Nine Continent Vs. Bafang

[johnrobholmes]

The controller can make a lot of vibration (through the motor). My shenzen controller makes random pings and vibrations, while my Castle controller runs silent after about 4 mph.

 

[Microbatman]

Both are made with really thick mild steel lamination, the most inefficient stator material available. Both probably use N36 magnets as they are readily available and cheap. I can't effectively measure the stator gap on them as without the side cover on the stator flops to one side.

John

How much of a difference to you think it would make using high quality materials?
In other words how much more potential do these motors have?
Lets say we
#1 Used some N45-N50 range magnets
#2 Used some quality .35mm M14 C5 Silicone steel laminations
#3 Quality bearings that allowed the airgap to be thinned.

No need to run simulation program to answer my question. Just looking for your opinion about how much more room for improvment these things have.

 

[Rassy]

I'm using 48V LiFePO4 with my Bafang. Still all nylon gears. No vibration, just a whine under load. On a ride last weekend there was a 1/2 mile hill that exceeded 15% grade. Full throttle and hard pedaling got up the hill at about 7 MPH. Many of the road bike guys pushed part way up this hill (I was the only electric assist bike out of more than a hundred on the ride). No over heating issues. My recumbent currently weighs about 80# and I weigh about 215#, so it's about the same total weight as Docnjoj. Watts Up on the battery shows a max of about 23 amps. I have the "slower" Bafang that is made for 26" wheels laced into a 20" wheel and it tops out at about 15 MPH. The motor, controller, and lacing were provided by JohnRobHolmes. This is just the perfect setup for long distance rides with pedal only guys. I used under 15AH for 50 miles with just moderate pedaling, except for the few very steep hills.

 

[Russell]

Maybe the vibration is a problem with my motor then. I am changing my plans since the 9C is working well on my Raleigh I'm going to lace the Bafang into a 700C Rhyno Lite rim and use it on my Kona Smoke 2-9. We'll see how the little motor performs with some even bigger tires

-R

 

[docnjoj]

Docnjoj,

Does your motor vibrate under a heavy load? I like the Bafang but the vibration that I can hear and feel bugs me. I'm wondering if it's just my motor or if it's Bafangs in general that do this. The spokes are all nice and tight and the wheel runs true.

-R

Very little vibration now.It used to be really bad with the old analogue Crystalyte 36-72 volt. Ecrazyman controller fixed that!
otherDoc

 

[johnrobholmes]

John

How much of a difference to you think it would make using high quality materials?
In other words how much more potential do these motors have?
Lets say we
#1 Used some N45-N50 range magnets
#2 Used some quality .35mm M14 C5 Silicone steel laminations
#3 Quality bearings that allowed the airgap to be thinned.

No need to run simulation program to answer my question. Just looking for your opinion about how much more room for improvment these things have.

Magnets won't do much for efficiency, but if everything else is optimized a point or two could be had.
Good laminations with the right shape would boost the efficiency a TON, probably 10% from where these motors sit.
Better bearings and airgap would give a few more points.

Just by looking at the construction I would say these motor may hit 65 or 70% eff. I wouldn't be surprised if it was lower though. Without modeling the motor or hooking it up to a dyno it is a seat of the pants guess.

 

[Russell]

Just by looking at the construction I would say these motor may hit 65 or 70% eff. I wouldn't be surprised if it was lower though. Without modeling the motor or hooking it up to a dyno it is a seat of the pants guess.

The Bafang website rates the motors as 78-80% efficient. My own guess is that with the freewheeling hub they are as efficient on the bike as the best direct drive. So far I have gotten the best energy efficiency with the Bafang in the low 6Wh/mi on long rides averaging 16.5mph. The 9C is very difficult to ride at those speeds because it wants to go faster however I have managed 6.9Wh/mi with the 9C though 8.0Wh/mi is more the norm. If I used the Bafang on 48V to match the speed of the 9C at 36V I'd probably get closer results. Still the long distance champ for me is the Bafang at 36V riding with moderate+ pedaling.

