This DIY Linux mini-laptop is made from an old smartphone
The phone that was sacrificed for this build is a Xiaomi Redmi 2 Prime, which is a 2015 smartphone with a 4.6 inch, 1280 x 720 pixel IPS LCD display, a Qualcomm Snapdragon 410 quad-core ARM Cortex-A53 processor, 2GB of RAM, and 16GB of storage.
While the phone only had a 2,200 mAh battery, there’s more room in the mini-laptop, so once you know the power requirements it’s possible to add a connect a larger battery to the BSI board: modified version has a 4,000 mAh battery.