more efficient hub or mid drive

Discussions related to motors other than hub motors.
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dustyearlobe   100 W

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more efficient hub or mid drive

Post by dustyearlobe » Aug 18 2013 6:11am

was thinking about how efficient my cyclones were ,im sure this is going to be already investigated in full or just be a matter of opinion or drained down to the most technical point but heres the question ,my twin cyclones get 18-19 miles at WOT (45mph fresh charge 38mph low batt)on a 24ah 12 cell 44v(50v full charge) lipo pack,seen a video of two 4500w hubs battling for supremisy 88v hitting 45mph both having done 7.5miles but using just under 1 ah a mile .can you see what im getting at yet .
so if the hub uses 88v 24ah pack to get say 30mile at WOT (being generous)
2xcyclones using same size pack but at usable voltage would be 44v 48ah pack
can you see it yet
that woud mean at similar speeds 36-38miles =more efficient
im sure there are some rc set ups getting even better figures

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Re: more efficient hub or mid drive

Post by recumpence » Aug 18 2013 6:52am

I can tell you that my bikes using 9,000 watt (peak) 3220s average 18 wh per mile at twenty mph.

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Re: more efficient hub or mid drive

Post by dustyearlobe » Aug 18 2013 7:04am

recumpence wrote:I can tell you that my bikes using 9,000 watt (peak) 3220s average 18 wh per mile at twenty mph.

Matt
hi matt how do you convert wh to ah ? (the hole in the box is getting bigger)

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Re: more efficient hub or mid drive

Post by gwhy! » Aug 18 2013 7:15am

dustyearlobe wrote:
recumpence wrote:I can tell you that my bikes using 9,000 watt (peak) 3220s average 18 wh per mile at twenty mph.

Matt
hi matt how do you convert wh to ah ? (the hole in the box is getting bigger)
Ah's x battery voltage = Wh ( total ) then wh (total)/miles traveled =wh/per mile

edit:
the wh/per mile is only a good way of working range of a battery pack IF a identical route is used by the different setups. In real terms it does not matter what the peak power output is of a system its all down to how often you use that peak power which comes down to riding style top speed and the route.

Edit2:
Nearly all my bikes (mid and hub) all workout around or just above the 1ah per mile ( on a identical route and riding style ) and this do not really change from a 2kw peak output to 15kw peak output unless traveling more than around 28 -30 mph or the total weight of the bike(and rider) is increased

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Re: more efficient hub or mid drive

Post by recumpence » Aug 18 2013 10:42am

I can tell you my wife's bike runs 20 miles on a 10 ah 44 volt pack.

Matt
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Re: more efficient hub or mid drive

Post by bowlofsalad » Aug 18 2013 12:10pm

ebike.ca/simulator Playing with this tool for a while, messing with various settings might help you gain some level of understanding things like efficiency and range.

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Re: more efficient hub or mid drive

Post by gwhy! » Aug 18 2013 1:00pm

recumpence wrote:I can tell you my wife's bike runs 20 miles on a 10 ah 44 volt pack.

Matt
Not at constant 30mph with no pedaling at all, not even to start moving off... and like i say it depends on route.. my bikes can to 100 miles on 10ah if it was all down hill :mrgreen: ... All im saying is there are just to many variables to use the Wh's or Ah's per mile ..

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Re: more efficient hub or mid drive

Post by crossbreak » Aug 18 2013 2:06pm

Since this is route dependent:
You could drive the same route with a friend who has a DD or geared hub, or whatever you wanna compare. Then compare the wh consumed for that route.

Did this with a friend who uses a Goldenmotor DD motor, and can say that even on flat routes geared motors get much better figures, when there are corners and you have to brake/accelerate frequently. My MBG geared hub consumed ~13wh/km he used 18, went about 30km at 45km/h max speed, flatt terrain.. Middrives are almost equal here, their advantage is at steep hills,that his bike would simply never climb.

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dustyearlobe   100 W

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Re: more efficient hub or mid drive

Post by dustyearlobe » Aug 18 2013 3:03pm

think we need to get a hub and middrive together for same run and speeds would be real interesting to get some real time facts

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Re: more efficient hub or mid drive

Post by John in CR » Aug 18 2013 3:58pm

Ah per mile or miles per ah are meaningless numbers without being at the same voltage. eg My bike typically gets almost 2 miles per ah, and I cruise at 35-40mph and hit 60mph or more on most rides. Of course, if I get on the highway and push it past 90mph, it really sucks down the juice. While the low ah consumption seems like I'm using little energy, the high voltage makes it misleading, because I use 50-60wh/mile typical cruising around, and that go higher we I ride fast. Wh per unit of distance is the valid unit for comparison.

