Universal bike light battery

Step 9 Leave yourself some room

Of course make sure you leave enough length in your wire to remove and install the batteries. In this example I am wiring two separate four-cell battery packs. Each battery pack will have a separate connector. This will allow me to run two lights from two separate battery packs, or I can run a single light and have one battery pack as a back-up. Having a back-up battery and light is important when you are out in the woods at night. All of the 24-hour races I've competed in require that riders have two completely independent lights.