-R

 

[tostino]

Is there anything at all we can do about the laminations to improve efficiency?

Would re-winding the motor have any effect? I bet they are they pretty well wound as it is though, so it may not make a difference.

What user-changeable things can be done to boost the performance and efficiency of this motor John?
Edit: Keep in mind I don't have mine yet, it's in the mail still.

 

[WonderProfessor]

The 9C is very difficult to ride at those speeds because it wants to go faster however I have managed 6.9Wh/mi with the 9C though 8.0Wh/mi is more the norm.

Stupid Questions Alert!

How do you translate 6.9Wh/mi? Is that 6.9 watt-hours per mile? (watts = volts * amps, right?) What relation does that have to amp-hours per mile? Using a 36-volt, 20 amp-hour battery, how many miles would that translate into?

Still trying to figure out how to interpret reported results while figuring out the best configuration for electrifying my 'bent,

WonderProfessor

 

[tostino]

Amp hours is a measure of energy stored. So volts (36v) * amp hours (20ah) = watt hours (720 Wh).

So at 6.9 watt hours pr mile, you would be able to go roughly 102 (720/6.9) miles pr charge at 100% DOD. 6.9wh/mile is not an easy value to achieve. Expect more like 15-20wh/mile.

Hope that helps!

Edit: Amp hours pr mile is not a good measure! Don't use it or pay attention to it please, it is only comparable to other users with the same voltage battery pack.

 

[Russell]

Amp hours is a measure of energy stored. So volts (36v) * amp hours (20ah) = watt hours (720 Wh).

So at 6.9 watt hours pr mile, you would be able to go roughly 102 (720/6.9) miles pr charge at 100% DOD. 6.9wh/mile is not an easy value to achieve. Expect more like 15-20wh/mile.

Wh/mi in the 6's is pretty easy to do with a Bafang at 36V with a 15A controller since this motor/battery combination produces a top speed in the low 17 mph range unassisted (700Cx35 tire/255 lb load). This means when conditions are favorable, down grade or tailwind, I'm often exceeding that speed on my own with no or minimal assist from the motor even at full throttle. Because of the lower speeds (generally 16-17mph) the overall energy requirement per mile is lower and my pedaling input is more significant.

Since the 9C is wound for higher speeds it's more difficult to ride near my normal cycling speed, to do so requires a good deal of restraint using the throttle. when I set out on a ride I pretty much know how far I'm going to travel and I use the throttle accordingly. I have gotten the hang of it and with self control can maintain around 16.5-17.0 mph with the 9C and get efficiencies under 8 Wh/mile. The most I've ever used was a no holds barred full throttle ride where I used 14.7 Wh/mile at a trip average of 20.8 mph. This was with a 15A controller and a LiMn pack charged to 41.3V.

Edit: Amp hours pr mile is not a good measure! Don't use it or pay attention to it please, it is only comparable to other users with the same voltage battery pack.

Exactly! Watt-hours/mile is a much better measure of energy use unless someone specifically states the voltage along with the Amp-hour data they present.

-R

 

[tostino]

I won't be using a 15a controller, and will be running 51v with delta/wye, so i bet my wh/mile will be a little higher. its really good to see how well it works for you though, and your wh/mile seems very good!

 

[Zoot Katz]

Russell's Wh/mi data is an outlier. He pedals a lot and adds substantial energy to the equation. How it's measured and calibrated is another factor.

My setup is quite a bit different. It was specified for a 60 kilometer range. It's an X5304 with a 48A start immediate controller. On 48 volts, it will do 43 kmh. Figuring 10-12 Wh/km usage, I went for an 18Ah NiMh pack just in case I picked up a hitch hiking honey on the way home. As a result, I've gone over 100km on a single charge. My Wh/km has averaged around eight. That would be about thirteen Wh/mi. Justin set-up and calibrated my CA for this controller. I pedal 120 lbs. bike just enough to get in the aerobic zone. It looks and feels stupid to not pedal uphill.

