OpenEnergyMonitor Community


@stuart is the one who can really help.

If I recall correctly from the “somewhere” in the thread, it was indeed changed to give more stable results.

One other thing that should help is to wrap the charge cables in aluminium foil (not the bare contacts) and ground those 2 shielded power cables.

Alu foil on the communication wire (TX/RX) can help also.

Please do ground all aluminium foil you are planning to use.

Chicken wire (fine mesh) is perfect barrier also.

The noise is low frequency waves, and mesh of 2.*.2 cm (or so) is small enough to catch the noise.

Catching = getting charged.
Call it static electricity, electro magnetic field, noise, leaking current or what you like.

Without grounding, in a few hours/days it could give a nasty bite. (Depending on mass, and noise)
(Shock hazard)

Most of you who are stupid like me use higher power inverter for some time, without grounding the casing…
And then get small (or larger) bite from touching the casing :slight_smile:
I’m sure I’m not the only one who first needs to feel before I start grounding.

Did you see the recent YouTube video I did on this exact issue?

Thank you for the video, I have not seen it before,

I’ll change the resistor and if I still have issues I’ll do the foil shielding on the power leads as mentioned a few threads up

thank you :slight_smile:

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Hi together,
at first i would like to thank @stuart for this great product.

I finaly ordered a bunch of modules (5x controller ESP32 and 50x 4.40) and received them 2 days ago. Now i have seen on Github, that the resistor R16 had been exchanged a few days ago, so do i need to do the same on al my modules or will it run with the 4,7ohm?

Thanks :wink:

No, you will be as is.

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4 posts were split to a new topic: MQTT and ioBroker

CAN协议1.0.pdf (612.8 KB)
Here is the can protocol from my hybrid Inverters.

Please see if you can implement.


This protocol is pretty straightforward and it looks like only a handful of ID values are needed. What I’m not seeing in this doc is if the inverter will broadcast these or if the BMS should be sending/requesting these sort of CAN frames.

@stuart I believe we will need a pluggable CAN protocol as each inverter will potentially use a different set of ID values and byte/bit mappings.

that’s an excellent idea.
We know the values interpreted by each of our inverters (and if we cannot investigate them) we need a configurable panel in which to each field and value of the DIYBMS we can assign a specific position for the CAMBUS messages once the interpreter has been performed we can share the different interpreter settings. In the same way, the interpreter can be used for our batteries to emulate the Cambus messages of commercial batteries.


Few questions:

  • Is the MicroSD card socket necessary on the new esp32 controllers? And either way, what is its purpose? ( received the new controller pcbs the other day and was going to check one of them out this evening after work when I remembered I haven’t ordered any SD card sockets yet)

  • is there a tutorial of any sort or a guide on connecting a current sensor to the Esp8266 controller? I remember coming across some information I’m here a while back about what sensor people were using but not any information about hey, if it needs to be a particular type, if anything needs to be done so the information shows up on the DIYBMS, etc…

The sd card is optional, it allows local logging at greater detail than Mqtt etc.

Going forward is also allows firmware updates and saving of configuration.

I’ve not officially supported current monitoring on the old controller. I think a few people started looking at it, and I remember some code and ideas being shared.


Oh okay. Yeah I remember seeing something on here about it while back and I noticed that the controller board has 3 pads labeled current sense hey, so I just assumed

I guess for now I’ll have to use a separate device the monitor the current and send it to influxdb.

Oh by the way, how is the new current sensor pcbs / project coming along?

Very well, I keep forgetting to post the update on here, I’ve been keeping my patreons up to date!

Should hope to release in the next couple of weeks


hey there does anybody have one of the new version controller board over for sell ? There are actually 2 parts missing at JLCPCB :unamused:

Annoying isn’t it! I’m trying to order some more boards, and every time, there is a different part missing!

I ordered 5 old controller boards and 20 cell module (in blue) last wednesday. Except the Atty, everything was available.

this is so sad they got other parts in 2300000000000000 pcs and some 0 i dont know…
corona is NOT the issue ! Same problem long before on your version 2 xD

info from Mouser:




Auf Bestellung:


verfügbar ab 12.10.2021


Erwartete Daten anzeigen

Lieferzeit ab Hersteller:


Wochen Geschätzte Produktionszeit des Werks für Mengen, die größer als angezeigt sind.

Lange Lieferzeit für dieses Produkt.

I ended up ordering from PCB way. They sourced parts from LCSC and other vendors. Some parts ended up coming from Digikey but those are through hole components.

Can you share the cost breakdown for parts? I’ve considered using PCBA from PCBWay but so far have only used their PCB/stencil services.

I got 5 controllers that included all surface mount components and most of the through holes ones (skipped due to an error on my end) for $280 USD. For the cell monitors I got 50 of them fully assembled for $624 USD. With shipping and bank fees my total was $904 USD.

Let me know if you want a deeper breakdown.

For the quality I an happy, I have an older DIYBMS from JLCPCB and feel the assembly is on par. Assembly time was a little longer because some parts took about 10 days to arrive.

From the time I put the order in to when it shipped was 20 days, that included a holiday and for them to review the order.