Hi Guys,
I post this information, as a work/response for old threads for this device : Earu EAKCB-T-M.
Device is not listed in device database.
Device was listed as work in progress 3 years ago
Device was reported unstable (restart when button pressed) (Original Polish thread here)
Room temperature not reported, but some information already existing.
Device characteristics
CBU board using BK7231N chip.
Magnetic Polarized Relay (energized only when switching) using Relay Driver IC MD7620 (Shanghai-Mingda-Microelectronics).
Watt/Volts/Amp/Power factor/Frequency meter: BL0942 chip.
Room temp (well electric box temperature) from onboard thermistor.
Flashing device
Flashing is straight forward.
You need to open the device (6 small rivets to drill), then it opens.
CBU doesn't need to be de-soldered from PCB.
You need a 3.3V power supply, to power cycle device when asked for by BK7231 GUI Flash Tool.
Connect TX/RX and GND to your USB/Serial adapter, launch BK7231 GUI FlashTool, and start writing firmware.
When BK7231 GUI FlashTool ask to power cycle power, just supply 3.3V to VCC pin and it should work.
Here is a Firmware dump of this Earu device :
Config file to support device
Here is the config file to support this device:
Next reboot should welcome you with a working device.
You can customize your device with NTP settings, and energy statistics.
Caution: there is NO DNS resolver onboard device. Please use IP adress to connect to an NTP server.
Prefer first using a local NTP server (ie: the one provided on your net box).
If not, use external NTP server, like 0.pool.ntp.org that convert to IP: 108.35.166.21
Meter calibration
Meter needs to be calibrated. I use another OpenBK device Tuya EU20A to read meter data and use it as a reference. I know i have Tuya device consumption added, but I don't care.
My goal is to have an overview for dynamic load cut off/on.
Our home is 100% solar, not connected to grid, using a home made 15KW battery with a 5KW inverter. I must no exceed it!
In case of over power, I switch off load by priority.
CALIBRATION PROCEDURE
I used first a 230V 10meters LED strips (reactive power).
Then, I read values from Tuya EU20A and set Volt/Current/Power values on Earu device.
On left Tuya reading, on right Earu writing.
On device, I launch 'Launch Web Application', goes to 'Logs' tab (on the left) and type following commands:
Where 242.5 is actual voltage mesurement in Tuya, could be also from a multimeter.
0.449 is actual current in Tuya, could also be from an amp clamp or meter.
108.93 is actual Power Factor in Tuya.
Settings are saved permanently.
Then I verify my calibration using a 2000W boiler.
Readings are OK :
CBU restart
I ordered two Earu relay from aliExpress, at the cheapest price (as I always do!).
By the way, I don't have any interest with EARU, even if my forum name is earurelay. Was lazy to find a nice name
One relay was working OK, the other experience the same behavior. Rebooting when switching.
I tried many differents things:
Swapping relays.
Bad earu relay condensator (always with a X) : 4.3uF instead of 4.7uF (400V).
Good earu relay condensator: 4.3uF instead of 4.7uF (400V).
Bad earu relay condensator (always with a X) : 442uF instead of 470uF (16V).
Good earu relay condensator: 469uF instead of 470uF (16V).
I even checked both primary resistor. Same 10.3 ohms for each (10 ohm from color code).
Even by swapping all this components, behavior is the same.
The good one is still working, even with 'bad' capacitor.
And the bad one doesn't work, even with 'good' capacitor.
I noticed that CBU board is not well aligned with main PCB on the 'bad' one. I will try ti reflow and align it.
Magnetic polarized relaye
This one is a 9V version. Some device use 12V. Device is using a 12V supply.
Room temperature
A thermistor is plugged to pin 23.
Using results from this post, I confirmed my device was working the same way. Same reading with same temperature.
As I'm lazy and really bad at math, I asked chatgpt to find the math formula for degree C conversion : Degree C = 106980 / (ADC reading ^0.75).
Would be nice to add a new ADCTemp driver, that read ADC value, compute it to Degree temperature, with two more optional commands: calibrating temp (or offset) and Fahrenheit/degree.
I'm sorry, I have no spare time to allocate on this, but will be happy to test/help).
Final thought: this forum is a goldmine for openbk device. Thank you!
AI: Just to clarify, are you mainly sharing your findings for reference, or are you looking for help or advice with the rebooting issue (or any other specific problem) on the Earu EAKCB-T-M?
Sharing my findings
AI: Did you have a chance to try reflowing and aligning the CBU board on the 'bad' relay, and if so, did it have any effect on the rebooting issue?
Not yet. Will do.
I post this information, as a work/response for old threads for this device : Earu EAKCB-T-M.
