Geek Special: How to analyze charging profiles of lithium cells? | Salvaging 18650 Cells

What if I told you that you could get decent lithium (Li-Ion) battery cells for much less than new - sometimes even for free? In this geek special we do a deep dive into individual cell refresh process (with charts!) We'll look into pre-charge, charge/discharge/charge cycles for good cells, and for the bad ones. We'll see how different bad cell cases look like: heater, exceeding capacity limit, internal shorts, no capacity and just dead. We'll also check the finally tally of our salvage operation and see what we ended up with. Stay tuned! [Use chapters if you want to jump to a specific section]
Li-Ion (lithium) batteries can be expensive if you need a whole bunch of them for your project. But in many cases there is no real alternative as lithium-based chemistries give the best performance as far as capacity/weight etc. Enter salvaging lithium cells project! We will be primarily working with 18650 cells (cylindrical cells 18x65mm). These cells can be found in laptop batteries, powertool packs, modem batteries, medical equipment powerbanks etc. When this equipment gets discarded, you can get these packs for cheap or even for free. So in this project we source some old packs, shuck them, deconstruct into individual cells and then try to revive these cells and see what can we get out of these cells in terms of performance. We'll take a look at a way of cataloguing the haul as well as analyzing charging profiles to determine what makes a good salvaged cell, and what should be discarded. So stay tuned!
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Disclaimer:
This video is only for entertainment purposes. Any injury, damage, or loss that may result from improper use of tools, equipment, or from the information in this video is the sole responsibility of the viewer.
00:00 Intro
00:39 Charging charts overview
02:11 Pre-charge cycle
05:06 Main charge/discharge/charge cycle
06:01 Charge
08:36 Discharge
11:08 Charge again
12:16 Bad cell: heater
15:06 Bad cell: capacity limit
18:43 Bad cell: internal short
20:03 Bad cell: just dead
20:34 Bad cell: no capacity
24:43 Salvage results
27:33 Thanks for watching!