Testing questionable LiPo Battery Charger Schematics I found on the internet!

Altium Designer: https://altium.com/yt/greatscott!
Previous video: https://youtu.be/ohQF79cMODw
AC VS DC video: https://youtu.be/trmxzUVT2eE
How dangerous are LiPo Batteries video: https://youtu.be/osfgkFyq7lA

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You can get some decent LiPo chargers here (affiliate links):
https://www.elektor.com/diy-lipo-supercharger-kit-by-greatscott
https://s.click.aliexpress.com/e/_AM68Dj
https://s.click.aliexpress.com/e/_A8nfZn

Websites which were shown in the video:
https://cdn-shop.adafruit.com/datasheets/503562+1200mah.pdf
https://sites.google.com/site/donutscience/various-projects/the-easiest-diy-lithium-polymer-battery-charger/the-easiest-diy-lithium-polymer-battery-charger---the-schematic
https://www.circuitstoday.com/lipo-battery-charger-circuit
http://www.tp4056.com/d/tp4056.pdf
https://www.ti.com/lit/ds/symlink/bq24091.pdf?ts=1625045712665&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ24091
https://www.ti.com/lit/ds/symlink/lm317.pdf

In this episode of testing circuits I found on the internet I will be having a look at LiPo battery charger schematics. I will build up 2 very simple circuits which claim to charge a LiPo battery and test whether they can truly do that. One circuit is based around an LM317 adjustable regulator while the other one is based around an Op-Amp. I will show you the flaws of those simple design and while I am at it also show you my own super simple, very inefficient but safe LiPo charger. Let's get started!

Thanks to Altium for sponsoring this video.

Music:
2011 Lookalike by Bartlebeats

0:00 LiPo Battery charging in general
1:45 Intro
2:25 How to properly charge a LiPo battery
3:56 Testing circuit 1 (LM317)
7:58 Testing circuit 2 (OpAmp)
10:20 Making my own LiPo charger (CC/CV)
11:49 Verdict