I am not talking about how long a charge lasts, but how long the battery lasts.
Should top it off every night to 100%, no matter what % is left? Should I let it get down to 30% or lower before I charge it? Should I leave it in the charger once it reaches 100% or should I unplug it immediately?
Advice for battery optimization has changed so much over the years I’ve no idea what the latest wisdom is.
Newer Samsung phones have a setting called “Battery Protect” that if selected will limit charging to 85%.
The general rule is still to try to keep it anywhere between 20-80%.
Generally speaking, I think the idea is to avoid high temperatures. Years ago I noticed a smartphone in navigation mode, constantly searching for a signal on the road would start to go Chernobyl. High temperatures can cause swelling or bloating of the battery cells and a permanent loss of capacity. Still, there are only a finite number of charge/re-charge cycles for any battery before it is time for replacement.
I’d try to discharge the battery less, I prefer keeping the battery above 50%.
Another general rule is that the less the battery is discharged within one cycle, the more cycles you can go.
I hadn’t heard of this before, so I went looking for information and found this:
It seems to confirm what @DCnDC said, saying that charging puts the most strain on the battery when it is nearly full or nearly empty.
I was wondering the same thing, so I found many of the same advice.
As an extra data point my car also starts whining when it is below 20% or if I want to charge above 80%. This is of course for li-ion batteries, to get the most out of lead batteries of older ni-ca batteries the best practices are different.