Battery Sizes and Codes Explained: UK Retailer Guide

Battery customers usually arrive with one of four pieces of information: the old cell, a device manual, a familiar size name such as AA, or a code such as CR2032. The retailer's job is to match the complete requirement rather than choose a battery that merely looks similar. Size, chemistry, voltage, terminal arrangement and pack format can all matter.

This guide explains common household, rechargeable, coin, button and specialist battery references for UK retailers. It has a narrower purpose than the main wholesale buying guide: it focuses on identifying the correct cell and translating product codes into a clear shelf and ordering system. Current products, wholesale outers, prices and availability can be checked in the Wholesale Batteries UK collection.

Use the old battery or device instructions as the starting point

The safest match is usually the exact code specified by the device manufacturer or printed on the old battery. Ask the customer to bring the original cell, a clear photograph of both sides, or the device manual. For a battery compartment, check how many cells are required, their orientation and any voltage or chemistry instructions.

Do not rely on diameter alone. Two coin cells can have the same diameter but different thicknesses. Two cylindrical cells can be similar in length but use different voltages or terminal arrangements. A rechargeable pack for a cordless phone may be built from familiar cell sizes but have a specific connector, wire position and pack voltage.

A complete retail check records:

• size or reference code;
• chemistry where stated;
• voltage;
• capacity for rechargeable or specialist products where relevant;
• terminal or connector arrangement;
• cells in the retail pack; and
• retail packs in the wholesale outer.

AA and AAA batteries

AA batteries and AAA batteries are the most recognisable cylindrical sizes in a general retail range. AA cells are larger; AAA cells are slimmer. They are not interchangeable, even when the packaging and brand design look similar.

Common references can vary with chemistry and manufacturer. AA packaging may use AA together with codes such as R6, LR6, HR6 or MN1500. AAA packaging may use AAA with R03, LR03, HR03 or MN2400. The first letter or code can indicate a different chemistry, while an MN reference may be a familiar manufacturer designation. Treat the printed code as information to compare, not as permission to replace one chemistry with another without checking the device instructions.

The current 121 Wholesale catalogue includes AA and AAA trade packs from brands such as Duracell, Eveready and Panasonic, together with rechargeable AA and AAA lines from Lloytron and Infapower. The live product title should state the cells per retail pack and the number of retail packs supplied. This distinction is commercially important: a four-cell blister in an outer of 20 packs is 20 retail packs, not 20 individual batteries.

C, D and 9V batteries

C and D cells are larger cylindrical formats used by devices that require the corresponding physical size. Common code families include R14 or LR14 for C and R20 or LR20 for D, depending on chemistry. The 121 Wholesale catalogue includes branded C and D trade packs alongside the core AA and AAA range. These larger formats can move more slowly, so order depth should reflect local demand rather than copying the AA stock level.

9V batteries use the familiar rectangular case and snap terminals. References may include 9V, PP3, 6F22, 6LR61 or manufacturer codes such as MN1604, but the exact description should be read from the packaging and device instructions. Smoke alarms are a familiar use, yet retailers should not assume every alarm uses a replaceable 9V cell; some products use other battery types or sealed power sources.

A useful shelf separates AA, AAA, C, D and 9V visually. Customers often know the common size name and want to find it quickly. Codes can then be shown as supporting information rather than replacing the familiar label.

Primary and rechargeable batteries are different products

A primary battery is intended for one discharge cycle and is not designed to be recharged. Common household alkaline and zinc-based cells fall into this broad retail group. A rechargeable battery is designed for repeated charging with a suitable charger. Nickel-metal hydride, often shortened to NiMH, is common in rechargeable AA and AAA products.

Nominal voltage can differ. A typical primary AA or AAA cell may be marked 1.5V, while a NiMH rechargeable cell is commonly marked 1.2V. Many devices are designed to use one or both, but the device instructions determine suitability. Do not promise that a rechargeable cell will be a direct replacement solely because the physical size is the same.

Rechargeable packs also state capacity in milliamp-hours, or mAh. Capacity helps distinguish products within a comparable type, but it is not a universal runtime guarantee. Device load, age, temperature, discharge pattern and charging condition affect performance. A higher printed mAh value should not be compared across unrelated chemistries or used to make an exact runtime claim.

The rechargeable battery collection and battery charger collection should be navigated together, while still remaining separate categories. Check the charger's supported chemistry, cell sizes, number of bays and included batteries. Never attempt to recharge a primary cell.

Coin and button battery codes

Coin and button batteries require more exact matching than the main household sizes. A few millimetres or a different chemistry can make a product unsuitable even when it fits loosely into the compartment. The button cell collection and watch battery collection contain several code families, so staff should use the code on the old cell rather than choosing by appearance.

Lithium coin cells

CR2016, CR2025 and CR2032 are common examples of 20mm lithium coin cells with different heights. Renata's official lithium battery specifications list CR2016 at 20.0mm diameter and 1.6mm height, CR2025 at 20.0mm by 2.5mm, and CR2032 at 20.0mm by 3.2mm. The shared diameter does not make the three references interchangeable. A thicker cell may not fit, and a thinner cell may not make reliable contact.

The numerical pattern is useful for reading these examples, but it should not replace the exact code. Check polarity, chemistry and device documentation as well as dimensions. Avoid suggesting stacked smaller cells as a substitute for one thicker cell.

Small watch and alkaline button cells

Watch and small button cells may be sold under manufacturer, IEC and cross-reference codes. Product ranges can include silver-oxide watch references, alkaline AG references and lithium coin references. A chart can help locate an equivalent, but the equivalent must match the required dimensions, voltage, chemistry and performance category. If the only evidence is that the cell fits the hole, the match is incomplete.

