Commuter Booster - <1kg Friction Drive

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This includes R/C motors, botttom bracket, roller and geared drives.
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adrian_sm   10 MW

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 12 2010 8:41pm

Update:

Batteries
Good news:
Got two 5s 5000mah LiPo packs.
No load speed on 5s is now ~54kph. That should be kinder on the whole drive system.

Bad news:
One pack had a dodgy cell. :x
And there is no return centre in Oz, even though they have a warehouse. Great.

Throttle
Good news:
I managed to find a easy way to mount a throttle button in a great ergonomic spot.
Using a $2.41 delivered rubber and velcro flash light mount from DealExtreme
IMG_1329.JPG
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IMG_1334.JPG
IMG_1334.JPG (80.19 KiB) Viewed 6297 times
IMG_1326.JPG
IMG_1326.JPG (96.29 KiB) Viewed 6303 times
Bad news:
Still no success in integrating the button and CA override in to the servo tester.
The button is a momentary switch. So I put it on the wiper output of the pot. Thinking that if the button isn't pressed, it breaks this line meaning zero throttle. Then when you press it down, you get what ever throttle the pot is set to.
But in practice when the button is held down eveything is fine, as soon as I let go of the button, it goes full throttle.


Well two steps forward, one step back....
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by full-throttle » Nov 13 2010 2:08am

adrian_sm wrote:But in practice when the button is held down eveything is fine, as soon as I let go of the button, it goes full throttle.
you need a pull down :)

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Re: Commuter Booster - <1kg Friction Drive

Post by drifter » Nov 13 2010 3:34am

Adrian, try this.
Image
For every uphill there is an equal and opposite downhill.

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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Nov 14 2010 4:41am

drifter wrote:Adrian, try this.
Image
Adrian it will be even simpler if put the swith you have on +5V so it connected wene push the buttom wene realesed you have no power to the pot and it will set the outpot to zero.
E-Bike friction RC-drive
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Re: Commuter Booster - <1kg Friction Drive

Post by drifter » Nov 14 2010 5:47am

umejopa, have you tried that. I know that with my ESC, that will not work. If you press the button the ESC will go to start routine and the throttle setting will be set to maximum depending on position of pot then pot has to be turned to low position to start motor.
For every uphill there is an equal and opposite downhill.

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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Nov 14 2010 8:00am

Well I have test it with my own built servotester then I have swith to max ,center , low but you have to learn the ESC the "low" off setting and high.
The auto learning trottel will not work good soo you have to do that evry time you power up.

//Jonas
E-Bike friction RC-drive
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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 14 2010 8:25am

Well I worked out that previously when I made the mods to the servo tester, I cut a trace in the wrong spot. Fixed that up, played with trying to get the CA override working, but failed. I think I will have to remove the 1k Ohm resistor inside the CA to get it working. I was just trying to avoid this, because of how I use it on my other bike, but looks like there is no way around it, while keeping the upper end of the throttle range.

Jonas,

Thanks for the tip. Putting the momentary switch on the 5.5V input to the pot works perfectly.

Drifter,

What servo tester are you using? It worked for me. Have you got the switch on just the pot 5.5V, or the whole 5.5V rail.
BTW, my servo tester uses a 10k pot, and the switches I want to use are normally open.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by drifter » Nov 14 2010 11:49pm

I have not tried it with a CA.
For every uphill there is an equal and opposite downhill.

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 19 2010 7:40am

Update:

Made a few mechanical adjustments, to fine tune the torsion spring.
I upgraded the spring to a heavier guage wire.
Added an adjustement screw, so I can tweak the angle the motor sits at without disassebmling the whole drive system to bend the spring.
And added an softer deadstop.

Here are a few pics.
IMG_1365.JPG
Drive in bits, and random springs I will try to use.
Note the old torsion spring at the bottom centre of the image.
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IMG_1366.JPG
New Spring ready to be installed. This is a thicker guage wire, and started life as an extension spring so each coil is in contact with it's neighbour.
Much better.
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IMG_1367.JPG
Spring installed. One of the legs sits in the main clamp threaded hole.
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IMG_1368.JPG
The new adjustement screw on the top right, acts on a leg of the spring which sits in the hole on the right.
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IMG_1369.JPG
Here it is all together. Note the second leg tucks under the deadstop screw head.
Here you can just see that I now have 8 active coils, versus 4. Much better.
IMG_1369.JPG (39.42 KiB) Viewed 5937 times
- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 20 2010 6:35am

Update:

Took the bike out for a quick shake down with the upgraded mechanicals, and 5s battery. Seems good so far.

