Automotive, Electronics, hardware, Networking, Reverse engineering

How to power Starlink terminal from 12V without PoE injector and DC/DC converters

Today it has become popular to convert rectangular Starlink terminals into a flat “automotive” version.

There are tons of projects like this one or this. People cut the terminal case and pack it in a custom flat housing. Typical usage: RV.

An essential part of such modifications is the change of the power scheme.

In the automotive version, powering the terminal from 230/110 AC is inefficient. Power supply modification includes a custom PoE injector and DC/DC converter (12V – > 48V). I propose an even more efficient power supply scheme without additional voltage conversions.

Please note that most information below applies only to current rectangular rev3_protoX terminals.

Rev3 terminal PoE circuit

Let’s look at the PoE schematic on the board.

Here we can see Ethernet/Power connector, PoE transformer, current measurement circuit (0.05R shunt + AD8541 opamp), and primary DC/DC converter L3751. Plus, the PoE detection circuit and PD controller.

Here is the block diagram:

The primary internal power bus is 12V. All other Dishy’s voltage regulators feed from this bus. Thus we can bypass the input voltage regulator and provide 12V directly to the primary bus.

To protect the primary voltage regulator from reverse current, we need to disconnect it from the 12V bus. This can be done simply by removing the big inductor and feedback diode. You can see them in the picture below.

I do not recommend removing L3751 IC or MOSFETs. It’s more complicated, and there is a risk of messing up.

You may have noticed that we are also bypassing the current measurement circuit. This is okay. The Dishy firmware doesn’t care about zero consumption in runtime.

12V connection

After the components removing it’s safe to connect external PSU wires directly to the board. The most optimal connection point is the output ceramic capacitors array.
I highly recommend connecting an electrolytic capacitor in parallel.

(-12 it’s just a zero point or ground. Not some negative rail)

The minimal capacitance is 470 ยตF when you have relatively short wires from the 12V source. If your wires are a few meters long, you can use a 2200 ยตF capacitor. I tested with 5 meters 12AWG cables. The capacitor voltage rating should be 25V.

Ethernet cable connected directly to a host/custom router with 8P8C/RJ45.
Don’t connect the reworked Dishy to any PoE power supply or Gen2 Starlink router.

Measurements

I connected my shelf multimeter to the 12V rail and used the ut-reader to collect and plot current measurements.

As you can see, Dishy jumps to 7A, and the median consumption is around 5-6A, depending on the operation. The values can change very quickly, so your power supply must be able to handle sudden surges in consumption. When stowed, Dishy consumes a constant 1.1A.

The minimum supply voltage is 10V, and the absolute maximum is 15V. Please, do not exceed 15V value. It might damage your Dishy.

Please note that powering the Dishy from the car’s 12V line might be dangerous when ICE is running. The voltage levels might be pretty unstable.
Also, Tesla’s low voltage line is 16V instead of 12V (Li-ion low voltage battery). Consider this if you plan to power your Dishy from the modern Tesla car.

Thanks for reading.

 

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27 thoughts on “How to power Starlink terminal from 12V without PoE injector and DC/DC converters

  1. Amazing work. Would love to see a chart that compares power efficiency. Eg 48v PoE vs 12v

    1. Also any possibility to add a photo close up of the output ceramic capacitors array and removed inductor pads, to show where you connected 12v+ and 12v-(Ground)?

      1. I agree! A clear picture of the 12v, capacitor connection would be appreciated very much. I will do this conversion this weekend if the pic is supplied. Thanks mate.

        1. Conversion complete, working beautifully.
          Averaging a power usage of 20-45W at 13.52V (Starlink data plan currently paused).
          Dishy SW version: e055302d-93ee-44c0-9f18-4d927a6ee54e.uterm.release

          Very impressive. Thanks for the research and info ๐Ÿ‘

          1. and successfully updated:
            4c0c479d-d59a-4a0b-a7bc-fc4fc0bbe55d.uterm.release
            ๐Ÿ˜Š

    1. It’s way more complicated. There are two identical PoE DC downconverters inside. They work in parallel powering different parts of the PCB. I tried the same trick with the HP, but it’s not starting. I think some “ENABLE” signal is required. More research is needed.

