Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: Polar Bear on 14 March, 2017, 07:00:53 pm
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The wife* (J) of one of my Rugby Regulars** had to give up cycling some time back due to health problems. She has been tempted by the lure of electric assist but did not really want a clunky, lumbering electric bike, rather a conversion of a graceful and elegant bike.
Keen to get her back in the saddle I was cajouled by the husband, (P), without much difficulty I hasten to say, to help convert the bicycle of her choice.
We paid a visit to CFC (http://www.cyclistsfc.org.uk/), a very worthy charity recommended by our own volunteer, Robgul, and bought one of these (https://www.decathlon.co.uk/elops-100-classic-style-bike-black-id_8305485.html?gclid=CjwKEAjwqZ7GBRC1srKSv9TV_iwSJADKTjaDimRbrHGM9qv8AdnDYyCkCPl5LhHC7cB81VsOdH66zhoCd37w_wcB#s26"?iv_=__iv_p_1_g_35592448699_c_152710109749_w_pla-158276640776_n_g_d_c_v__l__t__r_1o2x_pla_y_15177021_f_online_o_35932_z_GB_i_en_j_158276640776_s__e__h_9046164_ii__vi__) that they had in stock.
I was also offered a secondhand front wheel conversion kit (http://www.electricbikeconversions.co.uk/product/250w-front-wheel-electric-bike-conversion-kit/) which came at a seemingly good price and have started the conversion. I will detail progress in subsequent posts.
* Also a friend
** A pool of local cyclists with whom I ride out with on a frequent basis.
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There are a number of challenges in getting this kit installed and the bike working.
1: The front wheel as supplied was a 700c, the bike has 26x1 3/8 (590) rims.
2: The bottom bracket as installed is not suitable for the sensor provided.
3: The battery is a bottle mount version but step through is vital for J so the battery will have to be mounted elsewhere.
4: We have had difficulty in getting the battery to fully charge.
5: As yet there is no sign of life in the kit.
Each one of these I will deal with separately in further posts.
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The Front Wheel
It was decided by P and J that we should get a new rim for the bike and keep the existing front wheel intact as it could be put back into the bike and the bike sold in the future if necessary whilst retaining the electric gubbins.
SJS Cycles had two suitable rims in stock and the Ambrosio Benelux (https://www.sjscycles.co.uk/rims-tape/ambrosio-benelux-26-x-1-38-590-rim-silver-36-hole/) was chosen. On arrival it was apparent that the rim was drilled for 13g or smaller spokes with the holes being too small for the larger nipples of 12g spokes used in these kits. A Rolson reamer (http://www.rolsontools.com/12mm-tapered-reamer.html) used with care has enabled me to spend less than an hour enlarging the 36 spoke holes in the rim which is now ready for spoking.
12g spokes are required for the build given the cavernous drillings in the hub flanges and Spocalc has indicated that 248mm 12g spokes are required. I have found a place to order these spokes and hope to get them ordered in the morning.
The hub is slightly offset (248.1 offside, 248.4 nearside) but not enough to make a significant difference.
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The Bottom Bracket
Fitted to the bike was a crude but effective square taper cup and open bearings BB. This was fitted with a notched lockring at the driveside and a hex profile on the nearside cup. The pedal sensor is of a type which is entirely enclosed and fits between the crankarm and the bottom bracket cup held in place by splines which sit in the BB cup and the crankarm itself.
When I locate the image of the sensor online I'll add it to the post.
In my vast box of bits I found a suitable UN53 square taper BB and did the transplant. It was surprisingly easy - I had expected the bike to be odd size being cheap but no, it was a standard 68mm bottom bracket shell threaded as most are these days.
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The Battery
The bike has extra braze ons at the dropouts for a rack as well as a crude extra plate near the top of the seatstays for a rack to be mounted. I have a spare topeak rack which has a solid platform which is due to be drilled and modified to allow the battery to sit on said rack.
At first the supplied charger seemed not to be doing anything but finally, perhaps due to P not pushing the mains to charger wire fully home, life has been sparked into the battery. There are two peculiarities though:
It's a 36v battery but reads 42v, and, no matter how long we leave it to charge it only goes green on three out of four indicator lights, the fourth remaining red.
