Battery charger - Vanxson V-66x80 - Disassembly, backlit modification

This is a compact battery charger for 1-4 AA and AAA cells. It features a blue backlit LCD display showing the status of the charging process.

It has a hardware fault that has been reported on some review sites. The backlight stops working after some use.

The problem is possibly that some component gets too much power and cannot cope with it in the long run.

You also get to pay on the electricity bill for this very bright LCD display. With only one battery inserted the charger draws about 1-2 watts.


Solution - add on/off button and a resistor

A solution to this problem is to put a resistor and then a button in series with the blue LED that lights up the display.


Disassembly - how to open it up

To open it up you need to unscrew the three screws on the back side. These are special screws so you need a special screwdriver or bit for it

One screw is hidden behind the specification sticker. This is however not so hard to work around because on the screw location there is a smaller sticker on top of this big sticker containing a B/N serial number. Xarefully pry off this smaller sticker and move it to the right. Then you can unscrew the bottom screw behind the bigger sticker by punching a hole in the sticker.

The front and back parts are also hold together using latches on the sides of the battery slots.

Put a toothpick in the top screw holes and carefully bend out the front part a little so you can get a plastic card in between the front and back part, then carefully slide down on the sides and carefully unsnap the parts. Then the front part comes off.

The whole circuit board is placed in the bottom of the back part. It s just laid down except for a little glue in the top left corner. Use a flat screwdriver and remove the glue. Then you can lift out the circuit board a bit.

There are two cables going from the circuit board down to the socket.
The socket is unscrewable with a star screw if you want to completely detach the circuit board to work with it.

On the top right of the display you will find the LED connection that needs to be modified. It is very obvious it is even written on the front of the circuit board. The top pin is plus and the bottom is minus. Over this lead there is 2.84V. It should not be such a big deal since this is a blue led.


Big fat warning

It is very tempting to just unsolder the top or bottom LED connection and put a resistor and a button in series with it.

There is free space on the left of the display where you possibly can fit a toggle switch or if you want to slim down even more a PCB button with some hot glue.

This is however a trap. I managed to create a crater for the plus connection after removing the LED pin and then trying to solder a cable in the hole. The solder refused to stick. The reason could have been too high temperature but the iron was set to only about 300C.

My advice here is to take a cutter and cut one of the legs of the LED from the top in the middle, then solder the resistor and button on these two Pins instead of messing with the circuit board.

I tried to find another place to reconnect the LED. After a long search I messed up with a short on both the LED and some powering part and the battery charger was finished.

Conclusion, yes it is possible to modify this charger. But be careful with the circuit board it does not work well with soldering.






This is a personal note. Last updated: 2022-09-17 20:34:16.



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