French connection, the Cybien.

[silversurfer]

Back in June I was on holiday in Brittany with some friends. We happened to spot a mature (circa. 1930!) gent about to get on an electric scooter. Being interested I engaged him in conversation.... bad move! Before you could say 'mais non' we were invited back to his place and were picking up the finer points of testing French wine! However, he was an electric bike enthusiast, lots of newspaper cutting of celebrities on bikes including Madam Royale, the then just defeated Presidential candidate.

He told us of an electric bike manufacturer 20 miles away, so next day, suitably sober we made a visit.

Wow.... the showroom attached to the small factory would have done justice to a BMW dealership. 20 + bikes of all options on display, a rolling road to test them, accessories etc. The owner/designer and his wife were very helpful giving me, in broken English that matched my even more broken French, lots of data.

The bike were superb, like Swiss watches, super light (20 kg. all up) and powered by two American motors behind the seat gripping on a special insert fitted into the wheel rim. Assistance limited to 15 mph, and at that speed a solenoid pulls the motors off the insert. His Battery claims were quite amazing. I quote from his notes (made on a bit of scrap paper I gave him).

Motor grip /efficiency, 60 to 70%. Whilst the friction drive technique is old hat, this is certainly a new way to apply it to the wheel.
25 volt 16 Ah Li ion battery, one charge gives up to 100km/62 miles (if no hills and some pedalling, 200km/124 miles !). One customer had apparently done 30,000km in two years!

Of course this quality costs money. However...2,500 euro (probably £1,700 ish) relates favorarably to our top end 'Chinese built' purchases, and the French price includes TVA at almost 20%.

Sorry, but It was not diplomatic for me to ask for a ride, as it was obvious we were just looking, and they knew it!
You may or may not like it, but it is different! SS.

http://users.tinyworld.co.uk/flecc/images/cybien.jpg

 

[ITSPETEINIT]

Bas Move? You must be y-oking!

Back in June I was on holiday in Brittany with some friends. We happened to spot a mature (circa. 1930!) gent about to get on an electric scooter. Being interested I engaged him in conversation.... bad move! Before you could say 'mais non' we were invited back to his place and were picking up the finer points of testing French wine! However, he was an electric bike enthusiast, lots of newspaper cutting of celebrities on bikes including Madam Royale, the then just defeated Presidential candidate.

He told us of an electric bike manufacturer 20 miles away, so next day, suitably sober we made a visit.

Wow.... the showroom attached to the small factory would have done justice to a BMW dealership. 20 + bikes of all options on display, a rolling road to test them, accessories etc. The owner/designer and his wife were very helpful giving me, in broken English that matched my even more broken French, lots of data.

The bike were superb, like Swiss watches, super light (20 kg. all up) and powered by two American motors behind the seat gripping on a special insert fitted into the wheel rim. Assistance limited to 15 mph, and at that speed a solenoid pulls the motors off the insert. His Battery claims were quite amazing. I quote from his notes (made on a bit of scrap paper I gave him).

Motor grip /efficiency, 60 to 70%. Whilst the friction drive technique is old hat, this is certainly a new way to apply it to the wheel.
25 volt 16 Ah Li ion battery, one charge gives up to 100km/62 miles (if no hills and some pedalling, 200km/124 miles !). One customer had apparently done 30,000km in two years!

Of course this quality costs money. However...2,500 euro (probably £1,700 ish) relates favorarably to our top end 'Chinese built' purchases, and the French price includes TVA at almost 20%.

Sorry, but It was not diplomatic for me to ask for a ride, as it was obvious we were just looking, and they knew it!
You may or may not like it, but it is different! SS.


http://users.tinyworld.co.uk/flecc/images/cybien.jpg

Hello Ted:
How is that a bad move? "Wine tasting". It was not Vin de Bretagne I hope.
The bike looks interesting. Very 'Sportif'. I can't think why a rim driving motor should be more efficient. Perhaps it was the capacity of the Battery which would of course put up the price a little as would TVA at 20% (17.5% en Angleterre). Then again it was only 24 volts.
I am not sure I favour the Road racing/Touring position any more. Conversion would cost bars, brakes and gear levers (which I note are for Double chain rings). Perhaps too expensive unless one can convince the manufacturers to do a bespoke modification.
A trip to Brittany would not be a penalty - quite the reverse. Make it a week and one could have some fun as well.
Cheers
Peter

 

[silversurfer]

Hi Peter, Of course the French (being well into racing) feature the racing version largest on the brochure, but they do a nice range of others on the same drive theme, a high handle bar gents (like a torq) and a step through, both with rear carriers, also a velox, a stright H bar racer. even a tandam for the family man !
Rim drive motor more efficient ? depends what you compare it to... belt drive motorcycles were efficient, until someone used a chain !
Oh I do have the Full brochure (A4x2) takes up about 5mb as a tiff file, unless someone can advise how to reduce it, you are wellcome to a download SS

 

[Leonardo]

Hello - the Cybien is quite appreciated in France as a sport pedelec... as far as I know it seems to be the only friction drive system working really well

here is a competent review in French

 

[flecc]

Silver Surfer let me see a leaflet on this and a graph on that supports the French language review that Leonardo has linked to. In other words, the motor drive is biased towards hill climb ability rather than speed, and it looks particularly strong at climbing at around 8 mph.

