9C front hub question

Paul T

10 mW
Joined
Feb 2, 2012
Messages
31
I have a 9C front hub on my bike it was sold to me as a 2000w motor, what puzzles me is that on the side of the motor is a long number with letters, the following JZ36V500W110615009. Its the 36V500W part that I don't get, that must mean 36volts 500watts? but its a 2000w motor. I have a 36V 500w front hub on another bike and this 9C has far more torque so it must be a 2000w...I guess. Why would Nine Continent put that number on the side of the hub case if that's not the case? no pun intended :shock:
 
The motor does not produce the power..it only converts it from electrical to mechanical.

so if you supply it with 2000watt the motor will probably take it. The manufacturer has stamped it with 500W probably for legal and safety reasons..they know that if you run it at that power level, then it will be OK.

.run it at higher power levels will get it hotter but probably still OK..but monitor temps..I do not know these motors personally
 
It's a 500w motor design. This means, at 500w continuous, even when running at very poor efficiency in stop and go conditions, It will NEVER overheat and melt. It's NOT a 2000w motor. It also means that the common winding you likely have will cruise at full speed, using 500w of 36v. It will barely get very warm cruising at 500w.

But it's not going to overheat if you are careful how you ride it, and don't lug it. Keep it above 15 mph on steep hills, and it will run efficient and cool enough. I have a shitload of these motors in various windings, and have many thousands of miles of riding on them. You will be hard pressed to overheat one running 1200w max unless you have long hills above 10% grade. Or many short hills above 15% grade, or ride too slow in very deep sand. On the street, I could not kill one with 1200w. I tried very hard to, really.

What's 1200w? That was a 22 amp, 48v controller. Some spikes of more amps, but never more than 1200w continuous.

I also say a lot, that 1500w is fine, 48v 30 amps, or 72v 20 amps, won't melt your motor unless you are riding hard on dirt trails.

So many of us have also run 3000w controllers, 72v 40 amps. That gets you into the 40 mph club. That melts your motor too, if you have a battery bigger than 10 ah. :twisted: But it's fun for a short run.

Since you have a front hub, I would seriously advise running no more than 1500w. It's real tricky doing front wheel power drifts in the corners at 3000w. And the motor will want to rip right out of the forks really bad at 3000w. A 48v 20 amps setup should be all you need.
 
Thanks guys, and dogman for all that info. I'm running it on the road only, I have a controller that makes the motor run at 2000watts, the controller and motor hardly get warm after a run and the set up is on a Basman cruiser, that's a pretty big heavy steel bike, and with the pedals so far forward I cant help it too much, I haven't tackled any big hills on it yet. The front forks are steel and I have a torque arm fitted so I hope I have no problems. I have heard the 9C motors are very reliable and robust.
 
At 2000w, it should be pretty hard to do any damage to it. Most of the time, cruising speed should be drawing less than 1000w. I put thousands of miles on mine. Perfect application for the front hubs, on a cruiser.
 
I ruined the hall effect sensors on my very first e-bike (a 9C) by not really understanding the whole heat vs wattage thing. Even when limited to 1500 watts, sand and slow grindy off-road will overheat a 9c.

My recommendation is to put a temp sensor probe in your hub like TG3, or Traxxas on-board. These can be had for about $15 and are as easy to install as popping the lid off your hub and poking the sensor into the windings.

A temp sensor probe will allow you to pump 3000+ watts into a 9C without risking overheat.
 
I just assumed he wasn't riding in deep sand or trail riding a cruiser with front hub. He's relatively safe on streets, if the grades are not above 10%. But that doesn't mean tow skateboarders up hills.

But yeah, nothing heats up motors like deep sand. I have a lot of it here, and have really gotten a hot motor riding through that stuff. Melted some motors in it too.
 
What Dogman says. I have thousands of miles on my 9c too :shock: I think on relatively flat terrain and/or short rides you can still do 1500w continuous. I often ran my 9c at 1000-1500 w for a flat ride of 13 miles without issue. FTR I have 9x7 9C from ebikekit very robust motor for everyday use and commuting.
 
Hard to say if he even has a 2000w controller on it anyway. But if he does, he will be using only about 1500w to cruise at 35mph, if he even has the volts to reach that speed.

If he is running 48v, then he'll stay below 30 mph, and use closer to 1000w. On the street that is.
 
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