Esp32 hangs after several hours


Controller V4.4.
ESP32DWROOM external antenna
CAN active
16 Modules V4.40.
Gap 2000ms.

After several hours of operation the WIFI connection does not answer.
The controller works.
I can see data’s sent via CAN on my Victron.
Also the display works. And the switches.
The display shows the right IP.
But if I try to open the website no response.
Only power reset helps. For further several hours.

The heat shield is hand warm. So it seems the ESP has work…

Any one else with this behavior?

I want to figure out:
Do I have a weak ESP? or
Is there a problem in the software? ( Release 43 )

I hadn’t had any problems wit board V4.2 and SW release 16.

I can confirm this with my 4.2 board and release 44.

The device works fine but the web server does not respond.

In the network the device is pingbar with me, with you also

I have a workaround:
Let the controller run normally, since do nothing. Turn off your WLAN briefly at the router and then turn it on again. Then it should work again. I haven’t had time to look into the debug console yet.

Ok. Will try next week. On duty in the moment.
Will report.

Nevertheless should be fixed.

Can the misconduct still be confirmed by the other user?

I’m at home.
In the moment it works.
Didn’t change anything.

Seems it’s from time to time.
No idea why.

Yes really crazy, it works for me now too. The last 3 days the web server did not work. I have not changed anything.

Just reporting I have the sam problem. In my case changing the power source didn’t help so at the moment I was thinking of changing the existing ESP32 to a different one.

I have tried 3 ESPs and from AC power supply via DCDC directly from battery. That is not the reason…


Are you using a Fritzbox as a router? Does the ESP32 dial into the WLAN of the Fritzbox?


Several days now no error.

I use Unifi AC Lite devices for Wifi. When the ESP32 hangs I can still ping it through wifi. I don’t think it’s a communication issue, its something else. For me it still hangs and it happens every 6-12H. Only reconnecting ESP32/controller power helps.

Check if its hot. Maybe its a temperature issue…

I have used 2 other ESP32 boards, all of them have the problem that the web server does not respond. But all work fine with communication to my Victron system, only the webserver is the problem.

@Philipp S
You can also test if it is enough to deactivate your WLAN for a short time and then activate it, after that the ESP should be reachable again. What router model do you use?

I’ve changed my ESP32 from a non-antena version (the one with antena on PCB) to a external-antena-version (the one with a 10cm wire and screwed-on 12cm long antena) and the hanging stopped, works stable now with uptime 3d15h.

I have the version with external antenna. And had the problem…

In my case, after changing the ESP32, in past 7 days the system works very stable, no issues. This could mean the problem is in the ESP. Maybe try a diffrent type of ESP32, there are some minor changes in the build… just guessing.

I must have tried 3 different types of ESP32 now. With all of them the web server does not work at some point. When the error occurs I have tried with different devices (PC, tablet, smartphone) to get to the website. It does not work from any device anymore, you get from the browser “ERR_CONNECTION_RESET” or “CONNECTION_RESET, -101”.

But you can still ping the ESP32 in the network, that’s no problem. I have also run the serial console.
After this entry, no connection with the web server is possible anymore:
“(1002258) diybms-webreq: API call: monitor”.

Here is the log file, but I don’t see anything abnormal
diybms.txt (906.2 KB)

Here is a log file where I deactivated and reactivated the WLAN:
diybms_wlan_off_on.txt (163.2 KB)
(Hier habe ich mit dem Browaser zugegriffen “(4042403) diybms-web: default.htm”)

What helps is a reboot or deactivating and activating my WLAN. Then the ESP32 connects again and it gives good again for a while. This can take a few minutes, hours or days. It can’t be interference from inverters etc., they are currently off.

do you have any ideas?

I have the latest release 44 from 6 Sep. Are there no lower debug levels?

Ok, I have very occasionally seen this issue as well.

Are you monitoring the web interface from more than 1 device at the same time?

The esp has limited resources on the network and can get overwhelmed by multiple requests at the same time.

I also seem to have issues from an Android phone more than a windows pc. Android seems to do some weird stuff on the networking front.

I use an Android phone with Chrome and a Linux PC with Firefox for monitoring.

I have other ESPs on the network. There I do not have the problems.

Can I test anything else?

What do you do now to recover - do you reboot the ESP32 ?

I find if I do nothing, in 30 minutes or about that, it works normally again.

This doesn’t happen as frequently as you mention though - I probably get it once in a week.