I wanted to modify it for my laptop so that i can charge my laptop. Even though the capacity is less my purpose was to just charge or behave like a micro ups. For the purpose i tear it down to check the components inside. Below are some pictures of it.
The mini ups is a pre built module using Lithium Ion batteries 18650-20. 3.7volt with 20 Ampere current delivery. Two cells are used in series to make 7.4v (7.7 actual). Batteries have a protector circuit integrated.
7 volt is step up to 12v using buck-boost DC-DC converter. The chip used is 6019 (XL6019E1) https://datasheetspdf.com/pdf/839862/Xlsemi/XL6019/1.
Most of such circuits are modularly made. Means separate modules are used instead of designing whole circuit as a single web.
The purpose of this article is to help you get access to commercial product circuit and therefore utilize the information to do DIY activities. My purpose didn't require whole circuit modification but after looking at batteries i think i needed higher wattage buck module to boost dc to 19v. The batteries can easily deliver 45watts for my laptop.
Max battery power without protection chip => 7.4v X 20A ( 148 watts )
Divide it by 19v to get max output current 148/19 = 7.78A. Using battery with protector module it gives ~7.7v with ~7.7A current i.e. ~60watt. 60÷19 = 3.15A at 19v. Laptop requires 2.37A at 19v max for fast charging with running laptop. This can easily deliver it. But it would be better to add more batteries to reach 1.5 times capacity of laptop to use it as laptop power bank or better say laptop mini ups.
This mini ups is available here -
