OpenEnergyMonitor Community

ESP V4.x wifi firmware

I see we have V 4.x beta firmware and it requires the OpenEVSE firmward 7.1.2. Unfortunately it looks like that firmware is only EU. Wanted to see if there was anyone maintaining and updating the US firmware.

The dev version is US by default. You can get it from GitHub - lincomatic/open_evse: Firmware for Open EVSE

Thanks, will that work with the V 4.x of the wifi I see?

Hi all,

is there a compiled .bin UK version of 7.1.2.?


Yes, the EU version of V7.1.x controller FW is available on the releases page: Releases · openenergymonitor/open_evse · GitHub

Controller firmware is for the ATmega328 AVR microprocessor on the OpenEVSE controller, it’s a .hex file and requires avrdude and an ISP programmer to upload. See instructions in the repo.

The only difference with the EU version is that it’s limited to 32A maximum. If you’re in the USA and are happy with 32A max it’s fine to use EU controller firmware. Just select openevse.hex which is the tethered (non-socket) version which works for all OpenEVSE kits: Releases · openenergymonitor/open_evse · GitHub

@glyn.hudson Thanks, all now updated :slight_smile: Is there anything that you need us to test/report back on?


Thanks, since both the EU and US versions are dev versions is there anything that might be of concern or are things looking fairly stable with them?

See the known issues mentioned in the release notes: Release V4.0.0 Release · OpenEVSE/ESP32_WiFi_V4.x · GitHub

The push button issues should now be fixed in the latest version, will be doing another relase soon.

The controller FW has been tested extensively and no known issues so far.

Sounds good. My main concern was the controller FW as that is not nearly as easy to load verses the WIFI. Just need to get the right Arduino compiler for the controller FW.

I would recommend using the tried and tested pre-compiled version of the controller firmware rather than compiling yourself to avoid any issues: Releases · openenergymonitor/open_evse · GitHub

I happen to have an emonPi located close to my home openevse, I have an ISP programmer connected to the openevse controller plugged into the emonPi USB port. I then SSH into the emonPi and upload controller FW via avrdude to the openevse. A normal RaspberryPi would also work. This setup works well for me for dev testing but probably overkill for most users. It’s on the roadmap to work on being able to update controller FW via the WiFi module, that would be nice :slight_smile:

Something I am wondering, why is the EU controller firmware limited to 32A? The only reason I am considering compiling it myself is to keep my charger at the 40A limit they are at now.

32A is the per-phase European limit for EV charging. There is actually nothing gained by increasing this since the onboard charger for every EV sold in Europe is limited to 32A maximum per phase. Apart from the very early model Tesla roadsters!

There is no way to make a European EV charge faster than 32A on a single-phase.

That makes sense. But then you have Type 2 there which allows 3 phase charging on AC. I only wish we had that here.

Correct, if three-phase is available up to 22kW is possible (32A per phase x 3). However, this does depend on the EV supporting three-phase. Currently, most are single-phase AC only. I think only the Renault Zoe can take 22kW AC and some first gen Model S with duel chargers, the current Teslas are limited to 16kW, 16A x 3-phase.

I’ve heard of Dueling Banjos. Dueling chargers? That’s a new one. :wink: :grin:


I seem to have found an issue, after charging the next day when I remove the charge cable the system use to report how much charge was put into the car. This is now not happening. However if I power-cycle the EVSE it then reports the charge. Any clues? As you can see although there was a charge on the 27th the total charge did not increase



went back to the V3.2.2 WiFi firmware and the daily charge is reporting OK again when the charge cable is removed . One question I have which is the correct version of the firmware for the current WiFi board I have OpenEVSE WiFi Gateway V3.x EP32­wifi V3.x as the one I used was the firmware.bin shown below as it looks like there is a new WiFi board on the shop site for V4



Mmm interesting, I’ve been running V4.0.0 for a number of months now and I’m unable to replicate this issue. The Energy is reporting correctly, I can’t see any charging sessions that have been missed. What controller FW are you running?

If you will almost certainly have a Huzzah32 WiFi module, but the only way to be certain is to take a look at the hardware inside your unit

The Huzzah 32 can run V4.0.0 but make sure you select the compiled version for the huzzah.

I’ve added a note to the docs on how to identify WiFi module hardware and which FW versions each WiFi module will support: GitHub - OpenEVSE/ESP32_WiFi_V4.x: OpenEVSE V3 WiFi gateway using ESP32