it doesn't go fast but start fast which is what I need.
Maybe it could be the same principle with the xiondga
lowspark said:
You got everything just about right. One thing to bear in mind though: At peak efficiency, you're fairly well past peak power. Peak power comes at approximately 2/3 maximum speed, i.e. about 20km/h with an efficiency of about 70% in top gear and 7 mph in low gear. I would have thought that you need power rather than efficiency in low gear for hill-climbing.
Yes, you are correct d8veh. Hill climbing power is what I am looking for although knowing the speed at which the motor is most efficient may be useful if one wants to pedal a bit harder to hit that speed on a long climb to extend battery life.
menvert points out that the load must be considered. I was thinking that whatever energy I put in would compensate for that load but there is probably more to it than that.
I was playing around with this calculator to try to get a rough idea of the speeds I might be able to climb at, and/or the effort that I would have to expend, to climb various slopes:
http://www.gribble.org/cycling/power_v_speed.html
I don't know how close my results were to reality but they were encouraging. Feel free to tell me that these numbers don't seem realistic or match with your experience but it appeared that I could climb:
a 5% slope in high at 12 mph (or low at 8.3 mph)
an 8% slope in low at 7.5 mph
a 10% slope in low at 6.6 mph
a 14% slope in low at 6.2 mph
From what menvert says, he is able to climb very steep hills without peddling, even though speed drops very low, around 4 mph or so. So maybe the climbing speeds would be lower that what I calculated. Those speeds were unassisted but I also looked at the speed if i added 100 watts of my power, which would be my target effort. I guess the main thing, which is probably already obvious to all of you is that at very low speeds the motor is still putting out 350 watts and not shutting down which as I understand is the problem with single speed hub motors that are typically set to run at about 20 mph.
menvert points out that the load must be considered. I was thinking that whatever energy I put in would compensate for that load but there is probably more to it than that.
I was playing around with this calculator to try to get a rough idea of the speeds I might be able to climb at, and/or the effort that I would have to expend, to climb various slopes:
http://www.gribble.org/cycling/power_v_speed.html
I don't know how close my results were to reality but they were encouraging. Feel free to tell me that these numbers don't seem realistic or match with your experience but it appeared that I could climb:
a 5% slope in high at 12 mph (or low at 8.3 mph)
an 8% slope in low at 7.5 mph
a 10% slope in low at 6.6 mph
a 14% slope in low at 6.2 mph
From what menvert says, he is able to climb very steep hills without peddling, even though speed drops very low, around 4 mph or so. So maybe the climbing speeds would be lower that what I calculated. Those speeds were unassisted but I also looked at the speed if i added 100 watts of my power, which would be my target effort. I guess the main thing, which is probably already obvious to all of you is that at very low speeds the motor is still putting out 350 watts and not shutting down which as I understand is the problem with single speed hub motors that are typically set to run at about 20 mph.
Alan B
100 GW
I've done some measurements with my DD hub and found that I can pedal at 500W for helping on short hills. I estimate this by dropping throttle as I pedal hard and keeping the speed the same while watching the battery power drop.
It is important to keep the speed up since significant heating will occur if motor RPM is too low.
It is important to keep the speed up since significant heating will occur if motor RPM is too low.
That all sounds about right. I weigh 100kg, and my 36v one can easily take me up a 15% hill at 20A without pedalling (26" wheels). It could just do it at 15A, but the motor was struggling. I don't pedal too hard, which gives me about 18mph on the flat. If I pedal with a bit of purpose, I can probably sustain 20 mph, so your cadence of 90 at 20 mph will be about rightlowspark said:
mountain biker
100 W
- Joined
- Sep 26, 2014
- Messages
- 244
yeah I would like to see some data sheets for their 24 volt stats and 48 volt stats....and the magic question still remains unsolved...what was the load they used on the 36 volt...150 pound man on flat ground.???
