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Help requested identifying "ampedbikes" hub motor...

ax57ax57

ax57ax57

10 mW
Joined
Mar 16, 2015
Messages
20
Location
Northern Arizona
Greetings to all,

I've had an interest in electric bikes for several years, but procrastinated on acquiring anything until the last few weeks, when two deals came along on Craigslist that seemed to offer a lot of value for the money. The first was a pristine 24v EVG e-bike for $50. It lacked a battery box, but that should be coming soon thanks to this forum. Today, another e-bike popped up locally that I bought for $300. It is an "ampedbikes" front hub motor kit mounted on a Sino-Schwinn women's cruiser. It's a turnkey bike, complete with a barely used 36v 8ah battery pack that was at 41.4 volts after charging. The Schwinn is unbelievably heavy, I think that it's even heavier than the EVG. The electrics will be coming off to be installed on my own Frankenbike, but I'm curious as to the specifics of the hub motor. (Specifically, is it direct drive or geared, and what is the wattage at 36 volts?) I Googled the part number but came up with absolutely nothing. Pics are attached below.

IMG_0787 by ax57, on Flickr
IMG_0788 by ax57, on Flickr
IMG_0785 by ax57, on Flickr
IMG_0782 by ax57, on Flickr
 
That's a direct drive motor manufactured by MXUS and is a 9c clone.
- info about 9c clones can be found all over this site

for your reference this is the ampedbike geared motor which is about 5" in diameter
donut hole.jpg
 
The dd motor runs fine on 1000w, and better on 1500w. So a 48v 30 amps controller for it will make it hum really nice.

They can be taken to 3000w, like 72v 40 amps, for a 40 mph bike. But they over heat fast if you run them hard at that wattage.

Front hub, much more than 1500w gets hard to control, so I'd run it on that. You might be able to do the shunt modification (blob of solder on the shunt) to the original controller to get to that wattage, or just run it as is.
 
The MXUS is a good motor. I have one that's been used on a few of my bikes. The Ampedbike version I have is identical in performance to a "2807" or "9x7" Nine Continents that I also have. So you can use a 2807 as a reference on this motor simulator. you'll need to go the the bottom of the list and hit "Show All" in motor selection to find it.
http://www.ebikes.ca/tools/simulator.html
 
Thanks for the information guys, it pointed me in the right direction to search the forums. I've concluded that a 48v battery paired with a 25 amp (limiting) controller should be a reasonable configuration. Given that the motor is wound more for speed than torque, plus my commute is hilly and I live in Arizona, I think that I should head off potential heat issues with the hub before proceeding. I have some milspec, 10 AWG, Tefzel insulated wire that I will take all the way to the windings if I can get it through the axle. I'll also drill ventilation holes in the covers. The controller that came with the setup is a generic Chinese one that I haven't yet researched or opened up.
 
So, after stripping the electrics from the Sino-Schwinn girls bike, I found a suitable frame on Craigslist to serve as a testbed.

IMG_0790 by Rick T., on Flickr

This vintage, steel-frame Specialized Rockhopper was only $50.00.

IMG_0797 by Rick T., on Flickr

The dropouts and tabbed washers needed a little fitting.

IMG_0800 by Rick T., on Flickr

IMG_0805 by Rick T., on Flickr

Then I had to mount an old rack that I had in order to provide a mount for the battery and controller.

IMG_0806 by Rick T., on Flickr
IMG_0808 by Rick T., on Flickr
IMG_0813 by Rick T., on Flickr

I'd found some nice Wald collapsible side racks on Craigslist at the same time that I found the Rockhopper. The insulated clamps that secure the side racks will do double-duty and secure the soft case for the battery and controller too.

IMG_0832 by Rick T., on Flickr
IMG_0834 by Rick T., on Flickr
IMG_0837 by Rick T., on Flickr

Some cellulose composite...

