Axa HR Traction bottle dynamo

The last holdout bike in the household has finally ditched battery lights. After giving her Brompton a dynamo wheel by selflessly buying myself a new Brompton, I had been promising Ms C. that I would sort out her Kona Africa bike with dynamo lights. Due to various upgrades I had managed to end up with a spare B&M Lumotec Retro front lamp and a spare Brompton Spanninga rear light. All I was waiting for was the next time I needed to order something from Rose Bikes and I could add on one of their cheap Axa HR Traction bottle dynamos. Thanks to worn out stock Brompton brake pads, that time finally came.

This is the same dynamo which used to be specified by Brompton (the left mounting version) before the Shimano dynamo hubs became available. Rose sell them for £14-15, depending on exchange rate, which is probably quite galling for anyone who bought them as a Brompton part. Thankfully, the parts needed to run this dynamo on the Brompton rear wheel (a special stay and a mudguard with a cut-out) are still available as spares, making this particular dynamo probably the cheapest (and fully supported) route to dynamo lighting on a Brompton.

The bottom of the dynamo has two pairs of remarkably simple wire connectors, simply insert stripped wire into plastic housing and push it into the dynamo body. The arrangement allows front and rear lights to be connected to the dynamo independently of each other, rather than requiring the rear light be connected through the front as is the case with most hub dynamo set-ups. In the end I ran the rear light from the connectors on the Lumotec Retro so that it would be less work if the Kona Africa Bike ended up with a hub dynamo.

Axa also make a dynamo mounting bracket which screws onto cantilever/linear pull brake bosses (front left/rear right only – requires left mounting version of dynamo). A simple design which works well, although the screw shown connecting bracket and dynamo was not included.

Since the Africa Bike was kitted out with a front rack in 2011, the front lamp could not be mounted on the fork crown or using the headset bracket. Instead I used the cork-lined p-clip supplied with the front rack to fix the lamp in place on the right hand supporting leg, Japanese style.

Not exactly elegant, but it does the job.

Similarly, the rear light attachment was a bit of a bodge. Since the rear rack in integral to the Africa Bike’s frame and lacks a rear light mounting plate, I drilled four holes into a roughly 100 mm section of trunking lid I had knocking about. Two of these were for the fixing bolts on the light, the other two were to create a slot for the jubilee clip used to attach the creation to the rear rack. Not pretty but it does the job.

I took the bike out for a spin with the dynamo on to make sure I had set it up without too much pressure causing excessive drag. Thankfully it was spot-on; other than the whirr of the roller it was barely noticeable. For a bike such as this which is used as practical transportation rather than high speed, high effort riding, this set-up works really well.

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B&M Toplight Line Plus Braketec rear light

For a while now I’ve had my eye on the B&M Toplight Line Plus with Braketec. The standard Line Plus uses a pair of LEDs and some clever optics to produce a line of red light rather than just two spots. The logic behind this is that diffusing the light into a line makes it easier for following traffic to judge the distance of the light, whilst also being less likely to irritate those following.

The Braketec version of the light also features a signal processor which detects the change in the dynamo AC frequency when the bike slows rapidly, momentarily increasing the brightness of the light to indicate the rider is braking. Whilst I have my doubts about the usefulness of turning signal lights for bicycles, I expect that a brake light will at least be correctly registered by following motorists despite the relative rarity of brake lights on bicycles. However, the main reason for wanting to try this light out are not because of the potential minor safety benefits which come from the brake light function, but because it is quite a clever idea, executed in an interesting way.

The light is bright, although the rack mounting on the Brompton makes for rather poor side visibility. Thankfully this is made up for by the reasonable side visibility of the front light an the reflective sidewalls of the Marathon Plus tyres. The brake light function works without any calibration required, regardless of whether you are using a hub dynamo with large wheels, small wheels or a bottle dynamo. It just works.

The effect is pretty clear in the video, but viewed by the human eye rather than through a digital camera it is much more pronounced.

Electrified Brompton Luggage

Although expensive, I’m a big fan of the Brompton luggage system. Much like the fold of the bike itself, it is simple, elegant and involves the only the minimum amount of fannying about. It is this functional design which inspired me to finally revisit one of my old projects; USB charging using a bicycle dynamo. Whilst my previous attempt was rather crude (both electrically and aesthetically) the Brompton luggage system presented the opportunity to do this idea right.

