Six rules that cover almost every safety scenario

Modern regulated vape mods are designed with multiple layers of protection including overcharge protection, short-circuit protection and reverse polarity detection. The vast majority of battery incidents reported in the news involve one of three things going wrong. A loose 18650 cell short-circuits in a pocket against keys or coins. A counterfeit battery with mis-stated amp ratings overheats under load. Or a damaged wrap allows the metal casing to contact the device tube. Following these six rules eliminates almost all of that risk.

Rule 1. Use the right charger

Use the charger that came with your device or a dedicated external charger from a reputable brand like Nitecore, Efest or XTAR. Cheap unbranded chargers often lack the safety circuits that prevent overcharging. For removable cells a dedicated external charger is preferred over USB charging through the mod itself because external chargers monitor each cell individually.

Rule 2. Never charge unattended

Modern protections help but no charging system is foolproof. The few minutes saved by leaving a device on charge overnight are not worth the small chance of a fire if something fails. Most vapes charge fully in 1 to 3 hours. Unplug at 100 per cent rather than letting the charger trickle the cell at full voltage.

Rule 3. Never carry loose cells in pockets

This is the single most important rule and the one most often broken. A 18650 cell carried loose in a pocket can short-circuit if it touches a metal object such as keys, coins or another battery. The cell rapidly heats up, vents flammable electrolyte and can ignite. Carry spare cells in a rigid plastic battery case which costs around two pounds and prevents virtually all pocket fires.

Rule 4. Inspect the wrap and insulator

The plastic wrap on a 18650 or 21700 cell is what stops the metal casing (which is the negative terminal) from touching anything else. A torn, nicked or peeling wrap exposes the negative terminal. If the wrap is damaged in any way either re-wrap the cell using a replacement sleeve or dispose of the battery at a recycling point. Re-wrap kits cost about a pound and most local vape shops will re-wrap a battery for free.

Rule 5. Match amp rating to wattage

Every cell has a continuous discharge rating in amps (CDR) which is the maximum sustained current it can supply safely. If your mod draws more current than the battery can provide the cell overheats. Use Ohms law and the manufacturer specification to check that your cells can handle the power your build needs. As a rough guide most regulated mods running at 60 to 80 watts need batteries rated at 20A CDR or higher. High-wattage mech mods need 30A or higher.

Rule 6. Store at 50 per cent charge in a cool dry place

If you are storing batteries unused for more than a week aim for around 50 per cent charge. A full charge accelerates capacity loss because the cell sits at maximum voltage. An empty cell can drop into deep discharge and become unrecoverable. Store between 20 and 25 degrees Celsius away from direct sunlight, hot cars and metal objects.

If you want to skip the manual battery management entirely the simplest path is a regulated pod kit or pod mod with a built-in battery. Our full kit and mod range includes plenty of integrated battery devices that take the safety question almost entirely out of the user's hands.

For more on hardware fundamentals, charging best practice and what to do when a vape goes wrong head over to our full vaping guides hub where every vape question is covered in plain English.