After extensive testing, we have found that some of the 18650 lithium batteries which ship with the headlamp we currently use have been DOA. Research has found that some of the batteries included with the headlamps we purchase are either defective or not performing as advertised. In some cases the advertised Mah rating is nowhere near the actual capacity. This is a common problem with batteries coming out of China. In addition, some of the batteries have zero circuit protection, and could potentially be dangerous.
To combat this issue we will be replacing all of the batteries with high quality 18650 lithium replacements with circuit protection. These batteries use quality cells made by reputable companies. In addition, we are testing every unit for charge/discharge performance and trashing any that fail our inspection. This will keep the headlamps lasting longer and running brighter.