Overclocking Unite Motor MY1016

[blueb0ttle2]

I built a chain drive ebike using the MY1016, and I was wondering if it was safe to clock it up to 36 volts, whilst using a better controller than the one I have. It already runs fairly hot if I don't pedal it up to speed (Due to my ~1:5 gear ratio). So would changing the gear ratio and overclocking be a safe option? I'm not a daredevil, I just want my cruising speed to be 20 MPH instead of 15.
Cheers.

 

[blueb0ttle2]

Oh, and this is my bike. I wanted a practical commuter on a classic-style frame.
http://evalbum.com/3389

 

[def215]

i believe some people on this forum are running higher voltages on motors rated at a lower voltage, like your unite motor. i have a 24v 250watt rated currie motor and i run it on a 32 volt lithium battery from time to time. not problems with it so far but im waiting for the magic smoke to come out of it in the near future. :wink:

but the 5:1 gear ratio seems really tall for your setup, especially on a 26 inch wheel. maybe if you gear it down to a higher gear raio, there will be less heat. your motor must struggle to put out power at that gearing. i have a 20 inch rear wheel on my bike and my gear ratio is around 9:1.

but very nice and clean setup. i like how the motor is mounted to your rear rack and is out of the way of things.

 

[blueb0ttle2]

Someone told me that TNC Scooters had a 72 tooth sprocket that could fit in my set-up. So 72:11 is the best ratio I can think of so far.Unless I replace the whole drive-train. It looks like torque is not the strong point of my design

 

[veloman]

You are WAY overgeared, especially on 36v. These motors want to spin at ~3000rpm, and at 20mph it's only doing 1300rpm on your setup. You need at least a 10:1 gearing, which is hard because you really need a reduction unit unless you get a custom mega size sprocket. If you keep riding your setup, I would bet your motor is going to fry.

 

[vanilla ice]

The motor will take double volts no problem. I think my sla pack back in the day was like 62v off the charger on the 24v my1016. But like the others warn, direct drive on one of those requires a very small wheel diameter. Like a 12.5" scooter wheel.

 

[blueb0ttle2]

I haven't overclocked YET, I'm just thinking about the possibilities. But, given my gear ratio and your suggestions, it seems impractical. No matter, 15MPH is not bad, considering that I have to navigate through heavy bike traffic in a large University. Maybe RANGE should be my focus, and not speed. Overclocking limits range I hear, so I'd be shooting myself in the foot.
So, in conclusion...
-Try to get a better ratio for more torque, 11:72 is the best if I want to use *affordable* pre-fabricated parts
-Consider better batteries, if a rich relative dies
-Eat more beef so I can work up some muscle to get up those dern hills

 

[vanilla ice]

You need to keep the motor in its happy rpm range to increase range. Try to get at least a 90 tooth and run it on std volts. You will probably be able to feed it more amps for longer without overheating, after you gear it better.

 

[blueb0ttle2]

The motor I use, according to my vendor's website, runs happily at 2650 RPM. After some calculations, at 15mph I am running the motor at 952 RPM and at 20MPH I'm at 1239 RPM. Which is pretty bad of me
After some more calculating, in order to run happily at 20 MPH I would definitely, as one of you suggested, need a ratio of ~10:1. I'm going to look into prefab reduction drives, but if I don't find one that fits, it looks like I'll have to use a MY1018Z (Like the Currie Ezip) with an internal reduction drive. It's not that hard to install (There's a readily available prefab adaptor that's only $10, and some other parts that cost even less than that).

 

[blueb0ttle2]

Ouch! Gear reducers are pricey and very specialized. I'm going to make some measurements and see if I can squeeze a 90 tooth sprocket on my bike (This will not give me a 10:1 ratio, but it's close enough). If it doesn't fit, I'll have to use the MY1018Z, and overclocking an MY1016 will become a moot point :wink:

 

[spinningmagnets]

Consider a jackshaft, you could even use the rear hub from a 18-speed MTB, (Motor drives the biggest cog on the cluster, then the smallest cog drives the left side of your wheel). Just cut off the spokes and make a wooden axle-holder until you acquire the resources to make a mount from metal.

Look over all of amberwolfs threads, just skim the pics, he covers a lot of tech advice.

