Universal bike light battery

Step 11 Choose your batteries

I picked up Radio Shack rechargeable NiMh "C" cells for this bike light. Each cell is rated for 1.2V and 3000mAh. This is a good capacity for bike lights. Four of these cells connected in series gives you 4.8V and 3000mAh. With all eight cells installed, the battery pack has 6000mAh capacity - good for hours and hours of night riding. Higher capacity cells are available for less money . Since the batteries represent the majority of the cost and control nearly all of the performance of this Instructable, do some comparison shopping before settling on a model.