You will need:

• A Brompton (or other bike which uses the Brompton luggage system, such as the Circe Helios) with luggage block and either an A, C/T or S bag luggage frame (plus bag) made after Brompton switched from their older all steel frame design to their current tubes and black plastic one.
• Switched* dynamo lights (and a dynamo)
• At least six M3 x 5 mm (approx) cheese head screws (flat tops)
• At least eight M3 washers
• At least two M3 nuts
• At least eight small (red insulation) 3 mm ring crimps
• Some double (bell) wire, or two strands to twist together (1.5 m approx)
• A 2.5 and 3 mm drill bit (and a drill)
• A set of pliers
• A flat head screwdriver of suitable size for the M3 screws
• A few square cm of thin (approx 0.5 mm) sheet metal (a bit if old drinks can might do in a pinch)
• It would also be advantageous to have a set of M3 taps, although a screw can be used for tapping if you do not have taps.

If you don’t have any of these parts, consider ordering them from Farnell (for reasons which will become apparent later).

The first task is to drill two holes on the top of the luggage block using the 2.5 mm bit as shown in the picture and then tap the holes (this can be done, with sufficient patience using one of the M3 screws if you do not have taps). Fit ring crimps (remove the insulation and crush the crimp closed with the wire inside the crimp using pliers) to a length of wire long enough to reach from these holes to the connector on the dynamo and connect the crimped ends to the luggage block with a screw and washer each. Connect the other end to the dynamo connector in parallel with your existing (switchable) dynamo lights. If you want the wiring to look tidy, fit a couple of P clips on the luggage block to route the wire.

Next comes the luggage frame. Drill two holes on the plastic part of the frame just above the cut out for the luggage block, as shown in the picture below and tap these holes as before. Make a pair of connectors from the sheet metal as shown below and drill them with the 3 mm bit. Fit these connectors to the luggage frame using a screw and a washer each in the holes tapped in the frame. The top of the luggage block does not usually make contact with the top of the cut-out on the frame, so your contacts will need to protrude downwards enough to make good contact with each of the screws on the top of the luggage block.

Congratulations, you now have a set of terminals supplying ~6V AC on your Brompton luggage. What you do with it is only limited by your imagination.

I decided to build a new USB charging circuit, based on this post. The post contains a list of all the parts you will need to build the circuit neatly on a bit of strip-board (veroboard) from the Farnell catalogue. I added a PCB USB socket from Maplin so that the 5V DC produced by could be used to charge a range of devices such as smartphones, MP3 players or GPS devices and a simple plastic enclosure to keep it all together. I drilled a pair of 3 mm holes for two screws to be used as electrical connectors and linked these connectors to those on the luggage frame using a ~400 mm section of paired wire with 3 mm ring crimps on each end. When using the referenced post, if you buy different but equivalent parts, be aware that capacitors 1 and 3 are polarised type and capacitor 2 is a non-polarised type.

The circuit on the strip-board (the layout may appear confusing due to an earlier mistake).

I added a switch to the enclosure so that the circuit can be switched off when the lights are in use. The strip-board and components can just about be stuffed into the remaining space in the enclosure, which has had a hole cut in it to allow access to the USB port. In the mark II I will probably think more carefully about the arrangement of parts and the inputs within the enclosure before I start drilling. The wire linking the assembled enclosure to the luggage frame is routed through a hole which had started to develop without any assistance from me in the bottom of the C bag’s left pocket.

The circuit charges my Android smartphone when the front wheel is spun by hand and I will update this post after I take it for an extended test ride in the near future. When running the charging circuit, simply turn off your dynamo lights. When using your dynamo lights, be sure to turn off the charging circuit. Happy charging.

* If you add additional switches, non-switched lights and a bottle dynamo could be used in place of a hub dynamo.

