A few short decades ago, fighting rifles wore a sling, held a cleaning kit and that was about it. Those were simpler times. Today your average carbine or rifle intended for self-protection will also be fitted with some type of optical sight, a white light and perhaps other accessories.
The big difference between a couple decades ago and today is our modern accessories require electricity. While there was an interim period when some preached against battery-powered accessories, those days are largely over. Today, battery-powered accessories are embraced, and shooters understand their benefits (properly utilized) outweigh their drawbacks.
With that being the case, the question becomes which type of battery best suits your requirements. Typical accessories such as optical sights and white lights are powered by "button-type," CR123 three-volt or AA batteries. All three have certain advantages and disadvantages, and shooters should weigh these pros and cons before choosing accessories.
Let's start with lithium button batteries. These are compact and lightweight and the only option for powering many optics. They're disposable and have lithium metal or compounds as an anode. The design normally provides a long service and shelf life thanks to a high charge density. The shelf life of 10 years or more is a plus, especially if long-term storage is a consideration.
One model commonly used to power optical sights is the three-volt CR2032, and if you've ever wondered what CR2032 (or other battery designation) stands for, here is how the designation is broken down — according to the International Electrotechnical Commission:
- C means it has a manganese dioxide electrode.
- R stands for the battery's shape: round.
- 20 is the diameter of the battery in millimeters.
- 32 indicates the battery is 3.2mm tall.
Typical capacity is 225 amperes per hour or mAh. This model of battery is intended to operate in a temperature range from -4 to 140 degrees. If you need a battery for colder conditions, you can usually substitute the almost identical BR2032 (the B means it has carbon monofluoride electrode). This is rated for conditions from -22 to 185 degrees.
Common brands of CR2032 lithium battery are Energizer, Maxell, Panasonic, Sony and Duracell. Beware of cheap no-name batteries produced in China. My recommendation is to buy a more than sufficient quantity of the correct button cells from a respected manufacturer. Keep them on hand and change them before you need to.
The most common battery used to power white lights is the CR123/CR123A (IEC designation CR17345). This is a disposable three-volt lithium primary battery with a typical capacity of 1,500 mAh. In profile the CR123A looks like a short AA.
Positive attributes of this compact battery include a high charge density and long shelf life — 10 or more years. A proven design widely utilized in cameras, CR123As are much more common today than they were 10 years ago. However, depending upon where you live they can still be a chore to find and often are expensive. That's the downside of the CR123A.
While a good reliable design when properly manufactured, there are potential problems to be aware of. Due to its lithium design this type of battery can provide extremely high currents and rapidly discharge when short-circuited. A too-rapid discharge can cause the battery to overheat, rupture, catch fire, even explode.
Consumer batteries usually incorporate over-current or thermal protection or vents in order to prevent explosion. However, last June the FBI released a warning concerning counterfeit and substandard CR123A batteries. "The FBI has received numerous reports of such batteries, which are not manufactured with the safety mechanisms of legitimate U.S.-branded batteries, spontaneously combusting while being used, transported, or stored, resulting in serious injuries to consumers and damage to tactical equipment and property." Please be aware of this.
I am not a fan of the CR123A three-volt battery due to its less than universal acceptance. By this I mean it's not as readily available across the globe as a mundane AA. That said, the majority of tactical lights run on CR123A three-volt batteries. So my suggestion is if you are running a CR123A-powered light to buy name brand batteries in bulk from a reputable company. You can save a heap of money this way. Just don't be lured into purchasing batteries offered at rock bottom prices.
Also note that some two-cell CR123A flashlights will accept a single 18650 lithium-ion rechargeable battery. The 18650s are slightly larger in diameter and do not fit all devices. However, this is a nice option and what I use if possible.
Lately, though, there has been a swing toward AA-powered lights. While common AA batteries lack the voltage punch of the three-volt CR123, in many ways it is a much better power source. The battery we know today as the AA was standardized in 1947 by the American National Standards Institute. It stands two inches tall and is approximately 0.55 inch in diameter. Voltage runs from 1.25 to 1.65 depending upon cell composition. Ampere hours also vary from 400 to 3,000 mAh depending upon composition.
When it comes to batteries, the AA is king. More than half of all general batteries sales are AAs. Not only can you find AAs in bulk in any small store but you can have them in a wide variety of flavors as well. Non-rechargeable types include zinc-carbon general purpose (400 to 900 mAh), zinc-chloride heavy duty and super heavy duty (1,000 to 1,500 mAh) and alkaline (1,700 to 3,000 mAh).
Non-rechargeable lithium batteries offer a step up from alkaline with a longer run time in high drain devices. Then there are rechargeable nickel-cadmium (NiCd) with a capacity of 500 to 1,100 mAh and nickel-metal hydride (NiMH), which run from 1,300 to 3,000 mAh.
Today there are number of excellent rechargeable AA batteries and chargers (including solar) on the market. Due to this I highly recommend considering rechargeable batteries for high-volume use. In particular I recommend Sanyo Eneloops. These 2,000 mAh NiMH rechargeable batteries are not only high quality and extremely reliable but more importantly they are low discharge. They will retain 75 percent of their charge after sitting for three years.
While I prefer the simplicity and widespread availability of AAs, they may not be right for you. I recommend choosing the batteries powering your accessories as carefully as the ammunition in your rifle.