# CHARGING AND DISCHARGING TIME

CHARGING AND DISCHARGING TIME

Time in Hours

At any particular instant the actual current delivered by any cell depends on the load. The Time in hours(H) theoretically would be

Time(H) = Capacity (Ah)/Current(A).

If current is measured in amps and Capacity of a cell/battery in amp-hour, then time is measured in hours for charging and discharging.

For instance,

A 20Ah battery pack delivering 0.5A will last for 40hours

A 20Ah battery pack delivering 1A will last for 20hours

A 20Ah battery pack delivering 2A will last for 10hours

A 20Ah battery pack delivering 20A will last for 1hour

CHARGING TIME AND DISCHARGING TIME

The charging and discharging rate are usually specified by the current.

Example, charged at 10A and discharged at 20A

Charging Time

Charging time is the proportion of charge added to the battery per unit time.

In general scenario charging Time is found by,

Charging Time = Battery Capacity / Applied Current

For instance,

Consider 80Ah battery pack, if the applied current is 20Ah, then the

Charging Time = 80 / 20 = 4 hours.

Discharging Time

Discharging Time= (Battery Capacity x Battery Volt)/Device Watt.

For instance,

Consider a 3.7V 20Ah battery, device watt=20watt

Discharging Time = 20Ah*3.7V/20 = 3.7 hours

Li-ion/ / LiPo batteries with power efficiency of 90%

Then,

Discharging Time = (Battery Capacity x Battery Volt x 0.9)/Device Watt

For instance,

Discharging Time = 20Ah*3.7V*0.9/20 = 3.33 hours