Use Laptop Battery As Back Up For Power Outage

There is a circuit in the battery to prevent the Li ion battery from overcharging or over-discharging. Once the battery is charged to 100%, it is cut off and won't charge so you are safe (otherwise it will explode). If you look carefully, the battery won't top up again until it lose some charge and reach around 95-97% before recharging. It is true that you can delay the deterioration of the total capacity of the battery for longer if you keep it below 100% (I think the optimum charge percentage is around 60%), but that means once the power is out, you won't be able to use your laptop for the max period of time. Some Samsung laptop has software to control the max charge percentage of the battery so it cut off before 100% to prolong battery life. However, a good battery should last around 2-3 years. IMO, it's a pain in the ... to keep an eye on the battery percentage all the time so I just keep it plugged in with battery. The laptop will run hotter when plugged in because it is in performance mode so your hardware will run hotter. If you set your laptop to run at max performance on battery, it will just be as hot (and the battery will drain fast).