5. Power Converter Harness
In order to power the Pi (at 5V) when the PSU operates at 24V, and the Einsy
converter is not necessarily capable of supplying the current required, a separate
24V to 5V converter is used.
These converters are readily available and inexpensive.
It is recommended that a 500mA fuse is installed in the positive 24V line before the
converter – there is space within the case to hold the fuse.
1. Cut two long (at least 70cm) wires for the power supply – you will be able to
adjust these to length later.
Ensure they are two different colours as connecting the power supply up
incorrectly will damage the electronics.
The power supply current will be in the order of 250mA at 24V - the cable should be
sturdy enough to attach to the Einsy power supply terminals. Make sure that the
cable will fit through the hole in the case.
2. Fit a fuse (recommended) in-line, 100mm from the end of the positive wire (so
there is 100mm of flexible wire tp attach to the PSU.
3. Solder the positive and negative wires to the inputs of the power converter board.
4. Solder an 80-100mm length of wire to the positive output of the power converter
– if possible, use a red wire from a patch cable as it will already have the connector
pin.
5. Solder an 80-100mm length of wire to the negative output of the power
converter, this time using a black wire.
6. Connect the power converter input to a PP3 battery, and test the output with a
multi-meter.
7. If the converter has an adjuster / potentiometer, adjust this until the output
voltage is 4.9 to 5.1 Volts.
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