Civil Engineering Reference
In-Depth Information
FIGURE 10-18
Constant current charging of nickel-cadmium and nickel-metal-hydride batteries.
FIGURE 10-19
Constant voltage charging of lithium-ion battery.
the charging when the continuously monitored
V is detected negative. On
the other hand, the Li-ion batteries, being sensitive to overcharging, are
charged at constant voltage, tapering off the charge current as needed
(
Figure 10-19
)
.
∆
10.8
Charge Regulators
For safety reasons, it is extremely important that excessive charging of the
battery is avoided at all times. Overcharging causes internal gassing, which
causes loss of water in the lead-acid battery and premature aging. The charge
regulator allows the maximum rate of charging until the gassing starts. Then
the charge current is tapered off to trickle charge rate so that the full charge
is approached gently.
The batteries are charged in the following three different manners.
10.8.1
Multiple Charge Rates
This is the best method, in which the battery is charged gently in multiple
steps. First the battery is charged at full charge rate until 80 to 90 percent of