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Re: more efficient hub or mid drive

Post by gwhy! » Aug 18 2013 6:17pm

John in CR wrote:Ah per mile or miles per ah are meaningless numbers without being at the same voltage. eg My bike typically gets almost 2 miles per ah, and I cruise at 35-40mph and hit 60mph or more on most rides. Of course, if I get on the highway and push it past 90mph, it really sucks down the juice. While the low ah consumption seems like I'm using little energy, the high voltage makes it misleading, because I use 50-60wh/mile typical cruising around, and that go higher we I ride fast. Wh per unit of distance is the valid unit for comparison.

I agree that ah/m is not of much use unless the voltage is stated but Wh/m is only valid for your bike and how you ride, its not a way of saying how efficient a system is unless more data is collected from the ride.

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Re: more efficient hub or mid drive

Post by jk1 » Aug 18 2013 8:23pm

Dustyearlobe

From the numbers you gave above, your dual cyclones do top speed of 45mph on 50v and you did 18.8 miles per 24 ah pack. Hence= 0.78 Miles per AH, Say your Average pack voltage is about ~ 46 volts during the ride, 46*24ah= 1104 watt hour battery pack, 1104/24 so you use 46 watt hours per 0.78 miles. which is = 58 watt hours per mile.

Now comparing the Hub that ALSO does 45mph top speed and it did 30 miles on a 30 ah pack. = 1 mile/ah For a 88v 24ah pack, say you avg voltage is 80.9v during the ride then the Total energy= 1943 watt hours battery pack, so every amp hour is 1943/24= uses 80.9 watt hours. Hence 80.9 watt hours per mile
Hence the hub uses 80.9/58, 39% more energy per mile , then you need to compare what their Average speed is on the exact same track on the same day.

If they both have the same average speed on the same track then the hub uses 39% more energy to do the exact same thing the dual cyclones do.

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Re: more efficient hub or mid drive

Post by recumpence » Aug 18 2013 8:40pm

gwhy! wrote:
recumpence wrote:I can tell you my wife's bike runs 20 miles on a 10 ah 44 volt pack.

Matt
Not at constant 30mph with no pedaling at all, not even to start moving off... and like i say it depends on route.. my bikes can to 100 miles on 10ah if it was all down hill :mrgreen: ... All im saying is there are just to many variables to use the Wh's or Ah's per mile ..
Flat ground, 20mph, no pedalling what so ever.

30 mph nets 10 miles on a charge.

I agree, there are too many variables to make sweeping judgements.

Matt
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Re: more efficient hub or mid drive

Post by Electric Junk » Aug 20 2013 6:32pm

Range feels like a pissing contest because there are so many values....an elevation algorithm would be a pretty reliable way to measure range. However instead of measuring the route, you would have to calculate the elevation gain and loss for a route.

Flat terrain is a nominal value (amps while riding flat) then any elevation gain is calculated and any downhill change is ignored.

Strava can give borderline watt outputs just by elevation change by GPS readings.

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Re: more efficient hub or mid drive

Post by recumpence » Aug 20 2013 6:49pm

I always judge range by starting in my driveway and ending in my driveway. That eliminates any elevation changes.

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Re: more efficient hub or mid drive

Post by fechter » Aug 20 2013 7:15pm

There is quite a bit of comparative data in this thread: http://endless-sphere.com/forums/viewto ... f=3&t=6615

Watt-hrs per mile is like gas mileage for a car. To test, a closed loop is best to balance out wind and hills. A steady speed is good too, and best to make measurements at various speeds. 20mph is the most common test speed. Power consumption increases exponentially with speed so 30mph uses way more than 20mph.
"One test is worth a thousand opinions"

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Re: more efficient hub or mid drive

Post by jk1 » Aug 20 2013 7:32pm

by dustyearlobe » Sun Aug 18, 2013 9:11 pm

was thinking about how efficient my cyclones were ,im sure this is going to be already investigated in full or just be a matter of opinion or drained down to the most technical point but heres the question ,my twin cyclones get 18-19 miles at WOT (45mph fresh charge 38mph low batt)on a 24ah 12 cell 44v(50v full charge)
So you used 1.3ah/mile

Dustyearlobe did you test out how a single cyclone motor compared to your dual ? what was the top speed of a single cyclone on your bike compared to dual ? and what was the range ? Is their any benefits to dual motors?

