openinverter forum

Hi Everyone,
Just have a quick but maybe stupid question on getting the charger configured. I know in the instructions, I need to use the STM32 programmer, but on the youtube video, as soon as you apply 12V to the unit, you can connect to the config panel by connecting to the charger wifi network and then going to 192.6.4.1.

Instead of getting the config page as shown in the video, I get the following image:


Do I really need to program through the STM32 or is there something I'm missing in the web interface?

Thanks in advance!

So the web interface is on the esp322 board, and the actual charger firmware is on the stm32.

The web interface can load regardless of if the stm32 is programmed or not.

If you bought a pre built programmed board, when and where from?

Might not be running the latest interface or firmware

I bought the board locally from someone that bought it from Damien I believe as I have the envelope it was sent in and I it has his info. So I agree it’s probably not running the latest interface or firmware.

I’ve ordered the Wemos D1 mini board to program the Olimex MOD-WIFI-ESP8266 wifi card and put the latest firmware/sofware on that.

The issue is with the openinverter interface card. I’m having a hard time seeing where to connect the STM32 programmer to it as I don’t see any USB port on it. I think I read in the documentation that it was removed because the wifi interface is now used to do all the programming.

Am I missing something? How do I update the interface card if there’s no USB? Is it really through wifi?

Thanks in advance!!

Please provide pictures of the charger board. There have been a few versions.

Here you go... I removed the wifi board currently because I'm trying to program it.

You have a v5 board. There’s 4 pins below in inductor in the middle of the board, labeled: “GND”, “swclk “, “swdio”, “3v3”

You just need gnd, swclk, swdio wired to a st link

And the board supplied with its own power

Doh!! Labelled “Programmng Port”. Boy do I feel stupid… and grateful. Thank you! So then I can configure the charger here via stm32 programmer. Do I still need to update the wifi board?
Thanks again!!!

I would update the esp to the de facto open inverter web interface.

Might as well get everything to the latest while your in there

Hi Guys,
I feel really stupid, but I tried connecting the ST-LINK programmer to the STM32 "Blue Pill" and it worked fine. But when I tried to connect the ST-LINK programmer to the charger board, it didn't detect it. The programmer just shows a red light flashing. Is this what I'm supposed to be doing? I tried both with 12V power applied and not.

What software are you using?

With these cheapo st link programmers, the order of operations dose matter to make things work (in my experience)

-12v power to the board
-plug st link into usb
-open st link utility
-connect to device

Something along that order of operations


But have you tried just updating the esp322?

That might be all that’s needed

That worked! Sequence is important. Thank you again!

But it didn't do anything to get me access to configuring my charger.
In Damien's instructions in the the manual, it refers to making a serial connection to a USB port on charger board but I guess that was phased out when the wifi card was introduced.

I guess I need to update the wifi board. I'm. trying to use these instructions:
https://github.com/jsphuebner/esp8266-web-interface

I have a serial FTDI interface so I assume I have to solder GPIO0 to 0 on the wifi board first? I tried without it and the connection timed out.

Okay. So I was able to update my wifi card. For anyone curious, use the Arduino IDE 1.xx, not the latest 2.xx version.
Unfortunately, it didn't allow me to configure the charger. This is what the charger website shows now:

I noticed the firmware is "null". Is that the board firmware or the wifi firmware? Is this why there is a Connection problem between ESP and STM?

spiff wrote: ↑Tue Jun 10, 2025 1:14 am Okay. So I was able to update my wifi card. For anyone curious, use the Arduino IDE 1.xx, not the latest 2.xx version.
Unfortunately, it didn't allow me to configure the charger. This is what the charger website shows now:
[

What firmware did you load onto the board?

Johu took over software dev, and his version is the one that works with the web interface

I'm not sure if I have the original or Johu's updated one. Where do I find Johu's?

The name of the one I used is Charger_Gen2_V5.bin or .hex.

So Johu was kind enough to confirm the STM32 code was https://github.com/jsphuebner/stm32-teslacharger.

I downloaded and compiled the code and tried to upload using the wifi interface but unfortunately no luck.

Looks like I'm now facing the "Communication problem. between ESP and STM" issue. The wifi board is directly connected to the STM board.

Anyone have any other troubleshooting tips?

Thanks all in advance. This is the last issue I have before test driving!

did you upload the bootloader first? Then the charger firmware?

On the esp, did you solder the bridge to flash it then un solder it?

I recall loaded a v5 file, then the stm32 file on the charger.

And on the esp, yes I soldered to flash and then unsoldered which gave me the latest screen I posted.

Anyone know if there is a way to force the charger on just to see if it works?

spiff wrote: ↑Wed Jul 02, 2025 2:32 am Anyone know if there is a way to force the charger on just to see if it works?

Works? As in CAN comms with the modules or moving actual power?

spiff wrote: ↑Sat Jun 21, 2025 2:30 pm I recall loaded a v5 file, then the stm32 file on the charger.

And on the esp, yes I soldered to flash and then unsoldered which gave me the latest screen I posted.

Looks like your esp is sorted.

when programming an stm with any of the oi firmware, you need to upload the bootloader first. Then the firmware.

You know it’s successful when the acty led is blinking

Is the V5 file the bootloader? If not, can you point me to where it is?

There’s no dedicated bootloader for the Tesla board, it’s just the oi generic bootloader from johu.

Thanks for the quick response. I just need clarification then:
The bootloader from John…. I don’t see anything in the instructions other than the V5 file that Damien originally release on his GitHub account.

The file from Johu is the STM32 bin file. Is this correct? Because I loaded both of those in sequence and got the correct LED blinking and responses that the instructions said I should get. So I’m trying to figure out if somehow I’ve screwed up which files I’m supposed to be loading.

It’s called a bootloader… it’s just used to for starting up the stm to run what ever firmware is loaded. In this case, the Tesla charger firmware.


Loading other firmware, such as stm32sine, which is designed for different hardware, will do nothing.

Load the generic bootloader, then the Tesla charger firmware

https://github.com/jsphuebner/stm32-teslacharger

OTA (over the air upgrade)
The firmware is linked to leave the 4 kb of flash unused. Those 4 kb are reserved for the bootloader that you can find here: https://github.com/jsphuebner/tumanako- ... bootloader When flashing your device for the first time you must first flash that bootloader. After that you can use the ESP8266 module and its web interface to upload your actual application firmware. The web interface is here: https://github.com/jsphuebner/esp8266-web-interface

Bootloader .bin/.hex You need to use .hex with ST-link
https://github.com/jsphuebner/tumanako- ... s/tag/v5.2