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RS-485 Porn on Junteks Monitors

saracatlee

saracatlee

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Jul 19, 2022
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Has anyone messed with the Junteks (Junctek, Juntek, etc.) battery monitors? They're quite popular and on Amazon too under different names. Apparently the bluetooth module has an RS-485 port and the manual states that you can "connect it to your computer" but no other information on software or how to do it.

www.aliexpress.com

45.86US $ 47% OFF|Juntek Dc 0-120v 0-400a Kg110f 2.4 Inch Tft Color Screen Bt Connection Battery Coulometer Battery Monitor Check Voltage Current - Battery Testers - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com
 
I have the KG140F on my 24V off-grid system. I like the display, and use the App to connect via BT to my iPhone or iPad, but I have not tried to connect the RS485 to any computer. I do not recall it coming with any kind of software.
 
saracatlee said:
Has anyone messed with the Junteks (Junctek, Juntek, etc.) battery monitors? They're quite popular and on Amazon too under different names. Apparently the bluetooth module has an RS-485 port and the manual states that you can "connect it to your computer" but no other information on software or how to do it.

www.aliexpress.com

45.86US $ 47% OFF|Juntek Dc 0-120v 0-400a Kg110f 2.4 Inch Tft Color Screen Bt Connection Battery Coulometer Battery Monitor Check Voltage Current - Battery Testers - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com
Click to expand...
I have one and it looks pretty good but it also did a reset on me after 2-3 days and lost the data.
i decided not to use it and now it sits in its box.
 
hello everyone!
(it is my first post here :D)
I got two kg140f and need to say that the rs485 is very tricky on them, as both were death after around of month of using.
That lead to no refresh on screen and no ability to send data to home assistant.

As I am really in need to have the monitoring I decided to open one of them and removed the IC that looks like max 485, but hard to say as all labels are removed... To the places where RX and TX are going I connected esp32 and then I am using just ttl and serial communication to read data and publish on mqtt.

On the attached picture there is an empty space after the IC removal and two wires connected to esp32.

Have a great day!
profesor79
 

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profesor79 said:
As I am really in need to have the monitoring I decided to open one of them and removed the IC that looks like max 485, but hard to say as all labels are removed... To the places where RX and TX are going I connected esp32 and then I am using just ttl and serial communication to read data and publish on mqtt.
Click to expand...
(y) That's the spirit for a DIY Solar Forum :)... Welcome.
 
They do seem to be MAX485 chips.
Mine has worked great for over a year, but I did find it stuck the other day, a quick power cycle restored it to normal.
 
In the first case, my receiver was connected to the PC that was powered by inverter, and Juntek was powered from battery. As the circut is not isolated, the PC rebooted and there was no RS485 comms anymore.
The second case: a HP minipc powered directly from battery over buck converter, Juntek powered from battery and RS485 fryied on the arduino breadboard - checked pins and there was short between positive and negative. Reboot and lcd is saying that is connected but nothing is refreshed (this box is still connected - waitng for replace with the modified one)
 
(y) Sounds like you may need to galvanically isolate the devices so it doesn't blow again.
 
Very good job..!
Did someone tried to use an elfin wifi to expose rs485 data to mqtt directly...?

And what about sending junctek data to a cerbo gx...?
 
I don't have those devices (elfin, cerbo) - so can't say anything, but Juntek has just a text data exchange, so there is no modbus under rs485.
With that in mind - probabbly - there is a need to add a interface/translator to make this industry standard capable.
 
Elfin EW11 is able to take RS485 data and inject those into MQTT, i will try that.

e67a9e4005702fb94634dcf2900fb416387e2abd.png
 
profesor79 said:
hello everyone!
(it is my first post here :D)
I got two kg140f and need to say that the rs485 is very tricky on them, as both were death after around of month of using.
That lead to no refresh on screen and no ability to send data to home assistant.

As I am really in need to have the monitoring I decided to open one of them and removed the IC that looks like max 485, but hard to say as all labels are removed... To the places where RX and TX are going I connected esp32 and then I am using just ttl and serial communication to read data and publish on mqtt.

On the attached picture there is an empty space after the IC removal and two wires connected to esp32.

Have a great day!
profesor79
Click to expand...
I have kg140f with broken bluetooth chip at position U2. Any simple fix with esp32? I have SMD solder tools if necessary? Thanks
 
mabrams said:
I have kg140f with broken bluetooth chip at position U2. Any simple fix with esp32? I have SMD solder tools if necessary? Thanks
Click to expand...
hey
that looks a bit different as probabbably you would like to use the app to connecte to the device - so that's something different that I did.
My goal was to inject data to home assistant (and as I fried rs-485 chip) i just "replaced it" with en esp32 with mqtt.

So in fact you could use esp32 connect to rs485 pins and have small webapp to use the device.

I think next month I will have some time to help you with it.
Bluetooth comms are not exposed on the board as it is internal only (this is what I think)
 
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