We're hoping that this is not a significant issue.
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There's life Jim but not as we know it...
With everything plugged in the lcd screen flickers into life. However,
1: The screen does not register any life in the battery even though the battery shows 3 out of 4 green lights.
2: Turning the pedals does not result in any activity at the motor.
3: There is indicated on the screen some sort of indicator for the motor but nothing shows there.
Now, it could be that, as suggested by the vendor, that the controller unit is fubar'd and that once replaced life will be fully resorted. The box is £40 if that is the problem so I think that we'll just have to bite the bullet and see.
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Fitting the kit
The kit includes replacement brake levers, a pedal sensor, a wheel magnet and sensor, a box of tricks, a trigger for extra boost, the motor, an lcd panel with a separate switch panel for on/off and assist level selection, the battery and the controller. Most of this is now installed but it's not yet finished as I still have to build the wheel, secure the battery, fit the brake levers and tidy the wiring loom as well as potentially replace the controller.
I will keep you updated on progress.
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There's life Jim but not as we know it...
2: Turning the pedals does not result in any activity at the motor.
Are there sensors in the brakes, and are they adjusted correctly? At work I recently solved a problem with a electric assist bike by adjusting the brake sensors - they should have cut the motor out when brakes applied...
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It's a 36v battery but reads 42v
This isn't unreasonable when fully charged. 36V is a nominal voltage. (I assume it's some sort of Lithium-ion.)
and, no matter how long we leave it to charge it only goes green on three out of four indicator lights, the fourth remaining red.
Hmm...
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There's life Jim but not as we know it...
2: Turning the pedals does not result in any activity at the motor.
Are there sensors in the brakes, and are they adjusted correctly? At work I recently solved a problem with a electric assist bike by adjusting the brake sensors - they should have cut the motor out when brakes applied...
It *might* be interlocked against a moving bike (ie. the hub needs to be turning before power is applied). Barakta's system won't apply power below some configurable threshold road speed, even with the pedals turning in the right direction[1]. But I don't think that's common.
[1] That's a point: You have installed the pedal sensor the right way round? These things are directional, so the bike doesn't leap forwards when you backpedal.
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Not sure about the brake levers Wobbly - I have not yet dissected them in any detail but I cannot recall any obvious adjustment for the little micro switches.
Kim: yes, I think that I will not know for sure until I put the built wheel in and give it a whirl. The pedal sensor is definitely fitted correctly - I had to investigate this in detail last week but I managed to find it online and am certain that it's fitted correctly.
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The brake switches will just be switches, so you can buzz them out with a multimeter to confirm they're working.
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Brakes - They were reed switches on the one I worked on...
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I have no idea what the switches are but they appear to be hidden in the lever housing and the lever presses against it when not braking.
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Spokes ordered and a pending call with tech support.
Should be interesting.
We'll be putting the multimeter across all the sensors I'm guessing, the pedal sensor, the brake levers and the throttle.
I am told that the throttle should operate independently of pedalling so it's a sign of something not being quite right that with everything being connected up nothing is happening.
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As it needs to determine direction, the pedal sensor is likely to be a hall-effect sensor with some electronics, rather than a simple switch like a cadence sensor. I'd expect connections for power, ground and the output signal, and probing with a multimeter is unlikely to tell you much unless you provide power at the appropriate voltage at the same time.
At this point my spidey sense is saying "battery", though it could equally be a problem with the controller.
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Whenever you find that an electric bike is just not working, it is usually the controller.
Loads of them are made which can't cope with the levels of current that they receive and they tend to blow. When my wife had one, I used to carry a spare controller on our tours, wired with all the necessary connectors, so that I could swap it out in a few minutes.
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Your dedication and determination screams for the proper recognition.
I'm sure the toys would have been well and truly hurled from the pram by now had it been me . . .
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Whenever you find that an electric bike is just not working, it is usually the controller.
Loads of them are made which can't cope with the levels of current that they receive and they tend to blow. When my wife had one, I used to carry a spare controller on our tours, wired with all the necessary connectors, so that I could swap it out in a few minutes.
Interesting. Have you ever taken a controller apart? I'm wondering if there is anything in there that a skilled exponent of the soldering iron could perhaps replace.