I have seen on the sphere a single 48v cyclone kits that do 45mph top speed, like this one :

http://endless-sphere.com/forums/viewto ... 28&t=48110

And this one only uses 48v 20 ah to do 65 km 40 miles range , 0.5ah/mile

So yours used nearly 3 times the energy per mile ? was their something wrong ?

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Re: more efficient hub or mid drive

Post by John in CR » Aug 20 2013 9:00pm

The comparison is invalid because typical hubmotors are too steeply geared, while the cyclone needs variable gearing of the correct reduction to function at all over the speed range you mention.

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Re: more efficient hub or mid drive

Post by rp3 » Aug 20 2013 9:36pm

Maybe something like this will be more accurate... ;)


..
Attachments
20130818_171905.jpg
......................
- BEONE HORNET PLUS - Bafang BBS02 750W -16kgs-(unpowered) - 12s 5.8Ah LiPO- 23kgs
- "Flight" DS bike - Bafang 500w rear (code11) soldered controller for 1.85kW. EM3ev triangle bag holding 14s 9Ah LiPO. CA v3. -28kgs-
- Giant Rincon 2002. Bafang 500w rear (code13) soldered controller for 1.35kW. 12s 4.5Ah LiPO. -23kgs-

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Re: more efficient hub or mid drive

Post by gwhy! » Aug 21 2013 10:52am

jk1 wrote:
by dustyearlobe » Sun Aug 18, 2013 9:11 pm

was thinking about how efficient my cyclones were ,im sure this is going to be already investigated in full or just be a matter of opinion or drained down to the most technical point but heres the question ,my twin cyclones get 18-19 miles at WOT (45mph fresh charge 38mph low batt)on a 24ah 12 cell 44v(50v full charge)
So you used 1.3ah/mile

Dustyearlobe did you test out how a single cyclone motor compared to your dual ? what was the top speed of a single cyclone on your bike compared to dual ? and what was the range ? Is their any benefits to dual motors?

I have seen on the sphere a single 48v cyclone kits that do 45mph top speed, like this one :

http://endless-sphere.com/forums/viewto ... 28&t=48110

And this one only uses 48v 20 ah to do 65 km 40 miles range , 0.5ah/mile

So yours used nearly 3 times the energy per mile ? was their something wrong ?
using A single motor may even give you worst wh/m as has been said a couple of times in this thread it has nothing to do with the amount of power you have on tap but how you use that power. With less output power you will spend more time accelerating upto a desired speed and if on a hill this can take OVER 2x longer getting upto that speed where as if you have 2x the power you will get upto speed in half or UNDER the time but this is dependant on the desired top speed and wind resistance. on one of my bikes I have 15kw on tap but if I dont use this 15kw and keep the top speed down to a sensible speed then there is very little difference in range over another one of my 3kw bikes.. there are just to many variables to compare even with a identical setup on a bike due to being ridden different,total weight or the route maybe completely different

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Re: more efficient hub or mid drive

Post by gwhy! » Aug 21 2013 4:13pm

ok I have been thinking about this a fair bit now and I am going to go out on a limb and say .. as long as either system do not start slowing down from its max flat land top speed ( if its a fixed gear i.e hub ) on the steepest hill that you need to climb then both have the same efficiency ( not sure if efficiency is the best term to use ) as this means that the current limit is not really being hit. Now if you have a mid drive that the gear ratios can be changed on the fly then even if the current limit is hit in a high gear this current limit can be reduced by selecting a lower gear ( so now the flat land top speed is reduced but the new top speed can be maintained up the hill ) . So looking at this way I would say that a mid drive with gears is more eco friendly with its Ah's than a hub (fixed gear) as there is not much you can do except increase the current limit with a hub to maintain the flat land top speed, and the longer you are at the current limit of the controller then the less miles/per wh you will get, but this can now all over spill into the other debate in another thread 'use a gear box or not' but then you also need to take into account if using a mid drive through the gears that you will be going slower up the hill so pulling more current ( but not necessary at the controllers current limit ) for longer..
.. well either way the only really positive thing is that the batteries and controller will have a easier life with a mid drive geared system.

