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8.3 Power Transfer
While in Line Mode (aka Shore Power Model), the AC input is continually monitored. Whenever AC power falls
below the trip voltage (154VAC, default setting for 230VAC, 90VAC for 120VAC), the Power Pak automatically
switches to Inverter Mode to minimize interruption to connected appliances. This allows the batteries to act as
a backup in case of a power outage for the grid or generator. The time to transfer from Line Mode to Inverter
Mode is approximately 8 milliseconds. Though the Power Pak is not designed as a computer UPS system, this
transfer time is usually fast enough to prevent a computer from shutting down.
When AC power is connected, there is a 15-second delay from the time the Power Pak senses that
continuously qualified AC is present at the input terminals to when the transfer is made. This delay is built in
to provide time for a generator to spin-up to a stable voltage and avoid relay chattering. The Power Pak will
not transfer the load to a generator until it has locked onto the generator’s output. This delay is also designed
to avoid frequent switching when utility power input is unstable.
8.4 Alarms & Protections
The Power Pak is equipped with protection against various harsh situations or faults. Protections include:
● AC input over voltage / AC input low voltage
● Low battery voltage alarm / high battery voltage alarm and shutoff
● Over temperature protection / overload protection
● Short circuit protection (1s after fault)
● Back feeding protection
After the reason for a fault has been cleared, the Power Pak has to be reset to start working again. Do this by
turning the Power Pak Switch on the front of the unit off and on again.
The low battery voltage trip point can be toggled using DIP Switch SW1.
An over temperature condition may be caused by overload (i.e. too many high-power appliances running from
the Power Pak), inadequate ventilation or an external heat source.
To resolve an overload condition, connected appliances can be shut off / turned down / disconnected.
The back feeding protection which avoids presenting an AC voltage on the AC input terminal in Invert mode.
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