The new throttle buttons works a treat. The location is great, could even change gears while holding the throttle button in.
5s battery is definitely more gentle on the motor, I will stick with it.

Cycle analyst is now hooked up. Here are the stats from some quick stop/start runs around the block, going up and down hills, and a flat speed run.
Max Speed: 49.2 kph
Avg Speed: 26.0 kph
Time: 8 mins
Watt-hrs: 22.8
Wh/km: 7.3

Motor pickup on the tyre was very good. Still need to tweak it, as managed to get it to slip.
No sync issues.

Biggest issue I have is the throttle. For a few reasons:

1) Button throttle is annoying when you don't want to use full power.
Let me explain. If I am not wanting to blast around at 1500+ watts all the time I might set the pot throttle at say 60%, so I have maybe 800-1000w.
This is great, helps me up the hills, nice lazy cruise on the flat. But then I start going down a hill, suddenly I start actually peddling quicker than the motor is set for. Then the motor lifts away from the tyre and is just spinning in free air. Then I start slowing down on the next flat, or up hill.
Now unless the drive is set such that it is always dragging on the tyre, it will not engage again, unless I let off the throttle and hit it again. Not exactly intuative for the user.

Solution 1a: variable trigger/thumb/twist throttle
Solution 1b: current limiting controller, so I can drop the power but not the top speed
Solution 1c: get the CA to limit current. But response will probably be too slow

2) Button throttle is annoying when you first engage it
Okay now I think well I'll just turn the power up. But these little motor/ESC combos spin up pretty darn quick and have a lot of power, so the pick up is pretty savage. Even when I have the ESC set to the softest start.

Solution 2a: somehow get a slower throttle ramp up, in the ESC, or a uC taking control of the throttle signal.
Solution 2b: some sort of spring/dampener like kepler to soften the engage
Solution 2c: tweak the geometry to use the tyre in similar manner to soften the engage
Solution 2d: have a soft dead stop, rather than hard and leave it at that.


At the moment I am leaning towards trying to get a variable throttle working somehow. So I would welcome any thoughts on how to achieve this on road bike handle bars. Extra points for links to suitable parts, and sketches. And I'll buy you a beer if I end up using it.

3) Slip
Well not exactly button throttle related, but if the drive does slip it is not obvious to the user. The problem with this is, to make the drive system as efficient as possible you actually want to have just enough contact force to avoid slip. As anymore is just deflecting the tyre, and the motor is just wasting power deflecting the tyre. But you don't always have control over the co-efficient of friction. So if it rains you actually want more contact pressure to overcome the lower friction coefficient, and still be able to lay down the power. It can also start to slip if you bounce over bumps, and the motor lifts of the tyre a bit.

Solution 3a: dry & wet setting for the drive engagement. This could be a simple adjustment of the dead-stop that sets the maximum tyre engagement
Solution 3b: traction control. Have a uC monitoring motor, and tyre speeds, and it can actually cut the power if the motor starts spinning quicker than the tyre.
Solution 3c: fix up the grip tape (that has ripped holes from hitting the seat tube before I fixed the dead-stops) so it doesn't slip

Finally on a more positive note to keep me motivated.
4) Weight
This bike is so light it is amazing. Riding it without power feels just the same as without the Commuter Booster on.
One of the things I have found annoying with my dual suspension ebike is it weighs 30kgs, and is a real pain to move around unless I am riding it. Like I had to go rescue my wife when her car broke down, and it is not the sort of bike I can quickly throw in the back of the car, or on roof mounted bike racks, even the tow ball mounted bike rack I have I feel reluctant to put it on since it weighs so much. Where as my road bike + commuter booster weighs 12 kgs. So easy to put on a roof rack, dismantle and put in the back of the car, or on a standard bike rack on the back. It is still a bike with all the light weight, easy to ride, easy to throw around, easy to transport, easy to store advantages, but also the awesome advantages of an 1000+ watt ebike.

I have got to fine tune this thing and overcome these little annoyances so I can realise all the awesome potential of a 12-13kg 1000+ watt 50kph 50km+ ebike.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by recumpence » Nov 20 2010 7:32am

I agree on the weight issue. Many people do not care about huge weight on a bike, but I sure do. I want a bike to still be a bike when the power is not used.

Looks good so far.

