Use a voltmeter to measure the voltage of the assembled 7.4V battery pack. Charge the battery pack using a compatible 7.4V charger or one designed for two Li-ion/LiPo cells in series. Monitor the charging process and ensure the cells are balanced during charging. Part 6. How to charge a 7.4V battery?
The “7.4V” part of the name refers to the voltage, which is a combination of the individual cells inside the battery. Each cell in a LiPo battery typically has a nominal voltage of 3.7V. When two cells are connected in series (hence, “2S”), their voltages add up to 7.4V.
Part 1. What is a 7.4V LiPo battery? A 7.4V LiPo battery, also known as a 2S LiPo battery or a 7.4V LiPo battery pack, is a type of lithium polymer battery. The “7.4V” part of the name refers to the voltage, which is a combination of the individual cells inside the battery. Each cell in a LiPo battery typically has a nominal voltage of 3.7V.
The voltage range of a 7.4 V lithium battery is generally as follows: Nominal voltage: 7.4V. This is the voltage output by the battery under ideal conditions, usually marked on the battery. Full voltage: about 8.4V. When the battery is fully charged, the voltage will reach its highest value, generally around 8.4V. Low voltage: about 6V.
IMPORTANT - you must limit the charger VOLTAGE to a bit less than 8.4V which is the absolute maximum voltage across two LiIon cells in series. SO, with an accurate voltmeter set the charging VOLTAGE to 8.35 or so and set the charging CURRENT to, say, one tenth of the cell capacity.
3.7V batteries are commonly used in small, portable electronic devices like smartphones, cameras, and vaping devices. 7.4V batteries are often used in larger, power-hungry devices like power tools, drones, and some RC vehicles, where the higher voltage and energy capacity are beneficial.