DIY stage 8: Continuous improvements...

[andyh2]

So what's needed is a 4 position PAS switch with the 4th position as OFF.

I was asking as I've just got an eC contoller with similar throttle and PAS set up from Frank for my Tongxin. I just need some bullet connectors as I'd changed the original connectors on my Tongxin.

I was very pleased to see Franks' set up already has the connections to throttle etc already made which should make installation more straight forward than my original Tongxin kit. And he's also been very helpful with advice and information.

 

[jerrysimon]

Man I hope Frank comes back on line soon. Its like he is the only person in the whole world who you can actually buy a Tongxin motor off

The only other two, sell full kits.

I have emailed so many suppliers but none sell their motors and/or controllers. I can't believe Tongxin don't have more outlets in Europe. They could sell loads more motors.

Regards

Jerry

 

[Alex728]

I have emailed so many suppliers but none sell their motors and/or controllers. I can't believe Tongxin don't have more outlets in Europe. They could sell loads more motors.

Regards

Jerry

I think the market is actually tiny for inidividual e-bike components in the Europe compared to that for ready made bikes or kits. Even in China its not that big a market, there was a Chinese chap on here a few months ago who hinted that most work on ebikes is done by workshops and there isn't that much of a DIY / modification culture in China as you might think.

Worse still in England we are dumbed down at present with engineering being thought of as "uncool" and "nerdy" so it tends to be a very small proportion of people who are interested in this sort of stuff, compared to Germans or those elsewhere in the world where making things is still a valued skill.

I also suspect at present the profit on a small motor just isn't there for Chinese companies or distributors to invest in expanding sales of these small items.

 

[Artstu]

Man I hope Frank comes back on line soon. Its like he is the only person in the whole world who you can actually buy a Tongxin motor off

The only other two, sell full kits.

I have emailed so many suppliers but none sell their motors and/or controllers. I can't believe Tongxin don't have more outlets in Europe. They could sell loads more motors.

Regards

Jerry

So if for example someone pinches all the electronic parts from your e-bike can't you just order all the parts from a shop that sells said e-bike?

 

[jerrysimon]

Yes you probably could BUT in terms of the hub motor they would sell you the whole wheel e.g for my Cytronex that would cost £235, plus they would probably want to fit it all as well.

Depending on what Frank sells when he comes back on line I may just end up buying a kit for my Brompton when I get it.

Regards

Jerry

 

[daniel.weck]

According to this second set of GPS statistics, my e-Brompton and I can climb a 12-15% slope comfortably at 17km/h. That's around 20km/h average for the entire hill including flatter sections in between.

It's interesting to see how much time/distance I spend e-cycling below the 25km/h legal limit (and therefore with some level of assistance from the motor). Thanks to this diagram, I can clearly visualize the benefits of e-riding for my particular usage pattern. For any speed above 25km/h, I actually don't *need* assistance so I'm happy to carry the extra weight and drag.

With elevation figures based on GPS data:

Slight variation, with elevation figures based on online ordnance maps:

The same journey from a previous GPS tracker log:

...and after fixing the elevation data:

 

[daniel.weck]

Over a greater distance (12km), there *seems* to be a 50% distribution between motor-assisted (<25km/h) and human-powered cycling:

Unlike diagrams for short distances, here the elevation-corrected curve remains pretty much the same, due to the horizontal interval used to calculate statistics (the GPS tracking resolution is 1 second, but of course samples of greater sizes are used to visualize the logged data): http://daniel.weck.free.fr/BromptonBafangTongxin/RotherDetour_Elevation.jpg

Anyway, on this particular journey my maximum speed was 112km/h (!!) due to GPS inaccuracies, so I had to cleanup the tracking data manually...furthermore, the software I'm using to produce user-friendly visualizations applies some kind of normalization function based on a configurable horizontal interval, so what you see is not exactly what you get, unfortunately.

I wonder if the Cycle Analyst can log data ? This would allow me to correlate the electrical current draw (i.e. power consumption) with specific cycle routes. This way I could predict battery life more easily, and I could build a small-capacity Lithium battery (A123 ?) specifically for short recurrent trips.

