October 20, 200916 yr Author Now I understand the crank-rpm figures better, it puts things in perspective. If I had the skills and tools, the Tongxin motor I have in stocks (36V 180W 190rpm 80mm) could be coupled to the crank via some reduction gear and with a freewheel interface...just like what has been done recently on pedelec.de (on a full-size bicycle). The main problem would be calibrating the controller so that the PAS (Pedal Assist Sensor) could be used smoothly. In the meantime, the throttle could be used for testing the setup... - EDIT - video of the freewheeled crank: YouTube - Tongxin als Kettenantrieb 3 Wow ! Some guy in Germany built his own carbon-fiber layered bicycle frame with a custom-made Tongxin crank adapter. Awesome work, very lightweight e-bike: Tongxin Kettenantrieb am Carbonrad - Pedelec-Forum !
October 21, 200916 yr Author Another calculation tool, this time from Ben @ Kinetics: http://daniel.weck.free.fr/BromptonM6R+MeterDevelopment_Kinetics.png A few more geeky facts: The Meter-Development at highest 6th gear on my stock Brompton M6R+ is 6.7m. That's with a 50T chainring, 13/15 derailleur sprockets, SRAM/SACHS 3-gear hub (and 170mm cranks). http://daniel.weck.free.fr/BromptonM6R+MeterDevelopment.png (from Sheldon Brown's Bicycle Gear Calculator ) From the same webpage, I can immediately calculate that 120rpm at the pedal corresponds to 48.3 km/h. Some simple arithmetics can be used to find-out the rpm value for 50km/h: 50km/h = 50,000 m / 60 mn => (50,000 m / 6.7m) / 60 mn [rpm] ==> 124.3rpm
October 21, 200916 yr Author If I had the skills and tools, the Tongxin motor I have in stocks (36V 180W 190rpm 80mm) could be coupled to the crank via some reduction gear and with a freewheel interface... Here's a place to source Bottom Bracket / chainring freewheels: Sick Bike Parts LLC - Performance Parts for Your Motorized Bicycle
October 21, 200916 yr Author Can you suggest a supplier for a 36 hole, 349 Brompton rim? There is not much choice unfortunately (note that 36 holes are currently out-of-stock): Sun CR18 16 x 1 3/8 / 349 Side Wall Rim 36 Hole Sun CR18 16 x 1 3/8 / 349 ABT Side Wall Rim
October 21, 200916 yr T Garmin eTrex Venture HC Handheld GPS Navigator: Amazon.co.uk: Electronics & Photo I used to be a rave organiser and have been using GPS since the early 2000s for various purposes (for the benefit of any coppers on this forum I knocked this activity on the head over 3 years ago as things were getting out of hand) I've had one of these on my bike for about a year now - I think you have to buy the handlebar mount as an extra though. Its good for monitoring tracks and speed but not a street-level satnav if thats what you want.
October 21, 200916 yr PS: I forgot to add that the way I use my GPS terminal is much more the "old skool" way by logging grid references / waypoints of noteworthy areas and either using electronic or paper OS maps to look more closely at them - in other words I am investigating a place where I already have a rough idea where I am going (or saving a location for later reference) rather than using it as the main method of navigation to an unfamiliar area. For this I tend to use real maps - I don't want to be squinting a pokey little screen whilst riding, that way a nasty prang could well happen Its a bit like how most of use were quite correctly taught basic arithmetic first before being allowed to use pocket calculators.
