Garmin G1000 Nxi System Maintenance Manual page 148

3. Connect Digital Voltmeter leads to J1 connector pins 11 (+) and 7 (-).
4. Connect the Load Resistor across J1 connector pins 11 (+) and 7 (-) and start
timing the discharge period with a stopwatch.
5. Monitor and plot voltage values at 10-minute intervals.
6. Note voltage on Digital Voltmeter at 48.0 minutes (PS-835D) or at 20.0 minutes
(PS-835C). This voltage must be greater than 20.0 Vdc.
a. All INDIVIDUAL CELL MONITOR LED's (Figure 4-5, Item 1) must remain
on.
b. Any LED that does go OFF will represent a defective individual cell, which
must be replaced.
7. Remove the Load Resistor from J1 connector pins 11 (+) and 7 (-).
8. Position all INDIVIDUAL CELL DIP SWITCHES (Figure 4-5, Item 5) to the OFF
position.
9. Compare the voltage vs. time plot created during this test to that of curve
identified as typical for the External Load test method on the chart above. If the
plot reveals a discharge curve that meets or exceeds the MINIMUM
ACCEPTABLE DISCHARGE CURVE, the unit is considered satisfactory.
10. If unit discharge plot is satisfactory and no other failures were revealed, perform
the Charging Procedure within 2 hours of completion of the discharge test.
Return the unit into service.
Cell Isolation Test
No power should be applied to PS-835 Emergency Power Supply
during test. This test is performed with the battery removed from
the aircraft.
A. Press and hold TEST SWITCH (Figure 4-5, Item 4). If no OUTPUT VOLTAGE
MONITOR LED's come on:
1. Position all INDIVIDUAL CELL DIP SWITCHES (Figure 4-5, Item 5) to the ON
position.
2. Press and hold TEST SWITCH (Figure 4-5, Item 4) and observe the INDIVIDUAL
CELL MONITOR LED's (Figure 4-5, Item 1).
a. If all INDIVIDUAL CELL MONITOR LED's come on except DS12, the unit
is damaged and requires repair at an authorized repair station.
b. If all INDIVIDUAL CELL MONITOR LED's are on, a low-battery voltage
condition exists.
B. Perform the Charging Procedure. See 4.16.4.
Charging Procedure
(Constant-Voltage Charging Method)
Locally manufacture a power cable using 16AWG wire and the appropriate mating connector.
Include a Diode (15 Adc (min), 50.0 PIV or greater) to prevent battery discharge in case of loss
G1000 NXi System Maintenance Manual
King Air 300 Series
190-00716-N1
NOTE
Page 135
Revision 1