Radical New Thinking on Batteries

Our top choices: Energizer Lithium disposables, and Eneloop 4th Generation rechargeable batteries.

Why is the US military requiring that their new electronic devices and flashlights use AA-batteries?  The answer is simple, logistics. 


Our modern world is now battery-power dependent.  Militaries and civilians alike have become painfully aware that different battery-using devices require different sizes and types of batteries and chargers, but most solutions to this growing problem are inadequate.  As a result, it is now necessary to stockpile quantities of all sorts of batteries and chargers.

The US military has made a radical decision to solve this problem. We can learn from their plan.   

In our expanding electronic age, the use of different batteries and recharging devices is a reality of daily life. This development is only a mild annoyance to most of us, but it is a serious problem that is growing yet largely unnoticed. In an emergency, our current situation will deliver catastrophic consequences. 

How often do you find that you have spare batteries, but they are the wrong type for your dead device?  What if you couldn’t make a quick trip to the store to buy batteries? What will you do with your essential rechargeable devices like your mobile phone when the power grid goes down?  

We need to implement a plan to solve these problem.  We need to do it now. 

The US military has awakened to a simple solution.  They now require that all newly designed military devices use AA-batteries. (AA = Mignon, R6, Size-15, and UM-3).  Though some of these new devices will require many batteries, all must use off-the-shelf AA batteries.

Another logistical “win” that was part of this decision-making process is that AA batteries are popular and easy to find. They are available in grocery and hardware stores, gas stations, and even among street vendors’ displays. Today in most neighborhoods, it’s easier to get a few AAs from your neighbor than to borrow a cup of sugar from them. Almost anywhere in the world, AA batteries are easy to find. 

Why AA rather than AAA or another common battery type? 

After evaluating all battery types, the US military concluded that the AA-battery, whether used alone or in series, is the best choice.   It delivers adequate power for a wide-range of portable electronic devices, and it also provides long operational life. Plus, AA batteries are small in size, easy to transport, lightweight, and inexpensive. 

For military use, the US Department of Defense has identified the L91 Lithium AA-battery as their new standard.  A commercial version of this battery is the Energizer Ultimate Lithium AA.  Look for “L91” on the packaging. (The AAA version is the “L92.”)  The L91/L92 Energizer Lithium batteries are the most efficient, and cost-efficient, disposable battery.

Disposable vs. Rechargeable.  The new military AA-battery standardization disallows the use of rechargeable batteries except for use during training exercises. Their reasoning for this decision is twofold. First, rechargeable batteries are more costly.  Second, and more critical to military operations, the need to recharge batteries during a combat mission is an avoidable distraction. 

Military units can, however, use the more cost-efficient rechargeable batteries for training.  For this use, the new military standards specify that rechargeable batteries must be 4th generation NiMH (nickel-metal hydride) AA-batteries.  The best commercially available version of this battery is the Panasonic “Eneloop.”  You’ll find more about this battery later in this article.

Though the disposable military-standard “L91” is more expensive than Alkaline batteries, their extended life makes them more economical than using any major-brand Alkaline battery. However, even off-brand inexpensive Alkaline batteries are far superior to the major-brand ‘standard’ and ‘heavy-duty’ batteries which were the top choice a few decades ago.

‘Heavy-Duty’ and ‘Standard’ disposable batteries (typically, zinc-carbon or zinc chloride)

These are the batteries that frequently come with toys and less-expensive electronics. Manufacturers often include these cheap batteries as a service to the consumer who may have forgotten to purchase batteries. However, avoid prolonged use of these batteries in any device that is expensive or important. They aren’t just old fashioned; they often aren’t viable for extended use in modern electronics.

Our research suggests that these sub-standard batteries are a risky choice. Why?  1) They often deliver power that is not consistent throughout the battery’s life, and this can damage electronics,  2) After being installed, over time, they are prone to leaking battery acid,  3) Their operating-life is short, and  4) Their shelf-life is much shorter than a quality Alkaline or Lithium battery. 

Alkaline disposable batteries

“Alkaline” is a type of battery, not a brand. Though the price of Alkaline batteries will vary significantly between brands and vendors, this style of battery is the lowest-cost disposable battery that we recommend.  Of the brands of disposable Alkaline batteries we tested, Duracell Coppertop surfaced as our top choice for long-life, consistent power, and for being less prone to leaking. The recommended version of Coppertop batteries has an expiration date printed on each battery.   

