Laptop Charging Advice

By James Bowman, Data Doctors

Does it harm my laptop battery if I just keep it plugged into my charger all the time?


Battery life continues to be one of the biggest complaints of laptop users, so understanding what you can do to help prolong the life is important. Technically speaking, keeping any relatively current laptop plugged in and charged at 100% for extended periods of time shouldn’t be a problem, but it’s best not to do so for a number of reasons.

Battery Management System (BMS)
Today’s laptop batteries have sophisticated battery management systems that monitor your State Of Charge (SOC) and drop the voltage down as it gets closer to a full charge.

Once the SOC is at 100, it is designed to switch to the AC connection directly and only provide a trickle charge to the battery should it need it.

We should be able to rely on the BMS to keep things charging properly, but a number of things can impact the BMS which could lead to overcharging the battery when it’s plugged in all of the time. Overcharging can lead to overheating which can lead to catastrophic chemical reactions inside the battery. In severe cases, BMS failure can lead to ‘thermal run-away’ which can lead to hazardous fires or exploding batteries.

We’ve all heard the stories of devices such as hover boards, smartphones and laptops powered by lithium ion batteries which are generally caused by thermal run-away.  This is also what leads to laptop recalls from time to time. Keeping your battery charged between 40% and 80% has been shown to extend battery life and if you aren’t going to use your laptop for a while, turn it off and unplug it from the charger.

Improper Charger
If you use a third-party charger instead of the one provided by the manufacturer, this mismatch can cause issues, especially once the battery’s SOC goes above 80%.  This is when an adjustment to the charging voltage should occur and when it doesn’t, bad things can happen.


Charging Temperatures
charging your laptop when it’s above or below the recommended operating temperature can cause issues or degrade the battery, so make sure your laptop is at room temperature before you plug it in to charge it.

If you charge your laptop near a window which exposes it to direct sunlight, move it to a location away from any direct sunlight.

Make sure the small exhaust vents (typically in the back of most laptops) aren’t being blocked to prevent heat buildup as charging the battery generates heat.

Signs of a Damaged Battery
If you notice that the bottom of your laptop becomes uncomfortably hot when you are charging or using the laptop, it may be an indication that you have a damaged battery.

Other symptoms we often see with batteries that have clearly overheated and are bulging are touchpads and keyboards that are intermittently responsive or you can feel that they are no longer fully flat.

Anecdotally, most laptops that we service that exhibit these physical symptoms in the laptop from a bulging battery were confirmed to be plugged in all the time to a charger.