Regarding the charging method of 18650 lithium-ion batteries.

Regarding the charging method of 18650 lithium-ion batteries.

Lithium ion batteries are similar to lead-acid batteries, and safety should be taken into account when using them. Check the full charge voltage, usually 4.20V/section, and set the corresponding threshold. Ensure that the lithium batteries connected in series do not exceed this voltage. When the voltage of the lithium-ion battery reaches 4.20V/battery and the current drops to 3% of the rated current, or reaches the bottom where it cannot drop any further, the battery is fully charged. After fully charged, disconnect the battery. Do not let the battery stay at a voltage of 4.20V for more than a few hours, otherwise there is a risk of explosion.

Not all lithium-ion batteries are charged to a voltage threshold of 4.20V/battery. Lithium iron phosphate batteries are typically charged to 3.65V/battery cut-off voltage, while lithium titanate batteries are charged to 2.85V/battery cut-off voltage. Some power batteries can accept 4.30V/battery or higher. It is important to pay attention to these voltage limitations.

Charging nickel based batteries with a power source is a challenge, as the basis of full charge detection is voltage characteristics, which vary with changes in charging current. If nickel cadmium batteries and nickel hydrogen batteries must be charged using a regulated power supply, a temperature rise of 0.3-1C during fast charging indicates complete charging. When charging with low current, estimate the remaining power and calculate the charging time. At a voltage of 750-1000mAh, a 2mAh nickel hydrogen battery can be charged for approximately 3 hours. Trickle charging, also known as maintenance charging, must be reduced to 0.05c.