We only have laptops (a total of 4 in the house). I always have mine plugged into the powerpoint as I only use it at home meaning the battery is always at 100% (except in the case of a power outage). My two youngest sons do the same. I do turn the computer off at night. My eldest son was visiting and I notice that when he had charged his laptop to 100% he unplugged it. He says he always did this as it means the battery lasts longer. We had a discussion about this. Does anyone know which is the best practice? Also can people tell me if they leave their own laptop plugged in or not when they are at home?
Your son is correct, you shouldn't leave your laptop plugged in when it's 100% as it wears the battery out sooner, however a lot of newer laptops have a feature that turns off charging when the battery is full even if you leave it plugged in.
My understanding is the same as Third Nacelle's. I think this goes for anything that has a rechargeable battery. If it is older, then leaving it plugged in means that the battery is constantly recharging, wearing it out, but for newer electronics/appliances it is smart enough to switch off the power source from the wall when the battery is done charging. So basically, you and your son are both right! As for my own practice, I don't have a consistent habit with this. Sometimes I leave my laptop plugged in for days (even when it is turned off), and other times I will leave it unplugged until the battery dies.
I have an option to stop the battery from charging until the next time the computer reboots. Should I be using this option?
Most electronics these days (at least Apple gear, such as iOS devices and MacBooks) will not be harmed if you leave them plugged in all the time. It doesn't wear them out to be constantly recharging. It will wear them out MORE if you drain the battery down to the bone and then do a full recharge every time. Constantly draining the battery to zero and then going to a full recharge, is more of a strain on the battery than using it and then plugging it back in every night (one HUGE charge is more detrimental than a lot of little charges).
Is that so? The Apple website suggests keeping the electrons moving and even recommends letting the battery run down at least once a month and giving it a full charge.
I've tended to let mine go down to about 50% between recharges, and the battery's lasted pretty well for several years so far.
I recharge my iPhone every night (mainly because I also use it as a clock), and its battery has never given me a problem, even after a year and a half.
I just leave the laptop permanently attached to the power cord and accept the fact that the battery will have to be replaced once before the life of the laptop comes to an end. It definitely reduces the time a battery will stay charged when not connected to the outlet, but I don't usually have a need for the laptop to be cordless. Honestly, it's just not worth it enough for to me to be constantly checking the power level.
Perhaps the charging circuit in the phone turns off, but is the charger also designed to cut off? That would probably require some digital circuitry in the charger that the phone could direct through the cable. If such is the case, there would then be complications about how the phone would activate the charger if the user allowed the battery to completely discharge.
A lot of this comes down to battery chemistry. In the case of laptops, the battery packs contain individual cluster pairs of 18650 lithium battery cells. For some time now, laptops have had built-in battery management. When fully charged, the battery will receive a slight "trickle" charge to keep it topped off. Lithium batteries work best when kept fully charged, except in the case of storing them (where they somehow do better when down to like 75~80%). What wears batteries down the most is being frequently fully discharged, or allowed to sit at low charges for long periods. The next thing is simply time. Once a battery cell is manufactured, it starts on a path of gradual decay. The cells will eventually wear down, even when not used (some batteries will decay faster than others when not used). There's still some controversy as to how helpful periodically doing a nearly complete discharge is, but generally speaking it doesn't hurt to flex the battery chemistry. I think it's a good idea to do it once every couple of months minimum. Generally speaking a laptop battery pack will usually be down to 50% of original capacity after about 3 years, depending upon how it was used and environmental circumstances (this will also vary by battery pack type, as some have more cells than others). Don't forget to dispose of them properly, as the cells contain large amounts of lithium. Do not throw in the trash!