To prolong lifespan and ensure safety, the standard charging current for most batteries is 20%C to 50%C (C means capacity). For example, the suggested charging current for 2600mAh 18650 is 500mA to 1300mA. Charging with low current is good for battery’s lifespan. Charging with higher current is faster, but normally higher current creates more heat. The maximum charging current would better not higher than 100%C. Because the batteries might be over heat and have a shorter lifespan if the charging current is too high. The heat also depends greatly on the battery quality. Users can choose the suitable charging current according to the requirement.
Please kindly notice that this formula is applicable to most Li-ion batteries, but the standard charging current may vary from different brands. For accurate data, you can consult your battery supplier.