sol-ark 8K-2P-N, Install Manual & Owner’S Manual

Page: 36 / 45

October 26
th
, 2022 36
Batteries
Battery Charging Information
4-Stage Charging
The MPPT has a 4-stage battery
charging algorithm for rapid, efficient,
and safe battery charging. The figure
below shows the stage sequence.
Bulk Charge Stage
In the Bulk Charge stage, the battery is
not at a 100% state of charge and has
not yet reached the Absorption voltage
setpoint. The controller will deliver 100% of available solar power to recharge the battery.
Absorption Stage
When the battery has reached the absorption voltage setpoint, we use constant-voltage regulation to
maintain battery voltage at the absorption setpoint, preventing heating and excessive battery gassing.
The battery is allowed to come to a full state of charge at the absorption voltage setpoint. Absorption
lasts until batteries charge at 2% of the programmed Ah size.
Float Stage
After the Absorption stage charges the battery fully, the MPPT reduces the battery voltage to the float
voltage setpoint. If batts have 100% charge, there can be no more chemical reactions, and all the
charging current turns into heat and gassing. The float stage provides a meager rate of maintenance
charging while reducing the heating and gassing of a fully charged battery. The purpose of float is to
protect the battery from long-term overcharge.
MPPT Charging Algorithm