The external PSU is a transformer of 30VA  Input 0-115-230v Output 17v-0-17v

You can use a standard ring core transformer two times 18 volt / 1 Amp. If you want to build it inside the Fenix case you will have to make a hole for the power lead.  18vokt give more heat in the power supply.

There are 3 wires to the connector, two orange and one black.

Connect each orange wire to one 18 volt wire. The black goes to the 0. Pin 4 and 5 are joined together (These form the 0 connection)

The new transformer inside must have the two18volt windings set in series, the middle tap is the 0 volt. (in this case you can use a 19-0-18 volt transformer.

There are probably two small caps mounted at the Fenix rear power socket. These are for filtering HF signals. Since you want to build in the tranformer inside the case these are probably not needed: These hf signals usually enter the case through the power leads.

I have one warning. Do not build a transformer inside and also use the connections to the external transformer. When connected, the unused transformer will transform the18-0-18 volt back to 110/220 volt and you can touch easely touch the pins of the mains plug that now outputs mains power!

If you place the transformer outside you can use a plug to replace the standard power connector. The HF filtering will still work. Please check the new connector first, some versions can plug in 4 ways. Use only one which fits only 2 ways.

In this case you should use a transformer with 2 separate windings of 17 or 18 volt!!!!!

Winding 1 goes to pin 3 and 4 and the other winding set connects to pin 2 and 5.


Pin 4 and 5 must be connected to the wires which you normaly use when you set the transformer in series.

Never connect pin 4 and 5 together.