Lightweight Commuter Cute 100 CST

A

athletic91

100 W
Joined
Jun 18, 2013
Messages
128
Location
Singapore
LATEST SPEC









Build in progress.

Goals of project
1. Total bike weight to be less than 20kg
2. Speed of at least 25km/h
3. Range of at least 30km.

What inspired me to start this project is the availability of cheap CST motors offered by Cute. I currently have a 9 speed shimano system and wish to keep it. The 9 speed cassette should fit the rear hub motor. The motor kit ordered is a Cute 100 CST 36v 218 rpm

I bought the battery locally as i wanted to to make sure it had proper voltage. The sticker says 36v12ah but i believe its more like 8-9ah given its size. Fresh off the charger measured 43v.

Potential challenges faced.
- Motor kit from greenbikekit will arrive before 31 dec? ordered on 20/12/2013- Arrived on the 31/12/13 :)
- Whether it will fit nicely in the rear dropouts without filing- Required some filing, wheel not centred :(
- Whether I would able to successfully mount the PAS to the shimano hollow tech 2 crank. thinking of mounting the magnet disc and sensor reversed on the left side of the BB- Success

Challenges on arrival.
-Wheel not built centred.
-160mm rotor is pushed too out till it rubs the frame.
 


Box arrived with no punctures


Good packaging with lots of foam


Lots of foam bits around the wheel, had to spend some time removing it , and don't do it indoor unless you have a good vacuum cleaner ..


Controller and bits including the hydraulic brakes cutoff which i do not know how to install. They have wired up the LED meter with the PAS sensor


The thumb trottle has these extra wires for battery level which i will not be using and taping up.


Cute 100 CST motor laced up in 26". the rotor was push nearer to the frame so it does not work. may have to downsize to a 140mm rotor


Sadly my cassette tool did not work, i fit my cassette with a help of a sharp screwdriver.


THE BIGGEST ISSUE. Wheel was built way off centered. Hope i can fix it without changing the spoke lengths.


How the bike looks like currently, yet to install the PAS censor on the shimano slx crank. controller and pas sensor in the blue bag..

I have emailed to GBK regarding the wheel workmanship and am waiting for their reply.

PLS do not quote the entire post when replying as it is very long . Thank You
 
Looks like the 9spd cassette's giving you trouble aligning the hub into the frame? Dishing the rim enough will probably leave spokes on the cog side nearly vertical as it's built?

And/or, relace the wheel offset spokes in the hub flange? I'd probably use a different rim at that point - Alex, or something with eyelets, at minimum.

You should also use a thin steel washer inside the LH dropout IMO.
 
None of the wheels that you get from these Chinese suppliers are centred. You have to do it yourself. They always build it with the rim central to the motor flanges.

You should be able to make the wiring a bit neater. You have a motor connector at the back, so you don't need the ones at the controller. also, the battery is removable, so you don't need that one either. I'd open the controller, cut all the wires that you don't need (speed limit etc), cut the motor phase and hall wires and the battery wires. Then cut off the connectors and solder the wires directly together and cover with a bit of heatshrink. removing all those connectors will allow you to get the remaining ones inside the box, which will then keep them waterproof if you seal the top three sides. If ever you need to replace the controller, it's a two second job to cut the wires. This method also allows you to get the wires exactly the right length too, so you don't have to hide loops of surplus wire.

Is that the 201 rpm or 328 rpm motor?

You didn't show the charger. The aluminium case ones have a pot inside in the corner, where you can turn down the charge voltage to 42V however, I''d be surprised if the Con62 can't run at 48v.They're similar to the KU65, which definitely can.

You need one or two washers on the axle to push the disc away from the frame, and so that the caliper lines up with it. You'll have to spring the frame a bit to get the motor in.
 
d8veh said:
I''d be surprised if the Con62 can't run at 48v.They're similar to the KU65, which definitely can.
Click to expand...
I built a 44v pack for my ku65, because as I was told, It contains 50v capacitors. You have said before they are 53v, but I think you are confused. Caps come at 50v and 63v, and very few ku65's got 63v caps. What I read is they last a short time, which ties in with the reduced life you expect using caps at (or above) their upper limit. Even at 44.4v I'm over 50v hot off the charger.
http://www.avdweb.nl/solar-bike/electronics/ku63-motor-controller.html#h7-increasing-the-ku63-voltage
 
Its a 208rpm model

I have done a test ride covering 28km with a ave speed of 25.5kph. The max speed on flat ground with trottle only was 27.5kph.
At the start of the trip my battery voltage was 43.2v, at the end of the trip the voltage is 36.5v, i suspect there is still some power left although only 1 of the 4 led lights remain lit up. My bottle battery stated 36v12ah but i suspect its likely to be 8-9ah.

Can some pls teach how to calculate my wh/km and ah/km???
 
athletic91 said:
Can some pls teach how to calculate my wh/km and ah/km???
Click to expand...

You need a watt meter which will tell you directly.

