Because of a torches relatively high current draw, rechargeable batteries are often the better choice. A rechargable has the obvious advantage of being able to be re-used multiple times. Saving both money and reducing environmental waste. Why wouldn’t you?
Battery voltage seems be be a point of confusion for many people. It is also a big difference between the traditional alkaline battery and rechargeables. Generally, an alkaline is rated to 1.5V, but will drop down to 1.V (or lower) when only 50% used – resulting in a dropoff in performance which speeds up as the battery discharges. This can mean a dimmer flashlight or less responsive piece of equipment. not so with Rechargeable Batteries.
Rechargeable NiCad or NiMH batteries are rate to 1.2v – but this is a constant output that will last right until the end of the batter. This means more constant performance and is a major reason that many people utilise Rechargeable Batteries for torch applications.
Rechargeable Battery Types
Though there are other systems available – mainly variations on Lithium – these are the options you are most likely to come across in NZ stores.
Nickel-Cadmium (NiCad) – 1.2V/cell
The first commonly available consumer rechargeable battery. Retains charge, but highly toxic.
NiCad will tolerate a trickle or overcharge better than NiMH. But also suffer from memory problems – meaning they may not fully charge and discharge.
Nickel-Metal Hydride (NiMH) – 1.2V/cell
A much better option for rechargeable – easier to recycle, high capacity but will lose their charge faster than the NiCads. So much better options for a torch you regularly use, rather than the emergency once you keep stashed in the truck.
However, there is a newer generation called Low Self-Discharge that are able to hold charge for a longer time, but have lower capacity in total. A great example of these being the Eneloop Batteries from Panasonic (formerly Sanyo). These hold their charge much longer – making them suitable for those items where you want it to still work those rare times you pick them up to use them.
Lithium Ion (Li-ion) – 3.7V/cell
Li-ion really warrant’s its own article. However –
Important: These are not the Lithium batteries you are likely used to. Put them in the wrong device and you will damage it.
So, Rechargeable Batteries make sense for torches. They generally keep a more constant output, and for the LSD options, will keep their charge longer when not in use.
I am also looking into the newer, higher output Lithium Ion rechargeables – these may be the best bet for the times where you are putting in a fresh set of batteries before heading out, every time. That’s the standard LandSAR drill – now to confirm the torches will deal with the extra power!