Note:  When selecting batteries, look at the batteries themselves to determine the expiration date. A fresh Coppertop boasts a shelf-life of 10-years. A fresh Lithium L-91 battery has a shelf-life of 20 years. Don’t assume that high-volume retailers, such as Walmart and Amazon, are always selling recently manufactured batteries.

Lithium ‘L91’ (L1) disposable batteries

Energizer L91 Lithium is our #1 top-choice in disposable batteries. 

Granted, the purchase price of a package of disposable Lithium (military ‘L1’ / civilian market ‘L91’) batteries is twice that of a similar-size package of major-brand Alkaline batteries.  However, the L91 lasts longer and has twice the shelf life, making it the top choice even for budget-conscious purchasers.  

This battery has a 20-year shelf-life from the date of manufacture. Plus, it will last 3-5x longer than an Alkaline battery, it will continue to operate in temperature extremes (-40 – +140 F / -40 – +60 C), and it weighs 1/3 less than an Alkaline battery. And also important, they are far less likely to leak battery acid, so they are safer for you and safer for your electronics.

Rechargeable batteries

Eneloop NiMH (4th Gen) is our #1 top-choice in rechargeable batteries 

Rechargeable batteries provide both the lowest operating cost over time and a long shelf-life.  Based on our research, the best rechargeable battery is the 4th generation AA Panasonic “Eneloop.”  Its price may be slightly higher than other rechargeables, but it’s well worth it.  Rechargeable Lithium-ion batteries do not deliver as many re-charge cycles as the Eneloop NiMH, but are still popular.

For most people, purchasing the Eneloop Super Power Pack kit is the place to start. It contains 12-AA and 4-AAA rechargeable batteries, 2-C and 2-D battery adapters, and a 4-bay ‘quick’ charger.

The “Eneloop” battery is the culmination of years of research by Sanyo and Panasonic, and their efforts have paid off.  The design and materials provide a radical leap forward in battery technology. 

This battery uses NiMH (nickel-metal hydride) technology, the military’s top-choice (and only approved choice) for rechargeable batteries.  But what puts the Eneloop in a class by itself is the number of times you can recharge it. Rated at 2,100 recharging cycles, it promises a useful life that is many times greater than its competitors.  

Traditional NiCad rechargeable batteries have “memory” problems.  When you recharge these batteries after they are only partially drained, they develop a ‘memory’ which gives them a much shorter useful life. 

Eneloop batteries don’t have this problem.  Users can recharge them after a short period of use to restore them to full capacity.  Flashlights, radios, and other critical equipment can therefore be kept ready to deliver maximum power during an emergency.

Several other battery brands of rechargeable batteries now have this same no-memory feature. Still, only Eneloop (white-colored version) batteries deliver such an astounding number of recharge cycles. 

Yet another advantage of the Eneloop batteries is their long shelf-life.  After ten years in storage, they can still retain 70% of their charge. This feature is yet another reason that Eneloop batteries are far superior to most rechargeable batteries, many of which drop to that charge-level in less than 6-months.  For these reasons, Eneloop has earned our recommendation as our #1 top-choice in rechargeable batteries.

The Eneloop 4th generation battery, which is better and cheaper than their ‘Pro’ version (which is black), is now the gold standard for rechargeable batteries.

14,500 rechargeable batteries

Made by many different manufacturers, these batteries look almost identical to an AA-battery.  However, unless they contain circuitry to step-down the power output, they produce twice the voltage (3.6-3.7 v) of an AA-battery (1.2-1.5 v).  For some electronic devices and flashlights, this does not create a problem.  But before substituting a 14,500 for an AA-battery, check the specifications for that device. Putting double-power into microcircuitry will fry many electronic devices.

Our Recommendations

Whether you buy batteries for emergency use or just for life in general, our recommendation is the same.  We recommend working toward the exclusive use of battery-powered devices that use AA batteries.  If this is not practical from the onset, we nevertheless recommend working toward this goal.

Recommendation: Same size, but three types of batteries.

For logistics reasons, we strongly recommend that you only use one size of battery. Ideally, the AA. But you may want to stockpile three types of batteries in that one size. Since these three battery types are interchangeable in your electronic and electrical devices, this does not create a logistics problem. However, for many people, utilizing two or three types of batteries is more practical or affordable.