Device is not listed in device database.
Device was listed as work in progress 3 years ago
Device was reported unstable (restart when button pressed) (Original Polish thread here)
Room temperature not reported, but some information already existing.
Device characteristics
CBU board using BK7231N chip.
Magnetic Polarized Relay (energized only when switching) using Relay Driver IC MD7620 (Shanghai-Mingda-Microelectronics).
Watt/Volts/Amp/Power factor/Frequency meter: BL0942 chip.
Room temp (well electric box temperature) from onboard thermistor.
Flashing device
Flashing is straight forward.
You need to open the device (6 small rivets to drill), then it opens.
CBU doesn't need to be de-soldered from PCB.
You need a 3.3V power supply, to power cycle device when asked for by BK7231 GUI Flash Tool.
Connect TX/RX and GND to your USB/Serial adapter, launch BK7231 GUI FlashTool, and start writing firmware.
When BK7231 GUI FlashTool ask to power cycle power, just supply 3.3V to VCC pin and it should work.
Here is a Firmware dump of this Earu device :
Config file to support device
Here is the config file to support this device:
Code: Text
Log in, to see the code
Next reboot should welcome you with a working device.
You can customize your device with NTP settings, and energy statistics.
Caution: there is NO DNS resolver onboard device. Please use IP adress to connect to an NTP server.
Prefer first using a local NTP server (ie: the one provided on your net box).
If not, use external NTP server, like 0.pool.ntp.org that convert to IP: 108.35.166.21
Code: Text
Log in, to see the code
Meter calibration
Meter needs to be calibrated. I use another OpenBK device Tuya EU20A to read meter data and use it as a reference. I know i have Tuya device consumption added, but I don't care.
My goal is to have an overview for dynamic load cut off/on.
Our home is 100% solar, not connected to grid, using a home made 15KW battery with a 5KW inverter. I must no exceed it!
In case of over power, I switch off load by priority.
CALIBRATION PROCEDURE
I used first a 230V 10meters LED strips (reactive power).
Then, I read values from Tuya EU20A and set Volt/Current/Power values on Earu device.
On left Tuya reading, on right Earu writing.
On device, I launch 'Launch Web Application', goes to 'Logs' tab (on the left) and type following commands:
Code: Text
Log in, to see the code
Where 242.5 is actual voltage mesurement in Tuya, could be also from a multimeter.
0.449 is actual current in Tuya, could also be from an amp clamp or meter.
108.93 is actual Power Factor in Tuya.
Settings are saved permanently.
Then I verify my calibration using a 2000W boiler.
Readings are OK :
CBU restart
I ordered two Earu relay from aliExpress, at the cheapest price (as I always do!).
By the way, I don't have any interest with EARU, even if my forum name is earurelay. Was lazy to find a nice name
One relay was working OK, the other experience the same behavior. Rebooting when switching.
I tried many differents things:
Swapping relays.
Bad earu relay condensator (always with a X) : 4.3uF instead of 4.7uF (400V).
Good earu relay condensator: 4.3uF instead of 4.7uF (400V).
Bad earu relay condensator (always with a X) : 442uF instead of 470uF (16V).
Good earu relay condensator: 469uF instead of 470uF (16V).
I even checked both primary resistor. Same 10.3 ohms for each (10 ohm from color code).
Even by swapping all this components, behavior is the same.
The good one is still working, even with 'bad' capacitor.
And the bad one doesn't work, even with 'good' capacitor.
I noticed that CBU board is not well aligned with main PCB on the 'bad' one. I will try ti reflow and align it.
Magnetic polarized relaye
This one is a 9V version. Some device use 12V. Device is using a 12V supply.
Room temperature
A thermistor is plugged to pin 23.
Using results from this post, I confirmed my device was working the same way. Same reading with same temperature.
As I'm lazy and really bad at math, I asked chatgpt to find the math formula for degree C conversion : Degree C = 106980 / (ADC reading ^0.75).
Would be nice to add a new ADCTemp driver, that read ADC value, compute it to Degree temperature, with two more optional commands: calibrating temp (or offset) and Fahrenheit/degree.
I'm sorry, I have no spare time to allocate on this, but will be happy to test/help).
Final thought: this forum is a goldmine for openbk device. Thank you!
AI: Just to clarify, are you mainly sharing your findings for reference, or are you looking for help or advice with the rebooting issue (or any other specific problem) on the Earu EAKCB-T-M?
Sharing my findings
AI: Did you have a chance to try reflowing and aligning the CBU board on the 'bad' relay, and if so, did it have any effect on the rebooting issue?
Not yet. Will do.
