Effects of Discharge Rate and Temperature on Battery Capacity and Life

Battery Application & Technology

The rate at which a battery is discharged and its operating temperature have a profound effect on its capacity and life. An example of the effect of discharge rate on battery capacity is shown in Figure A for traction batteries. This figure shows that batteries discharged at a low rate will be able to deliver a higher capacity than those discharged at a high rate.

The depth of discharge also affects the life of a battery. As shown in Figure B for a typical traction battery, discharges beyond about 80% of capacity can be expected to shorten battery life.

Colder operating temperatures will yield a little extra life, but also lower the capacity of lead acid cells. High temperatures yield higher capacity (see Figure C) but have a detrimental effect on life.

Figure A
Typical effects of discharge rate on battery capacity

Figure B
Typical effects of depth of discharge on traction battery life

Figure C
Typical effects of operating temperatures on traction battery capacity