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I have a 3p12s 18650 Li-ion battery pack that I use for my e-bike. I charge it with a balance charger. I know that charging with too high current is bad for battery life. But is it "the lower the better"? If not, is there any recommended minimal charging current? Is charging at 0.1 C safe? My only goal is to prolong the battery life (number of cycles). I charge it only at night so I don't care about it taking long time.
In the data sheet of the cells I use (Sony US18650V3) there is only specified maximum charge current 1 C. It says nothing about minimum charge current. What's more, I've never seen any batteries data sheet mentioning "minimum charge current".