By Nik Rawlinson

What you need: Battery-powered devices

Time required: Several hours

You’ve probably noticed that battery-powered devices, from phones to electric vehicles, charge fairly quickly to 80 per cent then slow down. This is a feature, not a glitch, as we’ll explain. Most rechargeable batteries use what’s known as a lithium-ion core (sometimes written as li-ion), which is a layered structure of gel and solid materials that can accept and hold a charge.

Li-ion batteries are at their most efficient when charged to between 80 and 90 per cent, and not discharged to below 20. Chargers, and the software in phone, tablet and laptops, are mindful of this, so work together during charging to manage a high incoming current until the battery is four-fifths full, before ramping down the power for the final 20 per cent.

This combination of technologies – at either end of the charging cable – is what we’re talking about when we discuss battery technology: not just the battery itself. The device inside which a battery lives, the hardware that manages the flow of current, and any associated software or firmware comprise an energy platform in which each part needs to work together.

When you understand this, you can optimise your charging and hopefully help your batteries – and any devices in which they can’t be swapped out – to last longer. Here we explain what you need to know.

1 Understand charger ratings

Ideally, you’ll only ever use the charger that came with your device, even though it’s not always necessary. Legislative bodies like the European Commission have introduced rules forcing manufacturers to use USB-Ccharging connections for phones, tablets and laptops. The goal is to reduce the amount of electronic waste generated when we upgrade our devices, but there are knock-on benefits for users: not only will we have fewer adapters littering our homes, we can also stop packing half a dozen when we head off on holiday.