11
Four Stages of Solar Charging
VO
LTAGE
TIME
NIGHT
NIGHT
4
FLOAT
3
EQUALIZE
2
PWM
ABSORPTION
1
BULK
CHARGING
Solar Charging Stages
1. Bulk Charging:
In this stage, the battery will accept all the current provided by the
solar system.
2. PWM Absorption:
When the battery reaches the regulation voltage, the PWM begins
to hold the voltage constant. This is to avoid over-heating and over-gassing the battery.
The current will taper off to safe levels as the battery becomes more fully charged.
3. Equalization:
Many batteries benefit from a periodic boost charge to stir the
electrolyte, level the cell voltages, and complete the chemical reactions.
4. Float:
When the battery is fully recharged, the charging voltage is reduced to prevent
further heating or gassing of the battery.
Battery Charging Notes
The SunWide manages many different charging conditions and system configurations.
Some useful functions to know follow below.
Solar Overload:
Enhanced radiation or “edge of cloud effect” conditions can generate
more current than the controller’s rating. The SunWide will reduce this overload up to
130% of rated current by regulating the current to safe levels. If the current from the solar
array exceeds 150%, the controller will interrupt charging.
Battery Temperature Compensation:
All charging setpoints are based on 25°C (77°F).
If the battery temperature varies by 5°C, the charging will change by 0.15 volts for a 12
volt battery. This is a substantial change in the charging of the battery.
Day-Night Detection:
The SunWide will automatically detect day and night conditions.
Any functions that require measuring time or starting at dawn, for example, will be
automatic.