The catalogue includes Renata watch batteries, Vinnic alkaline button cells and selected Maxell, Toshiba and other lithium or alkaline references. Keep each code visible on the shelf. Do not combine several references in one open tray or remove them from their original labelled packs.

Specialist battery references

A compact specialist section can solve high-intent replacement needs without turning the display into an unstructured list. Examples represented in the catalogue include:

• CR2 and CR123A lithium camera or equipment batteries;
• 23A and 27A high-voltage small cylindrical batteries used in selected remotes, alarms and controls;
• LR1 and other less common household formats;
• watch and coin cells identified by precise references; and
• rechargeable cordless-phone packs with model-specific voltage, cell arrangement and connector.

For cordless-phone batteries, compare the complete pack code, nominal voltage, number and size of cells, connector shape, polarity and cable position. A pack described as three AA or three AAA cells is not automatically compatible with every handset that uses the same cell count.

Read wholesale pack descriptions correctly

Battery titles often contain two levels of quantity. A description such as "B4 x 20 packs" generally indicates four cells on each retail blister and 20 retail blisters in the wholesale outer. That would produce 80 individual cells, but the retailer receives 20 saleable packs if the listing confirms that format. A description such as "B1 x 10 packs" usually indicates 10 single-cell retail packs.

Before ordering, record:

• individual cells per retail pack;
• retail packs per wholesale outer;
• whether variants share one listing;
• whether the displayed price applies to one retail pack or the complete outer; and
• barcode and SKU at the level used by the till or stock system.

Use the live listing where abbreviated catalogue text is unclear. Do not calculate a shelf price or unit count from a photograph alone.

Build the range around use and urgency

AA and AAA normally form the visible core because they cover a wide range of household devices. C, D and 9V provide additional utility. Coin, watch, camera, alarm and cordless-phone cells can be useful even at lower volume because the customer often needs an exact replacement immediately.

A practical general-store hierarchy is:

1. AA and AAA in clear brand and pack-size choices;
2. 9V, C and D in controlled quantities;
3. a labelled rechargeable section with compatible chargers;
4. a secure coin and button-cell section arranged by code; and
5. a small specialist section based on recorded local enquiries.

Brand recognition can help customers navigate, but size and code come first. A retailer may carry Duracell, Eveready and Panasonic for household formats and Renata or other specialist manufacturers for watch and coin cells. Avoid unsupported claims that one brand is always best for every device. Present the specification and let the customer match the requirement.

Storage, rotation and battery safety

Keep batteries in their original packaging, in a dry stock area away from excessive heat and direct sunlight, and separated from loose metal objects. Rotate by the manufacturer's date marking and inspect packs for damage, leakage, corrosion or swelling. Do not sell damaged cells or packs with missing safety information.

Do not mix old and new batteries, different brands, or different chemistries in a device unless the manufacturer expressly permits it. Do not encourage customers to recharge primary batteries, dismantle cells or use improvised spacers. Returned or damaged lithium products may require a specific safe-storage and disposal process.

Button and coin cell safety at the point of sale

Button and coin batteries can cause severe injury if swallowed or inserted into the body, particularly by children. The government's button and coin battery guidance points businesses to PAS 7055:2025 and recommends clear warnings on packaging, at in-store points of sale, and in online product descriptions or images. It also recommends that distributors satisfy themselves that relevant battery compartments and product warnings are appropriate.

Keep small cells in secure, labelled packaging and consider a controlled display position. Loose button cells should not be left where children can reach them. Staff should treat a suspected ingestion as an emergency and direct the customer to immediate medical help rather than offering a home remedy.

Retailer takeback responsibilities

The government's battery waste guidance for retailers and distributors states that a business selling or supplying 32kg or more of portable batteries per year must offer free takeback of used portable batteries. The guidance equates this threshold to about one four-pack of AA batteries per day over a year.

Businesses above the threshold must provide a collection point at premises from which batteries are supplied, accept portable battery types covered by the scheme, and tell customers that the service is available. The collection point must be suitable for safe storage. Smaller retailers are not required to provide takeback under that threshold, although they may choose to do so and should arrange it correctly. Check the current guidance and recycling provider's instructions before setting up or transporting collected batteries.

Battery ordering checklist

• Order by exact size or code, not appearance.
• Record chemistry and voltage where the device requires them.
• Keep primary and rechargeable lines separate.
• Match rechargeable cells to an appropriate charger.
• Check individual cells, retail packs and wholesale outers.
• Use clear shelf labels for AA, AAA, C, D, 9V and specialist codes.
• Retain small coin and button cells in secure original packaging.
• Review safety warnings, supplier traceability and product condition.
• Track enquiries for specialist cells before expanding the range.
• Check whether the 32kg takeback threshold applies to the business.

Battery size questions from retailers

Are AA and AAA batteries interchangeable?

No. They have different physical dimensions and are used in different battery compartments. Match the size stated by the device manufacturer.

Can a rechargeable AA replace any alkaline AA?

Not automatically. Rechargeable and primary cells can have different nominal voltages and discharge characteristics. Check that the device manufacturer permits the rechargeable chemistry and use the correct charger.

Are CR2016, CR2025 and CR2032 the same battery?

No. The common examples share a 20mm diameter but have different heights. Use the exact code specified for the device.

What should a retailer stock first?

Begin with AA and AAA, then add 9V, C and D according to local demand. Add rechargeable, coin, watch and specialist references in controlled quantities supported by clear code-based labelling.

When is battery takeback mandatory?

Current GOV.UK guidance says retailers and distributors supplying 32kg or more of portable batteries per year must provide free takeback. Check the official page for the complete requirements.