If a new controller is required I think I'll get my friend Martin who is a bit of an electronics bod to have a play. Unless, of course, Kim would like to?
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Whenever you find that an electric bike is just not working, it is usually the controller.
Loads of them are made which can't cope with the levels of current that they receive and they tend to blow. When my wife had one, I used to carry a spare controller on our tours, wired with all the necessary connectors, so that I could swap it out in a few minutes.
Interesting. Have you ever taken a controller apart? I'm wondering if there is anything in there that a skilled exponent of the soldering iron could perhaps replace.
If a new controller is required I think I'll get my friend Martin who is a bit of an electronics bod to have a play. Unless, of course, Kim would like to?
No. They always talk about mosfets though. The controllers you want are ones that have had higher rated ones fitted. There are (were) eBay sellers who did this sort of thing. I don't know what a mosfet is. Perhaps Kim will explain...
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AFAIK mosfets are little black things with tails that get soldered onto pcb's in all sorts of electronic gubbins such as computer monitors and now ebike controllers.
I'll have to dismantle this one when it is replaced and get my friend to check it out.
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Metal Oxide Semiconductor Field Effect Transistor: A type of transistor that's suited to efficiently controlling large currents, hence commonly found on the business end of motor controllers, audio amplifiers, power supplies, etc.
MOSFETs are powered by magic smoke, and much of their specification pertains to the limits within which it won't escape. With something like a motor controller, unless they've really cocked up the design, the big question is usually thermal - how much heat the MOSFET will produce, and how hot it can be allowed to get without damage. How hot it gets for a given amount of power will depend on the physical design of the product it's installed in, and this is the bit that molishers of cheap Chinese kit will tend to take liberties with in order to keep costs down. Overspeccing the MOSFETs, bigger boards, chunky heatsinks, fans, thermal cutouts, etc all cost money (and may add weight/bulk, and make waterproofing more difficult), and skimping on them when "it'll probably be okay if they don't thrash it" is good enough for a product that's being marketed primarily on price.
For added excitement, these sorts of components tend to fail so that they're stuck 'on' rather than 'off', opening up the possibility of further expensive failures as a result. Fuses, of course, cost money and do nothing in normal operation...
Of course it might not be the MOSFETs. A controller for this type of brushless motor needs some sort of feedback to know the exact position the rotor's in, so as to apply power to the right coils at the right time. That may be done via Hall sensors inside the motor, which - along with the associated wiring - are relatively delicate and therefore another potential point of failure (think corrosion or mechanical damage).
And of course it's electronics, which means there's the usual power supply stuff to go wrong: Cheap nasty smoothing capacitors (which might not take kindly to being baked by the output MOSFETs) etc. If the power supply for the control logic goes out of spec, all bets are off.
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For added excitement, these sorts of components tend to fail so that they're stuck 'on' rather than 'off', opening up the possibility of further expensive failures as a result. Fuses, of course, cost money and do nothing in normal operation...
The semiconductors are there to protect the fuses....
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For added excitement, these sorts of components tend to fail so that they're stuck 'on' rather than 'off', opening up the possibility of further expensive failures as a result. Fuses, of course, cost money and do nothing in normal operation...
The semiconductors are there to protect the fuses....
A truism. The fuses might still get an opportunity to protect a motor winding or speaker coil, of course.
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Spokes has arrived. :thumbsup:
I'll probably not get to wheelbuilding though until we return from Scotland. :(
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Enjoy the break. :thumbsup:
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This cursed project has bitten again and seen off a dremel now. There is something about this project that is bad, very very bad. It clearly is not meant to happen.
I'm going to be about £500 out of pocket now and there is no electric bike.
The moral of the story is to NEVER buy a secondhand electric bike conversion kit and NEVER get involved to try and help friends get theirs up and working. Just walk away.
I'm off to a darkened room now with a bottle of aspirin and a bottle of whisky. :( :( :(
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Bugger. No aspirin! ;)
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Necessity being the mother of invention and all that ...
Searching for inspiration I went for a wander in the garden and admired the flourishing rhubarb and rapidly advancing raspberry canes. At the far end of the garden there is a pile of cuttings, trimmings and clippings as well as a pile of building materials from recent projects.