Bad points for me are first the friction drive, not because it doesn't work, since that clamping between two motors clearly does, but because it is so dependent on the wheel's integrity. Second are the motors which will almost certainly be brush ones, and these are sometimes rather noisy under higher loads. Third, two motors are much less efficient than one, heavier and wasting more current for a given power. Finally, I don't like the motor's weight so high up.

On the good side, the bike has clearly been designed by someone who knows what a good bike is, and that is extremely rare in the electric bike world. Also, as SilverSurfer remarked, it's obviously well built and very high quality, again not too common in our field.

I'm in some agreement with the review's conclusions. It's clearly a good bike for a keen cyclist who mainly wants help on hills, while as far as possible retaining the advantages of a good sports bike. There's a small market here for that sort of quality bike, though I think the straight handlebar versions that they also make would suit our market better.
.

 

[ITSPETEINIT]

Cybien drive

What ever the apparent technical shortcomings of the friction drive, the problems really begin with 'lack of friction'.
I would certainly want to try the bike on a wet day/wet road. Up hill in the wet would be even worse - one would make no progress at all if it was like the tyre drive I had on a gasoline fuelled bike motor.
Water is a great lubricant for such systems.
The Velo Solex was a tyre drive friction roller. I did not have one but I saw many in France. Does anyone have any experience of how they reacted to the wet roads?
Peter

 

[flecc]

Yes Peter, they can slip like mad! I used to work on them years ago and my father commuted with one for some years. Silver Surfer still owns some of them and I'm sure he'll also tell of the slipping.

The Twin motors on the Cybien apparently grip ok by clamping though, and I understand the rollers are aluminium alloy on the rubber drive rim. That reads true, since the failings of brake blocks on steel rims in the wet with bikes years ago was cured by using alloy rims universally. As you know, brake pads do grip on alloy rims ok when it's wet, curing the accident prone problems of yesteryears steel rim bikes.
.

 

[silversurfer]

Hi Peter. Friction drives... flat belts been around for centuries, V belts are better and multi V's far better at transmitting power, especially if they have a good 'wrap' around the pully. But roller friction drive has no wrap, just a grip contact patch about as wide as your little finger on a Velo-Solex moped.
On British roller drives (circa 1950's) they used a ribbed aluminum roller onto the tyre, these did slip in the wet The Solex used a cabarumdum (not sure of the spelling here!) roller which gripped quite well, if set properly. But, tended to grind 'hollows' in the tyre tread with the action of dropping the pivotable engine down onto the tyre! What tended to make this form of transmision slip was acceleration (not that there was much on a 1/2 BHP Solex engine!). The sudden increase in power caused the roller to loose it's 'bite' and spin,especially if wet. But, on steady loads it was ok, remember, they were only good for about 20 mph.
To get back to the Cybien, it wins on this by 'pinching' the special hi-tech 'rubber' band between two rollers. I take flecc's point about the energy required on this system. Perhaps the 60 to 70% efficiency may be taking acount of electrical as well as frictional losses? I suspect the high km figure is because the assistance is only applied in a limited way, the bike looks like it is a real cyclist's machine and perhaps covers greater distances on pure pedal power? Over to you Peter, when are you planning to go for a trial run? I am over in France middle of October. SS

 

[flecc]

On British roller drives (circa 1950's) they used a ribbed aluminum roller onto the tyre, these did slip in the wet

The Power Pak was like this, and the worst for slip. Being quite powerful, they could destroy a block tread tyre in seconds in the wet, tearing lumps off it.

The Solex used a cabarumdum (not sure of the spelling here!) roller which gripped quite well, if set properly. But, tended to grind 'hollows' in the tyre tread with the action of dropping the pivotable engine down onto the tyre! What tended to make this form of transmision slip was acceleration (not that there was much on a 1/2 BHP Solex engine!). The sudden increase in power caused the roller to loose it's 'bite' and spin,especially if wet. But, on steady loads it was ok, remember, they were only good for about 20 mph.

That's what I remember, once rolling in the wet ok, but starting via pedalling if the bike was already thoroughly wet could sometimes be a problem with persistent slip instead of rotation, likewise acceleration. ( Carborundum )

To get back to the Cybien, - - - - -I suspect the high km figure is because the assistance is only applied in a limited way, the bike looks like it is a real cyclist's machine and perhaps covers greater distances on pure pedal power? SS

I think that's it too.
.

