(e-pok) gas Pocketbike upgrade to C80-100

[zEEz]

Finally, I decided to build an e-pocketbike too!



I found already the frame and I'm tinkering to provide a decent mount for a cloned 80-100 turnigy motor.
It is the one on the left, the smaller one is for an e-scooter with double belt reduction stage.



6kW max should be plenty of power!
I'm also adding hall sensors to the motor to be able to run it with a 12 mosfet ecrazyman controller
with IRFB3077 mosfets and the current limit maxed to 80 A.



Voltage will be 72V and will be provided initially with 3 packs of 6s lipos... turnigy as well.
In alternative, for cruising, I'll use 4x UPS SLA batteries giving a total of 48V and around 6 Kg.

Capacity is expected to provide only few minutes of fun, but it will be upgraded if needed!

I'm using a motor clone of the Turnigy 80-100B with a kV of 120 and no skirt bearings ...
I would expect it to be a reasonable load for a 12 mosfet controller ...

ps. the motor winding resistance is around 32 milliohm ...
... so it is ten times the 1 mosfet RdsON ...

... while the MARS MOTOR ME0907 I would like to
use in the future for a standard size motorbike with
a 36 Mosfet controller has winding resistance of around 13 milliohm ...
... and the Inductance Phase to Phase is 0.10 Milli-Henry ...

I'll stay initially on a cautious position with the current specs.
Indeed I'll want to get 6kW output for the pocketbike, but I suspect that in the beginning
anything above 3kW would suffice ...

I'll design the gear ratio to provide 50 kmph at around 6300 rpm.
It should be possible to achieve it with 48V, at that point ...

So I'll get a feeling of what is going on and I'll decide what to do next ...

Eventually, with 72V system voltage the motor will rotate up to 9500 rpm ...
bringing the minimonster to a speed close to 75 kmph ...

The petrol engine I took away is rated at around 3 ps and is supposed to bring the beast to a top speed of 70 kmph ...



.... perhaps those specs are a bit optimistic ... I calculated 45kmph maximum, from the actual gear ratio ...

The many chinese brushed e-pocketbike with power between 200 and 800 w are quoting 20 to 45 kmph ...


From calculations, my e-minibike will have a final reduction of 1:6.5 (10 teeth motor sprocket, rear with 65)...

Since the motor constant is around 120kV ... with just 48v I should be able to approach 50 kmph
Of course the wise man would up the voltage to 72v to be able to reach 75 kmph

have fun

[zEEz]

I'm a litttle slow with this project because of all the scratching and etching away of all the white paint
that the previous owner decided to put over all the frame ... the idea was not so bad anyway,
since it protected the metal and now it looks fine ...

here a sample of the front forks and a glimpse on the repainted cockpit:



apart from this, I never imagined it was so difficult to change the tyres to a pocketbike ...

I manged to make also a nice aluminum cover-adapter-cube to attach the motor to the bike, while
providing protected forced cooling channels, a cooling fan, space for the external motor halls and wires.

Also the motor axe is in preparation to be trimmed and reworked to adapt the M8 front sprocket
and some torsion steel bars traversing it and the aluminum of the motor bell to provide torque
transmission to the axe without troubles.

have fun!

[HumboldtRc]

What website did you but those motors from???

[zEEz]

What website did you but those motors from???

Hi, HRC!
I bought the small one on ebay, it is 400kV and 2kW ... quite common ....
the big one I found by chance at an open market in a RC plane meeting show in Germany ....

have fun!

[zEEz]

Hi guys (and girls?)!

I will not bother you for a bit ahead now, since I lost my patience and bled my fingers with this mod
The tyres are not progressing: I managed to take away the oldz, but the new are refusing
to mount .. One side is out and no way ... I should find a tyre-shop with a good tyre press

This is anyway the C80-100 mounted inside its cage:



Of course the problems are not limited to the tyres ... the cage box is slightly bigger than needed and
this results in a longer required chain (already ordered) . . .

Main problem to solve in the near future: turning with a lathe a chunk of steel to rebuild a proper
axe for the motor: this to provide a proper M8 thread for the front sprocket and also a cylindrical plate for the
endbell of the motor to reliably couple out all the torque ....

have fun!

[zEEz]

front and rear wheel are now functional, thanks to two energic guys in a tyre shop

[zEEz]

new longer chain received, found that the connection on the old chain was missing some part ...
I will possibly loose lot of time to have the motor axe ready.
In the meantime I fitted the front wheel in the fork and i discovered a minor mod
is required for optimal operation

have fun!

