Battery voltage separated by R3 before being fed to the two comparators in IC2, When it is below the threshold determined by the output of P2, IC2B goes high which also causes the output of IC2C high. T1 saturation and relay RL1 on, allowing the solar panel to recharging the battery via theD3. When the battery voltage exceeds the threshold set by P1, When the battery voltage exceeds the threshold set by P1, the output ICA goes low as well as IC-C … and therefore causes the relay off, thus avoiding overloading when charging the battery.
