ELECTRIC VEHICLE BATTERY CAPACITY
Table 3–1 Current and future VRLA battery specifications.
Specific Energy Energy Density Specific Power Recharge Time Cycle Life (C/3)
Figure 3–1 battery.
Current Pb-acid
Midterm Specifications
45 Wh/kg 95 Wh/L 245 W/kg <10 hrs. 600
80 Wh/kg 135 Wh/L 150–200 Wh/L <6 hrs. 600
The estimated Peukert plot at 80°F for an 80 Ahr
86 84
Time (min)
44
82 80 78 76 74 70
80
90
100
Current (A) Estimated Peukert at 80°F
For example, an 80 Ahr VRLA battery, Peukert constants n may vary between 1.123 to 1.33 and K may vary between 138 to 300 respectively. The graph in Figure 3–1 is a Peukert plot at room temperature, 80°F.
THE TEMPERATURE DEPENDENCE OF BATTERY CAPACITY The useful Ahr capacity available from the VRLA is dependent on battery temperature and may be represented by the following equation Ct = C77 ¥ (1 - 0.065(77 - t))
