eChopper: Nirve Switchblade with TSDZ2

[thowaa]

I bought a secondhand Nirve Switchblade with the purpose of making an eChopper.
This is what it currently looks like:


The motor is the Thongsheng TSDZ2 250W 36V Mid Drive Conversion Kit which is discussed here:
https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788

The project is far from done. The battery will be moved inside the frame.
I will post more later...


EDIT: Re-uploaded images because of server problems.

 

[beast775]

Very nice,very comfy.

 

[WoodlandHills]

How does the rear coaster brake work with the mid-drive. Are there disc mounts back there? It looks like a fun conversion candidate........

 

[thowaa]

How does the rear coaster brake work with the mid-drive. Are there disc mounts back there? It looks like a fun conversion candidate........

The coaster brake doesn't work with my motor, but the TSDZ2 is available in a coaster brake version. No disc mounts, but I have seen conversions with rear disc breaks, so it should be possible and I plan to do it. I don't like coaster brakes.

 

[thowaa]

When removing the original one-piece-crank I soon realized that the bottom bracket was too large for this motor which is made to replace three-piece-cranks. Adapters are available for this, but the clearing between the crank axle and the motor housing was too small, so I needed an asymmetric adapter. A friend of mine with a proper workshop made two thick adapter discs out of cibatool. After some filing and sanding they where pushed in place form each side and made a quite tight fit. It was later sealed with metal filler and painted black. The motor cover was removed to be able to mount the motor as the two brackets for the securing plate were in the way.

 

[leangains]

sick build, how does that compare to a bbs02?

 

[thowaa]

sick build, how does that compare to a bbs02?

I have no experience with the BBS02.
The TSDZ2 is discussed here: https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788

 

[thowaa]

When I bought the motor kit, the dealer said if I needed I could mill away quite a lot on the motor housing to make it fit the frame. With the large one-piece-crank BB this turned out to be the case, but to be sure I sent this photo and asked if it was safe to mill away the marked "tongue".


He answered "yes, no problem". So I went ahead... and got a hole into a magnet...


I just filled the hole with some metal filler, and so far it doesn't seem to have caused any harm. Later I milled away some on the other two "tongues" as well.


The motor is placed rather upside down, so I also made a hole for routing the speed sensor cable downwards. This will in addition work as a drain hole since the cover here is not water proof.

 

[spinningmagnets]

Since this drive is designed to slide into the common Shimano format 68mm bottom bracket shell, I am certain that you might have been able to use one of the spacers from the BBSHD system to avoid machining that portion of the drive.

http://lunacycle.com/parts/bafang-p...it-for-bbshd-bottom-bracket-fitting-4-pieces/

 

[thowaa]

Yes, a 3 mm spacer should work. You will then also have to replace the spacers for the securing-plate on the other side. The whole motor will then be placed 3 mm further to the right.

EDIT: Those rings on the photo above looks too tiny for my bike. They will probably just dig into the cibatool. A custom plate should work.

 

[spinningmagnets]

Yes, a spacer-ring would shift everything over a few mm...I didn't know if there were enough threads on the unit to accommodate that or not.

Could you post a pic of the lockring on the other side, to show how many threads were left exposed (on the machined version)?

 

[thowaa]

I didn't know if there were enough threads on the unit to accommodate that or not.

It fits a 73 mm BB, but you have to replace the M5 bolts and spacers for the securing-plate.
This question has already been addressed and verified in the TSDZ2 thread:
https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788#p1189090

I know I have also seen an adapter available for 100 mm fat bike BB, but I don't remember where.
Probably found at one of the dealers mentioned in the other thread.

 

[thowaa]

I searched for an extension cable for the speed sensor, but couldn't find any. It was even hard to find any info about the connectors, so I ended up extending the cable using a stub from an ethernet cable. I don't know why I did this at the motor side. Would have been better to do it on the sensor side. I assume the sensor is a simple reed switch, and it seems to work fine with only two of the six wires connected.



Btw: The connectors are Higo mini A and are discontinued according to the European distributor for Higo, but some Chinese manufacturers are still using these connectors. My local dealer told me yesterday that he now has got some extension cables from China.

 

[thowaa]

Here the motor and chain is mounted. The motor was tested at this stage using the 6 km/h 'walk assist' function.



The original bracket to secure the motor to the frame does of course not fit on this Nirve chopper frame. I was thinking of using a clamp around the frame or making a small bracket attached to the chainguard bracket, but I'm a bit lazy, so I ended up with a quick-and-dirty-solution using a 10 mm alu tube with a black shrink hose on the original M8 bracket bolt. The motor is then making a very tight fit with the frame, and it is not possible for the motor to twist around the bottom bracket.

 

[keithmac]

Looking good so far!, I've just bought a TSDZ2 as well so will keep an eye on your progress!.

 

[thowaa]

Have had problems with the system just shutting down. Now and then I could turn it on again, but as soon as I tried to pedal it just turned off. After some fail searching I found the problem: Bad soldering inside the battery holder.

 

[leangains]

any videos of the power it provides?

 

[thowaa]

It easily takes my 75 kgs up steep roads in 1st gear.
On flat road I cruise at about 30 km/h in 3rd.
The Switchblade comes with a 44T chainring and a Nexus Inter-3 hub gear with 22T sprocket.
The TSDZ2 motor comes with a 42T, so I have changed the rear sprocket to an 18T.
Works well for me.

 

[thowaa]

As seen on the first photo in this thread, I just mounted the battery in one of the holes for cable clamps and added two extra straps to be able to do some test rides. I have now drilled holes in the frame and added rivet nuts on the inside of the frame.

 

[keithmac]

How do you find the battery level display?, does it tally up reasonably well with your battery capacity or is it a mile out?. Presume it just works from the voltage?.

 

[thowaa]

When display shows just one bar of six at the battery,
still two of four green test-LEDs at the battery lights up.
Doesn't really say anything.
I'm waiting for a volt- and ampere-meter to arrive.

 

[thowaa]

Had the bike out today for test ride with the new battery mount.



Mounted a GPS to the handlebar to check speedometer and trip counter.
Had to adjust wheel diameter up from 24" to 25" for better readings.
Guess it is because of the dimensions of the 3" Fatass tire,
but this reed switch thing might also miss readings.
Not too bad though...

Trip counter GPS = 10.2 km TSDZ2 = 10.0 km
Average speed GPS = 22.6 km/h TSDZ2 = 22.9 km/h

 

[thowaa]

Found a fork bag at Biltema.
Current setup is still with temporary cabling because of the watt meter.



Did a trip of about 31 km with some steep hills.
The watt meter showed 6.89 Ah power consumption.

I was out and the motor was on for about 2.5 hours,
but the 'time' counter in the TSDZ2 display shows only 1.4.
Wonder if it only counts when the motor is active?
Seems like this number is used when calculating the average speed
which explains why average speed is higher than the GPS
even if the trip counter is lower.

 

[LI-ghtcycle]

Looks great! How does it ride? Pedelect or throttle? 8)

 

[thowaa]

Thanks.
This bike is a nightmare to ride uphill without a motor.
Now it is quite comfy.
Anyway, not a long distance touring bike. 8)

Pedelec only, and thus street-legal here.
I think throttle support on this motor requires another controller
or at least other software.