Matt
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Re: Commuter Booster - <1kg Friction Drive

Post by Solcar » Nov 20 2010 11:14am

Excellent analysis. One thing I am familiar with is "Solution 1b: current limiting controller, so I can drop the power but not the top speed." Well said. My present homemade controller is this way and it's great. I have yet to get my friction drive completed and have only used this type of controller on a through-the-gears drive.
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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Nov 20 2010 1:03pm

I have now make a controll loop in the wattmeter that take down speed if current go to high only thing can not test it on E-bike before the snow is gone :(
How fast have you the controll loop Solcar ?
Do you contoll a RC controller or have a complettly own ?
I now check current and adjust the speed evry 20mS
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Re: Commuter Booster - <1kg Friction Drive

Post by jbond » Nov 20 2010 2:34pm

Solcar wrote:Excellent analysis. One thing I am familiar with is "Solution 1b: current limiting controller, so I can drop the power but not the top speed." Well said. My present homemade controller is this way and it's great. I have yet to get my friction drive completed and have only used this type of controller on a through-the-gears drive.
How about using the CA to do this. Modify the CA to have a variable current limit on a pot. Then have the CA control the ESC throttle to keep the power below the current limit.

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 20 2010 3:56pm

Solcar wrote:Excellent analysis. One thing I am familiar with is "Solution 1b: current limiting controller, so I can drop the power but not the top speed." Well said.
I quite like this one, as it could be an off-the-shelf type solution. Which is in keeping with me wanting to make this an easy thing for people to copy.
umejopa wrote:I have now make a controll loop in the wattmeter that take down speed if current go to high only thing can not test it on E-bike before the snow is gone :( ......... I now check current and adjust the speed evry 20mS
That is fantastic news. Well done Jonas.

Need anyone to help you test it? :D I just happen to have a watt-meter and summer is just hitting us in Australia. :lol:
jbond wrote: How about using the CA to do this. Modify the CA to have a variable current limit on a pot. Then have the CA control the ESC throttle to keep the power below the current limit.
I only have v2.01 CA at the moment. So I can get it to limit the throttle based on current, speed, or voltage (at elast I could on my main ebike), but it doesn't do variable current via external throttle without a firmware upgrade.

I still haven't been able to wire it up properly yet either, and to be honest I would prefer a different solution as most people that would use this type of drive don't need a full ebike computer.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by JennyB » Nov 20 2010 4:15pm

Kepler wrote: Friction drives are not to hard to overpower with your brakes in an emergency however, we have brake sensor inputs built in. Hard to make them univeral though. Just using a hall sensor input for this.

As these drives are typically hill assists rather then full time assist, the switch is only being used for a short period of time. I have used a simple button setup before and actually found it quite compfortable as you arn't chasing a postion to hold it in. Also looking at using a pressure sensitive strip rather then a button.

Lots of options to test. PAS is already to go also to meet our stupid Australian requirements in the near future.

2 Seconds may prove to be too long for de activation. This off cause will be optimized during testing.

Should have the code by the end of the week so looking forward to some more testing.
I don't know much about this, but it seems to me that a suitable pedal sensor could replace brake switches, even with a hub motor. After all, the very first thing you do in an emergency stop, even before you hit the brakes, is to stop pedalling. Try it.

It would also prevent the uninitiated applying full power when the bike is not moving. In fact, you could have a power selector switch that stayed on with having to be held in, so you need not have any extra controls on the bars at all.

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Re: Commuter Booster - <1kg Friction Drive

Post by Kepler » Nov 20 2010 4:29pm

Looking really good Adrian. The remaining problems you have identified can be solved. And as with any set of problems, there are always anumber of ways to tackle them.

In relation to the advantages of a light weight drive on a lightweight bike, here is a great case in point.

My road bike is basically a Mountain Bike optimized for commuting. Runs ridged carbon forks, and 1.2" road tires on the standard 26" rim. Its a nice commuter, but nothing special. 13kg all up with drive and 2 x 5s 5ah LiPos.

Got invited to ride Beach road with a road cycling group of friends yesterday. Port Melbourne to Mordialloc and back. Group of 10 with all riders except me on full carbon high end road bikes. We rode at what they considered to be medium pace which held us at around 35kph to 40kph for most of the ride. At this pace we were doing quite a bit of passing with only the serious comp rides going past us. Man those big phaetons were scary. They were sitting on 45kph to 50kph wheel to wheel.

