Energy Preparedness
Disposable batteries. The complete household guide.
Which types to stock, how to store them safely, and the critical voltage difference between lithium families that every household should understand.
The Basics
What disposable batteries are, and are not.
Disposable batteries, also called primary batteries, provide a finite amount of power and are replaced rather than recharged. The common household types (AA, AAA, C, D, 9V, coin cells) are all primary batteries.[1]
They are classified by two separate things: their chemical composition (which determines voltage, shelf life, and performance) and their physical size (which determines what devices they fit). Understanding both matters, because the same size battery can come in different chemistries at different voltages.
This guide covers only disposable, single-use batteries. For rechargeable batteries (NiMH, lithium-ion, LiFePO4), see the Battery Systems guide.
The Most Important Distinction
Two lithium families, two voltages.
When people say "lithium battery," they could mean two completely different products. Confusing them is a genuine safety risk.
1.5-Volt Lithium
Lithium iron disulfide (Li-FeS₂)
These are the "lithium AA" and "lithium AAA" batteries sold under names like Energizer Ultimate Lithium. They produce 1.5V, the same nominal voltage as a standard alkaline cell, and fit the same devices.[2]
IEC designation prefix: FR (e.g., FR6 = lithium AA).
Key advantage: extremely long shelf life (up to 20 years), excellent cold-weather performance, lighter weight than alkaline, and almost no leak risk. The best choice for emergency kits and stored devices.
3.0-Volt Lithium
Lithium manganese dioxide (Li-MnO₂)
These include CR123A, CR2, and all CR-prefix coin cells (CR2032, CR2025, CR2016). They produce 3.0V, which is double the voltage of an alkaline cell.[2]
IEC designation prefix: CR (e.g., CR17345 = CR123A).
A CR123A is not "an AA in a different can." Putting a 3V cell where a device expects 1.5V can destroy the device or create a fire hazard. These belong only in devices specifically designed for them.
Bottom line: Both are called "lithium." Only one (1.5V Li-FeS₂) can safely replace an alkaline cell. The other (3.0V Li-MnO₂) cannot. Always check the voltage on the package, not just the word "lithium."
Chemistry Guide
Six chemistries, compared.
Each chemistry has a different voltage, shelf life, cold-weather performance, and leak tendency. These differences determine which battery belongs in which job.
| Chemistry | Voltage | Common sizes | Shelf life | Cold performance | Leak risk |
|---|---|---|---|---|---|
| Alkaline | 1.5V | AA, AAA, C, D, 9V | 5 to 10 years | Poor below freezing | Moderate, especially with age |
| Zinc-carbon / heavy-duty | 1.5V | AA, AAA, C, D, 9V | 2 to 3 years | Very poor | High |
| Lithium 1.5V (Li-FeS₂) | 1.5V | AA, AAA | 10 to 20 years | Excellent | Very low |
| Lithium 3V (Li-MnO₂) | 3.0V | CR2032, CR123A, CR2 | 10+ years | Good | Very low |
| Silver oxide | 1.55V | SR44, SR626SW (button cells) | 3 to 5 years | Fair | Low |
| Zinc-air | 1.4V | Hearing-aid sizes 10, 13, 312, 675 | Long while sealed | Fair | N/A (open cell) |
Discharge curve matters too. Alkaline voltage drops steadily as the battery drains, meaning a flashlight dims gradually. Lithium and silver oxide batteries hold a flatter voltage curve, staying near full brightness until they are nearly empty, then dropping off quickly. For critical lights and medical devices, that flat curve means more reliable performance.
About "heavy-duty" batteries: Despite the name, zinc-carbon and zinc-chloride batteries labeled "heavy-duty" or "super heavy-duty" have lower capacity than standard alkaline cells. They are adequate for low-drain devices like remotes and clocks, but not a good choice for flashlights, radios, or anything you are counting on during a power outage.
Size and Format Catalog
The sizes you need to know.
