Where to buy 9C Motors

[Farfle]

Electric companies have to carry the power the same distance. The motor does not, because the not only are each turn of the windings thicker wire, but they are also shorter. Identical copper fill in an otherwise identical motor will have identical efficiency with voltage and current changed proportionately for the same rpm and power.

I think what he is getting at is everything but the motor is less efficient, as with the half turn count motor, the phase currents are doubled, to give you the same torque. with stock 9C phase wiring and low fet count controllers(16awg IIRC) that's actually getting into a somewhat significant amount of loss.

 

[Farfle]

So, a 6fet at 100v with x phase wire and x turns will be identical efficiency to a 12 fet at 50V with 2X phase wire and 1/2x turns.

 

[Jeremy Harris]

Electric companies have to carry the power the same distance. The motor does not, because the not only are each turn of the windings thicker wire, but they are also shorter. Identical copper fill in an otherwise identical motor will have identical efficiency with voltage and current changed proportionately for the same rpm and power.

John,

I don't think you've actually read anything I've written here!

I've not once argued with you about the motor, and have, right from the first, stuck firmly to the whole ebike as a system. I'm not disagreeing with you about the motor, never have. The facts speak for themselves with regard to the ebike as a system, though. A higher voltage, lower current system will a be more efficient for a given power, than a lower voltage, higher current system of the same size, weight and cost.

 

[Jeremy Harris]

I think what he is getting at is everything but the motor is less efficient, as with the half turn count motor, the phase currents are doubled, to give you the same torque. with stock 9C phase wiring and low fet count controllers(16awg IIRC) that's actually getting into a somewhat significant amount of loss.

Exactly.

 

[Farfle]

Electric companies have to carry the power the same distance. The motor does not, because the not only are each turn of the windings thicker wire, but they are also shorter. Identical copper fill in an otherwise identical motor will have identical efficiency with voltage and current changed proportionately for the same rpm and power.

John,

I don't think you've actually read anything I've written here!

I've not once argued with you about the motor, and have, right from the first, stuck firmly to the whole ebike as a system. I'm not disagreeing with you about the motor, never have. The facts speak for themselves with regard to the ebike as a system, though. A higher voltage, lower current system will a be more efficient for a given power, than a lower voltage, higher current system of the same size, weight and cost.

Not quite so sure about cost. lesser cell count , lower charger/bms cost and easier balancing as there is more cells to "average things out". no way a 30s 4115 setup will be more efficient as a whole, (weight and space efficient) than a 4110 setup.

 

[Jeremy Harris]

Not quite so sure about cost. lesser cell count , lower charger/bms cost and easier balancing as there is more cells to "average things out". no way a 30s 4115 setup will be more efficient as a whole, (weight and space efficient) than a 4110 setup.

I've not once mentioned a 4115 system though, the point that started this hare running was a comparison I made between a 2805 motor running at 36V and a 2808 motor delivering the same power at 55V, with both running the same 4110 controller. That comparison that showed there was a small advantage in terms of efficiency by using a higher voltage at a lower current and John took issue with it, calling it a myth, when it's quite clear that it wasn't.

There are certainly other factors that come into play once voltages increase, including cost, weight and safety legislation. Here, at least if you are to follow the letter of the law, you are supposed to get any electrical installation over 60V certified against the Low Voltage Directive. The same applies across all of Europe, I believe. This means keeping voltages below this level gives a degree of immunity in the event of an incident.

If we stay within the bounds of what's reasonable for those not prepared to go to voltages that need less efficient controllers, and then select a motor wind based on battery voltages between, say, 36V and 60V, then the slower wind motor ends up giving the best efficiency for the weight and cost, although again, as I said before, the margin is small and whether or not people feel it significant enough to bother about is entirely personal.

 

[Farfle]

I agree with you, the 4115 example is just an extreme case. The voltage level is probably dictated by a multitude of things, the best cost/performance fet, easy multiples of cell numbers for charging, max effective wire size to weight etc etc...

 

[John in CR]

Not quite so sure about cost. lesser cell count , lower charger/bms cost and easier balancing as there is more cells to "average things out". no way a 30s 4115 setup will be more efficient as a whole, (weight and space efficient) than a 4110 setup.

Don't forget the biggie, the high turn count motors and high voltage controllers are much more prone to failure, making the real world cost drastically higher. On the motor side, that's a big part of why they aren't being sold anymore....well that and such a small minority want slower and lower power, the true end result of these systems. The Chinese are smart enough not to go the high turn count motor route. Instead they use less motor for slow and low power. The little 15kph restricted emoped that I got for free has the same kind of motor, but with only a 19mm thick stator, so less weight, less copper, less magnet, so definitely lower cost.

Somehow the selling point now is a miniscule amount of additional losses in the wiring. Justin tested the 7 turn 9C and came up with 70A as saturation. That's phase amps, so what would it be for a 12 turn? Is it directly proportional and 41A? Who runs phase currents that low? That's where the high turn count house of cards falls down, and even explains why Dogman melts one a year.

