An Eltek Flatpack2 HE 48V/2000W rectifier is being used as the power supply for a 23cm 600W LDMOS Power Amplifier project.

This touchscreen controller has been developed to control the Flatpack2 HE 48V/2000W, and display its data.

This controller connects to a single Eltek Flatpack2 HE 48V/2000W rectifier and provides monitoring of these parameters:
• AC Volts in
• DC Volts out
• Load current
• Intake temperature
• Output temperature
• Operating status
• and any alarm/warning messages it generates

Note: There have been many subtle improvements since that video was shot.

Main screen:

Current (as in ‘now’) voltage can also be shifted up or down in 200mV steps by touching the UP/DOWN arrows.
This does not affect the default start up voltage.


Main Screen SET Button

A short press of the ‘SET’ button will reset the screen saver, if Screen Saver is enabled.

A long press of the ‘SET’ button will take you to the Set Menu page.


Parameter  Font and Colours

Foreground and background colours of each parameter (Status, ACV in, Intake Temp, Output Temp, DCV out, I out, Warning messages, Alarm messages) can be adjusted.

Simply touch the parameter to set the colour and font.

There is a choice of two fonts.
Adjust the R, G & B slider to set the desired colours.

eg: Set DC Volts Output Font screen:


Set Menu:


Screen Settings page:

• Screen brightness
• Screen saver (enter 0 to disable screen saver)
• Output voltage 2 decimal place checkbox  (unchecked = 1 decimal place)


General Settings page:

• Current Limit entered as deciAmps by kepad, ie: 200 deciAmps = 20.0 A
• Long ‘walk-in’ checkbox   (unchecked = short walk-in)


Set Current Limit Keypad page:


Set Default Volts page:

• Voltage entered as deciVolts by keypad, ie: 48.00 V = 4800


Set Default Voltage Keypad page:


Warning/alarm Condition:

If an alarm state or warning state (or both) is detected, the appropriate icons become red.
Clicking on either of these icons will take you to the Warning/Alarms page.


Warnings/Alarms page:


Arduino and Nextion Reset

Touch the un-highlighted login icon to reset Arduino Nano and Nextion display.

This is handy if, for some reason, the serial number is not read correctly on boot-up.


PCB Mounting scheme


Purchase a PCB only and receive the Arduino .hex file and Nextion .tft files via email.

Warning: SMD soldering skills required. 
The two smallest parts are U1 (SOIC8, pin pitch 1.27mm) and D1 (SOD-123W).

Or purchase a fully assembled and tested controller from the Shop.


Construction Notes:


Note: the CAN bus adapter module is the 8 MHz variant – not the 16 MHz variant.




Downloadable Files:

VK4GHZ Eltek Touchscreen Controller BOM


VK4GHZ Eltek Touchscreen Controller Schematic, Rev 2


The following assumptions are made:

• You have correctly assembled the controller board, and have inspected your work (polarities, solder bridges etc), cross checking against the schematic

• You have a suitable FP2 breakout board plugged into the rear of your FP2

• You have made a suitable power lead and CAN bus lead ready to interconnect the FP2 and controller board when needed

• The Arduino NANO is not yet inserted

• The CAN bus adapter is not yet inserted


Test the 5V rail:

Connect the FP’s DC voltage output to the Controller’s DC power input via the lead you have made.

Turn on the FP2.

Using a DMM, verify you are seeing +5V on the controller board.

There are test points for GND and +5V to the right of L1 inductor.

If all ok, then turn off the FP2 for now.

Plug in the CAN bus adapter module.  It only goes in one way!


Programming Arduino Nano with the .hex file

Unfortunately you cannot use the Arduino IDE to program an Arduino with a hex file.

Major fail, Mr Arduino.

Instead, download the (free) ArduinoSketchUploader program from Github.

On that page, click on: Download the latest Windows binaries here (.zip file, version 3.2.0).

Unzip it into a folder.

For simplicity, I unzipped it into a folder called “asu” straight in the root directory. ie:    C:\asu

Copy the .hex file into that same folder.  (You won’t need to worry about paths then)

Using a USB mini B cable, connect your Arduino Nano to the PC.

Use Devices & Printers to determine the COM port number the Arduino is connected to, and make a note of this com port number.

Press the Windows key, and type CMD, <enter>

This brings up the CMD line dialog.

Navigate to the folder where you unzipped the ASU program

In my case: 


cd asu

Once in the ASU folder, type:

ArduinoSketchUploader.exe --file=Eltek-v133.hex --port=COMnn --model=NanoR3

(where nn is your com port number)

The ASU program should now upload the code to your Nano.

When finished, disconnect Nano from USB lead.

Plug Nano into controller PCB, observing polarity.

Look at the PCB’s silkscreen for direction. 

The Nano’s USB port end should be above the silkscreen “USB” marking.


Programming Nextion 3.5″ Enhanced HMI

Programming the Nextion is very easy!

Copy the .tft file onto a (FAT32 formatted) micro SD card.

Connect the Nextion to the Touchscreen connector: black, yellow, blue and red wires as per the image above.

Insert the microSD card into the Nextion’s micro SD slot.

Turn the FP2 on again so the Nextion powers up.

Programming should start automatically.

When programming has finished, turn the FP2 off again.

Remove micro SD card.

Now connect up the CAN bus lead you made.

You’ve already checked that ‘L’ goes to ‘L’ and ‘H’ goes to ‘H’ and that the CAN GND  connects to CAN GND?



You’re done!

Turn on the FP2 again, and the display should come to life with the splash screen.


Please note: If the above does not make 100% sense, then consider purchasing a ready made controller instead of attempting this yourself.

Sorry, but if you take this on yourself, I’m not in a position to be answering random queries about why things may not be working.



Source code will not be provided, and a refusal may offend!

This controller has NOT been tried with other Eltek rectifier variants, only a single Flatpack2 HE 48V/2000W, so there is no need to ask if it will work with other variants!