B&M Lumotec IQ Cyo senso plus T

The Cyo T is much like the 60 lux Cyo, but with a row of four LEDs under the main lens which direct light at oncoming traffic for enhanced visibility

I have replaced my ailing B&M Lyt plus with the catchily-named Lumotec IQ Cyo senseo plus T also made by B&M. There are currently around ten+ variants of the Cyo, including 40 and 60 lux versions (the 40 lux incorporates a reflector which the 60 does not) bottle or hub dynamo versions, near-field lighting versions, automatic on/off via light sensor versions, versions with daylight running lights and either a black or silver finish for some of these models (as discussed previously).

The Lumotec IQ Cyo senseo plus T is the hub dynamo version of the 60 lux Cyo, with automatic on/off via light sensor and daylight running lights. In this version, the light sensor switches the light between day and night modes. The daylight running lights consist of four LEDs underneath the lens for the main beam. Unlike the main beam which is directed at the road, these LEDs are directed at oncoming traffic as an aid to ‘being seen.’ During the day the main light beam is at significantly reduced intensity, whilst the four LEDs underneath the lens are all illuminated. At night, the main beam is illuminated to full intensity and only two of the daylight running light LEDs are illuminated, with these two LEDs also forming the stand-light feature in this model.

Whilst I am very happy with the Philips Saferide lamp recently acquired for the DL-1, the unique proportions of the Brompton mean that only a handful of front lights can be fitted without causing problems with the front luggage system. The Saferide is not one of these due to the lack of mount compatibility with B&M fixings (unless modified). Brompton specify either the bottom-of-the-line Lumotec halogen light with the Shimano dynamo wheel or the top-of-the-range (ish) 40 lux Cyo with the SON dynamo wheel. This is perhaps a little unfair to customers, as it suggests that the Shimano dynamo wheel can only power a low end light, despite it being capable of powering the same range of lights as the  SON*. As I discovered, as an alternative option the Lyt can be fitted to a Brompton by using a Cyomount, although my initial research suggested that this was not common.In complete darkness the Cyo T provides almost as much illumination as the Saferide. The beam is a bit less wide and the throw seems a little less too. The apparent subjective reduction in throw compared to the Saferide is likely a result of the central bright spot which comprises part of the beam shape. Whilst useful for avoiding potholes (especially so on a small-wheeled bike), the bright spot does make the rest of the beam which is projected beyond it seem less intense than it actually is. The slightly reduced beam width and throw compared to the Saferide is likely being exaggerated in this case by the lower mounting height of the Cyo on the Brompton (~350 mm) than on a conventional bike (~750 mm), but the beam is still entirely sufficient.

Where the Cyo T excels is in its urban-friendly features, such as daylight running mode which to helps mitigate the risk of not being seen by negligent motorists, and the automatic switching between day & night modes via light sensor. The daylight running lights are particularly effective at drawing extra attention in daylight, directing a good amount of light at oncoming traffic. At night, the two lower LEDs which remain turned on are illuminated to a lower intensity, to avoid blinding oncoming traffic. The automatic light sensor can be over-ridden if desired to keep the Cyo T in daylight mode at night. The level of road illumination provided by the light in ‘day mode’ is sufficient in well-lit areas where being seen may be of more concern than lighting up the road itself, still meeting the minimum standard for a ‘proper’ light.

The stand-light is different to other lamps I have used. Like the Lumotec Retro, the stand-light is provided by auxiliary LEDs rather than using the main beam as the Saferide and Lyt do. However, unlike any of these other lights the stand-light does not merely stay illuminated until the capacitor has been discharged, it is timed to shut off after around four minutes despite the capacitor having a capacity for a greater length of time. The result of this is that the stand-light is immediately available if the bike (dynamo) is moved again.

The rotary switch on the rear of the Cyo has three settings, off, sensor and daylight mode

Unlike the 40 lux version of the Cyo and the Lyt, the Cyo T does not come with an integrated reflector. A reflector is available for adding to the bottom of the standard Cyo mount, although the Brompton mount is not compatible with this. It is also worth noting that the Torx bolt which comes with the standard Cyo mounting bracket is not compatible with the Brompton Cyo mount due to the different tube thickness. Whilst this set-up has left the Brompton without a front reflector, the daylight running lights are definitely a replacement which is in the spirit of the law even if it does not conform to the letter of it.