While I'm on the topic of busting myths, this latest one that showed up on the forum this year is the term "9C clone". You've got to be kidding. No one clones a 9C. It would be like a Tata clone. Just because different motor winding shops buy some parts made in the same factory doesn't make one a clone.

 

[Farfle]

Not quite so sure about cost. lesser cell count , lower charger/bms cost and easier balancing as there is more cells to "average things out". no way a 30s 4115 setup will be more efficient as a whole, (weight and space efficient) than a 4110 setup.

Don't forget the biggie, the high turn count motors and high voltage controllers are much more prone to failure, making the real world cost drastically higher. On the motor side, that's a big part of why they aren't being sold anymore....well that and such a small minority want slower and lower power, the true end result of these systems. The Chinese are smart enough not to go the high turn count motor route. Instead they use less motor for slow and low power. The little 15kph restricted emoped that I got for free has the same kind of motor, but with only a 19mm thick stator, so less weight, less copper, less magnet, so definitely lower cost.

Somehow the selling point now is a miniscule amount of additional losses in the wiring. Justin tested the 7 turn 9C and came up with 70A as saturation. That's phase amps, so what would it be for a 12 turn? Is it directly proportional and 41A? Who runs phase currents that low? That's where the high turn count house of cards falls down, and even explains why Dogman melts one a year.

While I'm on the topic of busting myths, this latest one that showed up on the forum this year is the term "9C clone". You've got to be kidding. No one clones a 9C. It would be like a Tata clone. Just because different motor winding shops buy some parts made in the same factory doesn't make one a clone.

For a given amount of iron, you can make a given amount of torque , it is independent of the amount of copper. Doesn't matter if it's at 1 turn and 200A or 10turns at 20A both are at saturation torque

 

[Jeremy Harris]

Don't forget the biggie, the high turn count motors and high voltage controllers are much more prone to failure, making the real world cost drastically higher.

OK, just how is a 12 FET 4110 controller used at, say 27A at 36V less likely to fail than the same 12 FET 4110 controller used 18A and 55V? The answer is that the higher current is far more likely to cause failure than the lower current - voltage stress just isn't an issue. It's pretty obvious that the power loss in the controller is proportional to the square of the current flowing through it, so the same controller handling 27A is going to generate a lot more heat than at 18A.

If you have demonstrable evidence to prove that I'm wrong with regard to this specific point, then please present it.

Somehow the selling point now is a miniscule amount of additional losses in the wiring.

You're the one marketing motors on a similar "miniscule" reduced loss........... :wink:

My point is clear , if you take two identical bikes, with the same weight, rider, controller and wiring, and fit one with a high turn motor and higher voltage, lower capacity battery and the other with a lower turn motor with a lower voltage battery of a higher capacity, such that both bikes have the same top speed and the same battery Wh capacity, then the one with the higher turn motor will be more efficient and will have the greater range.

If you can prove I'm wrong, bring it on, but you better back any claims with hard, demonstrable facts, backed with a valid explanation that we can check, rather than myths...............

 

[John in CR]

You're the one marketing motors on a similar "miniscule" reduced loss........... :wink:

Really? Which motors would that be?

 

[dogman dan]

Well this thread has been on a plane way above my understanding for a few pages now.

I just stupidly noticed that my motor temperature readouts were consistently lower with the slower windings climbing the hill to my house. Sure, the slow motor climbed the hill slower, but it did it without worrying about the motor melting. The fast motor never did melt btw, it just ran hotter, near my arbitrary redline of 200F the whole ride. And it had slightly less range if you held the speed back to equal the speed of the slow motor setup. Lots less range of course if you let it rip.

Niether system failed, nor was an extreme low winding needed. I just quickly started to not prefer the fastest winding since once in a while with an uphill into the headwind I'd run out of battery with about a mile to go to home. Never ever did that with the medium speed or slow speed motor.

Again, what type of system works best for you depends entirely on what you want from it. I just want different performance than most riders, so I like the slow winds. I don't recomend slow winds for everybody. But I do for people who will ride slow up a steep hill.

Neither approach is wrong.

Clone is just easier to type than " Motor with an astonishing similarity to a motor made by 9 continent"

 

[spinningmagnets]

I believe that the battery hasn't been mentioned as much as it probably should (not keeping score, but Jeremy gets a point for this). Many builders here are using LiPo, but the records show that thousands more E-bikes are being built in North America than are posting in ES, and apparently most of them still buy LiFePO4. I've often read that the LiFePO4 from Ping and others can be realistically rated as a 1-1/2 C.

If I understand it correctly (and I'm not saying that I do), a common 15-Ah battery at 1-1/2 C can safely provide about 22A? I seem to recall many respected posters agreeing that the easier you take it on the battery, the longer it should last. I am saving up for a Lyen controller with a CycleAnalyst, and one of the reasons is because of how easy it should be to change the amp-limits.

