1.Bulk :At this mode, a preset maximum constant amount of current (amps) is fed into the battery as no PWM is present. As the battery is being charged up , the voltage of the battery increases gradually

2. Absorption: When the battery reaches the bulk charge set voltage, the PWM begins to hold the voltage constant. This is to avoid over-heating and over-gassing the battery. The current will taper down to safe levels as the battery becomes more fully charged. 3. Float: When the battery is fully recharged, the charging voltage is reduced to prevent further heating or gassing of the battery

This is the ideal charging procedure.

The present charge cycle block of code is not implements 3 stages charging.I use a easier logic in 2 stages.It works good.

I am trying the following logic for implementing the 3 stages charging.

Future Planning for Charging Cycle :

The bulk charge begins when solar panel voltage is larger than battery voltage. When the battery voltage reaches 14.4V, absorption charge will be entered. The charging current will be regulated by PWM signal to maintain the battery voltage at 14.4V for one hour. Float charge will then enter after one hour. The float stage generates a trickle charge to keep the battery voltage at 13.6V. When the battery voltage falls below 13.6V for 10mins, the charging cycle will be repeated.