The IMAX B6 charger is well-known among battery enthusiasts, but many are discouraged by the need for a USB adapter to connect it to a computer. I wanted to monitor detailed graphs while testing batteries, so I ordered a cheap USB-to-serial adapter based on the PL2303HX chip from AliExpress for about $1.60.
In theory, the connection should be straightforward, but in practice there are many pitfalls. The first issue I encountered was mechanical: a protruding tab on the three-pin connector prevented the rightmost connector pin from fitting properly.
The metal is very soft and can be easily filed down if needed.
On the charger itself, don’t forget to enable the USB communication option in the settings. It might be labeled “Enable” or you might need to deselect the temperature monitoring option instead. Here’s what the menu looks like:
Like many others, I found that nothing worked immediately. I had to systematically check every possible connection issue and troubleshoot each component. After reviewing various online resources, I discovered that most people encounter two main problems: a flickering signal LED on the adapter’s RX (receive) line, and more seriously, the pins inside the IMAX charger might not be connected at all.
Start with the basics: verify that all wiring is correct. The most common source of confusion is that the RX pin on the adapter must connect to the TX pin on the charger, and vice versa. Many people get confused by this, and sometimes sellers do too. In my case, the adapter had no labels at all—just colored wires—and the seller’s description had RX and TX mixed up. So I opened the adapter’s casing and examined the PCB carefully:
Since RX stands for “receive” and TX stands for “transmit,” the IMAX’s TX pin must connect to the adapter’s RX pin.
The PL2303HX adapter requires the appropriate driver to be installed (pl-2303hx-drivers), which adds a COM port to your system:
In my case, it appears as “Prolific USB-to-Serial Comm Port” and is assigned to COM13.
Next, you should test whether the USB-to-serial adapter is working on its own. A handy tool for testing COM ports is a terminal program (like Terminal), which allows you to send data on the TX line and monitor what arrives on the RX line. To test this, you can create a loopback by connecting RX and TX together with a jumper wire. This creates an “echo” mode—whatever you send should immediately come back:
I typed four zeros and pressed “Send,” and they immediately appeared in the “Receive” window. This confirmed that the driver and USB adapter were working correctly. However, I still received no data from the charger.
Unfortunately, when I connected a logic analyzer to the TX line, I discovered that there was no data being transmitted at all. It’s possible I received a Chinese clone with limited functionality. If you’ve encountered this same issue and found a solution, please leave a comment.
P.S. For those charging 1.2V NiMh batteries with this charger: long battery cables with alligator clips can cause significant voltage drops of 0.2V or more (depending on the charge current), which is substantial for a 1.2V nominal voltage. Using a separate, shorter, thicker cable for NiMh cells will significantly improve results.
Maybe TX signal NOT is TTL level but standard RS232….
That charger has no PC connection. That 3-pin port is REALLY only for a thermistor.
The charger does have a PC connection, I’ve had it working though the software sucks and drains every scrap of system resources whilst it running, your CPU is made to run at max the whole time the monitor is active lol
SOLVED!!
The entire procedure is correct but in the chargers where Temperature Senson and Comunication (USB) share the same port you have to chose in the menu which of them to use (default is temp sens).