Weight of batteries can be trimmed to suit the ride planned. For a day ride no batteries need be carried at all.
If standard cells are used, spares are readily available at most garages.
The lights stay on when you stop.
Some Drawbacks
Good batteries are heavy. Lighter weight batteries will not last for many hours.
The lights get dimmer as the night goes on.
Batteries are expensive
Can be unreliable, and if contacts are not in A1 condition light output will be much reduced.
Used batteries have to be disposed of - and most types are not very environmemt-friendly.
Choice of the correct type of battery will be of interest to any cyclist who uses unlit roads at night, and who is not prepared to use a generator to power the front driving light. As the rear light is adequately covered by LED technology (which is so efficient that choice of battery is not critical), this page is concerned primarily with the use of batteries to power a front driving light.
Many serious cyclists now use a front light or lights powered from a remote battery pack, as opposed to the traditional type of light with battery compartment built-in. This has several advantages:
The light itself can be lighter and neater and much more reliable, as the vibration of heavy batteries against contacts is a major problem area in the traditional style of lamp.
The remote system lends itself to the 6 Volt (or even 12V) systems which are preferred by many serious cyclists, where the battery pack for several hours' use is likely to be too bulky and heavy to fit into the light itself.
With a remote pluggable battery pack, batteries of greater or lesser weight and performance can be selected depending on the anticipated need, eg, if the ride is going to end shortly after dark, a tiny 1Ah battery can be carried, whereas if an all-night ride (say 8 hours) is envisaged then a much heavier battery will be carried. For daylit rides some lighting 'insurance' at minumum weight penalty can take the form of an empty battery clip to take 4xAA cells, which can be bought if needed at any garage.
