What to do with ~40 18650 Li-On batteries?

A long story, made short:

I have 5 old Dell laptop battery packs that held their charge quite well. I sold the laptop, but the buyer didn't want to pay for the extra packs, so I kept them.

Each pack has 9 Panasonic CGR18650HG (1800 mAH) batteries in it. The batteries are the tab type and are connected in a 3x3 configuration. Without the laptop I have no way to charge them.

I was thinking about removing each of them and separating them into individual cells.

Other than an Olight M20 that I already have a couple of AW protected cells for, I have no use for them. Any ideas for use?

Also, would it be safe to charge them in the WF-139 charger I have for the protected cells that I own? I also have a Maha C777Plus II charger that is rated for Li-On cells as well - would it be safe to use it?

Thanks.

Alot of us here have 18650's that have been pulled from old laptop packs. Separate them and check the standing voltage on each individual cell. Discard the ones that are low (below proper voltage range, they probably won't back fully) and charge the others with you choice of Li-ON charger. Now you've got a nice stash!

The B/S/T forum exists for just such occurrencies.

DO NOT use the WF-139 charger on unprotected cells. The protection is/maybe part of the charging system. At the very least because of the extra voltage drop created by the protection circuit the charger needs a higher voltage output. This could cause a thermal run away.

Use your Maha C777Plus II charger in Li mode. I have about 20 18650's that I just topped up. You will need a battery holder I used a bar clamp with solid 12ga wire wrapped arounf the jaws. Of course the jaws have softer plastic pads.

There are several threads on the subject in CPF use the search. For flashlights most use the protected cells some can use the un-protected cells. Read the specs carefully and if in doubt ask.

=D~~ Kilted

To extract the cells, follow this thread, and pay close attention to all the safety precautions...
https://www.candlepowerforums.com/threads/246699

Once you get the cells free, measure them on a DMM. Cells less than ~3.25V get tossed. Personally I have not had any problems with my WF-139 charging unprotected cells. I charge 18650 and 16340 alike, and charging terminates at 4.20V. Cells measure 4.16 hot off. There are at least 2-3 different versions of WF-139, and they can be identified by the behavior of the status LEDs. FWIW, mine is the red/blink-green/solid green model. A CC/CV hobby charger is ideal, good ones start around $50.

Once your cells are charged, mark the date and set them aside to test the self discharge characteristics. I usually let mine sit for 4-5 weeks, thats the limit of my patience. After that time most of my cells will remain at/around 4.10V. The top performers are at/above 4.15V and the bottom feeders are at/below 4.05. The bottom feeders get tossed. I label all the ~4.15V cells with "LSD", the 4.10V cells are labeled "MSD", and I know that as long as I top them off every ~4 weeks I am good to go.

The last test I do is for internal resistance. My 6P/MCE draws 3A with IMR 18650 cells, so I use that as a baseline. I top off the cells and measure tailcap current. Any cell that draws more than 2.5A gets labeled "HC", and these get used in my higher current MCE and P7 lights. Note also that just because the cell doesn't deliver full current, doesn't make it a bad cell. A lot of times I prefer to use these cells when I want to keep emitter temperatures down, if I am using my lights in the garage or jobs around the house and I don't need every last lumen and want COOLER long running led temperatures. I also find higher internal resistance cells better for direct drive applications... again to help keep LED temperatures down.

Finally, invest in a good case. I use cases made by Plano

Panasonic cells are pretty good, and they hold a charge very well. Most of mine hold a steady ~4.10V after 4-5 weeks. I have teal CGR18650D and purple CGR18650Es. Pink=Samsung, Red=Sanyo (my favorites), Green=Sony



My charge setup for 18650 and 26650 cells:




WF-139 and the charge cradle I made for bigchelis


There you have it... everything I have learned about 18650 cells.:twothumbs