Many years ago, there was a poster with two bikes having identical systems (ypedal?), he mentioned that he and his GF both drove up side by side on a long uphill. Reaching the top the GFs bike was only warm, and his controller and motor were dangerously hot. He attributed this to the fact that he weighed about 100 lbs more than his GF.

On a flat beach community with cool air temps, the difference in efficiency between 48V / 15A and 36V / 20A probably can't be felt, and might barely be measurable in the batteries W/H consumption, but...Dogman will regularly climb long steep uphills in a place where the air-temp is over 100F in the summer. Changing the controllers amp-limit by only 5F could mean the difference between motor/controller survival and needing to buy a new kit.

So many other factors that must be considered, unless you're comparing the airspeed between a european sparrow and an African sparrow...

To the OP, I believe that direct-drive hubs similar to the 9C can be found at grin technologies, ampedbikes.com, cell_man and ebikekit.com
http://ebikes.ca/
http://ampedbikes.com/
http://www.em3ev.com/store/
http://www.e-bikekit.com/

 

[Jeremy Harris]

You're the one marketing motors on a similar "miniscule" reduced loss........... :wink:

Really? Which motors would that be?

Just a joke, John, as you've made a point of stressing the big advantage that a few percent better peak efficiency can make, that's all. Anyway, that's an aside from the main point about total system efficiency I've made.

Well this thread has been on a plane way above my understanding for a few pages now.

I just stupidly noticed that my motor temperature readouts were consistently lower with the slower windings climbing the hill to my house. Sure, the slow motor climbed the hill slower, but it did it without worrying about the motor melting. The fast motor never did melt btw, it just ran hotter, near my arbitrary redline of 200F the whole ride. And it had slightly less range if you held the speed back to equal the speed of the slow motor setup. Lots less range of course if you let it rip.

Niether system failed, nor was an extreme low winding needed. I just quickly started to not prefer the fastest winding since once in a while with an uphill into the headwind I'd run out of battery with about a mile to go to home. Never ever did that with the medium speed or slow speed motor.

Again, what type of system works best for you depends entirely on what you want from it. I just want different performance than most riders, so I like the slow winds. I don't recomend slow winds for everybody. But I do for people who will ride slow up a steep hill.

Neither approach is wrong.

Clone is just easier to type than " Motor with an astonishing similarity to a motor made by 9 continent"

Good summary, neither approach is wrong. Whether one works better for you than the other is personal choice, depending on how bothered you are about total system efficiency, voltage etc.

All I wanted to do here was show that things aren't as straightforward as one motor wind always being better than another motor wind for everyone and every application, nothing more.

 

[itchynackers]

FWIW, this summer my kid and I rode in a 66 mile ride. Identical routes, and we rode near each other the whole time. He was using my old 9c 8x8, and I was riding my 9c 6x10. As I recall, my wh/mile was just slightly better than his. I don't remember the exact numbers, but it was within about 0.5wh/mile of each other. Now, obviously I can't say how much he was pedaling compared to me, but those were the results nonetheless.

 

[SHARKBITEATTACK]

I don't have the best understanding of this stuff but I thought that a slower wind motor with high voltage would accelerate faster from a dead stop. :? At the same wattage the motor that is spinning at a slower RPM should make more torque. As for efficiency I've always been told that high voltage = better. Why else would the power companies spend the money on step up transformers to transport electricity at 765kV when all we need at our homes is 120V? Also with a higher voltage system won't each individual cell see less of a current draw when accelerating. And wouldn't the opposite be true that a higher voltage system could be charged faster than an equivalent energy low voltage system? I think for me the confusion starts with how the motor even operates in the first place. Maybe someone with a degree in Electrical Engineering can chime. Coiling a conductor increases the magnetic flux that opposes the field of the permanent magnets and thats what generates the torque? Or something of that nature

Anyhow it looks like I'm going to be using a 2808 motor in a 26" wheel. What will my top speed be at 72v? and what battery combination should I opt for if I want to cruise at 25mph on flat land and get a range of 20mi? 30mi?

 

[SHARKBITEATTACK]

anyone give me a rough estimate maybe?

 

[itchynackers]

You will need about 500 useable watt hours for 20 miles, and 750 for 30 miles. So assuming you will use 80% of a pack, then you need a 625wh pack, or a 937wh pack respectively.

 

[chisixer6]

not sure if this is what you are looking for, but ebike.ca has these motors on sale in the used section in ES.

LOT 61: Nine Continent 2810 FH154 front motor in 20" rim x many
picture: http://ebikes.ca/motorsale/Motor61.jpg
Nine Continent sent us the wrong motor in our last order! These are slow winding FH154 motors - they get about 40kph @ 72V and about 30kph @ 48V with about 6.3 RPM/V. These motors are brand new. You'll need to change the connectors over when you receive it as it comes with bullet connectors for the phase wires and an unwieldy white connector for the halls.
$90 each!