The size label tells you the physical form, not the chemistry. An AA can be alkaline, lithium, or zinc-carbon. Always check both the size and the voltage before buying a replacement.
Standard cylindrical
AA. The most common household size. Flashlights, radios, toys, remotes, lanterns. Available in alkaline (1.5V) and lithium (1.5V Li-FeS₂).
AAA. Compact flashlights, headlamps, small radios, remotes. Same chemistry options as AA.
C. Medium cylinder for larger lanterns, radios, and some older devices. Alkaline only in most retail.
D. Large cylinder for high-runtime lanterns, large radios, and water pumps. Heavier but lasts longer than C.
Rectangular and specialty
9V. Smoke alarms, carbon monoxide detectors, radios, some meters. Contains six 1.5V cells in series. Available in alkaline and lithium (Li-MnO₂, 9V pack).
AAAA. Thin specialty cell for penlights, styluses, and some medical devices. Not the same as AAA.
N. Short, narrow cylinder for small electronic devices. Uncommon but still specified in certain equipment.
A23 / 23A. 12V alkaline cylinder (internal stack of small cells). Used in wireless doorbells, garage-door remotes, and small alarm transmitters.
Coin and button cells
CR2032, CR2025, CR2016. 3V lithium coin cells. Key fobs, watches, scales, small remotes, some medical devices. The most common coin cell sizes.
LR44 / AG13. 1.5V alkaline button cell. Calculators, thermometers, laser pointers, small toys.
SR44 / 357. 1.55V silver oxide button cell. Watches, precision instruments. More stable voltage than LR44.
Zinc-air (10, 13, 312, 675). 1.4V hearing-aid batteries. Activated by removing a sealing tab; once the tab is off, the cell begins to drain.
Specialty lithium cylindrical
CR123A. 3V lithium. High-performance flashlights, alarm sensors, cameras, optics. Counterfeit CR123A cells are common in cheap flashlight kits.
CR2. 3V lithium. Some cameras, rangefinders, and sensors. Verify the exact designation before substituting.
CR1/3N. 3V lithium. Dog training collars, some medical devices, older camera equipment.
2CR5 / CR-V3. 6V lithium photo packs. Cameras and specialized electronics. Less common today.
Reading the Package
The label tells you more than you think.
Battery packaging carries an IEC (International Electrotechnical Commission) designation code. The letter prefix identifies the chemistry, the number identifies the size. Knowing this system saves guesswork at the store.
IEC Prefix Decoder
You do not need to memorize these codes. The practical point is simple: the letter tells you the chemistry, and the chemistry tells you the voltage. When you see "CR" on a battery, it is 3V lithium. When you see "LR," it is 1.5V alkaline. That distinction matters when a device stops working and you are reaching for a replacement.
Choosing by Job
Matching batteries to your gear.
Flashlights and headlamps
Alkaline AA or AAA for everyday household lights. Lithium AA or AAA (Li-FeS₂) for critical lights, cold weather, or long-stored kits. CR123A only if the light specifically requires it.
Smoke and CO alarms
Most use 9V or AA alkaline. Some accept lithium 9V for longer life. Follow the manufacturer's instructions exactly. Some alarms specify alkaline-only because of end-of-life voltage behavior.
Hearing aids and medical
Stock the exact required zinc-air size (10, 13, 312, or 675). Keep them sealed until use. Once the tab is removed, the cell drains whether you use it or not.
Cold-weather use
Alkaline capacity drops sharply below freezing. Lithium (both 1.5V and 3V) maintains usable output in cold conditions. If your kit lives in a vehicle trunk or unheated shed, stock lithium.
Long-term storage
Lithium AA and AAA (Li-FeS₂) hold a charge for 10 to 20 years and almost never leak. Alkaline batteries stored for more than 5 years should be inspected annually for leakage.
Key fobs, remotes, small devices
Most use CR2032 or similar coin cells. Keep spares on hand. A dead key fob is an inconvenience on a normal day and a real problem during an evacuation.
Substitution Rules
What you must never swap.