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Re: more efficient hub or mid drive

Post by Whiplash » Aug 22 2013 8:36am

I have run a Mac 6t in wheel, then ran one as a mid drive and while I don't have exact numerical data I CAN tell you in mixed terrain there was NO COMPARISON in efficiency as the mid drive when climbing steep hills uses less than half what I used to see with the hub when climbing and it also did considerably better from a stop as long as you shift it like a motorcycle using the gears to ease power consumption spikes on takeoff.

Overall, if you want a bike to do more than one thing, run it through the gears. If you want a hi speed road race bike then single speed hub is the way to go. If you want a little of both I'm thinking high rpm single speed mid drive... with a high efficiency motor! :wink:
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Re: more efficient hub or mid drive

Post by jk1 » Aug 22 2013 8:10pm

Whiplash

Thanks for your real world expereiince that a mid drive is a lot more efficient, that's the best way to compare actualy -to swap the exact same hub motor into the middrive position and then compare


dustyearlobe

If you could just chime in with your bike , did you compare top speed and efficiency with a single cyclone on your bike compared to a dual cyclone ? was their much difference to your 45mph top speed and power consumption single vs dual motor ?

It's strange that your dual cyclone only did 45mph top speed and used nearly 3 times the energy per mile , then that single cyclone AFT kit that also does 45mph ? Was something draging ?

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Re: more efficient hub or mid drive

Post by dustyearlobe » Aug 27 2013 5:55am

jk1 wrote:
by dustyearlobe » Sun Aug 18, 2013 9:11 pm

was thinking about how efficient my cyclones were ,im sure this is going to be already investigated in full or just be a matter of opinion or drained down to the most technical point but heres the question ,my twin cyclones get 18-19 miles at WOT (45mph fresh charge 38mph low batt)on a 24ah 12 cell 44v(50v full charge)
So you used 1.3ah/mile

Dustyearlobe did you test out how a single cyclone motor compared to your dual ? what was the top speed of a single cyclone on your bike compared to dual ? and what was the range ? Is their any benefits to dual motors?

I have seen on the sphere a single 48v cyclone kits that do 45mph top speed, like this one :

http://endless-sphere.com/forums/viewto ... 28&t=48110

And this one only uses 48v 20 ah to do 65 km 40 miles range , 0.5ah/mile
So yours used nearly 3 times the energy per mile ? was their something wrong ?

I would have loved to get 45 mph on a single motor but best it will do on ether motor is 33 mph takes a bit of time getting there (no peddaling on flat)the best I ever got on a single is 18miles on a 16ah headway pack (variable terrain)
I might be able to get 50mph with a lower gear as Im now running derailleur set up with 6speed cog without the 7 locking cog (tyers to fat)but lost 6 gear as it was to near the end of the splines of the free wheel
have the old headline controlers as well could bump up the power and save 1.3kg by changing to the small kellys
I still like the thinking that im 39% more efficient (unproven :P )than equivalent power hub
as for benefits I could never go back to a single ,if I want to pedal with the bike now at any speed to increase range I simple adjust throttle to my leg speed although the motors are now running slower than peak efficaince they don't mind and will only pull a couple amps and don't get hot (24ah pack should do 40miles estimated)I can run lower voltage 12s lipo instead of 16cell equivalent and fit up to 40ah instead of only 20 in my frame ,wheelie's :oops: (not that im very good at them yet!)we have some deep bomb holes near by and by the power of two they may as well be flat .
but most of all any one in uk will be used to the damp weather (ok wet)single motor on road is ok but I wanted off road, and single motor on soft muddy lumpy ground struggled to get 25 ,now I cover the brakes on the tracks and have good enough acceleration(could always do with more thinking of the kellys)also throttle control is more responsive and smother you kind of get what you ask it for

have looked at the other thread and it looks like these figures were achieved with peddaling ?

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Toorbough ULL-Zeveigh   100 MW

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Re: more efficient hub or mid drive

Post by Toorbough ULL-Zeveigh » Aug 27 2013 7:20am

if it wasn't on video rakesh would have wrote:the motors being delivered by bosch & panasonic to me are very ineffcient.

...it is an absolute insanity to be able to use a bottom bracket system on a bicycle.

http://www.youtube.com/watch?v=Q4PQbbFSbbM#t=532


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