How do you charge batteries safely at home?

Why a PMD battery fire is dangerous

The safe way to charge is simple: use the original charger, put the device on a hard, flat surface away from your exit and anything that burns, and stay nearby while it charges. These habits matter because of how fast a battery fire moves.

The Singapore Civil Defence Force (SCDF) says in its Civil Defence Emergency Handbook that fires involving active mobility devices (AMDs) with lithium-ion batteries can escalate very quickly. In thermal runaway, the battery may explode and toxic gases may be emitted. That can narrow your window of escape to seconds.

AMDs include personal mobility devices (PMDs), such as e-scooters, and power-assisted bicycles (PABs). An e-scooter fire gives you little time to react, so most of this guide is about prevention: how you charge, what you buy and how you check it. It ends with what to do if a fire starts anyway.

Charging habits

Good battery charging safety comes down to a few habits you repeat every time you plug in. These six come from SCDF's handbook, which has tips for PMDs and PABs as well as general advice on charging batteries and devices.

1. Use the original adapter. Charge with the power adapter that carries the Safety Mark and is recommended by the manufacturer. Do not use another charger just because its plug fits.
2. Let it rest after a ride. Do not charge the device immediately after use. Park it first and plug it in later.
3. Charge on a hard, flat surface. Set the device or battery on a hard, flat surface while it charges. A bed, sofa or cushion is not one.
4. Keep it clear of things that burn. Charge away from combustible materials, and never along an escape path or in a common corridor.
5. Do not leave it charging unattended. Do not leave a battery or device charging unattended for an extended period or overnight. Charge when someone is at home and awake.
6. Follow the manufacturer's instructions. Charge and store the device the way its manual says.

SCDF's advice on AMDs at home adds two points: keep a clear path to your exit, and charge the device away from that exit, as the handbook sets out. It also says not to overload electrical outlets. If your charger shares a multi-plug with other appliances, our guide to power strip overload explains what to watch for.

Buying and checking devices

Safe charging starts before you buy. SCDF's PMD and PAB tips say not to buy or use non-original batteries. They say to buy registered PMDs with the UL2272 Certification Mark, and PABs with EN15194 certification and the orange seal of the Land Transport Authority (LTA). SCDF also says it is an offence to use non-compliant devices.

Check the Safety Mark on the adapter before you charge. Our post SAFETY Mark explained covers what the mark means.

Once you own a device, maintain it in its original state. SCDF's handbook says not to tamper with, modify or attempt to repair batteries or devices yourself, and to dispose of a device with non-original parts through authorised e-waste recyclers.

If a device catches fire

If a PMD or PAB catches fire at home, SCDF's handbook says not to fight the fire, because lithium-ion battery fires spread quickly and may explode. Instead:

1. Shout to alert others in the home.
2. Leave the unit immediately and close the door to limit the spread of the fire.
3. Call 995.

If you cannot escape, SCDF's advice is to move to the room furthest from the fire and shut the door. Seal the gap beneath the door with a wet towel or rug. Do not jump.

Smoke alarms and the rest of the home

SCDF's AMD advice includes installing a Home Fire Alarm Device (HFAD). SCDF's HFAD page describes it as an automatic smoke or heat detector that sounds an alarm to give early warning of a fire. A smoke detector gives earlier warning than a heat detector and is recommended for the primary protection of homes.

HFADs are mandatory for new homes from 2018. For an existing home not doing fire safety works, one is not mandatory, but SCDF strongly encourages owners to install one, with a built-in battery with a 10-year life span. Our home fire alarm guide has more detail.

Charging is only one part of home fire safety. The household checklist in SCDF's handbook also asks whether plugs and multiway adaptors carry the SAFETY Mark, whether outlets are used within their safe capacity and whether wires are in good condition. Work through our home fire safety checklist and home electrical safety checklist. SCDF says frayed or exposed wiring should be replaced immediately; for that or anything else wiring-related, compare electricians in the directory.

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