Anyway, I rode within my comfort zone using light assist on most inclines to keep pace with my younger better equipped buddies. At the end of the 60km ride, I had used only 3ahs of the 9 usable ah's I had onboard with the drive not even being warm under these riding conditions. I had a great ride and workout and never once slowed down the group. In fact I needed to demonstrate a bit of self-control not to go too quickly up the inclines.

Goes to show just how efficient a reasonable quality bike can be when coupled up with a light weight efficient drive system.
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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 20 2010 4:34pm

Hmmm. Didn't think about PAS. This could be really nice. Even on my hub motor ebike, I am always pedaling when I am twisting the throttle.
Then I could have a modest amount of throttle by default, with a smooth ramp up set somehow. Then maybe an optional boost button at the bars, for when you want some extra kick.

Another reasons to try a little ebike sensorless controller, but with a PAS sensor input.

Thanks for that Jenny.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Nov 20 2010 4:38pm

Well the code is up and running. Have test it on RC controller and set the current limit to 3A to start and it will stop increse speed at that current soo it works.
May been some testing to get it cut the current nicer now it go up and dow by 0.3A but it may be better if the current is more normal ex 45A .
Have some testing with the regulator speed and how it slow down.
If you can make a connection and load the program you can test it :D
Have you working with ATtiny before ?
Some soldering is needed to be done to have a input for speed and output for RC controller and may a pot to set max current.
Think I will add that to mine soon. ( Now it fixed in the program)
//Jonas
E-Bike friction RC-drive
E-Bike mid-drive

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 20 2010 4:46pm

Kepler wrote:Looking really good Adrian. The remaining problems you have identified can be solved. And as with any set of problems, there are always anumber of ways to tackle them.

In relation to the advantages of a light weight drive on a lightweight bike, here is a great case in point.

My road bike is basically a Mountain Bike optimized for commuting. Runs ridged carbon forks, and 1.2" road tires on the standard 26" rim. Its a nice commuter, but nothing special. 13kg all up with drive and 2 x 5s 5ah LiPos.

Got invited to ride Beach road with a road cycling group of friends yesterday. Port Melbourne to Mordialloc and back. Group of 10 with all riders except me on full carbon high end road bikes. We rode at what they considered to be medium pace which held us at around 35kph to 40kph for most of the ride. At this pace we were doing quite a bit of passing with only the serious comp rides going past us. Man those big phaetons were scary. They were sitting on 45kph to 50kph wheel to wheel.

Anyway, I rode within my comfort zone using light assist on most inclines to keep pace with my younger better equipped buddies. At the end of the 60km ride, I had used only 3ahs of the 9 usable ah's I had onboard with the drive not even being warm under these riding conditions. I had a great ride and workout and never once slowed down the group. In fact I needed to demonstrate a bit of self-control not to go too quickly up the inclines.

Goes to show just how efficient a reasonable quality bike can be when coupled up with a light weight efficient drive system.
Your right there John. It is a pretty attractive offering isn't it.

Did you get many comments from the lycra crowd. If anyone is going to have a crack at the ebike, I would have thought it would be the weekend warriors on Beech Rd.

3ah @ 5s? That is pretty good for keeping up with the young'uns. Let's see that's about 60wh, over 90mins.
That is only averaging ~40w, and only about ~1wh/km assist. 8)

BTW. How is you new fandangle throttle controller uC thingy coming along.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 20 2010 4:53pm

umejopa wrote:Well the code is up and running. Have test it on RC controller and set the current limit to 3A to start and it will stop increse speed at that current soo it works.
May been some testing to get it cut the current nicer now it go up and dow by 0.3A but it may be better if the current is more normal ex 45A .
Have some testing with the regulator speed and how it slow down.
If you can make a connection and load the program you can test it :D
Have you working with ATtiny before ?
Some soldering is needed to be done to have a input for speed and output for RC controller and may a pot to set max current.
Think I will add that to mine soon. ( Now it fixed in the program)
//Jonas
Sounds like you are making some great progress. I haven't done any work with ATtiny before, but full-throttle on the forum has, and he works in the same building as me. So I am sure I can get him to help out, in loading the program, or setting me up so I can.

I would be pretty keen to get this working, and don't mind making the required mods to the watt-meter.

- Adrian
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

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Re: Commuter Booster - <1kg Friction Drive

Post by Kepler » Nov 21 2010 5:22am

adrian_sm wrote: Your right there John. It is a pretty attractive offering isn't it.

Did you get many comments from the lycra crowd. If anyone is going to have a crack at the ebike, I would have thought it would be the weekend warriors on Beech Rd.

