OK, I will never go over 1C, mostly I chrage AAA at 400-500mA and AA at 700-1000mA, depending also on the charger current selection and the capacity of the cell.
But after some experiments I saw if I charge a AA with 1500mA it stays cool for a long time, only at the end it will get hot. But some cells in some chargers get at the end hotter, even if only charged with 500mA, than the cell at 1500mA if not charged with this current to near the end.
So it would make sense to charge with a big current for most of the charging time but reduce the current a short time before the charge is finished. Should be possible if the charger decrease the current at a specific cell voltage.
Is it correct or am I missing something?
But only my Opus-chargers do decrease the current at the end automatically, my other chargers don´t do it and with most chargers it´s not possible to decrease the current while charging. With some chargers you need to eject and re-insert the cell, with others you can press and hold the Mode-button to change it but useally the charged capacity will be ressetted. Nitecore and some Xtar allow to change the current while charging and don´t reset the charged capacity. But it would mean you have to observe it to change the current.