"It fits" is not the same as "it works." A battery that slides into the compartment can still have the wrong voltage, wrong chemistry, or wrong discharge profile for that device.
Never substitute 3V for 1.5V (or vice versa)
A CR123A (3V) is not a substitute for an AA (1.5V), even though some devices physically accept both sizes with an adapter. Two 1.5V cells in series produce 3V, but they discharge differently than one 3V cell and may not be safe in every 3V device. Follow the manufacturer's instructions.
Never mix old and new batteries
Mixing a fresh battery with a partially drained one causes the fresh cell to push current through the dead cell, which can overheat and leak. Replace all cells in a device at the same time.
Never mix brands or chemistries in the same device
Different chemistries discharge at different rates and have different internal resistances. Mixing alkaline with lithium, or Brand A with Brand B, creates uneven discharge and increases the risk of leakage or failure.
Never recharge a disposable battery
Batteries labeled "alkaline," "lithium," "primary," or "do not recharge" can rupture, leak, or ignite if placed in a charger. If you want rechargeable batteries, buy cells specifically designed for recharging (NiMH or lithium-ion). The Battery Systems guide covers rechargeable options.[1]
Check the device manual when switching to lithium AA
A small number of older devices and some alarms are specified alkaline-only because of the higher fresh voltage of lithium cells (1.7 to 1.8V open circuit compared to 1.5V for alkaline) or differences in end-of-life behavior. Most modern devices handle lithium AA without issue, but the manual is the authority.
Storage and Maintenance
Store smart, rotate regularly.
Where and how to store
Keep batteries in a cool, dry place at normal room temperature. A closet or drawer away from direct sunlight and heat sources is ideal.
Keep them in their original packaging or in a dedicated organizer. Separate loose batteries so their terminals cannot touch each other, coins, keys, or other metal objects. This is especially important for 9V batteries, whose terminals are close together and exposed.
The refrigerator myth: Major manufacturers do not recommend refrigerating batteries. Modern alkaline and lithium cells do not benefit meaningfully from cold storage. The real risk is condensation forming on battery surfaces when you remove them from the cold, which can cause corrosion or create a short circuit.
Date codes and rotation
Buy dated stock and practice first-in, first-out: use the oldest batteries first and put fresh packs at the back. Most battery packaging carries an expiration or "best by" date.
Inspect stored batteries at least once a year. Check for swelling, white powder on terminals (a sign of alkaline leakage), or damaged packaging.
Remove batteries from stored devices. A flashlight sitting unused in a drawer for a year is a leak waiting to happen, especially with alkaline cells. Either remove the batteries or store the device with lithium cells, which are far less prone to leaking.
Testing a battery
Open-circuit voltage (measured with no load) is unreliable, especially for alkaline cells. A 1.45V alkaline reading can mean the battery is nearly full or nearly dead. A battery tester that applies a load gives a more accurate picture. The simplest practical test: put the battery in the device and see if it works. If you rely on a multimeter, know that any alkaline reading below 1.3V under load usually means the battery is nearly spent.
Battery Safety
The hazards that matter most.
Most battery safety issues are preventable. Three hazards require specific action.
Button and coin cell ingestion
A swallowed button or coin cell battery can cause serious internal chemical burns within two hours. This is a medical emergency.[3]
If a child swallows or may have swallowed a battery:
Call the National Battery Ingestion Hotline: 800-498-8666
Or Poison Help: 800-222-1222
Do not induce vomiting.
For children 12 months and older, the National Capital Poison Center recommends giving honey on the way to the emergency room. Do not let the honey delay transport.[3]
Under Reese's Law, battery compartments in consumer products must be secured against child access, and battery packaging must be child-resistant.[4] Keep loose coin cells away from children and in a secure location.
Short circuits and fire
Loose batteries in a pocket, drawer, or bag can short-circuit if their terminals contact metal objects (keys, coins, other batteries). A shorted 9V battery can generate enough heat to ignite nearby paper or fabric.
