Heltec Wireless stick v3

Support Wireless/RF
1

Hi Everyone,
Hope you all had a good weekend past.
Does anyone have a Heltec Wireless Stick V3 and are powering via the JST connector with a 18650 or external battery? i have been Googling and some say they got it going but it doesn’t light up anything, you don’t even know that it is running. I can do without the screen or blinking LED on the transmitter side as it is encased, but for the receiver side i like to see the screen and blink LEDs etc… powering using the USB-C is fine. Thanks in advance. PLEASE HELP or share your experience.

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Hey @song179682,

Good question, and it’s a common one with the Heltec V3 boards. Here are a few things to check when powering via the JST connector:

  1. Battery polarity:
    Make sure your 18650 battery is inserted the right way around and that it’s actually making good contact. The Heltec boards usually have reverse polarity protection, but best not to rely on it.
  2. Battery voltage:
    Check the voltage of your 18650 with a multimeter. If it’s below ~3.3V, the board may not boot properly. A freshly charged cell should be around 4.2V.
  3. JST connector wiring:
    If you’re using an external battery pack, double-check that the JST connector matches the board’s expected pinout (some battery holders have the polarity reversed compared to what Heltec expects).
  4. Power path behavior:
    On some boards, the display and status LEDs may only come on if USB is connected, depending on how the firmware is written. You might be powering the MCU just fine, but not the peripherals.
  5. Firmware debugging:
    If you’re using your own firmware, try putting a simple LED blink loop or serial print in the setup() function to confirm whether it’s starting up when running on battery.
  6. Boot button or reset:
    Try pressing the reset or boot button after applying battery power, it’s possible the board doesn’t auto-start cleanly from battery in some setups.
  7. Try another 18650 or USB meter:
    If you have a USB power meter, you can see if the board is drawing current when battery-powered. Or just try another 18650 to rule out a dud cell.

This forum thread may also provide some further clues for you:

Let us know what you find, hopefully it’s something simple!

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Thanks Ryan, many check points…
1,2,3, 7- checked and double checked with the multimeter for polarity and charged up a variety of 3.7V batteries i have
4,5,6 - have to check with the programmer about this

do its not a straight forward question … i am using a custom firmware. I might have to try and flash it with a Meshtastic firmware of some sort and check. whether it works

as for that article. it has been closed and i can’t see the history chat on the matter… Will let you know if a proven firmware work as expected

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Hey @song179682,

Thanks for the update! Sounds like you’re doing all the right checks so far.

Since you’re using custom firmware, flashing a known working image like Meshtastic is a great next step, it’ll help isolate whether the issue is hardware or firmware related. If the board powers up and shows activity with Meshtastic, then you know the hardware and power are solid.

If you want, once you’ve tested that, you can share the results and we can dig deeper into your custom firmware or setup.

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Thanks Ryan, i did manage to flash the WS with a Meshtastic firmware and it was able to power on with an external battery…. i guess this is the joy of custom firmware… each step is a another to the end goal and one just have to learn to turn things on that you want to use… i thought that the assumption of the + and - power pins either via the USB C or via the JST connector would be the same??? anyway…. live and learn…

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Hey @song179682,

Thanks for the update! Great job flashing the Meshtastic firmware and confirming the board powers on with the external battery. You’re absolutely right, custom firmware often involves tweaking and learning as you go, especially when it comes to power management and peripheral controls.

A good approach is to start with a minimal working example and gradually add features back in until you encounter an issue. Since the board uses an ESP32 chip, it supports debugging via JTAG, although it’s unclear if those pins are exposed on this particular board. Getting familiar with a debugger tool can save you a lot of time down the line.

Best of luck with your project!

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actually the programmer has said if it is controlled by software how is it going to get power to boot up LOL. He is absolutely right!!!

I subsequently flashed it with one of the sample code to display some graphic and it does power up with the battery…. may be it has been on all along… such a dufus I am LOL… thanks for all the feedback with this matter

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In my personal view…. you learn a lot more and tend to remember it when you have to work for it.
If things just work, you tend to gloss over the detail and dont learn as much.

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TRUE THAT :slight_smile: however it is uncanny that it tends to happen more when you are under the pump or just want to move onto the next thing because “IT SUPPOSED TO TAKE ONLY 5 mins” LOL

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