Because I live and ride in a hilly city, I'm only using the motor half the time. Stop and go traffic sucks the amps though. My average speed on the loaded Xtracycle is the same as my average speed on the skinny tire commuter. That's all I wanted though le Béte will exceed that speed up the lumps I'd usually detour. A long distance ride uninterrupted by traffic control signs and signals would yield better results for both average speed and consumption. I ride conservatively except when I'm smoking scooters.

Russell's review has me thinking about a lighter bike equipped with a 9C and smaller short-haul batteries.

 

[tostino]

I'm kinda getting the feeling that John has me on block. He hasn't responded to anything i've said on a couple threads now.

 

[WonderProfessor]

So, Friends, let's see if I am completely out to lunch. I have a 20-mile mostly flat (with a killer hill right at the end) commute and would be more than happy to cruise at 20 miles per hour on the flat while still pedaling. Given the numbers that have been thrown around, does that mean I can reasonably rely on using around 20 watts per mile? If I can reasonably rely on 20 watts per mile, then a 48-volt, 10-amp hour battery (from pingbattery.com) should be able to get me 20 miles. I can recharge at work. (My calculations say I should be able to go 24 miles but the census of opinion is that you don't want to discharge the battery more than 80%.)

Many thanks for all the help you have all given.

WonderProfessor

 

[Russell]

So, Friends, let's see if I am completely out to lunch. I have a 20-mile mostly flat (with a killer hill right at the end) commute and would be more than happy to cruise at 20 miles per hour on the flat while still pedaling. Given the numbers that have been thrown around, does that mean I can reasonably rely on using around 20 watts per mile? If I can reasonably rely on 20 watts per mile, then a 48-volt, 10-amp hour battery (from pingbattery.com) should be able to get me 20 miles. I can recharge at work. (My calculations say I should be able to go 24 miles but the census of opinion is that you don't want to discharge the battery more than 80%.)

Many thanks for all the help you have all given.

WonderProfessor

Hills, wind, speed and to a lesser extent weight are all things which can zap your power whether you're riding a regular bike or an ebike. On the flats with no wind you'll be able to maintain 20 mph easily using maybe 10 Wh/mi. Add a moderate 10-15 mph headwind to the mix and try to maintain that same speed and you'll probably consume 20 Wh/mi. Now hit a "killer hill" and watch your energy consumption soar. If you hold full throttle up a decent grade you'll easily peg the current limit on your controller. Let's say the hill is 1 mile long and you climb it at 12 mph at 20A on a 48V battery, that's 960W x 0.083 hrs or 80 Wh for just that 1 mile. So if you start with 480Wh (48V x 10Ah) and want to limit the DOD to 80% then you have 384 Wh to play with. Subtract the 80Wh for the one big hill and now you're down to 304 Wh and if you consume 20 Wh/mi you'll go 15 miles for a total of 16 miles with the killer hill included. Now maybe a mile long hill isn't what you face but the calculation sure shows what just 5 minutes of maximum power will do to your energy reserves, it's also one of the reasons there is no clear-cut answer to the question "how much battery do I need?" since everyone's needs are different.

I'm contemplating the purchase of a 48V/10Ah (or 36V/15Ah) LiFePO4 battery as well ( I have 36V/6Ah now) but I already know how much energy I use. Even then there is no one right answer since I figure I can go anywhere between 26 and 64 miles with either of the choices depending which bike I ride and how fast I go. Personally I'd say you'll be fine with the 48V/10Ah but since you will be tempted to open 'er up you'll likely get better range with a 36V/15Ah instead, which is why I might stick with 36V.

-R

 

[jag]

I pedal 120 lbs bike just enough to get in the aerobic zone. It looks and feels stupid to not pedal uphill.

Russell's review has me thinking about a lighter bike equipped with a 9C and smaller short-haul batteries.