PS: by the way, the controller temperature (on the alloy casing) remains at 36/37 Celsius degrees for most of the time. This seems pretty safe to me. I wonder what kind of temperature makes the Tongxin controller fail...

 

[daniel.weck]

I'm playing with the "statistical aggregation" feature in order to smooth-out the speed curve over the entire duration of the trip, and to visualize trends.

This diagram offers an interesting visualization: vertical white lines represent the horizontal resolution (distance units), from which each consecutive segment is used to sample statistical data. I assume that the dotted grey area around the blue curve represents the "cloud" of data points. I guess that 18km/h is the median, a more interesting figure than the average (I am no Math genius, so please be kind to me).

Note: I was cycling slow on this damp night ride, to avoid skidding on autumn leaves (my first time on this new route too). I then joined heavy traffic and was pretty much forced to move at snail pace.

The original curve is shown below. The fat vertical marker shows a 30mn shopping stop, which the GPS logging application picked-up correctly because I manually paused the tracking...I was happily surprised that the previously-recorded data remained when I resumed the software (my Linux-based solution involves Maemo-Mapper which is not exactly user-friendly, at least not according to Mac OS X standards).

By the way, if you're still reading this, you're probably a geeky git and you should get a life !

(says me )

 

[Sir_Bob]

tat

can anyone do this for there root to work.

thx

Bob

 

[daniel.weck]

I finally fitted my Cycle Analyst (Stand-Alone model). The Suzhou Bafang motor (rated 36V 250W 190rpm) on my 16" wheel pulls up to 25km/h at 37V and 370W peak power (well, the meter actually shows 15A max). It will be useful to figure-out when the battery starts sagging and fading (although I expect the Li Ping LifePo4 battery to be strong in that department). The statistics based on the correlation between speed and power consumption are so handy !

- EDIT - Here's a close-up of the spoke magnet + fork-mounted speed sensor (the CA-SA is a bike computer as well as a watt-meter). Finding the right spot within the recommended 1mm spacing tolerance was tricky. Neither the magnet or the sensor are super-tight by the way, due to the limitations of the fixing gear. They can both be finely adjusted by hand. This is why I placed the sensor "in front" of the folk, so that if the magnet was to get too close to the magnet due to unintentional move, the sensor would simply be pushed out of the way as opposed to being ripped off or snapped.

These photos below are taken in total darkness (the one without flash shows the back-lit display quite well). PS: the temperature display is a bit "too much", I know. It will be moved to a more discrete location when I have time to do so. By the way, I think that the CA shunt generates some heat too. This should be picked-up by the temp. sensor, as everything is located in the same frame bag.

 

[jerrysimon]

Looks nice Dan. An early Christmas present

Regards

Jerry

 

[daniel.weck]

Thanks Jerry ! Christmas present indeed

By the way, I added a close-up of the spoke magnet + fork-mounted sensor:

http://www.pedelecs.co.uk/forum/electric-bicycles/4825-diy-stage-8-continuous-improvements-5.html#post63455

(the positioning on a Brompton fork is a little trickier due to the lack of space)

 

[daniel.weck]

I have now sorted the cable looming on my black e-Brompton, using black electrical tape so it looks great ! (I was waiting for the Cycle Analyst before wrapping everything up in a more permanent manner)

The margins are really small when the bike is folded, so getting everything to fit neatly was a challenge (including the rather bulky Cycle Analyst display). The wires must be sufficiently loose to enable movement when folding/unfolding...whilst being tight enough so that they don't catch on anything when riding !

I don't think I'll post photos for this, as black doesn't come-out well...and I wouldn't like to abuse people's download bandwidth any more than I have already done !!

Cheers, Dan

 

[cirrus18]

I finally fitted my Cycle Analyst (Stand-Alone model

I think there is an interesting feature with the Cycle Analyst as from what I can read it could work as a speed/cruise control and I quote...............

Furthermore, the Cycle Analyst has the ability to over-ride the user’s throttle and regulate the power delivered to the motor, turning an otherwise dumb ebike into an intelligent device with a user programmable speed limit, current limit, and low voltage cutout.

