If you are thinking about using AA or AAA lithium batteries with your LED headtorch have a quick read of this...

LED light sources are susceptible to being damaged by the use of lithium batteries due to the different characteristics of lithium batteries in discharge. This has meant that some people have had problems with their headtorches failing when using such batteries... Petzl have reported this problem and other manufacturers are expected to follow suit. However this does not affect all head torches...

There are problems being reported over the LED lamps in certain headtorches when used with lithium batteries. Incandescent bulbs will also suffer a reduced burn-time when used with lithium batteries although this is less severe.

This is because the lithium batteries have a higher output during discharge.

The benefits of a lithium battery are the increased burn time, especially at low temperatures over the traditional alkaline batery.

LR6 or AA and LR03 or AAA are the two size of battery litkely to be used in a headlamp.

Petzl are one of the few manufacturers to advise on this at the moment. Other manufacturers products will also be affected.

The following Petzl headlamps should not be used with lithium batteries:

The following headlamps can be used with lithium batteries:

Why use lithium batteries?

Lithium AA batteries offer major advantages compared with alkaline AA batteries.
Greatly increased capacity coupled with a more stable voltage output means that the battery will last much longer, greatly reducing the frequency of battery replacement. The low self discharge means that the batteries can sit in storage for years before use, typically over 10 years. Improved performance at low temperatures will keep most equipment functioning, even in the coldest UK winter.
Huge capacity, many times more than that of typical alkaline cells.