Everyone has the drawer: a tangle of batteries, half of them flat, none of them the size you actually need right now. This guide is the quick reference for working out what your everyday devices take, and what is worth keeping stocked so the next dead remote is a thirty-second fix instead of a trip to the shops.
Most household batteries are 1.5V. The exceptions are 9V blocks and the 3V coin cells, which we cover at the end. If you already know you need a coin or button cell, jump straight to the coin cell guide or the button cell cross-reference.
AA and AAA: the everyday workhorses
These two cover the bulk of a home. They are the same 1.5V, just different sizes, and they are not interchangeable, an AAA is noticeably skinnier and shorter than an AA.
- AA: TV and aircon remotes, wall clocks, computer mice and keyboards, torches, kids toys, kitchen scales, game controllers.
- AAA: slimmer remotes, wireless mice, LED torches, thermometers, small toys, electric toothbrush bases.
If you keep only two sizes in the house, keep these. Our Energizer alkaline multipack covers AA, AAA, AAAA and 9V in one go.
AAAA: the one nobody can find
AAAA (yes, four As) is a genuinely uncommon size that most shops do not carry, which is a problem because of what uses it: active styluses. The Microsoft Surface Pen, many digital and smartpens, slim laser pointers and some penlight torches all run on a single AAAA cell. If your stylus has gone dead and you cannot find the battery anywhere, this is almost certainly why. (Fun fact: some 9V batteries are built from six AAAA-sized cells stacked inside.)
We stock AAAA in the Energizer multipack so you are not hunting for it when your pen quits mid-meeting.
9V: smoke alarms first, then everything else
The rectangular 9V block (also called PP3) shows up in a handful of places, but the one that matters is the smoke alarm. With more Singapore homes fitting detectors, a flat 9V is the difference between a working alarm and a chirping one at 3am. Beyond that you will find 9V in multimeters, guitar effects pedals, wireless microphones and some walkie-talkies.
For anything safety-related, use a quality cell with a long shelf life, our Energizer MAX 9V is the one to keep spare specifically for alarms and detectors.
Coin and button cells: the flat discs
The small silver discs split into two families that look alike but are not the same. 3V lithium coin cells (CR2032 and friends) power car key fobs, scales and PC motherboards, covered in the coin cell guide. 1.5V button cells (LR44, AG13, SR41 and the rest) power watches, calipers and small toys, decoded in the button cell cross-reference. The codes are printed on the old cell, read it off and match it. If you need to swap one coin cell size for another, the CR2032 equivalents guide covers what substitutes safely.
Disposable or rechargeable?
This is the question that actually saves money. The split is about how the device uses power:
| Use rechargeable (NiMH) for | Use disposable (alkaline) for |
|---|---|
| High-drain, high-use gear: game controllers, wireless mice, kids toys, camera flashes | Low-drain or set-and-forget: remotes, wall clocks, torches you rarely use |
| Anything you replace often enough to feel it | Emergency and backup items that must just work after sitting for a year |
For the rechargeable side, our rechargeable AA/AAA bundle with USB charger pays for itself within a few cycles on a busy controller. One important exception: do not put rechargeables in a smoke alarm. NiMH cells self-discharge over time and their voltage can drop more abruptly than the alarm's low-battery warning expects, so alarms are one place to always use the specified disposable cell.
Test before you toss
Before binning a battery, check it is actually flat, a surprising number are not. A BT-168 battery tester reads AA, AAA, C, D, 9V and button cells under load and tells you good or replace at a glance, no batteries of its own required. It is the cheapest way to stop throwing out cells that still have life in them. For how to read the good, low and replace zones, see our guide to testing batteries with a BT-168.
What to keep stocked
For most Singapore homes, a sensible kit is a few AA and AAA, a spare 9V for the smoke alarm, the odd AAAA if you own a stylus, and whatever coin or button cell your car key and watch take. You can put most of that together from the Alkaline Batteries and Coin Cell Batteries collections, with fast local delivery so the drawer is never empty when you need it.
Frequently asked questions
What battery does a Surface Pen use?
A single AAAA (1.5V) cell. It is an uncommon size most shops do not stock, which is why a dead stylus is so often a mystery; the fix is just one AAAA.
What battery does a smoke alarm in Singapore use?
Most use a 9V block; some newer models take AA or have a sealed 10-year lithium pack. Check the compartment. For a replaceable 9V or AA alarm, fit a quality disposable alkaline, not a rechargeable.
Can I use rechargeable batteries in a smoke alarm?
It is not recommended. Rechargeables self-discharge and can drop voltage abruptly, which can defeat the low-battery warning. Use the disposable cell the alarm specifies.
What is the difference between AA and AAA?
Same 1.5V, different physical size: AAA is thinner and shorter than AA, and holds less charge. They are not interchangeable; the device dictates which one fits.
How long do unused AA and AAA batteries last in storage?
Quality alkaline cells keep for roughly 5 to 10 years unused thanks to low self-discharge, so buying a multipack to keep in the drawer is not a waste.
