I always hear that it’s bad for lithium batteries to charge over 90% or over 90% so why is there no setting to stop charging after a certain threshold on my phone, kindle, pc or e-skate?
In: 129
It’s not bad to CHARGE over 90%. It’s bad to let a lithium cell SIT over 90% charged.
(There’s a little nuance here depending on the exact lithium chemistry. LFP does fine at 100%)
The reason is that as you put more energy into a cell, the voltage rises. This increase in energy/voltage is then available to power undesirable side reactions within the cell that permanently decreases the capacity of the cell. Over 90% those bad reactions really speed up. The longer you allow a cell to sit at a very high state of charge, the more side reactions occur. Hence why it’s fine to charge up if you plan to use the power right away, but if you are not going to use the device right away then maybe don’t fill it up. It’s one reason why electric cars allow you to schedule your departure time, so they can complete their charge just as you’re ready to leave.
Latest Answers