Feeling a little flat when riding? Maybe it's your headlight batteries!

When it comes to lighting up your life, cyclists have a choice. The two most common are: dynamo lighting systems that require no batteries but generally don't work when stopped (unless you have the newer, more expensive capacitor assisted ones) or battery powered lights.

The 'old style' dynamo. These metal cased ones manufactured last century by 'Sturmey Archer' & this one from 'Anlun', last almost forever before wearing out. They were spring loaded to enable a quick flick, even whilst on the move, to engage with the tyre and retracted just as easily when not in use. One unit like this will power both front and rear lights at the same time.

For energy conscious riders, the most annoying complaint heard is that dynamos add rolling resitance to your bike and thus require more pedalling effort to operate.

Most night cyclists these days use battery powered lights. Many cyclist today use Light Emitting Diode (LED) lights using Lithium Ion (Li-Io) watch-type batteries. These can last the average user for months. Other lights can use 'AAA' "pen-light" batteries. However, the higher "candle-power" requirements of headlights, especially those utilising indandescent and particularly, modern Quartz Halogen bulbs, mean that something more substantial should be used.  These typically require larger capacity batteries than the rear "red" tail light. Often these headlights, like mine, need 'C' batteries. If you are the type of rider who listens to an MP3 player whilst cruising on the dedicated cycle paths of Hervey Bay, Maryborough, Pacific Haven or bush tracks (but not when riding on main roads, eh?), then these may also need 'AAA' batteries. You may find that your high drain batteries are going to be 'AAA', 'AA' and 'C' batteries. A complicated mix requiring a pocketfull of differing battery sizes. Right?

Not really.

Here is a nifty idea that will appeal to the autodidact DIY'ers out there. For virtually no cost you can make adapters to allow 'AAA' batteries become 'AA's and 'AA's become 'C's. Of course, using two adapters together (one inside the other) 'AAA's can also become 'C's.

Here are some of the batteries & adapters I made & have used for years. L to R: AAA to AA adapter, AAA battery, AA to C adapter, AA battery The coin is shown for scale.

How do we do it?

I have successfully used strips of cardboard, like cereal packets, trimmed to be slightly narrower that the length of a 'AA' battery then tightly rolled around the battery until it reaches the thickness of a 'C' battery. Sticky tape the end so that it doesn't unravel and that's it! Easy!

The 'AAA' to 'AA' adapter is slightly more elaborate as it also requires the addition of a metal packer at one end of the adapter. 'AA's and 'C's are the same length but 'AAA's are slightly shorter. I use a small neatly filed bolt, nut and washers glued in for this.

The AAA to AA adapter showing the filed off bolt end resembling the posivive end of a battery. The painted '+' & '-' are there to make it obvious. The inside end of the bolt comes in contact with the positive battery terminal.

This all works simply because the 'AAA', 'AA', 'C', 'D', and others are all 1.5 volts. Ordinary carbon batteries are fine but even 'AAA's are a capable power source in 'C' devices with the use of new Nickel Metal Hydride (Ni-Mh 900 milli amp hour) rechargeable batteries. Simply slide out the depleted battery and replace the adapter with a freshly charged one and off you go again. Life can certainly be made simpler by standardising on just 'AAA' batteries only.