Like most of us, I've used lithium ion batteries in many everyday devices. I also use a few lithium polymer batteries in RC-airplanes. In the last years I read about their correct usage and charging. These are some of the things I learned:
- Discharging a cell below minimum voltage kills it (capacity decreases.)
- Overcharging a cell above the maximum voltage kills it.
- That is why you use a balancer while charging a pack of cells in series. It balances the cells to an identical voltage level by discharging the higher-voltage-cells.
- There's nearly no memory effect. No need to discharge before charging.
- For long term storage charge it to 65-80%. Not less to avoid undercutting the minimum voltage. More voltage would mean more wear and ageing, because of a higher amount of chemical reactions.
- You should wait some time after using a battery before charging it again.
How long should you wait after usage before charging?
For example, if I use a battery powered string-trimmer or lawn-mower and the battery has gone empty (and probably quite warm,) how long should I wait before connecting it to the charger?
I guess reasons you should wait are temperature, or ongoing chemical reactions. Also I think you should wait longer if the battery had to deliver very high-current like the lawn-mower or a fast rc-airplane which will lead to higher battery temperature.
Sidequestion: If it's about temperature would it help to put the battery in the fridge after use, to be able to charge it earlier?