Am I correct in my thinking and have you tried it as a cruise control?

 

[daniel.weck]

There's an "advanced" configuration panel with tons of expert features.
There's a speed limiting feature but it requires keeping the throttle to full, so I'm not sure I would call it a cruise control. Could be useful though.

Info:

The Cycle Analyst Homepage - Ebike Amp-Hour and Watt Meter

PDF:

http://www.ebikes.ca/drainbrain/Cycle_Analyst_Manual.pdf

or view online:

Powered by Google Docs

 

[daniel.weck]

Although I'm thrilled with my 10Ah battery and the kind of range/hill-climbing power it offers, I'm thinking of "building" an alternative, smaller battery pack for these short cycling trips (the Cycle Analyst would help me figure-out exactly what range I can reliably achieve with say, 3 or 5Ah).

A123 "nano" batteries are a possible option (as used in the Freedom e-Bike kits). I'm toying with the idea of modifying an original Brompton front luggage rack, to obtain something like this:

Large photo:

http://www.emeritus.biz/forums/Picture 043_2.jpg

This would make it possible to reduce the luggage footprint, or better even, it could be used for the battery itself: the wire looming on my Brompton is primarily designed to accommodate the battery on the rear-rack, but the whole thing (including the frame bag that neatly contains controller, temperature gauge, Cycle Analyst shunt and a handful of "spaghetti" wires) is easy to re-route to the front using quick-release fasteners.

The problem is finding a luggage frame that is cheap-enough to justify butchering it ! ...oh, and finding a reasonably cheap 36V A123 battery pack...

 

[jerrysimon]

Ok Dan here is where I am in my similar quest to yours.

1. Just buy a Freedom E kit.

2. Build 36V packs based on 6s 19.8v 2.3Ah A123 cells.

You can buy these ready made and connect them in series for a light 2.3Ah five mile.. ish journey :

Either recycled ones here :

A123 6S1P LiFePO4 19.8V 2300 mAh EACH Ω is <7.5 - eBay (item 200395134439 end time Nov-15-09 06:04:04 PST)


New packs in the UK nice but a little expensive here :

A123 Triangle Pack 6 Series 2300mAh - Buy online from Puffin Models>

I prefer the triangular packs which would go together nicely back to back.


3. Use single cells with tabs which you can then make up your own 6s packs with balancing tabs and deans plugs here :

3 PCS New A123 2300mah 26650 Lifepo4 Battery Cell - eBay (item 190343634018 end time Nov-20-09 08:37:02 PST)


It appears that these cells can be charged without balancing and appropriate 36v chargers are readily available here :

36 Volt Battery Charger Electric Scooter ATV Bike 36V :eBay Motors (item 330378597294 end time Nov-19-09 11:10:51 PST)


But I think I would want to balance them occasionally, hence why I would want them split into 2 * 6s packs and then use one of these :

Turnigy Accucel 1~6s Balance Lipo,NiMH,NiCd Charger UK on eBay (end time 23-Nov-09 08:37:13 GMT)


BTW looks like I won't get my Brompton until tomorrow or next Monday


Regards

Jerry

 

[daniel.weck]

Thanks for the advice Jerry !
Maybe Li-Ping can build a 36V 5Ah LifePo4 battery including a balancing circuit board (and 2.5A charger)... This would probably cost 150$ + postage + duties though...

 

[cirrus18]

I have the Bafang 36 V motor , controller, throttle, pedlec sensor as supplied by Frank. The same setup as Daniel here.
I want to be able to switch off/on the pedlec sensor and only use the motor assistance when climbing hills.

Question, would anyone please explain where in the wiring to the sensor or wherever to put the on/off switch. Many thanks.

 

[daniel.weck]

I have the Bafang 36 V motor , controller, throttle, pedlec sensor as supplied by Frank. The same setup as Daniel here.
I want to be able to switch off/on the pedlec sensor and only use the motor assistance when climbing hills.

Question, would anyone please explain where in the wiring to the sensor or wherever to put the on/off switch. Many thanks.

There is a small bypass connector on the controller, but to be honest it's not very useful. Simply use the throttle to override the pedelec signal, that's it