IMG_0843 by Rick T., on Flickr
IMG_0844 by Rick T., on Flickr
IMG_0838 by Rick T., on Flickr

At this point, I connected everything and took the bike out for a test ride. Every time that I hit a significant bump in the road, the power connector between the battery and the controller would come out. The connector had been soldered in backwards, forcing the wires to bend 180 degrees to reach the controller. This put a lot of tension on the connector which was loose-fitting to begin with. Also, there was approximately 45" of excess wire on the positive side of the battery connnector which was comprised of several different gauges of wire and 5 different crimped connectors. I cut out the excess wire and resoldered the connector with the proper orientation. I also color-coded the positive side with a small piece of red heat shrink tubing, and applied a small bead of solder to the blade terminals in order to tighten up the connection. Lastly, I cut the bottom out of the controller compartment and attached the controller to the battery compartment with Velcro. All remained secure for a 12 mile shakedown cruise after these changes. (Unfortunately, the battery only lasted for 9.9 of those miles, most of which were at full throttle.) Top speed was 29.9 mph on a downhill leg, and I averaged 15.5 mph which even included several stops to figure out a cheap cycle computer.

IMG_0817 by Rick T., on Flickr
IMG_0818 by Rick T., on Flickr
IMG_0848 by Rick T., on Flickr
IMG_0842 by Rick T., on Flickr

I intend to continue the test rides for a while before I commit to using this bike to commute to work. My major concern is a significant hill that I have to climb on the way home. I'll post an elevation profile of that hill later.
 
First thing. Get at least one torque arm on that bike!!!

Even in AZ, you won't fry that motor climbing a big hill, on a 25 amps controller. But do try not to climb it less than 10 mph. That should be easy enough, with some brisk pedaling on the worst grades of your hill.

I wouldn't hesitate to climb up oak creek canyon on that motor, and 48v 25 amps. All the talk about melting them, and cooling holes, etc, is for running them on 3000w. you'll have about 1200w max. 48v 30 amps is about the practical limit of those motors for reliable use. If you haven't done it yet, don't bother with new wires into the hub. But if you like, nothing wrong with fat wire to just before the original wires enter the hub. If your wires are getting warm, fat wire outside the hub will heat sink them some. But really, it's not needed at all till you are running 2000w.

The above, assumes you and the bike won't weigh too much over 300 pounds.

Battery range. Well, that is a small battery, so I'm not surprised. But the good news is for the way you were riding, it's spot on, so the battery looks plenty healthy. You just will need a second battery for really long, fast, or uphill rides.
 
Ditto the torque arm. Even a 10mm box wrench hose clamped to the fork would be better than nothing, because teh torque that motor/controller is capable of using those torque washers to spread the dropouts apart and let your wheel roam off by itself. ;) I'd use one on each side, for redundancy.


As for overheating it, at low speed with a load (like hills, or stop-and-go traffic, etc) you might, but at higher speeds or without a load it should be fine.

I have virtually that same motor, in a rear style, and I did damage mine (halls, I think, has been too long with too many events between) one day on the heavy CrazyBike2 in a tiny little neighborhood with full stops practically every single street, and I think a 40A controller.

But it didn't have any problems until then.
 
Do someone say torque arm ? Make one yourself a 10mm slot in steel with two nuts welded on the end with one drilled and a bolt to pinch. I like the old rock hopper perfect. And if you need a 48t front ring you can take a hammer to the frame to make some room. Steel frame +.
Get some kool stop brake pads.
 
The 1204 on the side-plate likely means 12 = 2012, and 04 = April...date of manufacture, to help identify variations in the assembly line (sometimes they switch parts vendors)
 
Re overheating, this bike won't weigh near what Crazybike does. (unless just you weigh 350 pounds) I see no problems with overheating as long as he's not running 72v.

On a hot day, sure, the motor may get very warm. But it won't make that much heat climbing hills if you can keep speeds up to about 15 mph with some pedaling.
 
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