Safety Information; Diagnostics - Generac Power Systems PWRcell Reference Manual

Section 7 PWRcell Battery

Safety Information

DANGER
Electrocution. Initiate a system-wide shutdown and turn the
PWRcell DC Disconnect Switch OFF on all connected
batteries before performing service. Failure to do so will
result in death, serious injury, or equipment and property
damage.
Due to the ability of the battery to bring up and hold
REbus voltage, there are several important safety
precautions to take when servicing:
The battery disconnect switch in the upper left corner of
the battery cabinet only acts as a disconnect between the
lithium-ion battery stack and the charge controller in the
BMU; it has no effect on the cumulative battery module
voltage or the REbus voltage from the inverter.
•
When the switch is off, there will still be battery
stack voltage at the battery fuse block inside the
BMU. For safety purposes, while working inside
the battery cabinet, it is recommended to always
disconnect one of the DCB modules or power
jumpers to break the battery stack circuit.
•
Even with the battery disconnect switch off, there
can still be REbus voltage supplied from the
inverter on the REbus terminals of the BMU. It is
recommended to always perform a system shut-
down before working inside the battery cabinet.
•
If the inverter is disabled, but the battery is left
enabled with the battery disconnect switch on, the
battery will still maintain REbus voltage inside the
battery cabinet, inside the inverter cabinet, and on
all connected REbus wiring. It is recommended to
disable the battery, turn the battery disconnect
switch off, and turn off the DC disconnect inside the
inverter before working inside the inverter wiring
compartment.
38

Diagnostics

The diagnostics defined below detail inspections for
common scenarios. Reference and use in the order
prescribed in
1. REbus DC Wiring
•
Verify REbus wiring (positive, negative, and
ground) between the battery REbus terminals and
(000600)
the inverter DC disconnect and ground bar.
– It is recommended to label both ends of each
REbus home run during installation to avoid con-
fusion.
– If suspected mismatching has occurred, use a
digital multimeter (DMM) to "ring" out the runs
using the continuity function.
•
Verify correct polarity of positive and negative wire
runs at both battery and inverter.
•
Verify REbus ground connection.
2. REbus Communications
•
At inverter, turn on DC disconnect to battery, then
power on and enable inverter to bring up DC bus.
– Verify correct REbus voltage (360–420 VDC, dis-
played on inverter home screen) at DC discon-
nect terminals of inverter
– Verify correct REbus voltage between RE+ (red)
and RE- (blue) terminals at battery terminal
block.
– Verify symmetric half-REbus voltage between
RE+ and RE- to GND (green) terminals at battery
terminal block.
•
Verify that battery status LED illuminates.
•
Verify that PWRcell battery device appears on
inverter screen.
3. Battery Disconnect Switch
•
Verify switch is in the "On" position.
4. Battery Power Wiring
•
Verify power connections to all li-ion battery mod-
ules.
– Power harness must be connected to all mod-
ules.
– Looped jumpers must fill in all open slots in
power harness.
6 module system
5 module system
4 module system
3 module system
•
Verify battery stack voltage by measuring DC volt-
age between the positive (red wire) and negative
Table 7-1 Troubleshooting.
no jumpers
1 looped jumper
2 looped jumpers
3 looped jumpers
Diagnostic Repair Manual