Disposable 123A Lithium Batteries
As a commitment to our customers and products, SureFire sells its own brand of quality 123-type lithium batteries at a very low price. Our WeaponLights and non-rechargeable flashlights use these lithium batteries because of their advantages over alkaline batteries. These advantages are:
Shelf Life Lithium batteries can be stored 10 years and still supply up to 90% of their power. Alkaline batteries have a significantly shorter shelf life.
Temperature Tolerance Lithium batteries function over a wide temperature range (-60° to 80°C, or -76°F to 176°F), although power is reduced at the extremes. In contrast, alkaline batteries function poorly below freezing and at higher temperatures. The temperature tolerance of lithium batteries also benefits their shelf life. Storing alkaline batteries at higher temperatures can kill them in a few months, but lithium batteries stored for years at similar temperatures can still function effectively.
Power Density For a given size (volume), lithium batteries produce much more power than alkaline batteries. For example, given same-sized batteries and the same power load, it would take about 2.5 alkaline batteries to match the power output of one lithium battery.
Weight For a given size (volume) lithium batteries weigh about half as much as alkaline batteries. For example, an alkaline battery the size of a SureFire SF123 battery would weigh about twice as much.
Voltage Terminal voltage for lithium batteries is 3 volts compared to 1.5 for alkaline batteries.
Voltage Maintenance A lithium battery maintains fairly constant voltage for up to 95% of its life, depending on discharge rate. At moderate to high discharge rates, alkaline battery voltage drops rapidly due to internal battery resistance, which wastes power. The large reaction area provided by a lithium battery's wound-plate construction provides very low internal resistance, ideal for high current loads.
Rechargeable LFP 123A Lithium Batteries
SureFire also offers a rechargeable version of the 123A battery, the LFP 123A, as well as an advanced charging system that can be powered by a regular 120-volt outlet or by a 12-volt automotive socket (see here). These rechargeable batteries exhibit almost all of the excellent qualities of their disposable counterparts, including a discharge rate that permits a similar lumen output as the disposables, but at a given output level they deplete themselves in about half the time. For that reason they are best suited for applications where the illumination tool is used extensively on a regular basis, such as night duty, where using disposable 123A batteries would be cost-prohibitive.
Rechargeable Lithium-Ion Batteries
Some SureFire illumination tools use rechargeable lithium-ion (Li-ion) batteries that have more capacity and can deliver even more power than 123A lithium batteries, enabling SureFire to produce relatively compact rechargeable lights that deliver higher outputs and more runtime between charges. This option can even be more cost-effective in cases where recharging between uses is possible and practical.