DIY Lithium Battery Charger Circuit

DIY lithium battery charger circuit is working based on an op-amp of LM358 IC. Lithium-ion batteries are very powerful and compact in size, which is very useful in today’s electronics. Connected 3v lithium-ion batteries in series will produce a high voltage with less size and easy to transport. The lithium-ion batteries are different than the lead-acid and nickel-cadmium batteries.

The charging also different than the lead-acid batteries. The 3.9v Lithium-ion batteries need 4.2 v of charging voltage and 1A charging current. The charging time is about 2-3 hours. if the optimized charging is not done, the battery will be damaged or reduces the battery capacity.

The proper voltage and current needs for the proper charging of the battery. in this circuit a IRF9540 P channel mosfet control the charging voltage. When the charging voltage exeeds the pre determined voltage the mosfets gets turn off and disconnect from charging. while charging the red led startts to blink and turn off when battery fully charged.