Lithium metal batteries that are crushed, punctured, or physically damaged can ignite. Treat any damaged lithium cell as hazardous waste. Do not attempt to use it.
Prevention: Keep batteries in original packaging until use. Cover exposed terminals on 9V and lithium batteries with electrical tape if you are storing them loose. Never carry loose batteries in a pocket with keys or coins.
Air travel rules
The FAA requires that spare (uninstalled) lithium metal batteries be carried in carry-on baggage, not checked luggage. This applies to loose CR123A, CR2, lithium AA and AAA, coin cells, and any other lithium primary batteries.[5]
Lithium metal batteries for personal use are limited to 2 grams of lithium content per battery. This covers nearly all consumer primary cells. Protect terminals from short circuits during transport. Damaged or recalled lithium batteries must not be carried on an aircraft.[6]
Counterfeit batteries
Counterfeit CR123A cells are common in cheap flashlight kits sold online. Counterfeit batteries may have lower capacity, inconsistent voltage, or inferior safety protections. Buy from established retailers and recognized brands.
Disposal and Recycling
Getting rid of them safely.
The EPA divides disposable batteries into three disposal categories, each with different rules.[1]
Alkaline and zinc-carbon (AA, AAA, C, D, 9V)
In most U.S. communities, these may be placed in household trash. The EPA recommends recycling when possible. They are no longer made with mercury (since the Mercury-Containing and Rechargeable Battery Management Act of 1996).
Lithium metal batteries (all CR types, lithium AA/AAA)
The EPA recommends taking these to a battery recycler or household hazardous waste program rather than placing them in regular trash or curbside recycling. Tape the terminals before disposal to prevent short circuits.[1]
Button and coin cells
Keep away from children and recycle through an appropriate program. Many modern coin cells contain lithium metal. Some older button-cell chemistries contained small amounts of mercury.[7]
Check your local rules. Several states have enacted battery stewardship laws or disposal requirements that go beyond the federal baseline. State and local hazardous waste programs may accept all battery types regardless of federal disposal guidance. When in doubt, treat it as hazardous waste rather than trash.
Sources
- Used Household Batteries. U.S. Environmental Protection Agency. Accessed September 2026.
- Compare Batteries. Energizer. Accessed September 2026.
- Button Cell and Coin Battery Information Center. U.S. Consumer Product Safety Commission. Accessed September 2026.
- Reese's Law and Button Cell Battery Safety Standards. CPSC. 16 CFR Part 1263. Accessed September 2026.
- Lithium Batteries in Baggage. Federal Aviation Administration. Accessed September 2026.
- PackSafe - Lithium Batteries. Federal Aviation Administration. Accessed September 2026.
- Mercury in Batteries. U.S. Environmental Protection Agency. Accessed September 2026.
Quick Reference
The household battery audit.
Walk through your home with this list and find every device that runs on disposable batteries. Record the size and quantity you need. This is your household battery inventory.
Check these locations
- Smoke and CO alarms (every floor)
- Flashlights and headlamps
- TV, streaming, and A/V remotes
- Vehicle key fobs
- Wireless doorbells, thermostats, sensors
- Bathroom scales, thermometers, blood pressure cuffs
- Garage door remotes
- Clocks, kitchen timers
- Weather radios and emergency radios
- Hearing aids and medical devices
What to stock
- AA alkaline: The workhorse. Stock at least 20.
- AAA alkaline: For compact devices. Stock at least 12.
- AA lithium (Li-FeS₂): For critical lights and kits. Stock at least 8.
- 9V alkaline or lithium: For alarms. Stock at least 4.
- CR2032: For key fobs, scales, small remotes. Stock at least 4.
- C and D: Only if you own devices that use them.
- CR123A: Only if you own a light or sensor that requires them.
- Hearing-aid batteries: Stock the exact required size.
Write the list down. Tape it inside the cabinet where you store your batteries. When you use the last spare of any type, add it to your shopping list before you need it.
Related Guides