[vanilla ice]

Could you not just find a new sprocket for the motor and place a bearing outboard?

[zEEz]

Could you not just find a new sprocket for the motor and place a bearing outboard?

well, it is a matter of simplicity ... or at least intended and hoped simplicity

With the Alu-cubebox-motormount there is not too much space around for additional things: in order to have a fine
path for the chain the sprocket must be less than 3 cm from the cube side where the axe is coming out ...
and actually the sprocket I bought is indeed new: there are just few options for those sprockets:
fixing is expected to be made either as an M8 or an M10 ... I did not find any other kind of mounting

have fun!

[vanilla ice]

Ah bummer. Seems like in a lot of builds the sprocket to axle mounting is more of a pain than one would think it would be.

[zEEz]

Ah bummer. Seems like in a lot of builds the sprocket to axle mounting is more of a pain than one would think it would be.

Yeah, definitely ... In the beginning I was hoping to buy (find) a sprocket with hole and teeth inside for fixing.
At that point I would have needed just to make the correct slots on the axe with a Dremel or similar thing ...
... and to use a M4 screw in the provided axe hole for fixing it, from the side, with a large washer ...

NOTHING: no such a sprockets around .....

And the additional problem is that you must build the stuff for something like 50Nm of torque ....
You cannot use plastic gears

[zEEz]

still dismounting the motor axe to find the most effective modification to adapt it to the sprocket ...
... and received the IRFB3077 to complete either the 12 and the 36 mosfets controllers ...

First test will be with 12 mosfet and 48v LiPO ... but I have a bit of things still to work out

have fun!

[zEEz]

... in the meantime, the frame is going to sandblasting and zinc bath soon after.
LiPOs combinations for 60v and 72v are ready and controlled via 3x BatteryMedics.

At the moment the new motor axe and hall sensors are under investigation

have fun!

[zEEz]

new motor axe in preparation, thanks to a friend!
the frame is under preparation and
the hall sensors are going to be installed outside the rotor bell, to provide
a easy way to deal with the timing of the motor in order to maximize the efficiency

have fun!

[zEEz]

rough piece made of stainless steel ... final turning still required.

already got the special bearings for the motor: code 6801 and 6901
...they are specified for a max speed of 23k and 19k rpm and definitely
better than original ...

have fun!

[zEEz]

The custom axe for the motor is almost done ....

At the moment I'm upgrading mosfets in the controller and providing an external programming connector.
This way I can tweak the settings even when everything is mounted on the bike.
Controller will have 60V and 50A initially ... 3kW .... lvc to 50V to be ultrasafe ....
Future programming test with ready bike will go up to 72V and 70-80A ... 5-6kW

have fun!

[zEEz]

The 12 mosfet ecrazyman controller got his IRFB3077 mosfets and
the current limit maxed to 80 A, plus some additional 120°C caps.
Also I added an external mini-Din connector to reprogram it on the fly.
Not it will operate between 48V-40A and 72V-80A

have fun!

[Xanda2260]

Looking forward to this one, very nice work.

[zEEz]

Looking forward to this one, very nice work.

Unfortunately it is going slower than expected, but it should see some early test
during the summer. Thanks for the support
schedule is:
1-controller + motor test
2-transmission completion
3-early runs
4-bodywork and final painting
5-final runs

have fun!

[zEEz]

this thread:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=38901

...is really suggesting a top performer battery for this bike...
one single 7s3p module for around 300$ would provide a very cool 18s battery
with around 9Kg and 20Ah and 68V ... total badass e-pok would be the result ....
for a projected usage time of 1h fun each charge .... and a top speed in the range of 70Kmh

have fun!

[zEEz]

this stuff is very slowly progressing at the moment ...
but initial battery pack is now fixed:
will be 48V - 6.7Ah ... obtained by 2x series 6s HK Lipo packs 24v - 2.2Ah in parallel
with 4x series connected hi-current SLA with 12v - 4.5Ah ...
2x LiPO Balancer permanently connected and charging via 2x 24V - 2A chargers

Total weight of the pack will be 0.9+5.6 Kg= 6.5 Kg quite fine ...
Controller will be set at 48V - 60A giving around 3kW ...
Speed up to 50Kmh will be possible with good acceleration and sufficient run-time.

have fun!

[zEEz]

great news!
I discovered that a friend managed to convert part of an internal parking lot
of a nearby supermarket in a full-spec racetrack for electric car models.
So the next goal is to finish the bike in order to go there to practice at
FULL SPEED !!!!

have fun!