Having just built a bike with 9C 2709 and 72V 8ah NiCd batteries, I'm thinking a BMC 600W or BMC/Ezee 400W at 48V
with lithium batteries would be a nice 10-12kg weight reduction. My bike weighs 32kg, which is not unwieldly when riding,
but a chore to carry up even small stairs or obstacles I tend to encounter.

When I visited ebikes.ca in Vancouver I test rode their EZee equipped bike. Nice and light, but could use a few more
volts than the 36V it comes with standard. With an even lighter bike to start with, it should be possible to build a
good performance (40-50km/h, 30-40km range) weighing no more than 15-20kg.

Martin

 

[WonderProfessor]

Personally I'd say you'll be fine with the 48V/10Ah but since you will be tempted to open 'er up you'll likely get better range with a 36V/15Ah instead, which is why I might stick with 36V.

Well, you've convinced me to go with at least the 48 volt, 15 amp-hour battery and maybe even go with my initial idea of getting the 48 volt, 20 amp-hour battery. I'd rather err on the side of more power since I plan to use this thing for a long, long time if all goes well. The only problem is the more amp-hours, the bigger and heavier the battery. But still, 20 pounds for a 48 volt, 15 amp-hour battery is pretty darned good. Couple that with an eZee motor which is only about 10 pounds and that's an extra 30 pounds. My bike is supposed to be able to handle 300 pounds. I weigh 200 pounds.

I'm also agonizing over my choice of motors. I really like the eZee hub motors (and the Nine Continents, too, but I like the eZee more) from ebikes.ca because of the reported reliability and stealth. The midrange, external motors are pretty darned tempting, also, because of the ability to use your gearing with the motors. But they are not stealthy, to be sure. Most all peace officers will not give you a second look, I am certain. But one day, some officious jerk -- probably a woman police officer for who you look like her ex-husband, the big jerk -- will give you a really hard time for having a motor that goes over 20 mph. ebikes.ca now offers the StokeMonkey which looks pretty darned interesting and given ebikes.ca's reputation, I'm sure they are well-built and reliable and should last a good long time.

Decisions, decisions, decisions.

 

[dnmun]

stoke monkey is made here in portland by cleverchimps.com so you can see more of them there.

 

[dogman dan]

It''s hard to have too much battery. Extra range has a way of finding fun ways to use it on the weekend. But carrying the thing day in and day out can be hard for some sizes. The 48v 20 ah in particular, has caused some to have problems with bike handling, or just finding a good box to carry it in. With the pingbattery packs, the 48v 15 ah size , or the 36v 20 ah size are pretty nice. 15 or so pounds, and fits in a lot of avaliable toolboxes, and in the triangle of some bikes. It's a good size, garanteed to get you 20 miles at speeds faster than 20 mph, and further depending on rider , wind, and speed. My personal best on the 36v 20 ah and an aotema brushless, is 39 miles riding about 15 mph, on mostly flat ground.

 

[Russell]

My personal best on the 36v 20 ah and an aotema brushless, is 39 miles riding about 15 mph, on mostly flat ground.

A few days ago I rode 37.86 miles using 6.10Ah or 5.9Wh/mile at an average speed of 16.1 mph. It was a mix of slower city bike path and country roads with some rolling hills. I used the throttle most of the time until at 32 miles I saw I had consumed 5.4Ah and had a ways to go yet to get home. I pedaled more than I wanted to the last 6 miles and like the little battery pack was pretty much drained myself after 2 1/3 hours on the bike without stopping or eating. This is the lowest energy I've ever used with the Nine Continent motor. Yesterday was a more normal ride doing a flattish 22.95 miles at 17.5 mph using 5.02Ah or 8.1Wh/mi. I must say it's fun accelerating from a normal cruise speed up to the low 20's even with a half-used battery. It takes a lot of self-control to keep the speed down. Usually however I ride into the wind first and if I'm a good boy and save my energy the ride home with the wind and using more throttle is the reward

The 9C will be staying on the Raleigh and the Bafang is now on my Kona Smoke which is nearly complete. Ya know it's funny when I read that someone installed a motor kit on their bike in an hour or two, heck it took that long for me to grind down the torque washers so they would fit with the lawyer lips in place!

