Question about battery life
Question to Knivesandtools:
We are asked this quite frequently. There can be various reasons but it is almost never a defect of the torch.
Answer of Knivesandtools:
The reasons are usually the type of the used batteries and the way the life was measured.
Measuring the life:
An ANSI standard was introduced 2 years ago for the measuring of the life of a torch. That standard prescribes that the life is measured to only 10% of the original indicated light output.
That is of course not what the consumer expects. The height of the difference with a real expectation depends considerably on the torch. If it progressively gives less light, there is a huge difference. If the light output suddenly collapses the standard is perfectly usable.
For torches that operate on AA (penlite) or AAA (mini penlite) batteries:
Many powerful torches work on AA batteries. Examples: the Fenix TK20 and TK45.
Those torches optionally work on 'normal' alkaline batteries or on rechargeable NiMH-batteries.
The requirements those torches set on the batteries are very high. So high that even the best Alkaline battery does not measure up.
Alkaline batteries are usable but at the highest setting of the lamp the maximum power of the battery is insufficient and it empties prematurely.
Rechargeable NiMH-batteries do the job however. They are very resistant against the high power required. You will see that when using NiMH-batteries the torch becomes a lot less warm and the indicated life is reached or achieved.
The indication of the life given by manufacturers like Fenix is based on the use of NiMH-batteries. The use of Alkaline batteries is no problem. The life is halved when using at high setting. This also strongly depends on the quality of the used alkaline batteries. And also whether the high setting is used consecutively or that it is used with intervals. In the latter case the life is longer because the batteries get the chance to cool off.
For torches that work on CR123A or 18650 batteries:
For torches that work on CR123A or 18650 batteries there are fewer deviations between the indicated and actual life. Both types of batteries are perfectly suitable for supplying high power.
But for lamps that are suitable for two types of batteries the life with the use of (rechargeable) 18650-batteries is longer than the life with (non-rechargeable) CR123A batteries.