I use these #18650 rechargeable lithium batteries in several of my headlamps. They work well for me and they have a great longevity in terms of number of recharges before they no longer will hold a charge.
As I was packing a few to take along on an upcoming fishing trip, I had a "light bulb moment".
How to differentiate between the "fully charged" batteries and the "used" batteries? Blue painters tape to the rescue. Wrap the fully charge batteries in such a manner the tape must be removed to install them into a headlamp. Thus the unwrapped or "opened" ones are the depleted batteries. The painters tape easily peels away without leaving any sticky residue.
Pretty simple, yet it never crossed my mind before this, DUH!
As I was packing a few to take along on an upcoming fishing trip, I had a "light bulb moment".
How to differentiate between the "fully charged" batteries and the "used" batteries? Blue painters tape to the rescue. Wrap the fully charge batteries in such a manner the tape must be removed to install them into a headlamp. Thus the unwrapped or "opened" ones are the depleted batteries. The painters tape easily peels away without leaving any sticky residue.
Pretty simple, yet it never crossed my mind before this, DUH!