i have noticed another bug if the shunt mV reading is over 30mV it displays wrong data

i have a shunt 200A 60mV and on 30mV i have exactly 100A if i go over 30mV and 100A it display sometimes 60A or less total wrong numbers and over 30mV the reading in the shunt pcb is inacurate

so to solve this problem i ordered a 500A 50mV shunt because i need 300A so 30mV would be enough

it is working with my sunny island 8.0h-13 THIS IS AWESOME
but cant be mixed with victron dvcc because the charge voltage need to be 1v higher its a sunny island thing
if i set 57V the charge voltage in sunny island is 56V but 57V on Victron

Ah good news.

Can you raise an issue on GitHub for me about the mV reading problem please.

Any chance you can share your sketch? I am trying to use the KG-F to test and record the voltage and current on a small cell test station I am using to test cells for an EV conversion…

EDIT:I Saw now that you attached it above… Thank you!

done, with detailed information

additional question
what is this calibration value 4095 for?

So…I got it partially working but I am getting a lot of Bad Checksum messages. Also, when I plug the serial interface in, the screen doesn’t work (it freezes)…

Any ideas? The app is still updating so I know the device is running…

Hey guys,

I’m selling off my DIY BMS stuff.
While I totally like this project, I just am not able to finish my build.
4x JKong BMS are now doing my batteries for over 1.5 years, its time to abandon this project for me.

I used to have a setup prepared for 80 cells…, 5 x 16 280AH Eve cells.
Life happened, now 3 x prebuild BYD 260Ah each and one DIY 280 Eve.
Running stable for a long long time…
Never change a winning team:-)

My hoarding collection is roughly this:

33 x 4.0 boards, the heatsink you see is with thermal tape
4.0 boards

30 x finished 4.40 boards. Heatsink is fixed with thermal epoxy (on 17)
4.40 board pic1
4.40 board pic2
picture of 16 with heatsink

20 x not yet finished 4.40 boards, all parts included.
20 4.40 boards new, incl. parts.
second picture

6 controller boards, not yet finished (all parts included)
controller boards

5 x new controller boards not finished, one with display, for 3x all parts included
new controller boards


6 x ESP8266

Relay boards

I have 25x attiny, 20 to be used for the not yet populated boards.

Possibly Ebay is a better place to sell.
Attiny goes for € 10 there (UK) ( € 2.50 poland)

That is not where the enthusiasts are :slight_smile:
This community has given me a lot, I like to give back.
I’m not giving away for free… absolutely not.
You also don’t have to expect to pay 10 bucks for attiny :slight_smile:

Just send me a message via OEM forum if you are interested to buy.

1 Like

Thanks for the support over the years @fhorst1 .


I have a question about flashing firmware via the ESP32 controller board.

In the menu “AVR Programmer” there are different module firmware for 4.40 modules:
V440 (be82379d)
V440_COMMS_5K (be82379d)
V440_COMMS_9K6 (be82379d)

Can someone explain to me what the 5k and 9k6 resistor values are all about?

I want to program an “EVE_v1.9F” module, but I don’t know which firmware is the right one.

In which repo can I actually find the commit “be82379d”?
Is always written behind each firmware.



Easy. Those are not resistor vales. These are baud rates.


So once 5000 and once 9600 baud.

What then has the firmware without specification?

  1. Read the source, it’s in the ATTINY’s platformio config file.

diyBMS-Code repository if I remember correctly.

I asked Stuard for price indication to sell.
He advised 4 pounds + price of Attiny

4.0 Cell module finished is $7.00 (33 available)
4.40 Cell module to solder is $7.50 (20 available)
4.40 Cell module finished is $8.00 (30 available)

While the cheapest attiny841 available I can find is $2.50, and regular price up to $10…
I didn’t invest to make profits.
I’m asking absolutely fair price.

Stuart advice 40 pounds for the new controller boards
The controller board is $45. All parts included
I have 2 x 2.8inch SPI Module, each $7.50. (when buying controller board)

I have 5 x older controller board, need to be soldered. (all parts included)
they include 4x relay boards, not the wifi modules.
Price $7.50 each

Slow transport is cheap but can easily take up to 6 weeks from Thailand.
FedEx (or other) is $40.
I charge half of it $20.
That is, if the order is above $100 :slight_smile:

Whole shebang:
83 cell modules, 5x new, 5 x older controller, 2x SPI, 5 extra Attiny841
incl globally transport = $750,-

The 5k and 9k6 refer to the speed of the communication (baud rate).

What is the eve module you refer to?

Hi Stuart, first of all thank you for your great work.

I used the forced module from vas (123mm specific version (v1.9)), see:

I’ve updated all the for sale cell modules to the latest firmware, 2022-07-06.

It was again a struggle to get it all working.

So I made dummy guide:
dummy guide diybms cell modules.pdf (359.2 KB)

Please share and make updates where needed :slight_smile:

When people have the urge to read all 4700 posts, they will come across my learning curve with soldering…

I have 27 (!!) 4.0 boards that need rework.
as far as I can say all 27 attiny841 are functional and working.

I had some troubles with the JST, and tried manually solder the thermistor inside the resistor part…
that is way too crazy tiny to do by hand!!
really… I spend hours and hours and hours
(that was before I learned about 177c solder paste, and bake it in an oven ad 180c)
So much simpler!!

Back then, better for me to just order some new boards and new parts (yes, JLC had the thermistor back in stock) then to spend more hours to do rework, as I’m beginner at that part.

27x 4.0 cell modules, need rework.
27 x attiny841, in great demand due chip shortage.

Price including global transport $100,-

Also available, 5 X older controller boards, with 5x relay.
Just 1 WiFi thingy.

Price $7.50 each.

10-20 days $10
8-15 day $ 15
3-7 day $ 32.50…

Regular mail with relay $7.50, takes 40 to 60 days (not tracked)
Regular mail without relay $5.00

Regular mail is price per.
As weight goes up fast, it’s quickly an (envelope) parcel, where the price starts at $10
Bigger (thicker) starts at $20, like 250 grams…

More units is more weight, possible little more expensive.

I’m not a business.
I don’t have all the numbers and rates.
This is indicative from what I can find using transport broker, to reduce the costs.

Directly via FedEx, think +$100 for one parcel :rofl::rofl:

anyone got a spare shunt board with smd;s mounted for sale ?

quick question. can you mix 4.4 and 4.21 cell modules on a v4 controller all in the same battery pack?