Battery Charge /Discharge Reference - sol-ark 12K Install Manual & Owner’s Manual

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.
MPPT Charging Algorithm
Bulk Charge Stage
In Bulk Charge stage, the battery is not
at 100% state of charge and battery
voltage has not yet charged to the
Absorption voltage setpoint. The
controller will deliver 100% of available
solar power to recharge the battery.
Absorption Stage
When the battery has recharged the absorption voltage setpoint, constant-voltage regulation is used to
maintain battery voltage at the absorption setpoint. This prevents heating and excessive battery gassing. The
battery is allowed to come to full state of charge at the absorption voltage setpoint. Absorption lasts until
batteries charge at 2% of programmed Ah size.
Float Stage
After the battery is fully charged in the Absorption stage, the MPPT reduces the battery voltage to the float
voltage setpoint. When the battery is fully recharged, there can be no more chemical reactions and all the
charging current is turned into heat and gassing. The float stage provides a very low 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.
Battery Charging Setpoint (48V)
Battery Absorption
Type Stage
AGM 14.4v (57.6v)
(or
PCC)
Gel 14.1v (56.4v)
Wet 14.7v (59.0v)
Lithium 14.1v (54.6v)
How to calculate Amp Hours for your battery bank (PCC 230):
Battery Voltage
Count per
Battery
4 12V
8 12V
12 12V
16 12V
Float Stage
13.5v (53.6v)
13.5v (54.0v)
13.7v (55.0V)
13.2v (54.3v)
Amp Hours Total Amp
per Battery Hours @48V
230Ah 230Ah
230Ah 460Ah
230Ah 690Ah
230Ah 920Ah
Equalize Stage
(every 30 days 3hr)
14.4v (57.6v)
14.7v (59.0v)
14.1v (54.6v)
Max Charge/
Discharge Amp
100A
185A
185A
185A
February 3, 2020
Note:
When batteries are
in series, the voltages
Default
add to each other.
When batteries are
in parallel the Amp
hours add to each
other.
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