To accommodate an assortment of power needs, you may want to stockpile a supply of both Alkaline and/or Lithium ‘L1’ disposable batteries, plus a quantity of Eneloop rechargeable batteries. The new US military standard is Lithium L1 disposables as the primary battery, and NiMH (Eneloop) for situations where recharging is practical. The US military prohibits the use Alkaline batteries.

Use ‘Smart’ Battery Chargers

(Only use chargers with ‘rechargeable’ batteries.)

If you opt for the rechargeable battery route, also purchase a quality “smart” charger.  Panasonic has designed a smart charger for their Eneloop batteries, but it only charges NiMH batteries. This limitation is not a problem, as long as you only have NiMH batteries like the Eneloop.  

The most readily available charger made for Eneloop batteries is the Panasonic BQ-CC55SBA. It can accommodate up to four AA or AAA batteries at the same time.  Since it is an advanced ‘quick’ charger design, it can recharge four batteries in half the time of a standard ‘smart’ charger.  

However, if you want to recharge other types of batteries or an assortment of battery sizes, a different charger is required.  Whatever brand you select, it should use ‘smart charger’ technology.

A versatile charger we tested is the 4-bay ‘smart’ D-4 charger made by NiteCore.  It will recharge NiMH as well as all of the other standard types of rechargeable batteries; NiMH, NiCad, and Lithium-Ion. With the optional adapter, the D-4 can also be used by plugging it into the 12-volt receptacle in a vehicle.

For those who have many flashlights or lots of radios or electronic gear, consider a recharger that can accommodate more than four batteries at a time. For example, the NiteCore i8 battery recharger can charge twice as many batteries at the same time. Plus, it can accommodate various battery sizes and types, even at the same time (see product directions).  

Larger capacity chargers are also available. However, as a reminder of our often-repeated redundancy theme, it is better to have several 4 or 8-bay battery chargers than a single unit with greater capacity.  With electronics, flashlights, and rechargers, the military truism holds, “Two is one, and one is none.” 

Establish a ‘Battery Plan’

1.  Now that long shelf-life is obtainable, we encourage you to stockpile a five year supply of batteries for flashlights and portable electronic devices.  Replenish it annually.  Extra batteries should also be stored with each device that you might use in an emergency situation.

With your primary inventory of batteries, establish a first-in-first-out usage plan that uses the oldest batteries first.  At the same time, set up a quarterly schedule to inspect, test, and recharge devices and batteries. There are many options for easy-to-use testing tools, including inexpensive models that cost less than a bag of coffee. 

2.  We recommend stockpiling a combination of three types of batteries.  Alkaline and Lithium L1 disposable batteries, and also Eneloop rechargeable batteries.  Plus, at least two 110/220/12-volt ‘smart’ chargers with 12-volt power adapters

3.  We recommend storing batteries in plastic battery boxes or plastic containers with tight lids. Store your batteries in a manner that keeps them aligned even when the container is nearly empty.

4.  Keep your battery containers, along with your chargers, in a tote bag(s). With this storage technique, you can quickly locate or transport your battery supply in an emergency. We recommend storing an extra emergency radio and at least two flashlights, or a flashlight and a headlamp, inside this same bag.

5.  For your devices that use a specialty battery, check to see if an AA-battery pack is available. Many popular handheld (HT) radios, night scopes, and other devices that use a specialty battery can use aftermarket AA or AA battery packs for power. If feasible, buy one of these for each item you will want to power during an emergency.  

If an AA-battery pack is not available for your equipment, purchase a 12-volt adapter. These are not as useful but are still helpful. 

Yet another option is to recharge these devices using a USB recharger that contains replaceable AA-batteries for its power source.  An added plus is that a 12-volt automotive adapter can be plugged into some of these units, making it possible to use the same auxiliary device to recharge or power various equipment.  

6.  For each critical battery-powered device, calculate how many batteries you will need for five days of emergency use. Store these spare batteries with each device, in addition to your primary stockpile of batteries.  Use either small battery boxes, a suitable plastic container, or plastic wrap that has been secured with clear shipping tape.  

