Bright Lights All Night?
(3 approaches to brighter lighting)
 High-Wattage bulbs and the LVR2
  Twin Headlights with a generator
   Three Micros with Lithium power

Bikecurrent Archive



Three Micros with Lithium power
by Francis Cooke

In 1998 I read an article by Jim Halay, describing his ride in the Boston-Montreal-Boston of that year. The BMB is a 1200km ride, so anyone undertaking such a project has to plan for a lot of night-riding, probably spread over 3 or 4 nights. Jim's lighting system, primary, secondary and tertiary, consisted simply of three CatEye Micros fitted with Lithium batteries. He said “the light weight, simplicity and long lasting batteries made the combination almost perfect”.

This system works because of three things:
> the remarkably compact design of the CatEye Micro front light, enabling three lights to be mounted in a small space, eg, all on the handlebars;
> the excellent bright light achievable with these 6V 2.4W lights;
> the use of Lithium primary cells for longer burn time, brighter light, lighter weight.
Take away any one of these three, and you don't have a workable system any more.

I have said the light from a Micro is excellent. The beam, though remarkably bright, is very narrow, and personally I have difficulty riding by the light of a single Micro on a dark unlit road. Of course the use of 2 or 3 lights when necessary overcomes this misgiving, giving an adaptable system which can allow even quite fast descending on dark roads.
In fact the Micro's beam pattern is very similar to that of the Lumotec generator headlight, which always gets very high approval from its users. Comparing the two side by side using a similar power source, it can be seen that, surprisingly, the Micro has marginally the better beam of the two.

The Micro is a 6V light using 4x AA cells. (There is an optional 4x D cell pack available from CatEye, which with Alkaline cells will run a single CatEye all night.) As such the runtime with AA cells is woefully short, probably less than 3 hours on a typically cool night.
The use of Lithium primary cells brings this runtime up to around 5 hours, and has other useful side-effects.
Most importantly, Lithium cells are much more resistant to low temperatures, so the light will still perform even at near-freezing conditions. Alkaline cells hardly function at all at this temperature, and even a moderately cool night will reduce their runtime.
The quality of light is also significantly better using Lithiums, which can handle the current drain much better than the Alkalines can. And this quality is maintained better, along a flatter discharge curve, throughout the life of the cells.
Lithium cells are also substantially lighter in weight than their Alkaline counterparts. This would not be very significant in the case of a single CatEye Micro - a weight reduction of just 28g - but of course because Lithiums are not easily available it is necessary to carry all the cells you are likely to need, at the outset.
Jim Halay said he bought four complete sets of batteries for the ride - that's 48 cells. In fact he only used half of those - looking closely at his story I estimate he rode about 14 night hours in total. I would suggest that it would be reasonable to set out on a 3-4 night ride with 32 or 36 cells (given that if you do run out you can always buy Alkalines to keep you going). The total weight of 36 AA Lithiums is just 540g, which is, remarkably, less than the weight of just 4 D cell Alkalines. For one 8-hour night, of course, 16 cells would suffice, perhaps with the spare 4 being fitted, ready to go, in a complete spare Micro light head in the luggage.
Lithium AA cells are available in the UK under the Energiser and Ucar brand names. They can be extremely expensive if bought at high street prices, but the rock bottom price in the UK is from MX2, a mail-order firm based in Guernsey, who sell them for £6.75 for 4. Worth it for that special ride.

Using the CatEye Micros in this way, each acts as backup should one of the others fail. However you might still want to carry a spare bulb or two. The light is very bright and efficient, but this means that the bulbs are highly stressed. So carry spares. At least they’re tiny.
If you need to carry spare batteries, there is no better way to store them than - in a spare Micro. This gives total backup of all aspects of the light - battery, bulb, connections, etc, at a minimal weight and space penalty.