The Torx bolt has instead been pressed into service mounting the Lyt back on the Yuba Mundo

I like the Cyo T. In plain terms of brightness and throw, it is not as good as the Saferide, but as I stated in that review, for urban utility riding the beam of the Saferide is overkill. The Cyo T also provides more than enough light for riding along unlit roads. However, the daylight running mode and the automatic switching between day and night modes make this an ideal choice for the primarily urban cyclist, whilst the beam it provides is more than sufficient for riding on unlit roads and paths too. Unless you do a great deal of your riding on completely unlit roads, these extra features probably make the Cyo T the better choice.

*The Brompton SON dynamo wheel could be used to drive a pair of front lights as is fairly common practice amongst SON owners. For typical Brompton usage it is probably not worth the extra cash.

Philips Saferide dynamo lamp

I briefly mentioned this lamp at the end of the recent post about dynamo lighting, having read universal praise of it online. I continued to look for more information on the lamp and I found an online shop selling it at a price which seemed too good to pass up. Wanting to find out more, I bit the bullet and ordered the lamp.

After a few days, the lamp arrived. The Philips Saferide has a rated light output of 60 lux, the same as the B&M Cyo (although this number alone actually tells us very little). Also like the Cyo, the housing is aluminium to facilitate LED cooling (however, only a portion of the Cyo housing is aluminium). Like most dynamo lights, the beam is dipped so that the majority of the light ends up illuminating the road rather than blinding oncoming traffic.

I was most intrigued by this; it appears that in some jurisdictions this lamp is sufficiently bright for use on 50 cc motorcycles too.

The light comes with a bracket and integrated reflector. The reflector also houses the wire after it leaves the lamp, which would have to be dismantled ion order to change the bracket. At the lamp end. whilst similar to the B&M mounting the Saferide mount is wider at this point, use of B&M mountings would require some bracket modification in order to work.

The light source of this lamp is indirect; the beam is formed by a pair of LEDs which sit at the top of the lamp. The optics then direct the light provided by these LEDs into an even beam.

The cables leaving the back of the lamp include a pair for connecting to the dynamo and a second pair which terminate in spade connectors, for hooking-up a rear light.

The only criticism I have seen of this lamp is that the bracket is weak at the fork crown end, due to the scoring pictured above. In order to mitigate this, I used large washers when the light was mounted in order to spread the load over a wider area of the bracket.

The Saferide on the DL-1 (which I should clean). Whilst the Brompton is more in need of a new front lamp, the bracket of the Saferide would not be compatible with the luggage block. The Saferide is less aesthetically appropriate than the Lumotec Retro which was previously fitted to the DL-1, but the DL-1 is a working bike, not a museum piece.

Unlike the Lumotec Retro, the Saferide does not have the automatic on/off via light sensor feature which I came to appreciate. The Saferide is controlled by an on/off switch on the top of the unit, which also turns off the stand-light when switched off. The capacitor holds the charge for at least a day even when switched off, so the stand-light can be turned back on when unlocking the bike.

Now, onto the performance of the light itself. This thing is bright, I mean seriously bright. The first ride I did with it was Halloween Critical Mass, which took place as it was starting to get dark. By the end of the ride it was completely dark and the mass was heading to Platt Fields park (which lacks lighting in many parts). By this point I was towards the back and the Saferide was illuminating the lower half of all the bikes in front of me and completely outshining the lights on the 15 or so bikes in front of me.

The best light I have to compare the Saferide to is the Lumotec Lyt. The Lyt provides enough light to ride quite comfortably on unlit country roads, producing a bright, slightly narrow beam with a halo of light thrown wide to provide visibility of the sides of the road, overhanging vegetation, visibility for oncoming traffic and illuminate road signs. In comparison, the Saferide has a taller, notably brighter beam which is about twice the width. The whole width of a country road is illuminated easily, and the beam stretches up to around 50 metres in front of the bike. The ‘halo’ of the Lyt is replaced by a slightly odd ‘broken halo,’ similar to the stylised rays surrounding a child’s drawing of the sun. These ‘rays’ provide visibility of the sides of the road nearer to the bike and do an excellent job of lighting up road signs and the reflectors on parked cars. When I took the DL-1 on a ride along some unlit country roads in the dark using the Saferide, after a while I wasn’t sure how dark it had been when I set off. Switching the Saferide off for a moment confirmed that it was indeed completely dark at the time.

