New to all this?
Start with these two
Fifteen minutes of reading covers most of what the rest of the site assumes you know.
How a battery actually works
No chemistry degree needed. Just two metals, a chemical in between, and electrons taking the long way round.
Volts, mAh, Ah and Wh explained
The four numbers on every battery label, what they actually mean, and how to compare fairly.
The full library
Every guide, by topic
Battery sizes explained: AA, AAA, C, D, PP3 and more
What the codes mean, which are rechargeable, and the sizes that look alike but are absolutely not the same.
Alkaline, lithium or NiMH: which should you buy?
A straight comparison of the chemistries in everyday batteries, including when rechargeable is the cheaper answer.
Coin cell codes explained: CR2032, LR44 and friends
How to read a button battery code, why CR and LR matter, and the safety rule that is worth reading twice.
How to make rechargeable batteries last
Charging habits, storage levels and the myths that quietly shorten battery life.
Battery safety: warning signs and safe storage
What a failing battery looks, sounds and smells like, and what to do about it.
Where to recycle batteries in the UK
The shops that must take them, the ones that cannot go in the bin, and why lithium causes fires in collection trucks.
Car battery numbers: Ah, CCA and AGM
What the label on a 12V battery means, and why stop-start cars need a different battery from older ones.
Seven battery myths worth dropping
The fridge trick, the memory effect, the eight-hour first charge, and other advice that refuses to die.
Power cuts: how much battery backup do you need?
Work out which essentials to keep running and how long a power station could support them.
LiFePO4 versus lithium-ion: what is the difference?
The chemistry trade-offs behind today's home batteries and portable power stations.
Balcony batteries and plug-in solar: a UK guide
Understand the difference between portable solar charging, plug-in systems and grid-connected storage.
Put the theory to work
Now that the numbers make sense, calculate them properly or find the exact battery a device needs.