Do not keep removable batteries in essential equipment. Installed batteries are more likely to leak, rendering the device unusable when you need it most.  A better option is to remove the batteries but keep them with the device, along with a Cyalume Glow Stick or inexpensive flashlight, so you can install the batteries while in the dark.  Though perhaps slightly inconvenient, this is a far safer option than to risk having a damaged piece of equipment at a time when you need it most.  

7.  Following the lead of the US military, only buy electronic devices and flashlights that are powered by AA-batteries.  For many, this will be somewhat difficult. Specific categories of devices, such as headlamps, typically use the smaller AAA-size batteries to reduce weight. Because of this, it may be necessary to modify this recommendation to meet your requirements.  

A word of caution.  Speaking from experience, don’t deviate from standardization unless it is necessary. If you need to modify this recommendation, we recommend that you only add one additional battery type, either AAA or CR123A. 

Battery Adapter Sleeves.  Often sold with kits such as the Eneloop starter package, various companies sell battery sleeves.  These slip onto a battery, adapting it for use in an electronic device designed to be powered by a larger battery.

For example, an AAA battery sleeve can transform the size of that battery, so that it can be used in a device that was designed to use AA batteries.  Or, an AA-battery sleeve can be used to adapt that battery for use in a  ‘C’ or ‘D’-cell device.

Work Toward Standardizing Your Battery Stockpile.  You may currently need to maintain a supply of batteries in various sizes.  But as you move forward, we recommend that you only purchase new products that are powered by AA batteries.  Just as for the military, for us, there is a distinct advantage to using only one size of battery. We need to work toward the objective of using a single battery-size that can power all of our portable devices.  

No matter how attractive an item may be, avoid purchasing any device that uses anything other than AA batteries unless it is unavoidable.  For day-to-day use of unimportant electronics, this may not be important. Still, it can become critical in the future when you encounter an emergency, especially those which last for more than a few days and you find it necessary to scavenge batteries from other devices.

What to Include in Your Battery Stockpile

1.  Purchase a supply of two different types of disposable batteries.  Choose the quantity you will need, and then calculate the percentage of each you will need, based on your situation. Plan for a minimum of five days of continuous power use for each device you may want to use in an emergency.

2.  Obtain an Eneloop battery starter kit, plus additional Eneloop batteries and battery sleeves to accommodate your need for different battery sizes.  Eneloop is our top-choice in the rechargeable battery category.  However, you may want to consider other NiMH options or Lithium-Ion rechargeable batteries.  

Use rechargeable batteries for four applications:  1. Frequently-used personal electronic devices.  2. Emergency-use equipment intended for use near your home or a base camp where recharging is practical.  3. When the use of alternative power sources such as generators or solar panels is available to power rechargers.  4. When traveling in, or using a vehicle that can be used to recharge batteries via a smart charger and a 12-volt adapter. 

In all of these situations, if a rechargeable battery needs to be set aside, a sufficient quantity of replacement batteries must be stockpiled for those times when recharging is not practical.

Battery-powered cell phone rechargers, radios, handi-talkies (walkie-talkies), and other critical items such as flashlights and headlamps should typically use rechargeable batteries.  

Stockpile disposable batteries in anticipation of four scenarios: 1. Use disposable batteries when you may be away from home or base-camp for an extended period and recharging is impractical; 2. For situations where needed electronics may burn through many sets of batteries quickly; 3. When there may be no time to recharge batteries, or recharging may represent a dangerous distraction; or 4. If it is impractical to develop a routine in which batteries are used and then recharged.  

In the above situation(s), use disposable Lithium “L1” batteries for critically important electronics, bike lights, navigation equipment, flashlights, emergency lighting, communication equipment, night-vision devices and scopes, mobile alarm systems and detectors, monitoring and detection devices, scientific equipment, health and medical devices, all essential gear, and irreplaceable or expensive equipment.

When to use Alkaline batteries: For devices and situations which are more trivial, it is reasonable to use disposable Alkaline batteries. This includes: 1. inexpensive and nonessential ‘cheap’ electronics, especially those which fail frequently or are considered disposable; 2. Toys for kids; 3. Items that may be easily lost or given away; 4. Inexpensive walkie-talkies and devices used by children, etc.