I would like to compare the Saferide to similarly-rated lights such as the Edelux and the Cyo. If Mr MiddleAgeCyclist would like to go for a spin somewhere at night, I’d be happy to see how the Saferide and Edelux compare.

For urban utility riding, the Saferide is complete and total overkill. For rural utility riding, the Saferide represents a worthwhile purchase, especially considering the battery requirements (and conical beam-shape) of a typical similarly bright battery light. Thanks to good (dynamo) lighting, I enjoy riding at night, both for utility and just for fun. For the most part of my riding the Saferide will be overkill, but it will come into its own when I’m riding for fun.

The Lumotec Retro is currently for sale on eBay, although I’d be willing to sell privately to a local instead.

UPDATE (6/11/11)

Yesterday I was able to meet up with Mr Middle Age Cyclist for a ride down the Floop after dark, to compare the Saferide with his Schmidt Edelux. The Floop is completely unlit, providing a good proving ground for the lights. Whilst the comparison is highly subjective, we both agreed that the lights are effectively equivalent in performance. The Edelux casts a slightly taller, more narrow beam whilst the Saferide casts a slightly shorter, more wide beam. The Edelux is effectively a super version of the B&M Cyo, possessing the same optics and LED, but housed in a more thermally-efficient aluminium housing with a glass lens. This set-up is designed to get that little bit more output from the same core light, suggesting that the Saferide is likely an equal, or perhaps marginally superior light to the Cyo. One day I will do another direct comparison with a Cyo.

Light is Running Out

It’s that time of year again. When Sunday comes it will be dark a lot of the time for anyone who works a conventional 9-5 shift pattern. This will be my second winter of riding with dynamo lights, with dynamos on all of the bikes this time, although still only enough lights for two of them; the Brompton and the DL-1. This is the perfect time of year to ‘go dynamo,’ not only for the long-term savings but, as I learned myself last winter, it’s extremely liberating.

Some people hang up their bikes for winter. If you are a utility cyclist however, this is unlikely to be the case. I have ridden through every winter since I started cycling again as an adult. However, until last year I never really got any enjoyment doing it.  Having to remember to take my lights everywhere, carry them around when off the bike was a minor hassle. What really bothered me was the persistent, nagging concern that I’d be caught out by flat batteries and have to risk a ride home without lights. The battery lights I had used in the past were adequate, but never truly that bright. I knew of the much brighter options available but the price never seemed justifiable to me, for something which could so easily become useless if forgotten of accidentally uncharged.

When I bought my first dynamo lamp, a B&M Lumotec Retro N senseo plus, it was mainly because I was concerned with having a light which was in-keeping with the aesthetics of my then new-to-me DL-1. English-language information regarding dynamo lights was pretty sketchy, I wasn’t sure what I was going to get. Because of this, I was pleasantly surprised to find that the light I had purchased was actually a lot brighter than my previous battery-powered LED lights, despite being a halogen bulb. It was always there when I needed it and would even come on automatically when darkness fell. This started to change the way I felt about riding in the dark, from something to be avoided to something to relish. As that first dynamo winter drew in, I found myself riding as much as I had during summer.

Naturally, I had to get the rear light powered by the dynamo too, whilst permanently attached to the bike, the rear the battery light which came with the DL-1 was still a weak link, dependent on batteries. Once again, information was lacking. B&M produced rear lights with the same automatic light-sensor on/off control as the Retro, although it seemed that this feature was only available with the battery or battery/dynamo hybrid models. Once again I took the plunge and purchased a B&M D-Toplight Plus. The tail-light was wired into the connectors on the front lamp for this purpose; to my surprise the automatic light sensor in the front light also controlled the power supply to the rear light. When it got dark both lights would come on automatically (including when passing through a tunnel). Brilliant.