 

[JohnInStockie]

I'm still intrigued by this bike. They have a courier version that comes with all the bells and whistles for our damp n dark climate.

Interesting as well are the front lights seen here. Does anyone know how/what they are?

 

[Ian]

I'm still intrigued by this bike. They have a courier version that comes with all the bells and whistles for our damp n dark climate.

Interesting as well are the front lights seen here. Does anyone know how/what they are?

They look like a pair of dynamo lamps mounted on a specially made bracket and probably adapted to run from the main battery. I am currently adapting a similar lamp for my Sprint by fitting it with 64 LEDs.

 

[JohnInStockie]

64

How are you getting on with it?
(asking as I am STILL not happy with my lights)

John

 

[Ian]

I'm actually making two lamps, one for each bike with 64 LEDs in each. At present I have one I made with 36 LED's which is bright but I want something which very clearly visible in daylight as well. I spent the morning making 2 circular aluminium plates to replace the existing reflectors, 64 holes in each took some time to drill and clean up. The LED's are on order from China so will probably take a couple of weeks.

A farly cheap but effective ready made twin headlamp is here I bought one last year and it certainly does the job. I did see the same thing in a Go Outdoors store at £19.99 although it's not on their website.

 

[JohnInStockie]

Do you think this could be rigged up to a bikes battery using a suitable voltage converter, if so, what sort of drain would they have?

 

[flecc]

Haku has posted some information on some DC to DC converters here John.

I'll leave the consumption question for Ian as I don't know those lights.
.

 

[Ian]

It would be possible, but the consumption is quite high and would affect range to some extent. They come with there own 6V 4.5 AH SLA battery in a neat bag and charger which is the easiest way to use them.

 

[Jeremy]

It's worth noting that LEDs need a constant current drive, not a constant voltage drive as seems to have been tried on the other thread. Driving LEDs at a constant voltage will inevitably lead to failure, unless there is a current limit circuit as well. The forward voltage of a single white LED is around 3.4V to 3.8V, but this is very dependent on current and temperature, so with constant voltage drive the current will vary wildly from LED to LED and with temperature.

Driving normal high brightness 5mm white LEDs at about 20mA constant current seems best from the experiments I've done over the past couple of days. I opted to drive nine LEDs in series from a simple 20mA constant current regulator for my front light, which seems to work OK on a 48V supply (the LEDs have combined voltage drop of about 32V). It would be easy enough to build several individual chains to run more LEDs, either using the circuit in the application note link I posted on the other thread, or just duplicating the simple current driver I used for each chain.

The flashing rear light I built uses one flashing LED in series with a chain of ordinary ones. Enough current leaks through the flashing LED when it's off to keep all the LEDs on, but a lot dimmer than when the light flashes. This seems to give a good compromise, as there is enough steady light to allow distance perception, yet the intensified flash really attracts attention well (especially if directly on-axis with one of the three slightly differently angled arrays).

Jeremy

 

[Ian]

I found with previous LED headlamps that series chains of 8 white LEDs with a 360 ohm resistor work well from a 36V supply. The current is not exactly constant varying from about 30mA to 20mA depending on the state of charge and load but in practice the brightness variation is hardly noticable. I also used a flashing LED in series with a chain of normal ones as described here.
My previous LED headlamps have had a switchable discrete monostable to provide a flashing function but the ones currently under construction will use a 555 timer.

 

[Jeremy]

I tried a simple series resistor for my nine LED chain, but found that to get the LEDs to work within the maximum continuous rating over a typical temperature range they'd see in use (20mA in the case of the ones I bought, they needed to be derated from 30mA at high temps) with a fully charged 48V battery (about 52V) meant that the brightness dropped off markedly as the battery voltage dipped. I originally used a 1k resistor, which just kept the LEDs inside their max rating with a full battery, but when the battery got down to 48V the LED current dropped to 16mA, which was noticeably dimmer.

The simple little LM317L circuit is tiny and hardly takes up more space than the resistor on it's own, but it does mean that the current (and hence LED brightness) remains the same over a battery voltage range of about 36V up to about 60V, pretty much irrespective of temperature. I didn't bother making up a circuit board, I just soldered the chip and resistor together and potted it in the epoxy I filled the back of the light with. Hopefully this will keep the weather out!

I'm inclined to experiment with some of the 1W LEDs available from here: Find MEGA-BRIGHT WHITE 1 Watt LED on eBay within LEDs, Components Supplies, Electrical Test Equipment, Business, Office Industrial (end time 17-Nov-07 22:59:34 GMT) . Has anyone tried something similar?

Jeremy

 

[Ian]

The high currents that high power luxeon type LEDs require has allways put me off, along with the problem that that they all have wide beam angles and so need a lens. I've allways thought it easier to use lots of low power devices.