Most of us plug our phones in to charge overnight as part of our bedtime routine. It’s virtually second nature at this point, and besides, who wants to start the day with anything but a full battery?
But is it necessary to charge the phone all the way through the night? Most experts say no, and that you may actually be damaging your phone’s battery and shortening its lifespan by doing so.
How long does it take to charge a phone battery?
Modern smartphones, like many electronics, run on lithium-ion batteries which contain a chemical mixture that degrades with time. Anybody who’s owned the same phone for more than three years will probably notice their battery doesn’t last as long as it did when it was new.
Fully charging a typical new smartphone-sized lithium-ion battery takes between two and three hours. If it’s taking longer than that to charge, the chemicals inside have most likely begun to break down.
But how is that harming the battery?
Modern smartphones will automatically stop drawing power from the mains when the battery reaches 100 per cent capacity. Which you would think would be the end of it.
But your phone is still on, still receiving emails and texts, as well as downloading background data for apps. It’s never truly off.
Because of this activity, your phone is still using power and every time the battery drops to 99 per cent it begins drawing power again. This is known as ‘trickle charging’ and means you’ll be drawing power in tiny increments all night.
Trickle charging has been documented to wear lithium batteries down prematurely and some manufacturers have even implemented measures to automatically cut charging off after a certain point.
Is trickle charging dangerous?
In general, no. The amount of power being drawn is miniscule and would be much less than your refrigerator or any other continuously running appliance.
Samsung phones made headlines globally in 2022 when many of the batteries in their phones began swelling and catching fire while charging overnight. After an investigation, this was found to have been caused by faulty battery components and not by the charging itself.
What should I do?
The difference in battery life between leaving it to charge overnight is noticeable (years in some cases), but you need to weigh that up against waking up every night to unplug your phone once its fully charged.
It’s probably not worth setting an alarm for, but if you wake in the night, it might be worth pulling the plug.
Do you usually charge your phone overnight? Have you ever noticed any issues? Let us know in the comments section below.
Also read: Best 4G-capable phones for seniors
As a volunteer firefighter for 55 years I can say that NO Lithium Iron battery should be left on charge over night. The number of house fires started by these batteries is becoming a real problem as they are almost impossible to extinguish once burning. They also burn extremely hot, and can explode violently. Any Lithium Iron battery can catch fire if it’s damaged, (dropped), or it gets wet. Always monitor these batteries for overheating, swelling or smoke while they are charging. DO NOT USE if there is anything unusual happening at any time as they can catch fire virtually without warning.
I have never left anything charging overnight, I charge them to about 80% in the evening and then again during the day if needed.