Battery Protection
The battery will act as a protective charge/discharge current limiter under any of the conditions
as below:
• Battery SOC (state of charge) is lower than I-DOD (depth of discharge).
• Battery voltage is lower than the discharge voltage.
• Battery over heating protection.
• Battery communication is abnormal for a lithium battery.
• Battery management system (BMS) limitation for a lithium battery.
When charge/discharge current limit protection occurs:
• In on-grid mode, battery charge/discharge operation may be abnormal.
• In off-grid mode, the back-up supply will shut down.
Note:
• In off-grid mode, if the back-up supply shuts down because of the battery having low SOC or
voltage, all PV power will be used to charge the battery until its SOC reaches 40% +(1-DOD)/2,
then the back-up supply will be activated.
• In on-grid mode, the battery is protected from over-discharge by DOD and the discharge
voltage. In off-grid mode, it is protected only by the discharge voltage as a priority.
• The battery's DOD setting prevents the inverter from discharging the battery's reserve power. As
soon as the DOD limit is reached, the load will only be supplied by either PV power or the grid.
After several continuous days in which little or no battery charging occurs, the battery may
continue to self-consume energy to support communication with the inverter. Behaviour varies
between batteries from different manufacturers, but if the battery's SOC reaches a certain level,
the inverter will boost the SOC back up. This protection mechanism safeguards against the
battery reaching 0% SOC.
2.4.3 On-grid and Back-up Connection
An external AC breaker is required for on-grid connection to isolate the system from the grid
when necessary.
Requirements for the on-grid AC breaker are shown below.
1. Use a separate AC breaker for each
individual inverter.
2. On the AC side, the individual breaker
should be connected between the
inverter and the grid, and before the load.
AC Breaker
AC Breaker
AC Breaker
Grid
AC breaker
Loads
Inverter model
GW3048-EM
GW3648-EM
GW5048-EM
AC breaker specification
32A / 230V (e.g. DZ47-60 C32)
32A / 230V (e.g. DZ47-60 C32)
32A / 230V (e.g. DZ47-60 C32)
Grid
Note: The absence of an AC breaker on the back-up side will result in damage to the inverter in
the event of a back-up side electrical short-circuit. The back-up function cannot turn off
during on-grid operation.
Wi-Fi
Reset/Reload
SYSTEM
GRID
BACK-UP
2019
ENERGY
COM
Wi-Fi
BATTERY
FAULT
Wi-Fi
Reset/Reload
SYSTEM
GRID
BACK-UP
2019
ENERGY
COM
Wi-Fi
BATTERY
FAULT
Wi-Fi
Reset/Reload
SYSTEM
GRID
BACK-UP
2019
ENERGY
COM
Wi-Fi
BATTERY
FAULT
Note:
1. The neutral cable should be blue, the line cable should be black or brown (preferred) and the
protective earth cable should be yellow-green.
2. For AC cabling, the PE cable should be longer than the neutral and line cables, such that if the
AC cable slips or is pulled out, the protective earth conductor will be the last to remain in place
and support any strain.
Make sure the inverter is fully isolated from any DC or AC power before connecting the
AC cable.
The procedure for on-grid and back-up connection is shown below:
Prepare the terminals and AC cables according to the information in the appropriate table.
Step 1-1 On-Grid
D
Grade
A
B
C
D
Description
Outer Diameter
Separated Wire Length
Conductor Wire Length
Conductor Core Section
Value
13-22 mm
10-15 mm
12-14 mm
8-10 mm
2
A CB
Prepare the terminals and AC cables according to the information in the appropriate table.
Step 1-2 Back-Up
D
Grade
A
B
C
D
Description
Outer Diameter
Separated Wire Length
Conductor Wire Length
Conductor Core Section
Value
10~14mm
7~10mm
7~9mm
4-6 mm
2
A CB
Note: If not using on-grid power or the back-up function to charge the battery, wire with a conduc-
tive core of 4‒6mm
2
can be used.
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