-R

 

[Russell]

I laced my front Nine Continent motor into a new rim and while it was out of the original rim I thought I'd answer that nagging question "how much does a 9C weigh?".

The answer: 12 pounds 10.2 ounces or 5.730 Kg




I weighed my Bafang motor before I laced it up too and it was 7 pounds 2 ounces or 3.2 Kg with the cable and supplied hardware.


-R

 

[Russell]

Today I added a 12V SLA (13V) in series with my 36V (41V) LiMn pack (54V to start) and the Bafang bike obtained the same top speed as the Nine Continet bike at 36V (41V to start), 23.5 mph. http://www.endless-sphere.com/forums/viewtopic.php?f=4&t=10458#p162238

-R

 

[DahonElectric]

So, Friends, let's see if I am completely out to lunch. I have a 20-mile mostly flat (with a killer hill right at the end) commute and would be more than happy to cruise at 20 miles per hour on the flat while still pedaling. Given the numbers that have been thrown around, does that mean I can reasonably rely on using around 20 watts per mile? If I can reasonably rely on 20 watts per mile, then a 48-volt, 10-amp hour battery (from pingbattery.com) should be able to get me 20 miles. I can recharge at work. (My calculations say I should be able to go 24 miles but the census of opinion is that you don't want to discharge the battery more than 80%.)

Many thanks for all the help you have all given.

WonderProfessor

Hills, wind, speed and to a lesser extent weight are all things which can zap your power whether you're riding a regular bike or an ebike. On the flats with no wind you'll be able to maintain 20 mph easily using maybe 10 Wh/mi. Add a moderate 10-15 mph headwind to the mix and try to maintain that same speed and you'll probably consume 20 Wh/mi. Now hit a "killer hill" and watch your energy consumption soar. If you hold full throttle up a decent grade you'll easily peg the current limit on your controller. Let's say the hill is 1 mile long and you climb it at 12 mph at 20A on a 48V battery, that's 960W x 0.083 hrs or 80 Wh for just that 1 mile. So if you start with 480Wh (48V x 10Ah) and want to limit the DOD to 80% then you have 384 Wh to play with. Subtract the 80Wh for the one big hill and now you're down to 304 Wh and if you consume 20 Wh/mi you'll go 15 miles for a total of 16 miles with the killer hill included. Now maybe a mile long hill isn't what you face but the calculation sure shows what just 5 minutes of maximum power will do to your energy reserves, it's also one of the reasons there is no clear-cut answer to the question "how much battery do I need?" since everyone's needs are different.

I'm contemplating the purchase of a 48V/10Ah (or 36V/15Ah) LiFePO4 battery as well ( I have 36V/6Ah now) but I already know how much energy I use. Even then there is no one right answer since I figure I can go anywhere between 26 and 64 miles with either of the choices depending which bike I ride and how fast I go. Personally I'd say you'll be fine with the 48V/10Ah but since you will be tempted to open 'er up you'll likely get better range with a 36V/15Ah instead, which is why I might stick with 36V.

-R

Russell,

Aerodynamic plays a big part riding on the flats, especially when you're exceeding speeds of up to 25km/h, whereas weight plays a big part climbing hills. Conceivably, if you want to conserve energy (watts output) on the flats, you would install aero wheels to try and cut down the drag, change the bike geometry and the size of the bike itself so you are more aerodynamic like a triathlete. That way, you can maintain high speeds, but require less energy per watt. Tire pressure and the tires used themselves can and will effect the power usage too, but to a very small effect.
As for the hills, the heavier the bike is, the more power you need to push it up. However, the motor size and the ability of the controller to deliver the needed current and the size of the battery can conceivably destroy all these variables to give you longer range and higher speeds. It's like comparing a Lotus Esprit (light weight smaller engine) against a Porsche 4x4 or a Ferrari Testarossa (both bigger, but more powerful cars) and they all have the strengths and weaknesses. I have ridden my Dahon against larger and nastier ebikes with more capacity, I know they are much faster than me if they want to and can attain longer range with full assist. But they are not as light weight as my setup is and if I go against them on century rides, I think I will win.