  2. You mention “When stowed, Dishy consumes a constant 1.1A”
    What is ‘stowed’ state?
    Is this on but no data transfer, or something else?

    1. This is the state when you press “Stow” in your mobile app, and Starlink is actually “stowed” to the transport state ๐Ÿ™‚
      The satellite link is not active in this state.

      1. Ok, thanks ๐Ÿ‘
        Such mode is obsolete in my specific scenario. Flat mount, RV install. Will be using your 12v mod.

  3. Hi Oleg. I followed your instructions and cannot get the router to see dishy now. I am getting a “no wan connection” error from the router…I tested the ethernet leads, and they are all good. I attempted to revert it back to original, and I damaged one side of the miniature feedback diode! Any idea why the router can’t see Starlink, and what type of diode could be used to complete the repair?

    1. Hello. Unfortunately, the original part number is unknown. You can try to put SOD-323 Schottky there, like this one: https://eu.mouser.com/ProductDetail/Diodes-Incorporated/BAT43WS-7-F?qs=m%2FDc%252BknW%252B3niQrMOMf2TDA%3D%3D

      About Ethernet. Make sure that you use the t568b pinout.
      Also, verify that your PSU is capable of providing enough spike current. A typical problem is when PSU cannot provide enough current and Dishy restarts on boot/Ethernet startup.

      1. Update! The problem seems to have been the termination of the ethernet cable! I was sure that I had followed your instructions to the letter, but error are always a possibility. Thanks for the reply, and a great hack!

      2. I have finally hooked up a 3rd party router to the modded Starlink and I am getting an orange (cable issue) internet LED. Is the main cable from the starlink board supposed to be t568b pinout as well?

  4. I assume this will also stop the motors from working, if they are still present and connected?

      1. Do motors have external logic board, or it that second connector are dummy bidirectional lines feeding two motors?
        I was wondering if we could utilize that second connector to feed 12V through it, if those 12V are magically at the same bus.
        Otherwise…
        Is there a much better location to solder in “-12V/ground”? Is it should be almost everywhere? No?

        Another idea, in theory I could utilize POE with dummy passive 12V injector (for analog cameras), just need to push enough Amps, let’s pretend the ethernet cable will be super short to handle all the power correctly without overheating or loses, etc. Antenna needs 48V via fat power wires just because 12V will never make it through 75 feet.

        Of course, I have to “redirect” the power to the new soldered point. Just +12V? or -12V/ground also? Or some bypass modification could be done easier? that soldered input just doesn’t look so stable and solid at all.

        thanks

        1. Do motors have external logic board, or it that second connector are dummy bidirectional lines feeding two motors?

          There is no additional board. Motors are just simple DC motors: https://www.ecutool.com/products/mercedes-benz-bmw-porsche-peugeot-toureg-folding-rearview-mirror-motor?VariantsId=11310

          I was wondering if we could utilize that second connector to feed 12V through it, if those 12V are magically at the same bus.

          You can’t use this connector to feed the 12V. This is the output of a DC motors driver IC.

          Is there a much better location to solder in โ€œ-12V/groundโ€? Is it should be almost everywhere? No?

          Technically, you can connect to any 12V bus point, where you can see a bunch of ceramic caps. But the input point is the most convenient.

          I could utilize POE with dummy passive 12V injector (for analog cameras), just need to push enough Amps

          There is a different pinout, and your PoE injector will not be able to sustain more amps. You will burn your Starlink and/or PoE injector.
          You can use only approved Starlink PoE injectors: DishyPowa, AB Production, Boondocker, or Yaosheng.

  5. Pardon my ignorance and lack of electrical engineering knowledge/understanding. With this modification you have totally eliminated 48v for the dish? Does the dish now function completely on 12v? I am trying to understand why SL would require 48v if everything can work on 12v. So, now you supply 12v to the dish and then you connect from the dish via ethernet cable to a router (not the original SL router).

    1. Hello. The internal Dishy primary voltage is 12V, but the PoE voltage is 48V. It’s all about the power and length of the cable.
      They need to transfer much power with less current over the long Ethernet cable. 12V can’t provide enough power unless you use a massive amount of current, which might be dangerous for the cable, Ethernet transformers, and connectors.

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