In probably what airsoft players should also pay attention to in trying to save on budget to power up their electronics such as holo sights, tactical weaponlights, and laser sights, the U.S. Army's PEO Soldier is promoting the use of Lithium AA Batteries rather than go for cheaper Alkaline batteries. To help push for more greater adoption by various units, they launched the Power-Up-Properly lithium battery campaign.

The main reason for the preference of the more expensive Lithium L91 Batteries is that it helps lessen the load for the soldier as stated in the FAQ: "The cost for both L91 and alkaline AA batteries can vary. On average you can purchase L91s for $1.40 - $2.50ea. Alkaline batteries on average can be purchased for $.60 -$1.00 each. However, because L91 batteries last significantly longer, you would have to purchase three times the number of alkaline batteries to get similar run times."

Thus, to achieve the runtime of a single Lithium AA battery, a soldier has to carry three Alkaline AA batteries and even a Lithium AA battery weighs less than an Alkaline AA one. If there are more than just one electronic gadget that the soldier has to carry, then just imagine the weight more Alkaline batteries will add to the load. Batteries are one of the load concerns by soldiers and there are several projects that are aimed to lessen or eliminate batteries. Examples are the energy generating gear demonstrated by the US Marine Corps during the last ExFOB'14.

The good thing is that Alkaline can power the same systems that Lithium batteries and can be easily procured at stores and households, so they are still a backup option when the supply of Lithium batteries runs out. However, PEO Soldier also explains that the Low Battery Indicator (LBI) in the devices used by soldiers work mainly with Lithium batteries.

Major Tom Beyerl of PEO Soldier explains the rationale further in this article he wrote for the North West Guardian:

High drain devices such as the AN/PSQ-20, 20A, 20B Enhanced Night Vision Goggle, AN/PAS-13 Thermal Weapon Sight and the AN/PED-5 Laser Target Locator Module, benefit most from lithium non-rechargeable batteries. The current requirements for these devices deplete conventional alkaline batteries at such a rate that operational use time is severely limited. Many of PM SSL’s current sensors, lasers and precision targeting devices were designed for the lithium battery with its far superior output capabilities and voltage curve. As expected, the number one issue Soldiers expressed with these systems in post-combat surveys is poor battery life when using regular alkaline batteries.

Lithium L91 batteries, apart from lasting longer and weighing less, can  operate better in extreme batteries, from -40°F to 140°F. Cold weather usually affects battery life and performance, but Lithium L91 batteries can provide energy better than Alkaline batteries in colder climates.

While various research centers of the U.S. military, especially DARPA, are working on portable and renewable energy sources to power up the various devices that soldiers carry into the battlefield, non-rechargeable batteries will still be playing that role of powering up the devices. Lithium L91 batteries are seen to provide the necessary power and at the same time help decrease the load for soldiers and improving their operational performance.

Thus, next time you are offered by your airsoft retailer Lithium L91 batteries to power your tactical devices for your next 3-day Milsim event, better take the offer. You'll be thankful for the offer, even if it makes a dent in your airsoft shopping budget.