Test

[Jeremy]

Presumably it would need to be able to take a screw on freewheel, does the Tongxin/Nano motor come in a rear wheel version?

Yes, it does. The rear wheel version has a standard freewheel thread and is about 135mm wide, rather than the 100mm width of the front wheel version.

Jeremy

 

[mk1]

Yes, it does. The rear wheel version has a standard freewheel thread and is about 135mm wide, rather than the 100mm width of the front wheel version.

Jeremy

Thanks Jeremy, I was wondering whether it would be possible to use the Tongxin motor to create a similar setup to the Cleverchimp StokeMonkey.
The hub would need to rotate in the opposite direction to normal though I believe.

Martin

 

[Jeremy]

As far as I know, it's not possible to reverse the rotation direction of the Tongxin/Nano motor, as it has an internal free wheel that I don't think can be reversed, plus the controller doesn't have a reverse option.

Any of the direct drive hub motors can easily be reversed though. The Crystalyte range actually have a reverse key switch on the controller, so you can select which direction you want the motor to run. It runs equally well in either direction.

I would think that some of the geared hub motors might be reversible, but it would depend on the arrangement of any internal free wheel, like the Tongxin.

Jeremy

 

[Ian]

The Tonxgin motor has in the past been available without a freewheel for regenerative applications. I have one awaiting conversion to a wind turbine gererator. This weekend would be ideal for testing

 

[mk1]

The Tonxgin motor has in the past been available without a freewheel for regenerative applications. I have one awaiting conversion to a wind turbine gererator. This weekend would be ideal for testing

Maybe you should connect one to a waterwheel too.

 

[Ian]

Maybe you should connect one to a waterwheel too.

That would be a good idea as whatever I do seems to be the opposite of what's needed. Last spring I invested in solar panels in anticipation of the forthcoming summer!

 

[mk1]

As far as I know, it's not possible to reverse the rotation direction of the Tongxin/Nano motor, as it has an internal free wheel that I don't think can be reversed, plus the controller doesn't have a reverse option.

Any of the direct drive hub motors can easily be reversed though. The Crystalyte range actually have a reverse key switch on the controller, so you can select which direction you want the motor to run. It runs equally well in either direction.

I would think that some of the geared hub motors might be reversible, but it would depend on the arrangement of any internal free wheel, like the Tongxin.

Jeremy

I am thinking of going for the Crystalyte 4011 motor and running it at 24v. Sound feasible?

Martin

 

[Jeremy]

Running a Crystalyte motor as a bottom bracket drive seems pretty feasible to me. There is a simulator on the Renaissance website (here: ebikes.ca Hub Motor Simulator that allows you to compare different motor types.

If you want to get best efficiency, then you might be better off choosing one of the higher speed motors, like the 405 or 406 and using a reduction drive to the bottom bracket, pretty much as that bike in the link had. Try a few simulator runs with different battery types, motors and speed combinations to get a feel for how they compare.

Depending on the amount of power assist you want at speed, you may find that 24V is a bit on the low side. The rule with these motors is that increasing the voltage increases the motor maximum speed, increasing the current limit increases motor torque. A 400 series Crystalyte is good for well over 1kW and will comfortably run at up to about 72V with the right controller. I'd recommend getting a 35 amp controller even if you don't need the extra capacity. I also think you'll be happier at 36V than 24V.

The only other issue with a Crystalyte is weight. It is a fairly heavy beast. The complete conversion kit on my 'bent (motor, battery, controller) weighs about the same as my 405 Crystalyte motor and wheel.

Jeremy

 

[mk1]

Thanks Jeremy, that's a useful link, I will have a play around with the software and try to see which one is the most suitable.

I am a bit concerned about it been too powerful at 36v as it will be driving through the gears, I don't want to damage my new bike!.

This is the bike in question http://bikehugger.com/images/blog/kona_ute_white.jpg , I am not worried about speed just hill climbing ability.

Martin

 

[flecc]

Perfect shape for that BB mounting Martin, weight well ahead of the rear wheel and plenty of clearance for it. Couldn't think of a better bike for this.
.

 

[mk1]

Perfect shape for that BB mounting Martin, weight well ahead of the rear wheel and plenty of clearance for it. Couldn't think of a better bike for this.
.

Thank's flecc, the bike is meant to be arriving this week, so once I get to see it 'in the flesh' I will have a better idea how best to mount the motor.

Martin

 

[flecc]

Of course, the English TGA Electrobike has been doing this for many years, but very much lacking the Kona style.
.

 

[mk1]

Of course, the English TGA Electrobike has been doing this for many years, but very much lacking the Kona style.
.

Lacking any kind of style!

 

[Jeremy]

You don't need to use the speed, just gear the motor to run at a higher, and hence more efficient, rpm at the speed you want. One thing all these motors hate is being run hard at low rpm, as the efficiency goes way down. The faster you can turn the motor, within reason, for a given power the lower the losses will be.

Running at 36V rather than 24V will reduce the resistance/heating losses alone by about 33% for any given power.

If you take a look at the shape of the efficiency curve on the Renaissance simulator you can see what I mean.

Jeremy

 

[mk1]

I know what you are saying Jeremy, but it would be quite difficult to gear it down too much. For example say the the faster motor turns at 300rpm max and I need the cranks to turn at 80 rpm max.
The sprocket on the motor would be say 16 tooth so that would mean I would need a 60 tooth chainring on the cranks. That is too big.

Martin

 

[Miles]

There's no pressing reason to use bicycle chain between the motor and the cranks, is there?

 

[mk1]

There's no pressing reason to use bicycle chain between the motor and the cranks, is there?

What else can I use?

Martin

 

[Miles]

219 chain would give you smaller sprocket sizes and be more durable than 3/32 bike chain.

 

[Miles]

The Extron sprockets would give a quieter drive, too:
Pitts Performance

 

[mk1]

I am not too experienced with this kind of stuff, It would be much simpler and easier if I could use existing bicycle components. I am open to suggestions though.

Martin