My thoughts are, if you are a strong cyclist to begin with, you only need to have a light ebike setup with a nominal battery capacity. The setup is no worse than riding a touring bike strapped with camping gear and I've done a straight 100 mile ride with 50lbs of gear strapped to it to a total of 8830miles for a year (that is the distance between Los Angeles and Sydney Australia across the Pacific Ocean).

 

[DahonElectric]

Russell's Wh/mi data is an outlier. He pedals a lot and adds substantial energy to the equation. How it's measured and calibrated is another factor.

My setup is quite a bit different. It was specified for a 60 kilometer range. It's an X5304 with a 48A start immediate controller. On 48 volts, it will do 43 kmh. Figuring 10-12 Wh/km usage, I went for an 18Ah NiMh pack just in case I picked up a hitch hiking honey on the way home. As a result, I've gone over 100km on a single charge. My Wh/km has averaged around eight. That would be about thirteen Wh/mi. Justin set-up and calibrated my CA for this controller. I pedal 120 lbs. bike just enough to get in the aerobic zone. It looks and feels stupid to not pedal uphill.

Because I live and ride in a hilly city, I'm only using the motor half the time. Stop and go traffic sucks the amps though. My average speed on the loaded Xtracycle is the same as my average speed on the skinny tire commuter. That's all I wanted though le Béte will exceed that speed up the lumps I'd usually detour. A long distance ride uninterrupted by traffic control signs and signals would yield better results for both average speed and consumption. I ride conservatively except when I'm smoking scooters.

Russell's review has me thinking about a lighter bike equipped with a 9C and smaller short-haul batteries.

Zoot, I don't agree with your analysis that his data is an outlier. I also managed to get about 80km on my Dahon Mu SL with a 24v 8ah battery, which is according to their website is a big far fetched. First of all, you do not add substantial energy to the equation, because energy is lost due to aerodynamic drag as speeds get higher (that's what racing cars are designed to be super aerodynamic and tri bikes have aerobars and aerowheels) and energy is lost due to the weight of the bike and rider as you go up a hill and minor energy lost on bike geometry (riding style), tires chosen and how smooth the rear hub spins and how true the rim spins if it's not rubbing the brake pads.

Normal human cyclists can ride 100 miles with 50lbs of camping gear and I know of a little old lady (a Grandma) who did a cross canada trip without a motor no problem begs the question, why a young person needs a motor to prove that he can do cross canada on the bike was a subject of ridicule in our human biking community, or at least the cyclists I frequent with. So the key to energy efficiency is the ability to use lower gears and spin and maintain an equal low cardio aerobic effort and basically use the motor purely for assisting in steeper hills or to fight nasty headwinds. The rider would expense the same energy output requirement as he or she would riding a heavy bike like a touring bike strapped with panniers. As MANY touring cyclist on the gulf islands would do (especially on Gabriola, Denman and upper North) and climbing up Duffy Lake road getting into Whistler from Cache Creek, climbing steep hills is not a problem as long as you've trained for it and you have the stamina for it. The key is training and you can ride long, as long as you are burning a large percentage of your fat vs glycogen. We humans have 2 energy storage, liver and muscle glycogen. Liver glycogen can get tapped out easily and that controls your motor function and your mental acuity. You loose that, you hit the wall and everyone has a different level of wall and thus, it is conceivable that Russell could be a fitter rider than he thinks and that he is able to maintain mental acuity because of his expanded storage of liver and muscle glycogen as opposed to a sedentary person who isn't fit, but rides an ebike. Liver and muscle glycogen is a human being's energy storage capacity to Ah on the bike. And with humans, you can not transfer your unused muscle glycogen into to your liver.
In fact, if Russell starts consuming gels every 30mins with water and continue to do so, his battery mileage would become even better!