3ah @ 5s? That is pretty good for keeping up with the young'uns. Let's see that's about 60wh, over 90mins.
That is only averaging ~40w, and only about ~1wh/km assist. 8)

BTW. How is you new fandangle throttle controller uC thingy coming along.

- Adrian
Its amazing how little assist you really need if you are willing to work hard as well. I think the guys I were riding with were pleased I had the assist as I am sure they thought I was going to slow them down.

New button throttle is very close to finished. It works a treat and think it is the perfect type of throttle for an assist drive.

Has some great features:

Still has a minimum start speed to avoid sync issues.
When you engage the drive, the interface matches your throttle input to the given wheel speed so you are close to the correct throttle setting for what ever speed you are going when you engage.
Quick repeated presses ramp the throttle up in controlled steps.
Multiple pre set current limits are mapped against speed to guard against overloading the ESC especially when throttling up at low speeds.
Release the button for 0.4 second and the drive drops out.
Works with any spring loaded button.
Lots of other goodies built in too but I will save all those details for later :)
Current Rides

Lightest true ebike on the planet: ON ROAD viewtopic.php?f=6&t=74269
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adrian_sm   10 MW

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Posts: 2404
Joined: Feb 23 2009 12:54am
Location: Melbourne, Australia
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Re: Commuter Booster - <1kg Friction Drive

Post by adrian_sm » Nov 21 2010 5:31am

That's a pretty impressive list of features already. :shock:

Your killing us here. Just release this thing. Or at least give me one to play with :D

In all seriousness, when do you think they will be ready for release. Because these sort of smarts is what will enable the friction drives to really have some user appeal. Ground breaking stuff. Well done in pushing its development along, it will be a real asset to the community.

- Adrian
Last edited by adrian_sm on Nov 21 2010 6:23am, edited 1 time in total.
Build #1 ~28kg ~ 700w Avanti Hardtail Crystalyte 408, 48V10Ah Headway. ~5500 kms to date. (retired)
Build #2 ~30kg ~2000w Giant AC Dually Crystalyte 408, 48V10Ah Headway + 6s10Ah LiPo = 70V. ~15000 kms to date [SOLD]
Build #3 ~13kg ~2000w Commuter Booster <1kg Friction Drive
Build #??? ~21kg ~1500w Adrian's Bafang BPM Hardtail MTB Bafang BPM code12, 15s LiPo, ~40kph, ~30kms

deVries   1 MW

1 MW
Posts: 1545
Joined: Jul 10 2008 11:29pm
Location: Solar Powered 3000w Texas

Re: Commuter Booster - <1kg Friction Drive

Post by deVries » Nov 21 2010 5:38am

Kepler wrote:New button throttle is very close to finished. It works a treat and think it is the perfect type of throttle for an assist drive.

Has some great features:

Still has a minimum start speed to avoid sync issues.
When you engage the drive, the interface matches your throttle input to the given wheel speed so you are close to the correct throttle setting for what ever speed you are going when you engage.
Quick repeated presses ramp the throttle up in controlled steps.
Multiple pre set current limits are mapped against speed to guard against overloading the ESC especially when throttling up at low speeds.
Release the button for 0.4 second and the drive drops out.
Works with any spring loaded button.
Lots of other goodies built in too but I will save all those details for later :)
I realize you have an ongoing commercial product to go with your new throttle, but can you make this new throttle available or "open source" it to the DIY crowd at ES too? It ought to be "adaptable" for other friction drive set-ups being done on ES. None of this would be in direct competition with your commercial product anyway. :mrgreen:

Thanks for such an innovative throttle, but I hope it too can be "free standing" and not locked into your product exclusively, well, at least for ES members. :twisted:

Thanks for keeping us up to date... :cool:

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Solcar   10 kW

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Posts: 508
Joined: Jan 07 2010 7:00pm
Location: Ohio River Valley

Re: Commuter Booster - <1kg Friction Drive

Post by Solcar » Nov 21 2010 7:13am

umejopa wrote:I have now make a controll loop in the wattmeter that take down speed if current go to high only thing can not test it on E-bike before the snow is gone :(
How fast have you the controll loop Solcar ?
Do you contoll a RC controller or have a complettly own ?
I now check current and adjust the speed evry 20mS
The control loop is very slow. I added capacitance in parallel with the feedback to slow it down.

It is my own design and build. I use a brushed motor though. It's simple with the trade-off of bigger size and lower power and general efficiency.
LTspice free electronics simulator was helpful in my electronics hobby.

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