October 22, 200916 yr Author I used to be a rave organiser and have been using GPS since the early 2000s for various purposes (for the benefit of any coppers on this forum I knocked this activity on the head over 3 years ago as things were getting out of hand) I've had one of these on my bike for about a year now - I think you have to buy the handlebar mount as an extra though. Its good for monitoring tracks and speed but not a street-level satnav if thats what you want. This SIRF III device looks like a perfect companion for logging GPS tracks (working off standard AAA batteries is a good thing, IMO): Amod AGL3080 GPS Photo Tracker Mac and PC: Amazon.co.uk: Electronics & Photo Amazon.com: AGL3080: Amod AGL3080 GPS Data Logger (SiRF III Driverless 128MB Push to Log) (Windows and Mac Image Software included): Electronics
October 22, 200916 yr Author The Holux GPSport 245 gets good reviews: Holux GPSport 245 review -- NaviGadget Review - Holux GPSport 245 — Vancruisers.ca - Vancouver Cruiser Calendar, Vancouver Cruiser Rides and more! Holux GPSport 245 Review :: chinamtb ...and its firmware is updated: HOLUX - The Pro Name in GPS http://chinamtb.com/english/wp-content/Holux-GPSport-245.jpg Edited October 22, 200916 yr by daniel.weck
October 22, 200916 yr Author The Q-Starz BT-Q1000P-F unit is both a pocketable standalone GPS tracker and a bluetooth-enabled receiver. Its high sensitivity means that it's ideal for hiking/cycling. http://www.qstarz.com/Products/GPS%20Products/BT-Q1000P-F.htm http://travellingtwo.com/gallery2/d/35209-2/1090_qstarz_bt_q1000_big.jpg
October 23, 200916 yr Dan can I just check I've understood your throttle and pedelec set up. You can run without pedelec attached and just use throttle on its' own, or you can install pedelec as well. With pedelec installed you can; 1. Use throttle as normal, with or without pedalling at any cadence. 2. Leave throttle alone and use the 3 position switch to choose max level of power input, with the actual power up to the max chosen being determined by cadence. 3. At any time you can over ride the pedelec system by using the throttle. If you do over ride the pedelec system by applying the throttle (you gave example of shifting hub gear requires backing off pedals causing pedelec to stop and then restart which is not what you want when riding up hill!) does it also over ride the 3 position switch as well and just operate as if the there is no pedelec system at all. Oh and thanks for BBB ergo grip idea I had some in the shed and replaced the Ergons I had on previously. Much better
October 23, 200916 yr Author Dan can I just check I've understood your throttle and pedelec set up. You can run without pedelec attached and just use throttle on its' own, or you can install pedelec as well. With pedelec installed you can; 1. Use throttle as normal, with or without pedalling at any cadence. 2. Leave throttle alone and use the 3 position switch to choose max level of power input, with the actual power up to the max chosen being determined by cadence. 3. At any time you can over ride the pedelec system by using the throttle. If you do over ride the pedelec system by applying the throttle (you gave example of shifting hub gear requires backing off pedals causing pedelec to stop and then restart which is not what you want when riding up hill!) does it also over ride the 3 position switch as well and just operate as if the there is no pedelec system at all. Not exactly. Here's how it works: (1) 3 "levels of assistance": This feature is available at all times, whether throttle or crank sensor is used to control the ride speed. In the real-world, this translates into limiting the maximum speed that is achievable with each of the 3 levels of assistance. The provided 3-stage thumb-switch is a selector for predefined speed limits, which values are specified in the controller firmware settings as percentages of the maximum power output (these thresholds can be configured using special PC software and a data cable between a USB port and the controller). The default fractional values are 50% 75% 100% but they give the wrong impression because the relationship with the perceived assistance is not linear. The first level is only good for walking along the bike, or for cycling amongst pedestrians. I use the second level when climbing a serious hill (as the top speed cannot be reached anyway) or when riding side-by-side with slow-moving traffic. The third setting is obviously the most used one. In all 3 cases, the torque is the same so any level of assistance can be used to start from a standstill (as opposed to how mechanical gears work to translate leg power onto the road). (2) Pedal Assist Sensor This is a basic "pedelec" feature, because it doesn't measure the torque applied to the crank whilst pedaling, it only picks-up the crank's revolution rate. Assistance is turned on as soon as a certain rotational speed is reached, and it increases gradually and proportionally to the cadence. The steeper the hill you want to climb, the higher the cadence you need (i.e. pedaling fast results in more power