Having this kind of set-up on the DL-1 made the Yuba Mundo seem almost a hassle to ride. The Shimano dynamo hubs available in my price range were all intended for use with Centerlock disk brakes, rather than the standard 6-bold arrangement used on the Yuba Mundo. The additional cost of a new Centerlock rotor or an IS adaptor pushed the price to more than I could justify spending at the time. A post from Lovely Bicycle! gave me the answer I was looking for, a bottle dynamo. Older bottle dynamos (and modern cheap ones) have contributed to the poor regard with which dynamo systems are viewed here in the UK. However, higher-spec bottles such as the Nordlicht 2000 or the B&M Dymotec seemed to offer a reasonable trade-off between performance and price. I decided to opt for the Basil Nordlicht bottle dynamo in combination with with a B&M Lumotec Lyt plus, a reasonably priced light with a higher light output rating than the Retro. Due to budgetary constraints, an additional rear light would have to wait.

Unlike the Sturmey Archer X-FDD hub dynamo on the DL-1, the Basil Nordlicht took a bit more work to find the optimum fitting. The advantage of the Basil Nordlichtis that the rollers can be changed. Multiple variants are available including a steel roller for running on the tyre, a rubber roller for running on the rim and a larger rubber roller for running on the rim at higher speeds. The larger roller is particularly useful as it allows the dynamo to be ‘geared down.’ As bottle dynamos are typically designed to produce full power output at relatively low speeds (<10km/h) they can produce too much drag when used by faster cyclists. The larger roller compensates for this by reducing the amount of dynamo revolutions per tyre revolution, and hence the resulting drag. Initially the bottle dynamo was mounted on the fork, unfortunately the pressure it exerted on the rim caused the rotor of the disk brake to rub against the brake pads when it was engaged. Eventually I mounted the dynamo on the seat-stay and adjusted the mounting angle which produced ideal dynamo contact pressure on the rim, enough to prevent slippage but not enough to create noticeable drag.

At present the Basil Nordlicht bottle dynamo is still fitted to the Yuba Mundo, although there are no dynamo lights fitted for it to drive. This is due to my acquisition of a Brompton. After a few weeks with the Brompton, I felt that a bike such as this really needed to be all in-one, including self-sufficient lighting. It was around this time that the annual price increases for Brompton components were being rolled out. The Brompton dynamo wheel RRP was about to increase by about 15% making that then the ideal time to upgrade to the Shimano hub dynamo wheel. I had considered the fitting the Basil Nordlicht bottle to the Brompton, but the relatively good price of the wheel and my uncertainty about clearances for fitting the bottle led me to choose the hub over the bottle.

Rather than splash out on a new front light, my limited budget led me to fit the Lyt from the Yuba Mundo instead. My intention was to replace the front lamp on the Yuba Mundo at a later date, which I have still yet to do. Initially I bent the Lyt mount to fit it into the tight space between the caliper brake and the luggage block, a solution which was far from ideal. I was later able to use a Brompton Cyo mounting bracket to fit the Lyt into the limited space offered by the Brompton. I also added a Brompton rear dynamo light (made by Spanninga) to complete the set-up

The version of the Lyt I had purchased for the Yuba Mundo was the bottle dynamo version; when connected to the hub dynamo on the Brompton, both front and rear lights ran whenever the bike was in motion. Whilst not as optimal as the automatic on/off light sensor of the Retro, this set-up actually works well, due to the extraordinary operational lifespan of LEDs. It now appears that I was a little ahead of the curve in choosing this set-up; B&M’s entire 2012 range of dynamo lighting comes with the option for daylight running lights.

My experiences with dynamo lighting have not been universally positive. The standlight functions on both of the lights fitted to the Brompton failed by summer, although they were both relatively easy to fix. However, it is my ‘off-label’ riding with the Brompton which is more likely the cause of this failure than any deficiency in the lights’ designs; Bromptons are not really ideal bikes for fast riding on cobbled paths, the resulting vibrations were obviously a bit too much for the capacitors powering the standlight. Under more typical riding conditions I doubt that this problem would have occurred. For this reason I would still strongly recommend dynamo lighting to anyone, including the models of light which I have had problems with.

