Battery life is generally measured in the number of discharge-recharge cycles that it can withstand. With that in mind, keeping it charged should provide a longer lifetime than cycling it. Keeping it on the charger will certainly not harm it – my last 2 work laptops’ batteries have lasted years being used that way. Some laptops provide battery protection settings for situations where a laptop is mostly kept on the charger – on my current Lenovo, the battery only charges up to 60% with those settings.
Latest Answers