Dave's 80:1 RC mid drive kit build log

A 7turn 3210 at 50V is 9700RPM, the drive is a 40:1 reduction, so the drive outputs a calculated 104ft-lbs @ 242RPM. We have several motor freewheels available, 16t, 18t, 20t, 22t; these yield pedal cadences of 121, 136, 151 and 167RPM.

The super-wide range available on the rear cassette means all of these freewheels are good options. The 18t is a great compromise, a comfortable climbing cadence is right in the middle of the motor revs which makes riding it nice. The freewheels can be swapped, takes me about 20 minutes.


-dave
 
tomtom said:
Just FYI

http://www.ncte.com/standard-sensors/pedelec-sensors/
Click to expand...

I took the time to contact a NCTE rep and here's what I found out:
- they are the OEM for Thun
- the shafts are hollow (not sure if this impacts durability in our use case)
- they do not offer spare parts so if you blow the bearings, it's off to buy another whole unit
- they have done a one-off alteration on ISIS/Octalink such that no BB drill hole was needed (all off the shelf models need a ~10mm hole drilled in the BB) for the sensor cable

I'm going to put PAS off as a nice to have and perhaps play with it later.
 
Very interested in one of these kits.
I'm going to take a big hit with he exchange rate with the Canadian dollar the way it is :(

Judging from the videos, I really like the sound! Doesn't seem too loud with high RPM, with the ability to tone it down when required.

Dave, using the longer mounting brackets will this fit inside the triangle on the Kona Stinky (same as yours)? Of course it would have to clear the coil/shock, but it seems if the brackets are long enough it might work?
 
Interesting you should ask, I've been working on a new center mount for frames with suspension in the way, like the Stinky.

kona.jpg

This arrangement is even cleaner than the bottom mount setup. I've tested it to 10ft-lbs on the input, 3x what the 3210 puts out, rock solid, the frame is the limiting factor. The stainless strap (it'll have a plastic cushion) is plenty strong- as the drive tries to rotate it also tightens the BB bearing cups, so the strap probably doesn't see the full torque (which is only 120ft-lbs at max current, and that metal strap can easily hold 120 lbs).

The strap is the same as those used to hold up the bottom mounts, same sort of adjustability via slot and clamping bolt (I'll make them wider). I'm using the rubber cushion on top of the downtube in a slot to prevent the unit from rotating clockwise from gravity. The weight is super centralized.

The prototype mount in the pics isn't quite long enough to clear the Stinky's coil shock, so I'll add half an inch. I'm planning on two lengths of this style along with two lengths of the bottom mount. This mount will be the long center mount. I'm almost ready to send a batch to the anodizing shop, which by the way, has been fixed. My lead time for black parts is now 1 week, zomg it's amazing.


-dave
 
Just posted my thoughts the Tangent kit in a new thread. I am very very impressed!!

https://endless-sphere.com/forums/viewtopic.php?f=28&t=76078&p=1148889&hilit=tangent#p1148889
 
[youtube]nWgNa1e-uYk[/youtube]

If you sit down, you slow down.

I rode like this for 2hours on Tuesday and still had juice left in a 1.1kWh pack. The ride outlasted the GoPro.

-dave
 
Hello Dave

Very nice RC ebike. How's the sensor less set up working out. I'm planing out a similar set up on a trike. Curious how the startup feels and if the sensors are absolutely necessary. Just looking for some imput from others on how they set there
RC e bikes.

Thanks
Afton Rider
Dom
 
The Castle Creations ESC works great, it has no problem starting the motor under load. Lots of low end grunt. I'm still playing with my BAC2000 (same logic as the Phaserunner), not near as good yet at starting the Astro motor. I feel it should be, gonna keep tuning it. The HV80 combined with a CA and throttle controlling the battery current make the torque super controllable and responsive. Even at low motor RPM, as low as a few hundred, and the motor makes torque without fuss. I've tried no-name hobby controllers also, they didn't work for me, couldn't start the motor under any load. Castle Creations has it down.
 
Ralith said:
It's been said plenty before, but I'll repeat that this kit has so much torque that you'll easily do a wheelie from a dead standstill if you aren't in a high enough gear. I also do start-stop commuting on the kit, including starting from nothing in top (38:11) gear on hills up to 20%, and the only thing I've ever ever strained is the controller's current safeties. No temperature issues whatsoever. The 3210 definitely heats up a bit when you run it over 2kW, but it's rated for 200°C and I can tell you I've never gotten anywhere near that. Good engineering goes a long way, and this kit is just swimming in it.

The only noticeable issue the HV80 has with starts is a bit of roughness due to a less-than-state-of-the-art low-RPM control algorithm. Despite that, the torque's fine, and it smooths out as soon as you're moving at all.
Click to expand...
Are you using the Edge HV 80 for the 3210 motor?
Need to find out what controller to use for a 3205. Any advice?
 
