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RS-485 Porn on Junteks Monitors

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.

 
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.
 
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.

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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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.
(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.
 
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