being fed to the hub motor). This contrasts with the throttle mode, whereby cycling at low cadence is possible, uphill or against the wind. (3) Throttle With this mode, one can manually fine-tune the assistance within the range of the currently selected assistance (out of the 3 predefined levels). Once activated, the throttle control overrides the PAS signal (Pedal Assist Sensor). As it turns-out, riding with throttle is sub-optimal because of the mental effort and physical distraction required to "get it right", i.e. to strike the right balance between pedaling effort / choice of mechanical gear / suggested power output. I find it much easier to adjust my cadence to suit the PAS mode, as it's pretty much like a regular cycling pattern. Furthermore, holding the throttle (thumb or handle) for more than a mile is not comfortable anyway. However, the throttle is very useful to kick-start the bike from a standstill, especially when one needs to quickly get out of the way at a junction with incoming traffic. To conclude, I like to have both the PAS and throttle control at my disposal, in fact I think that they are indispensable. Whether I use one or the other, I find that listening to the motor's noise helps me determining the ideal human/assist ratio (the more silent Tongxin might be problematic ). Accurate feedback could be obtained from a watt-meter (Watts Up, Cycle Analyst, Turnigy, etc.), as the readings provide live information about power consumption / battery draw. One note about riding steep hills: when I climb a stretch of road with assistance, I never stand on the pedals with a high gear (low cadence), because it produces uneven power surges to the crank and wheels. Instead, I remain seated with a low gear (higher cadence) and I apply constant torque through each pedal revolution (down and up strokes that activate opposed leg muscle groups), so that the motor delivers a constant amount of assistance for a given hill gradient. I consider this good practice, because when I don't follow it, I can hear the motor struggling to operate correctly. Final note: a crank torque sensor would obviously offer a much better cycling experience, as there would be a direct connection between the rider's intent and the delivered assistance. This, coupled with a tilt sensor (mercury accelerometer, like on the Wii console or iPhone), would create a very natural pedelec feel: an e-bike that reacts instantly to the environment, anticipating our every moves Cheers, Dan Edited October 23, 200916 yr by daniel.weck
October 23, 200916 yr Author Thanks Dan, that's nice and clear. You're welcome. The missing riding mode on my bike at the moment is "no assistance": sometimes I don't want the motor to be turned on at all, for example when going downhill or when I want to remind myself how much effort is actually required to cycle "on my own" I do not have a master switch, so the PAS signal always kicks-in... Cheers, Daniel
October 24, 200916 yr 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.
October 24, 200916 yr 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 Edited October 24, 200916 yr by jerrysimon
October 24, 200916 yr 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.
October 24, 200916 yr 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?
October 24, 200916 yr 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 Edited October 24, 200916 yr by jerrysimon
November 2, 200916 yr Author 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: http://daniel.weck.free.fr/BromptonBafangTongxin/TescoRother2.jpg Slight variation, with elevation figures based on online ordnance maps: http://daniel.weck.free.fr/BromptonBafangTongxin/TescoRother2_Elevation.jpg The same journey from a previous GPS tracker log: http://daniel.weck.free.fr/BromptonBafangTongxin/TescoRother.jpg ...and after fixing the elevation data: http://daniel.weck.free.fr/BromptonBafangTongxin/TescoRother_Elevation.jpg
November 2, 200916 yr Author Over a greater distance (12km), there *seems* to be a 50% distribution between motor-assisted (<25km/h) and human-powered cycling: http://daniel.weck.free.fr/BromptonBafangTongxin/RotherDetour.jpg 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...
November 3, 200916 yr Author 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). http://daniel.weck.free.fr/BromptonBafangTongxin/RotherBoresheadAggreg.jpg 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). http://daniel.weck.free.fr/BromptonBafangTongxin/RotherBoreshead.jpg By the way, if you're still reading this, you're probably a geeky git and you should get a life ! (says me )
November 16, 200916 yr Author 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. http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_4097.jpg 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. http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_4094.jpg http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_4095.jpg http://daniel.weck.free.fr/BromptonBafangTongxin/IMG_4092.jpg Edited November 17, 200916 yr by daniel.weck
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