Use the HV80, it works great if the motor is able to turn the load. The Castle Creations ESCs are way better than no-name imports, or even name brand hobby store imports. Heat builds up when the controller is near full load at low RPM, like 1000-ish. More RPM than that and it'll act like it should.


-dave
 
tangentdave said:
Use the HV80, it works great if the motor is able to turn the load. The Castle Creations ESCs are way better than no-name imports, or even name brand hobby store imports. Heat builds up when the controller is near full load at low RPM, like 1000-ish. More RPM than that and it'll act like it should.


-dave
Click to expand...

Thanks Dave,
This is my first time doing a system like this and I'm stuck with the electronics. So far what I need for the Astro 3205 is the Castle Creation HV 80 and what else do I need to control the speed of the motor?
I know sounds kinda of dumb question but I just don't know much.
Thanks again
 
http://www.ebikes.ca/shop/ebike-parts/ca-accessories/shunt-ca3.html

Use this to send the RC pulse signal from the CA to the ESC. The shunt allows the CA to read battery current and when you set the CA to current throttle and output RC pulse signal it will command the ESC correctly.

-dave
 
Hi,
I am very interested in this system but I would like to know if there is a delay between the time you open the throttle and when the motor starts to turn.
The reason I'm asking this is that I like to do trials-type riding, slowly in rough terrain, and therefore often have to stop momentarily and begin moving again. To avoid having to put a foot down to keep my balance, throttle response has to be instantaneous.

A sensored controller/motor is perfect, but I have never tried a sensorless one, so I worry that the controller will have to re-detect the position of the rotor each time it is stopped.

Thanks
 
I have the Tangent kit, and it feels instant to me. The throttle settings are also customizable in the CA settings so you can change how fast it ramps up and down. So just to clarify, are you doing actual trials riding where you're hopping around on one tire and jumping from boulder to boulder, or are you talking about tight singletrack trail riding where you may need to go into a track stand, change direction and have a predictable throttle response?
 
it would work for trials, just gear it way down
 
By trials, I was talking about tight single track and mostly no track at all riding :) I like to go to the most un-rideable places :twisted:
No single-wheel hopping. I have a fatbike that is under-powered by a MAC motor transformed as a mid-drive, and additional 2:1 reduction ratio.
Torque is good with this setup but speed is not.
One thing I don't like is that Dave's drive is not back-driveable, though.
 
Oh dude, thats my shit. I have Dave's unit installed on my Fat Bike. Check it out... I've got this bike geared with a 34T up front, but you could go as low as a 30T. 11-42 in the back. I like speed personally, but at low speeds this build is super predictable and responsive. This is the flowiest trail we have around here, but I a planning on doing a couple videos of tight technical spots.

[youtube]rXsPd8o2JQA[/youtube]
 
The Castle Creations ESCs have no issues starting the motor, even under load on a hill. The freewheel causes you to spin up the motor before it catches, not needed at slower speeds since it catches sooner. Sometimes I'll find myself applying bit of throttle approaching an obstacle while using a brake to modulate speed- the motor tensions the driveline so when I pop the brake the punch is instant.

I ride slow trails all the time, the lower gears of the bike are plenty for anything you can ride.
 
Ha Ha! Endless choice of trails there! You could ride for a whole day without ever taking the same lane twice.
Nice vid overall. Where did you have the microphone located? There is no wind noise for a change, which makes for a great experience in viewing the video.
You seem to be very tough on that poor shifter, heh? :)

We still have snow here, but I can still ride most of the time thanks to the large VeeRubber Snowshoe XL footprint. Can't wait to go back to the tough rocky stuff however.

Cheers!
 
Thanks Dave,
I thought there would be a small dealy when for example, the motor is stopped and all the slack is taken from the driveline, so on powerup, it cannot really turn freely by itself to re-synchronize, before the slack is taken up from the driveline.
I really wanted to be sure it is instant-on :)
 
Altair said:
Ha Ha! Endless choice of trails there! You could ride for a whole day without ever taking the same lane twice.
Nice vid overall. Where did you have the microphone located? There is no wind noise for a change, which makes for a great experience in viewing the video.
You seem to be very tough on that poor shifter, heh? :)

We still have snow here, but I can still ride most of the time thanks to the large VeeRubber Snowshoe XL footprint. Can't wait to go back to the tough rocky stuff however.
Cheers!
Click to expand...

There's atleast 25 miles of singletrack in Robinson Park. Thats a regular $149 GoPro on a chest mount, it sits right on your sternum, and cuts down the wind noise a lot. Just have to be aware of things bumping off it, like hoodie strings, and camelbak mouth pieces. As far as the shifter, ya... I installed a new shifter and rear derailleur the night before. In the beginning of the video theres some grinding gears and crunching, but I adjusted it while I was out there, and I bang the shit out of it with no issues.

Where are you located?
 
I'm in Quebec, Canada.
I saw you adjust the cable at some point in the video.
I have a 24t in front and a 11-36 in the back.
Here is my beast.
 

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