edubb256
Well-known member
That's me... And you can't refute what is fact. Making a habit of holding lithium ion batteries at their saturation voltage reduces their lifespan. Anyone telling you otherwise are the ones giving bad information.
Now, some devices limit their peak charge point, which, in turn, mitigates the degradation. But most current phones crank up the peak voltage up closer to the cells maximum safe charging limit in order to maximize the amount of stored charge... They figure you'll get rid of the thing before it degrades to the point of annoyance.
Oh, since everything has safety circuitry, leaving a fully charged phone in the charger won't cause a fault.. I.e. booms. But safety and longevity are two different things.
In fact, there are several laptop manufacturers that now include charging features that will allow the laptop to drain down to a much more gentle zone, only allowing the laptop to charge up 100% based on a schedule (such as if you expect to take it off the charger or dock every day at 9am).
This is true, but not pertinent to OP's question. This is what causes confusion. Yes, leaving a lithium ion battery or lithium polymer battery at 100% for an extended period is harmful to the battery (causes reduced the number of charge cycles). So leaving the computer to plugged at 100% all the time (as mountainman does) is not good for battery life unless your PC has software that automatically detects that pattern and discharges to lower charge level and limits the maximum charge level, as you state. However that is not the same as charging a phone overnight to 100% and then taking off the charger and using the phone during day (the scenario pertinent to OP's question). In that case, the average charge level of the phone is less than 100%. Keep in mind that max charging voltage is less than 100% of the battery's capacity on purpose given that charging overnight is a common practice with cell phones.