I purchased a few of these battery testers and they work well. You can solder just about anything you want and accuracy is very good with 18650's and 1S and 2S chemistry I hate having to pull out my DMM to check cell voltage. I attached one of these to cell charger i no longer use with an adjustable bay.I drop a cell inside and i glued the display on top of the charger (charger is no longer in use)..Best $5.00 i have spent
I got one off ebay mounted in a little housing that I will glue one of my mini cc/cv li-ioncharger boards to, nice combo!
Here´s one for almost half price of dx, $2.88 Mini Lithium Battery Digital Voltmeter DC 3.3v - 17V