Plan for Redundancy and Versatility

To be ready for emergencies, consider purchasing more than one charging unit.  Redundancy is essential.  If a charger stops working, your purchase of rechargeable batteries will be a wasted investment. In an emergency, this inability to recharge batteries may create a serious, even life-threatening, problem.

Versatility is also important.  Whereas ‘smart’ chargers such as the NiteCore may not recharge batteries as fast as the Panasonic NiMH ‘quick’ charger, the ability to charge other types and sizes of batteries may become essential. 

Another advantage of chargers such as the NiteCore, is that many of their models can use an optional 12-volt car adapter.  With this adapter and their charger, you can recharge batteries in more ways than just traveling in a vehicle. You can also use this adapter to attach your charger to a battery that you have removed from a vehicle, to a deep-cycle marine or golf-cart battery, or directly to certain solar panels.  It gives you options.

Protect Your Stored Batteries

Battery Box. Available in all sizes, a battery box is made from plastic or some other non-conductive material. The best models hold each individual battery in place so that as the supply is used, the batteries which remain are kept from touching the terminals of each other. Inexpensive compact boxes are available that hold as many as 200 batteries.

Store your batteries in a dry, cool place. You may not have room in your refrigerator for your entire stockpile of batteries, but it is the ideal place to keep batteries fresh for a long time. However, when possible, keep your inventory of batteries out of freezing temperatures.

Caution.  Don’t store batteries in a metal box or wrapped in tinfoil.  If you want to keep batteries in a water-tight metal container such as a military-surplus ammo can, use corrugated cardboard (or some other insulator) to keep the positive (+) side of the battery terminal from touching any metal surface or conductive material. 

Insulation.  Eight layers of plastic wrap may be sufficient to protect a 1.5-volt AA or AAA battery from draining when it touches a metal surface.  However, for batteries with a higher voltage, you must use thicker insulating material such as corrugated cardboard.

Plastic Battery Boxes.  For most people, battery boxes designed to lock each battery in place are the best storage option.  (Some battery boxes are just plastic boxes. Stay away from those.) If you don’t want to purchase a battery box designed to keep batteries from shifting around, use a plastic food storage container with a tight-fitting lid, and add cardboard between batteries to keep the terminals from touching each other.  

Original Packaging.  The easiest storage solution is to keep batteries in their original plastic blister-pack package. To minimize the space needed for storage, trim away the unneeded cardboard portion of each package and reseal them with shipping tape. This is space inefficient, but it is easy.

The design of consumer packaging for batteries keeps the battery terminals from touching each other.  However, this protection may not suffice once you have taken a few batteries out of the package. If the batteries can move around inside the package and the terminals touch each other, the protection has become inadequate. 

General Storage Tips and Warning.  To safely store batteries and maintain optimal shelf-life, keep the “positive” (+) end of each battery away from other batteries and anything metallic. Failure will result in the battery becoming discharged before use. In some situations, if the positive terminal maintains contact with a metallic object, it can cause a fire. 

Heat. Exposure to high temperatures, such as in the glove box of a vehicle, will rapidly decrease a battery’s useful life.  

Batteries in GO-Bags. For batteries that are stored in a GO-Bag, consider keeping them in an external pocket.  This makes it easy to replace them every 6-months, at the same time you replace the bottled water stored with your bag.

CME and EMP Protection.  For the protection of electronics from a Solar Flare (CME) or EMP incident, a “Faraday Cage” is necessary. If you are using this type of protection, don’t forget that many modern batteries also contain microcircuitry.  Batteries, particularly rechargeable batteries and their chargers, need to be similarly protected. 


To be ready for an emergency, similar to the planning done by militaries and logistics-savvy organizations, we need to make similar plans for emergency power. Batteries for mobile electronics and lighting need to be part of that plan. In reality, these preparations may become even more vital for individuals, families, and small businesses than for the military. 

Whether you encounter a natural disaster or some other emergency, the ability to have long-lasting power for light and electronics will likely be a critical need. To maintain this advantage, we need a ‘power plan’ for portable devices, such as the one we have presented in this article. 

With the implementation of this plan, you will have a cost-efficient and logistics-efficient supply of one (or two) sizes of batteries. And, during an emergency, if your stockpile of fresh batteries becomes depleted, you will have the option of switching batteries between devices. With this option, you can continue to power the devices you need most.  As a result of these efforts, you will have a distinct advantage at a time when portable power is desperately needed.