Let me start out with a little background.
I quit smoking about 4 years ago and got into electronic cigarettes. When I moved up to the larger mods I needed 18650 cells. So, I started scavenger packs which got me into flashlights and mobile power banks for charging my phones and tablets off of.
I’ve busted a lot of packs and probably have 250+ 18650 cells here at the moment and given away another 150-200. I have about 2.5 shoe boxes full… And not little ones…the kind that hold size 12’s …so my count may be way off.
The numbers on the pack don’t give a lot of insight, you can grab 2 packs with the same WH and voltage etc and 1 could have Sanyo 2200mah cells and the other sony 2400mah cells.
I try to pick the smallest pack, so obviously the least amount of cells which is usually 6, with the highest WH rating.
As long as you stick with the name brand packs you will always get good UL listed cells. Stay away from the knockoff replacements from china.
I’ve got a few newer packs and they seem to be using Sanyo 2800’s as of lately. But generally you will harvest cells between 2200-2400mah and the occasional 2600mah. Newer packs may contain 2800’s.
Do not get the newer apple brand packs as they are no longer lithium ion cells. The older square ones that are about 3/4” thick will contain 6 cells.
You will normally get Sanyo/Samsung/Sony/Panasonic and LG’s, which are all great cells.
Here’s how I test them…
Be careful because stabbing yourself in the hand with a screwdriver and paper cut like slices from the very thin steel bands happens too. Wearing gloves is challenging so being very careful and taking my time is my method.
Once i bust them out I start disconnecting them in groups…usually groups of 2’s. Be very careful not to jump a pair of them. The tabs that are spot welded on the tops of the cells have weaker/smaller welds and come off the positive and negative terminals much easier than older cells. Either way I use a pair of needle nose pliers and get an edge up enough that I can get a grip on it…snug the side of the pliers over as close to the welds and grip on, then with a twist of my wrist roll the pliers. Usually they come off pretty clean. But, sometimes you will have some tiny sharp barbs that may need a little grinding. Try to keep the cells in the same pairs you took them out in.
Now it’s time to test voltages. I have the colors and marking pretty much memorized, you can decide if you would like to search what they are during whichever step you choose so you know what you have.
Usually the electronics in the packs go bad before the cells. Any group of cells that are lower voltage than the rest…and usually there will be a big difference, they get pitched.
Any cells showing signs of heat or corrosion get tossed. Usual cells will be above 3.0v anything down to 2.5v or so I try to bring back but it may not always happen. Below 2.5v I toss.
Now you can start charging the cells. Never leave the room for more than 10-15 minutes without checking the cells for excess heat. If the cells are just a tad bit warm that’s ok, but if they start getting hot they need pitched, due to the internal resistance and to reduce chances of having an issue down the road…it’s just not worth it.
DO NOT start charging cells and leave your house for an hour or 2 unless your insurance is paid up and you don’t mind living in a hotel or with your In-laws for awhile.
Once fully charged I check voltage make sure they are topped off…obviously any cell that took much longer than 2-3hours to charge to 4.2v is probably done for.
Over tenet month or cell I do checks on the cells… A few days after the charge I check voltages crossed all cells and not e them if it helps you. Then again at 1 week, 2 weeks and 1 month.
If they went from 4.20v to 4.18v in a month or so that’s within the normal range. But if you check them and a week late they are at 4.12 or 4.09 etc then you may want to consider putting them in a cool dark corner for emergencies or just get rid of them. That’s a person preference as you can decided what’s acceptable to you.
Manufacturers tell you that cells will degrade less over time if left at a half charge, which from what I have seen is usually around 3.5v or so. I haven’t found this to be true. I have cells I charged 2 years ago that still have a voltage around 4.12-4.18 and work just fine and if their capacity has diminished, it’s not noticeable to me over some fresh cells.
I leave all my cells charged fully should I need them.
If there’s any information I might bye able to share with any of you please feel free to let me know. I have browsed this forum for about the past 18 months off and on and after reading this topic I figured now is the time to make an account.
This really is a great resource for flashlight and battery related info.
Regards,
–30cal
