Typical Installation Diagram
Operation
In the event of a loss of DC input to the NAV-PAC, the
navigation equipment is being powered by the NAV-PAC’s
internal battery only. The timed battery disconnect circuit
will initiate. After approximately 15 minutes with no DC
input, the NAV-PAC’s internal battery will automatically
disconnect from the NAV-PAC’s output. This is to protect the
battery discharge if the input is switched off. To reset this
circuit, input to the NAV-PAC must be restored. The timer
will automatically reset once DC input voltage recovers.
Bear in mind that the NAV-PAC has another disconnect
circuit which may cause it to shut down sooner. The battery
is also protected by a low-voltage disconnect circuit. Should
the current draw of teh device being powered cause the
battery voltage to drop to 20.4 VDC before 15 minutes have
passed, then this circuit will disconnect the battery from the
output. The amount of time the equipment will continue to
function normally before the NAV-PAC will shut down will
depend, in this case, upon the current draw of the device
being powered. (See
Back-Up Power
in the
Specifications
section.) To reset this circuit, the internal battery must be
recharged. Reduce or shut off the electronic load, and insure
that an adequate charge voltage is restored to the input.
(See
Battery Charging/Replacement
).
If you are unable to restore DC power immediately, it is
probably a good idea to turn off the equipment being powered
by the NAV-PAC. Most communication or navigation
equipment with built-in memory has a “keep alive” or “soft”
shutdown that is activated by the on/off switch. But if the
input voltage is slowly reduced, as will occur when the NAV-
PAC battery discharges, this “keep alive” feature may not
activate, resulting in loss of memory, waypoints, etc.
Remember:
When you wish to shut off your comm/nav
equipment, you must shut it off with the power switch to
the equipment itself.
Do not shut off the input to the NAV-
PAC
. The NAV-PAC will simply treat this the same as an
emergency loss of DC input, and will continue to supply
the comm/nav equipment with DC power from its internal
battery until auto-shutdown occurs.
Battery Charging/Replacement
Caution: Do not leave the battery discharged for extended
periods of time. It may be permanently damaged and may
not take a recharge.
The battery requires no maintenance and is completely
sealed. Battery life is up to five years. To charge, the battery
requires an input voltage of 27.6 to 29.6 VDC for 3-4 hours
or more per month. To prevent discharging, the battery
requires a nominal input of 26.8 to 28.8 VDC. These voltages
are normally produced by an engine alternator or good
quality battery charger.
The battery storage time @ 23° C is 400 days. The battery
should be replaced no less frequently than every five (5) years
to guarantee proper operation of the NAV-PAC. (Request
P/N 591-0412-0). The NP-24 uses two (2) 591-0412-0, 12 volt, 5
amp-hour batteries. We recommend replacing both batteries
at the same time.
To determine the age of the battery in your NAV-PAC, check
the quality control sticker on the end of the unit. The first four
digits of the serial number (designated “s/N”) refer to the
year and month of manufacture. For instance, a unit with
a serial number starting “0835” was manufactured the 35th
week of 2008. Be sure to mark the date of replacement on
this sticker for future reference.
Battery Replacement Proceeds as Follows - Refer to Figure
1 & 2
Caution: Take care to ensure that you do not short the
battery terminals during installation. The resulting high
current can melt wires and cause other damage to the unit.
1)
Turn off power to the input wiring and disconnect all input
and output connections to the NAV-PAC. Remove the unit
from the mounting surface.
2)
Remove the fuse from the fuseholder labeled “BATTERY”
on the front panel.
3)
Remove the four screws on the top of the unit and the
foure screws on either side of the unit.
4)
Remove the cover.
5)
Disconnect the wires from the battery terminals.
6)
Remove the four (4) screw/washer sets from the forward
battery braket. Loosen the four screw/washer sets on rear
battery bracket. Slide out the forward battery bracket and
both batteries from beneath the PCB
7)
Carefully observing battery terminal location and polarity,
slide the replacement batteries and forward battery bracket
in beneath the PCB.
8)
Re-install the four battery bracket screw/washer sets for
the forward battery bracket and securely tighten all eight
(8) battery bracket screws.
9)
Re-connect the battery series jumper wire and the -24V
Battery Black and +24V Battery Red to the correct terminals.
Critical 24V Equipmment
(Ground following
manufacturer’s
instructions)
To Other Criti-
cal 24V Loads
DC
INPUT
(Connect to
fused, un-
switched DC
source or one
which is always
powered)
(+)
(-)
Circuit Breakers
(Optional)
