The question: “Should one leave the battery in while the laptop is plugged into the mains or not?” brings up many debates. The answer depends only on how sensible you are and on your circumstances.

Managing your laptop battery

As we have previously seen, the optimal charge temperature is 20 degrees C, and even if your laptop recharges your battery completely, as soon as it loses 10%, it will require 10 recharges of 10% before it will complete one cycle of recharging – that is, recharging 10% and unplugging does not constitute one cycle, so don’t fear small charges. At an ambient temperature we know that the battery – sitting on its own without being in a device, charged or depleted - loses, on average, 10% of its charge per month.

6 to 7 % is attributed to the accumulators. The electronic circuit that regulates the battery is responsible for another 3%. Generally, a computer will proceed to recharge as soon as its battery loses 5% of its charge. Two charges per month would not pose any problems, and having your battery plugged into your PC or having your battery on a shelf would yield the same result. Know that on average, a Li-ion accumulator has a life of between 500 and 1000 cycles.

Leaving your battery sitting on a shelf in a room of ambient temperature would yield the same results as leaving it sitting in your computer. Truth be told, if your computer is permanently plugged in, you will have a tendency to forget about it. The only piece of maintenance required in this case would be to recalibrate your battery once a month by discharging it to 5% and recharging it completely.

Keeping your battery in the machine is handy for those who regularly need it – if you have to leave your desk with laptop in hand suddenly, for example, or if you just don’t want to have to go hunting for batteries all the time; however we will later see that batteries are best stored at a cold temperature. If you computer’s temperature increases significantly after a certain period of use (45 minute -1hour), remove the battery when your computer is plugged into the mains.

A laptop possesses elements which generate heat and that can increase the temperature of the battery. If your laptop heats up significantly, it is possible that its temperature will be over 20 degrees C when recharging the battery, which is not recommended as we have seen above. Finally as we will see on the next page, if you are not using your battery for several months it is a good idea to store it in a cold (0 degrees C) and dry place, although taking it back out can be a tricky operation. Be careful not to forget the cycle of discharge/charge to calibrate your battery also.

Warning, danger

Finally, know that it is strongly inadvisable to take your battery apart and to try and replace its accumulators instead of replacing the battery once its lifetime is up; this is a very bad idea. Our battery became completely unusable once taken apart, and the manufacturer assured us that it would be destroyed once opened by a consumer. This is a feature as much as anything else, as taking apart a battery can damage the safety devices in