Buried within that pile I retrieved two 2' lengths of 6"x1" in the garden from the recent fence project. Placing these edges down and side-by-side along the "vice" of the Workmate, I find that I can clamp a spoke tightly between the timbers for sawing. It looks like my cutting can re-commence once I can find the large hacksaw.
One good piece of news is that the control boxes are back in stock having been out of stock for weeks. Perhaps there is light at the end of this very long and dark tunnel...
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And the rebuild has gone well this morning. :thumbsup:
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So, the bike is now 90% completed and will live tomorrow - hopefully. The new control box arrived today and I've been fitting everything in place including finding innovative ways to fit a rack and fit a bottle cage battery mount to the rack.
The bike looks the business and I'm really looking forward to seeing it live tomorrow.
I might have to get some Frankenstein transfers made up in silver on transparent to complement the black frame.
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Somewhere, IIRC, you should have a yellow Frankenhilda decal or two... :demon:
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I do but Frankenstein for the electric bike seems appropriate. :)
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I trust you'll be installing a BFO knife switch to go with them.
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MOAR voltz, Igor!
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Interesting conversation at my lbs today. They were admiring my wheel build of the 26x1 1/8. They commented that their wheelbuilder will not touch such builds as he considers them too troublesome and even indicated that they would be willing to pay for me to do so if I was willing.
It appears that my 2 cross build impressed them.
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P B Bikes is open for business!
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We are almost there, finally!
The replacement controller has arrived but has one less connection. A discussion with the tech guy reveals that early motors did not have an internal hall sensor. It appears that our motor probably does have one as it has the 'extra' wire in the loom so we don't need the wheel sensor.
They are obliging by checking their 'stash' to see if they have any of the older controller boxes left before we fit this one.
I cannot wait to see this baby roll.
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Alternate last line...
Can't wait to see the back of this bloody thing!
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It lives!!!
TFFT.
Though I say so myself, it's really rather impressive.
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Now that I am at a proper pooter i can do a proper update.
Electric Bike Conversions have been extremely supportive though they were unable to unearth an older control box in their warehouse leaving us to take the risk on the newer controller without the wheel magnet sensor. Also, the newer box has the wiring for the hall sensor in the front wheel, something that the old controller did not. The hub had the wiring but we didn't know if it actually had the sensor installed.
I started this afternoon by removing the surplus wheel sensor and wiring and then tidying up the loom. I had to strip the pedal sensor wires and use a choc block to connect this as the pedal sensor had previously been butchered. Also, the power cables from the battery needed connecting as they too had no connections.
All done I slipped the charged battery into the cradle, pressed the on/off switch and waited for the battery on light to glow. Turning to the handlebars I pressed the power button and almost found religion. The lcd display flickered into life and everything was showing as normal including a level of charge in the battery. This was progress indeed from the previous controller.
Tentatively I reached down for the pedal and started to turn them. Last time nothing happened but this time after about an eighth of a turn of the cranks the motor kicked in. YES!!! I released the pedals and the motor cut, then turned again to restart the motor which worked. Still turning the pedals I operated each brake lever in turn which caused the motor to cut out. Excellent. One final test was to hit the throttle. I stopped turning the pedals and waited for the wheel to stop. I could have used the brake but my mind was racing to the throttle. I pressed the throttle and initially nothing happened. SHIT. But, just as I was losing faith (in about half a second by the way) the motor kicked in. JOY OF JOYS!!!
The bike was taken off the stand and into the close. I let the proud new owner give it it's maiden tarmac test before her husband and then I gave it a thrashing.
I am impressed, very impressed. We were riding using the motor in top gear and it didn't feel like it at all. It is going to be a great bike for this lady getting her back on two wheels. :thumbsup: :thumbsup:
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Congratulations. Electric bikes are superb. My wife and I did 50km today over serious hills in south of France. I was struggling to keep up with her up the hills and we had a wonderful ride together. ( she has the electric bike).
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The finished machine with happy owner:
(http://i952.photobucket.com/albums/ae1/brevet525/ElecBikeCreation_zpsgrxsila1.jpg) (http://s952.photobucket.com/user/brevet525/media/ElecBikeCreation_zpsgrxsila1.jpg.html)