[FACT OR FAKE #25] Charging Your Phone Overnight Is Bad For Your Battery... Right?

Should you be leaving your phone plugged in overnight? Does overcharging shorten the lifespan of your battery? It's a shame to lose sleep over this, so here are the facts, filtered out from the fake.

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Some people say leaving your phone charging overnight has a negative effect on your battery's lifespan in the longterm. Is that fact or fake?

At, Robert says, "I’ve had my Nexus 4 since late December; it’s a great phone! The thing is that, every night before I go to bed, I read social feeds to drain the battery and then I plug it in for a charge for the whole night. The question is: is it a problem if I leave my smartphone on a charge all night? Won’t the battery suffer from this?"

Basil Carolus from the Android Central App Forum: "Not a good idea chap. You're gonna kill your battery then your phone's going to be as good as dead hahaha."

So much charging to do, so little time.

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The fact is, if the battery is Lithium-ion (that's what most of our smartphones are running on) it doesn't matter if we leave it charging overnight, because:

Lithium-ion batteries are charged "intelligently" by your gadget, so they are never overcharged. Charging the device at night will not influence battery life. Lithium-ion batteries also lack the memory effect that is associated with older nickel-cadmium batteries, so recharging the battery before it is exhausted will not reduce its life.

Also, phones do have an automatic shutoff mechanism built in to prevent overcharging that might cause a potential fire hazard. If this is your concern, then rest at ease that the right charging hardware coupled with the right non-shady smartphone shouldn't be a hazard to your person or property.

Nokia Li-ion battery for powering a mobile phone

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However, lithium-ion batteries can be dangerous under some conditions and can pose a safety hazard since they contain, unlike other rechargeable batteries, a flammable electrolyte and are also kept pressurized. This makes the standards of these batteries high, and it consists of many safety features.

What about wasting all that electricity?

y. Yes, charging your gadgets for longer than necessary wastes some energy. Will better habits significantly reduce the footprint of your techno-lust? Not likely.

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As far as environmental sins go, you can file this one in the pardonable category. Yes, charging your gadgets for longer than necessary wastes some energy. Will better habits significantly reduce the footprint of your techno-lust? Not likely.

What happens if you leave yours plugged in all night? According to measurements from Lawrence Berkeley National Laboratory, the average cell phone draws 3.68 watts of power from the outlet while it's charging and 2.24 watts when charged.

Let's take the worst-case scenario and assume that you're over-juicing a charged battery for the entire night. Leave the average phone plugged in for eight unnecessary hours, and it'll use about 0.018 kilowatt-hours of electricity. Do that every night for a week, and the figure rises to 0.13 kWh; every night for a year, and you're looking at a grand total of 6.5 kWh of electricity.

How powerful exactly is 6.5 kWh of electricity? To give you a gauge, it takes about 2 kWh of electricity to boil water in a kettle.

Still, there are some compelling reasons to unplug your smartphone once it reaches 100% capacity. And the reasons are:

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As your phone runs throughout the night, it loses battery life. This causes the charging mechanism to kick in over and over again as measurable amounts of battery drain occurs during standby. Your phone checking email, receiving text messages, and various apps doing their updates can do a lot to your phone’s battery while you sleep.

Your battery may have a limited amount of charging cycles available to it throughout its life. Let’s say there are 1,000 cycles in your particular battery. If you charge 30+ microcharges (a fraction of a full charge) each night while you sleep, then you’re really eating away at your phone’s battery life.

If, however, you only charge your phone when it needs it and make sure to unplug it after it hits 99-100%, then you’re only taking away one partial or full charge cycle each time you plug it in.

This doesn’t mean that your phone’s battery will degrade and die in one night, either. Like laptops, you can leave your phone plugged in almost all the time and it’s likely your battery will still last quite a while, but that doesn’t mean you aren’t at some level chipping away at its capacity or longevity by doing so.

Buying a cheap, knock-off charger can also have an adverse effect. Often, cheap chargers won’t respond so well to the shutoff mechanism in the phone. The energy may also come through in sporadic bursts, which isn’t good for your battery’s life, either.

Now on a lighter note, not all of us can carry off the 'Extended Battery Bro' look. So, go ahead - charge your phone, sleep sound and leave it there till morning.

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