Transfer Relay
Installation and Operating Instructions

Ample Power Models XFER-12V and XFER-24 April 6, 2005

The Transfer Relay is used to select one of two input AC sources and connect the selected source to the output. Selection is automatic, but can be overridden with an optional 3-position, center-off, toggle switch.

The output from the transfer relay should be connected to a breaker panel which only serves loads to be operated by the inverter. Main shore power to other appliances should be independently connected to a different breaker panel.

Mounting the Transfer Relay
The transfer relay is protected against ambient humidity, but must be mounted in a dry location free of moisture, dust, and other environmental insults. The relay will operate in temperatures to 60$^\circ $C (140$^\circ $F).

Wiring Diagram
The wiring diagram above is the only way to wire the Transfer Relay. For safety purposes, always use fuses for connections to battery positive voltages. Such fuses should be close to the positive voltage connection and be rated for 3-5 Amps, slow-blow.

For the DC wiring, use AWG #16. AC wiring is typically #8, but may be bigger or smaller, depending on the size of the inverter loads, and the length of the wire run.

Battery Voltage
Transfer relays are made for 12 or 24V DC systems. Be sure to use the correct model.

DC Signal Names and Functions
Orient the internal controller so that the components on the board are on the near side, and the terminal block is on the right side. Pin 1 is at the top.


The transfer relay selects the inverter input when there is no shore power voltage present. When shore power is detected, and after about a 5 second delay, the transfer relay automatically selects shore power.

Automatic selection can be overriden by using the Select input. Connecting the select input to battery positive will select shore power ... connecting it to ground selects the inverter. For automatic operation, no voltage or ground should be applied to the Select pin.

Ample Power products are manufactured by Ample Technology, 2442 NW Market St., #43, Seattle, WA 98107 - USA