 

[blueb0ttle2]

Unfortunately I don't have the time/skills/money to do welding or machine work, I can only jerry-rig things with prefab parts. And if I hire someone else to weld things for me, it would end up costing too much. I'll stop whining and grab my socket wrench and see what I can do with what I have 8)

 

[gogo]

The first thing I'd suggest is to gear it down with the 80 tooth sprocket from TNC ($10+ship). If heat is still an issue after better gearing, I'd add a second motor in parallel ($35+ship). Two 350W, 19A motors with your 30A (720W) controller would be a good match to keep you within the motors' thermal limits. You may be pulling the full 720 watts from your controller now and wasting more than 2/3 of it as heat.

 

[vanilla ice]

I've seen cheap off the shelf steel 90t's. Matter of fact I have one bolted to my kid's coaster hub. I think its for #25 chain. Don't think I've seen anything larger though..

 

[blueb0ttle2]

electricscooterparts.com has a 90T sprocket for a standard bike mount. I'd need to replace the original hub, though. I thought of using something fixed-gear cyclists call a "Flip-Flop" hub. On one side it has a fixed gear, and the other side is a single speed freewheel. The 90T sprocket might be able to fit where the "fixie" sprocket used to be. The freewheel, of course, is for my pedaling . I'd need to do more research, but If I have room on my frame (It's already a tight squeeze), it will definitely be an option.

 

[blueb0ttle2]

This appears to be a good hub.

Here's the 90T sprocket that I think just might work...

the 90T sprocket uses the standard 1 3/8 inch inner diameter, that a bike sprocket normally has.

 

[gogo]

Try searching for left side drive on ES. Also see this thread:
Can someone here make a #25 pitch 80T CNC sprocket?

 

[vanilla ice]

The motor will try to spin off the sprocket on the left side of a flip flop hub. One of the modern crazy-strong epoxies might stop that though. I think some dude posted that it worked for him. I forget which epoxy he used..

 

[blueb0ttle2]

The motor will try to spin off the sprocket on the left side of a flip flop hub. One of the modern crazy-strong epoxies might stop that though. I think some dude posted that it worked for him. I forget which epoxy he used..

Hmmm. Thanks for telling me that. I guess I might be able to get someone to weld the sprocket on, since its a fairly easy job. There's a metal shop in town that does custom jobs for a decent price, and welding a gear unto something I've secured and aligned myself should be OK. The disadvantage is that the flip flop hub will not be usable on any other project. I'll keep my eyes peeled for a used one.There are several bike stores that have used parts in my town, but I'm suspicious about their source
BTW I might just barely be able to fit the 90T sprocket on my bike.

 

[spinningmagnets]

The 'flip-flop' hub option has been tossed around before. I think it might work if you used a dremel and a file to cut a couple keyways into both pieces. Then you would thread the sprocket on as far as it would go, back it off just enough until the keyways line up, then loctite a couple keys in. It might be worth a try, and both pieces would still have plenty of thread left, in order to return them to normal duties if needed.

 

[Miles]

EV Deals stock the Currie bi-drive hub: http://www.evdeals.com/USPD%20Drive%20Parts.htm (scroll down). There might still be old stock of BMX bi-drive hubs out there, too.

 

[blueb0ttle2]

EV Deals stock the Currie bi-drive hub: http://www.evdeals.com/USPD%20Drive%20Parts.htm (scroll down). There might still be old stock of BMX bi-drive hubs out there, too.

Huzzah! The Currie Hub is just what I've been looking for, and I see it's even cheaper than a new flip-lop hub. I cannot thank you enough!

 

[vanilla ice]

If the 90t is meant for the right hand side of the bike, then it will not thread on to reverse threads.. Also I have bought flip flop hubs for $20 new. If you're seeing pricing over $50, well that is a little steep. Those things are being mass produced for the fixie kids, and the prices reflect the quantities of the runs.

That key way method looks good, or you could try some set screws. Or if you can machine the sprocket flange thinner maybe you could use a fixie lock ring to keep it from spinning off? I haven't looked at my 90t for a while, but I think it is much too wide in standard form to thread on in place of a track cog.

Another method I have not seen is to weld or bolt a motor sprocket right on to a fixed gear lock ring. They are reverse threaded steel, and about $5 to $10 each. They are pretty small, not sure how easy it would be. But a lot of the hubs out there are already setup this way- with standard thread on one side and the reverse lock-ring thread on the other.

If you look at the surly hub up at the top of this page you can see the dual threading on the left side of the hub.

 

[Miles]

I would use a LH freewheel on the Currie hub. Mount the sprocket with bolts between the teeth of the freewheel, or fabricate an adaptor.

 

[gogo]

I've never seen anyone on ES comment about this.
http://www.staton-inc.com/store/pro...AND_thread_freewheel_sprag_clutch-967-25.html