WTB - Soldering Service

Buy / Sell Want to Buy
1

I purchased three DIY Micro USB TP4056 4.2V CC/CV Li-Ion Chargers from Mountain Electronics. They charge at 1.0A, but I would like one of them modified to charge at 0.5A so I can use it with my 16340 batteries.

I understand that the chargers can be modified to do so by changing the (REALLY TINY) resistor on the board. (There is a chart on the charger’s sale page linked above that identified the necessary resistor.)

I do not have the soldering skill necessary to change the resistor. Is there someone on this forum available for hire to make this change for me?

2

Its actually ~850mA max. With tp4056 boards a through hole resistor can work or a 0805 resistor. The original resistor is 0603 but 0805 also fit on the pads. FT $1.56 0805 3.9K-62K Resistor pack 270-Piece.

A Micro Lipo or LipoNano can be set to 500mA, solder bridge two pads.
Tho it looks like the chip averages more like 400mA unless you can heatsink it well. Lipo nano / MCP73831 test. Maybe encase the chip in thermal adhesive & place an aluminum heatsink on top.

3

Mountain Electronics might offer that mod. Have you asked them?

4

That’s an interesting little charger. I’ll look into that. Thanks for the head’s up!

I did not even think about that. he’s been a great guy to deal with, I’ll ask.

5

I can do this for free. but im too far from you.

for 500mA, you must change resister value to 2K~2.2K

6

I will do it for you, just need to change the 122 resistor (or Rprog [the resistor on pin 2 of the IC]) to a value of approx 2.5K ohm (I believe 252 or 2K5)

I need to do that to a few of mine too

7

You can build it yourself :wink: but that is a cheap $5.95

https://oshpark.com/shared_projects/M5kzWryl

I also like this one that uses a full size metal USB plug
https://oshpark.com/shared_projects/NclO046F

I wonder if a blob of clear silicon over the IC would help pull the heat away more efficiently, spread it out more evenly