A great deal of dynamo lighting technology is designed by (or for) the German market. German regulations stipulate that a bicycle must be sold complete with a dynamo lighting system (except lightweight sports-bikes), including lights which conform to specific regulations for beam shape and light intensity. These regulations are more strict than elsewhere and have effectively become the de facto international standard. The misconceptions about dynamo lighting which persist in the English-speaking world means that we do not constitute a huge proportion of the market for dynamo lighting components, with equipment and information  often difficult to come by. B&M in particular make great equipment but the English-language information about them is lacking. They also suffer from the Windows Vista effect; huge numbers of variants on each light model exist with relatively subtle differences between them and confusing nomenclature. These differences are seldom well explained in product descriptions on the handful of retailers which stock them.

Because of this, to help prospective dynamo light users I have produced a B&M dynamo light nomenclature guide:

Lumotec: The front dynamo light brand name.
Toplight: The rear dynamo light brand name.
Retro, Lyt, IQ Fly, IQ Cyo etc: The model name.
Plus: Includes standlight. The light (or a portion of it) remains illuminated for a few minutes after motion stops.
Senseo: Includes automatic on/off via light sensor.
N: Includes an on/off switch, intended for use with hub dynamos.
B: Basic version, lower light output but still meeting German minimum standard.
R: Taller beam, including near-field illumination of dark patch in front of wheel.
T: Daylight running lights. In addition to the beam aimed at the road, a series of small LEDs direct light at oncoming traffic to increase cyclist visibility. During the day these lights remain lit, whilst the main beam runs at reduced power or is switched off.


B&M are of course not the only manufacturer of dynamo lights, merely the one with which I have most experience. Mr Hembrow gives high praise to the new dynamo front lamp manufactured by Philips; the Saferide (repeated elsewhere). It is my hope to test out a Saferide in the future and share my impressions here. If anyone has any questions about ‘going dynamo,’ please feel free to leave a comment and I will endeavour to help you if I can.

Make Do & Mend

Way back in early August on a ride back to Manchester at night I was worried the see that the stand-light on my B&M Lumotec Lyt, the front lamp on my Brompton had stopped working. The back stand-light on my Brompton had been non-functional for a while too. I couldn’t really justify the expense of replacing either of these lights, especially after such a short time in service. Thankfully, I have some experience of electronics from sixth form college and  had also done some work with battery-backed full-wave rectification circuits previously. The fact that the stand-light had gone on both lights, but both still worked when the bike was in motion suggested to me that the capacitor used to power the stand-light is connected in parallel with the rectified current from the dynamo and in both cases had become disconnected. The rattle was a bit of a giveaway too. I firstly too a look inside the Lumotec Lyt.

The casing of the Lyt can be gently prized apart with the edge of a screwdriver.

The business part of the Lyt, the circuit board, containing the central LED, with the £1 coin-sized capacitor next to it.

After examining the circuit board, I found the part of it to which the capacitor attached. When assembled, the capacitor sits in this position at the top right of the circuit board which sits vertically in the housing. The relatively heavy capacitor is supported at this angle by two contacts soldered in to the board in a manner which is not really ideal for applications with a lot of bumping and vibration, such as in bicycles (especially on the Brompton).

One of the contacts had broken off with the capacitor, a wire was soldered to this end,

and soldered into the circuit board at the other end.

A contact for the side of the capacitor whose original contact was still attached to the circuit board was fashioned from part of the tab from a drinks can,

and placed in contact with the capacitor using tape. The remaining end of the wire pair was soldered to the contact on the circuit board,

and the whole thing was taped (crudely) to the inside of the housing of the Lyt. Whilst hardly a professional job, the result has held just fine for over two months. The situation with the rear light, a Brompton dynamo light (made by Spanninga) was similar, although the capacitor was positioned more sensibly in this design.

The capacitor as intended to be positioned on the circuit board of the Brompton rear light was re-affixed in a similarly crude manner to the capacitor in the Lyt; using solder and a lot of tape. This repair job has also held up surprisingly well since the beginning of August.

The long-term plan is to retire both of these lights to the Yuba Mundo, which is both used less frequently than the Brompton and which, with larger wheels and more voluminous tyres will likely be less demanding on these damaged lights, and replace the front lamp with a Cyo and a new Brompton rear light which I will pre-emptively reinforce. Until I have the funds for that though, I’ll have to make do & mend.