Absorption Charge; Float Charge; Output Current Limit; Optional Temperature Compensation - BLUE SKY SB3000i Installation And Operation Manual

Blue Sky Energy – Solar Boost 3000i

Absorption Charge

Once the battery recovers sufficient charge for battery voltage to rise to the Absorption Charge Voltage setpoint (factory set to 14.4V), charge
current is reduced as necessary to hold the battery at the Absorption Voltage. The 3000i will return to Bulk should battery voltage remain below
the Absorption Voltage setpoint for more than 10 seconds. The 3000i remains in Absorption until the battery is fully charged as determined by
either;
1) The 3000i remains continuously in Absorption for the Absorption Charge Time period (factory set to 2 hours).
2) With the optional IPN ProRemote display and battery system monitor, net battery charge current decreases to the Float Transition
Current (factory set in the ProRemote to 1.5 amps per 100 amp-hours of battery capacity).

Float Charge

Once the battery is fully charged a somewhat lower Float Voltage (factory set to 13.2V) is applied to maintain the battery in a fully charged
state without excessive water loss. The 3000i will return to Absorption should battery voltage remain below the Float Voltage setpoint for
more than 10 seconds.
2-STAGE CHARGE CONTROL
The 3000i may be configured for 2-stage charge control if desired by setting the Float Charge Voltage setting to "OFF" (NO Float).

OUTPUT CURRENT LIMIT

Should conditions be present where the PV modules are able to produce more than 30 amps of output current with 36 cell PV modules, or 22 amps
with 60 cell PV modules, the 3000i will automatically limit output current to this value. Note that when current drops and the 3000i exits current
limit it will first enter Absorption on its way back to Bulk even though battery voltage may be below the Absorption Charge Voltage setpoint.
➢ WARNING: Current limit should be thought of as transient PV over current protection and not a normal mode
of operation. If the 3000i enters 30 amp or 22 amp current limit on a regular basis it is possible that excessive PV
power is connected. Confirm that the PV modules do not exceed ratings shown in the Selecting PV Modules
section.

OPTIONAL TEMPERATURE COMPENSATION

The charge voltage required by batteries changes with battery temperature. Temperature compensation of charge voltage enhances battery
performance and life while decreasing battery maintenance. Temperature compensation of charge voltage can be provided using the optional
battery temperature sensor (BSE p/n 930-0022-20). The default compensation factor of –30mV/C (–5.00mV/C/cell) is typically appropriate for
most lead-acid chemistry batteries including GEL and AGM. If a proper temperature sensor signal is not detected the 3000i will operate as if battery
temperature is 25C.

EQUALIZATION

➢ WARNING: Not all batteries can be safely equalized. Equalization should be performed only on vented liquid
electrolyte lead-acid batteries. Always follow battery manufacturers recommendations pertaining to equalization.
Equalization applies a relatively high charge voltage producing significant battery gassing. Prior to performing
equalization disconnect equipment that cannot tolerate the high equalization voltage which is temperature
compensated as shown above.
Equalization is a controlled overcharge used to bring all battery cells up to the same specific gravity and state of charge. The 3000i may be configured to
perform an automatic equalization on periodic basis, or a manual equalization. Since sealed batteries should not be equalized the factory default
settings have Equalize Enable (EqE) set to OFF to disable automatic or manual equalization. Equalization may be enabled by setting Equalize Enable to
ON as described in the Charge And Load Control Settings section. When an equalization cycle is being performed the Float and Absorption charge status
5
FACTORY DEFAULT CHARGE VOLTAGE SETPOINTS -VS.- BATTERY TEMPERATURE
 OR 
FIGURE 2
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