Your battery will be 10.4 AH or 11.6 AH depending on which cells are in it. It's average voltage will be about 37V, so it contains 10.4 x 37 WH = 384 WH or 429 WH if it had 11.6 AH. You'd have to run it to empty to calculate your WH/km.
 
athletic91 said:
Can some pls teach how to calculate my wh/km and ah/km???
Click to expand...

You need a watt meter which will tell you directly.

Your battery will be 10.4 AH or 11.6 AH depending on which cells are in it. It's average voltage will be about 37V, so it contains 10.4 x 37 WH = 384 WH or 429 WH if it had 11.6 AH. You'd have to run it to empty to calculate your WH/km.
 
d8veh said:
athletic91 said:
Can some pls teach how to calculate my wh/km and ah/km???
Click to expand...

You need a watt meter which will tell you directly.

Your battery will be 10.4 AH or 11.6 AH depending on which cells are in it. It's average voltage will be about 37V, so it contains 10.4 x 37 WH = 384 WH or 429 WH if it had 11.6 AH. You'd have to run it to empty to calculate your WH/km.
Click to expand...

I manage to do a test ride with trottle only on flat ground till the LED meter light blink. The distance was 40km and the battery measured 35.6v. Assuming the battery is flat at 35.6v and its actual capacity is 10.4ah . I calculated to be 9.6wh/km, is this considered very efficient on ES standards?
 
converted to my language,
that comes to 15 watts per mile, very low for no pedal, you must have been at speeds of 17-20 mph?
25 miles on a 10.4 AMPHR battery That is great in my book.
I hope you will invest in a watt meter, even a cheap turnigy watt meter from hobby king, It will accelerate you education regarding batteries, range, efficiency, although I think you are already a fast learner.
 
http://www.ebay.com/itm/Digital-60V-100A-Battery-Balance-LCD-Voltage-Power-Analyzer-Watt-Meter-New-/330954111370?pt=LH_DefaultDomain_0&hash=item4d0e66f98a

Thinking of hooking this between my battery and controller, am I right to assume the battery connects to the source side and the controller connects to the load side?

Any cons if I use long wires for the setup so that the wattmeter can be mounted on the handlebars ? I assume only slightly more resistance. I have read thru the turning wattmeter mod thread and am not keen in opening it to mod.
 
athletic91 said:
http://www.ebay.com/itm/Digital-60V-100A-Battery-Balance-LCD-Voltage-Power-Analyzer-Watt-Meter-New-/330954111370?pt=LH_DefaultDomain_0&hash=item4d0e66f98a

Thinking of hooking this between my battery and controller, am I right to assume the battery connects to the source side and the controller connects to the load side?

Any cons if I use long wires for the setup so that the wattmeter can be mounted on the handlebars ? I assume only slightly more resistance. I have read thru the turning wattmeter mod thread and am not keen in opening it to mod.
Click to expand...

Yes, source is battery and load the bike.
I have not seen the mod thread you talk of, but you won't have to run 4 heavy gauge wires. Only the negative needs run through the meter to clock consumption. The positive is just there to power the meter, and can be a skinny wire. So just 3 wires t the meter. A big neg up to it, and a skinny pos. Then the big neg back from it. Then you would use this returning neg along with the big red from the battery to feed the bike.
 
That is very inexpensive but will do fine. you can use very short leads also and just check it after the ride or periodically
during the ride. That will save you the trouble of fabing a bar mount too. That unit likely has no memory so when it looses connection to the battery , you loose information , so maybe write down the info after a mile then check every few miles the first trip.I used to reinforce the leads with tape to make sure I did not loose connection to the battery and loose info. But later I got a Cycle aNALYST AND wish I had done that as a newbe. Live and learn.
 
You can run all four, It seems easy enough and not a big bundle. I would want to open it though and take your new wires in to the box, scrapping the stiff wires that stick out of it. Them stiff wires will need terminating which is just unnecessary mess if you can open it up to use your own wires. You could even consider taking your wires in the back and replacing the end plates with solid one's which would look loads better than having wires out the side of it.

This is the alternate method
 
Wire it like the above diagram. You only need thick negative wires, so in words: thick battery negative to negative source; thick negative controller to negative load; thin red from battery to source positive; thick red from battery positive to controller positive. This method cuts the resistance in half and saves having ugly thick wires all over your bike.
 
athletic91, You never mentioned how you fixed the problem. I take it that it works now?

athletic91 said:
[youtube]_ZYHS0ncOdU[/youtube]
Hope you guys can help me out. only after 7-8 tries then i would be able to switch on properly
Click to expand...
 
I wonder if my wattmeter is wrong readings.

The 14km commute to work takes 2.3ah, voltage drops from 42-38v ( Under sag it can go as low at 35.8v)
The same 14km commute home take 2.0ah,voltage drops from 38-36.1v ( Under sag it can go as low at 32.8v)

Its a mostly flat course and i understand the return trip takes less power as the motor pulls less watts due to the lower battery voltage

So it my wattmeter stats are true,
I completed 28km with just 4.3ah of a 36v battery which is cool

Comments welcome,
1) At 36.1v, how much % juice is still left in my battery? ( although the chinese sticker rates it at 12ah)
2) Do you guys think my wattmeter is faulty ?
 
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