Keeping Your Laptop Plugged in All the Time? Then You Need to Read This

Technically, there is nothing wrong with keeping your laptop plugged in always, but if you want the device to last longer, then there are a few things that you need to know.

In our tech-obsessed world, everyone wants the battery of their device to last longer. Even better than that is an unlimited supply of power. A lot of us only use the laptop when it is plugged in because of the higher performance when the device is plugged in. But if you are keeping your laptop plugged in even when it is not in use, then it could be worrying.

Most modern laptops work on Lithium-ion batteries. These batteries are light and they also provide a lot of power. They can keep a phone turned on for over a day and power a laptop for more than half a day. Even the LG Gram Z980, a laptop weighing less than a kilogram, manager to cram a 72 Watt-hour battery that gives it a rated battery life of 13 hours.

These lithium-ion batteries operate at around 90 percent efficiency, right out of the box. That is, we are squeezing out as much performance as we can from these batteries. But pushing the even further can be quite dangerous. Previously, it was really unwise to keep charging the laptop batteries, but now, batteries have become smarter. They can handle staying plugged in all the time. But then again, there are a few things that you need to know beforehand.

Batteries are temperature sensitive. With varying temperature, the performance of the battery matters a lot. If your battery is heated and is always charged, then over a period of time, you will notice your battery performance degrading. This effect has been studied by Battery University. You can look up the website for more information on how temperature affects batteries. You can also look at the charge below to see how temperature degrades battery performance.

Temperature

40% charge

100% charge

Estimated recoverable capacity when storing Li-ion for one year at various temperatures. Elevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.
0°C98% (after 1 year)94% (after 1 year)
25°C96% (after 1 year)80% (after 1 year)
40°C85% (after 1 year)65% (after 1 year)
60°C75% (after 1 year)60%
(after 3 months

In short, you can keep your laptop battery cool to improve your battery performance. Therefore, if your laptop is charging, it is normal for the battery to heat up. Using the laptop during that time will cause heating even more. Therefore, it is wise to not use the laptop until the charging is complete. A lot of manufacturers have already implemented this in their laptops. The batteries do not charge if the temperature is too high.

Often using a UPS helps. When your battery is completely charged and you are keeping your laptop plugged in, you can disconnect the laptop battery (given it is user-removable). A UPS helps smoothen out any power disruptions that may occur. Keeping the battery disconnected not only keeps it cool but also avoids unnecessary recharging.

Unnecessary recharging is another problem with laptop batteries. New laptop batteries do not charge if they are charged almost fully. A laptop battery which has been used for a few minutes without AC power and has discharged to only 95% or so, will not charge unless it is discharged even more. This is to avoid unnecessary recharging cycles.

Depth of discharge

Discharge cycles
(NMC / LiPO4)

Cycle life as a function of
depth of discharge. 
A partial discharge reduces stress and prolongs battery life, so does a partial charge. Elevated temperature and high currents also affect cycle life.

Note: 100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity.

100% DoD~300 / 600
80% DoD~400 / 900
60% DoD~600 / 1,500
40% DoD~1,500 / 3,000
20% DoD~1,500 / 9,000
10% DoD~10,000 / 15,000

You can manually reduce the number of recharge cycles by keeping the battery disconnected unless is it has been drained enough. You can charge it again once the battery charge level drops to 15% or so. This also helps in keeping the battery calibrated over longer periods. More about this is covered later.

Recharging cycles can also be improved by reducing the charging voltage. The charging voltage also determines what level the laptop gets charged. In most laptops, the lithium-ion cells are rated at 4.20 volts. However, by reducing the voltage, the number of charging cycles can be improved. But with voltages below 4.20 volts, the battery gets charged below 100%. This again is something that cannot be controlled by the user but has to be implemented by the manufacturer.

If your battery meter is not giving accurate readings of the battery level, then you can perform a battery calibration. This essentially involves discharging your battery completely and then charging it up completely again.

To do this easily, you need to go into Safe Mode on your laptop. First, make sure your laptop has enough charge to get switched on. Once powered up and on battery power, reboot into Safe Mode. Keep your laptop powered on like this and wait for the battery to drain. In Safe Mode, your laptop will not automatically turn off when the battery is low. You can use something like Prime95 to discharge the battery faster.

Once the battery is drained completely, you can plug it in again and allow it to charge completely. It is better not to switch on the laptop during this period. Now your battery should be calibrated and provide proper readings. If it does not, repeat the process again.

Source: Windows Central

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