I have those purple cells before, quiet old but being Panasonics they are robust cells. If those have not used up their life cycles yet and are displaying maybe higher than 75% of 2450mah on discharge, they still can be ‘played’ around for a long while.
My experience with used laptop batt packs is that it all depends on how it’s spent its previous life, which we don’t know and the only way to know is to check its IR and discharge capacity left.
The little 4 nubs I used to file off, now I just take a pair of needle nose pliers and pull off as much of it as possible. If there’s anything left I will place the tips of the pliers on the edge of 2 of the nubs, press down a bit, and squeeze. This scrapes of the remainder and smooths it out enough to where they won’t catch on springs and will sit flat on a flat surface.
The glue issue, probably a solvent or something more elegant than what I do, but I just rewrap them. It only takes a minute or so and about 6 cents in materials.
You already know what the purple ones are. The maroon looking ones are Sanyo, 1800mah both of these are made in Japan.
I have tried different methods of removing the glue and paper, the best way that I have found is to use your thumbnail and thumb, get it started with your nail and roll it off with your thumb, it’s not easy but it will leave the cells undamaged.
Yes, they are very useful just test them out good to determine what condition their in. Those Panasonic’s are really good cells.
the first 4 showed :
2423 - 2440 - 2434 - 2456 mAh
104 - 118 - 110 - 119 IR in quick test (with cells at 3,6 Volts - i have to restest them when they are full…!)
Isn’t amazing how effective and non destructive a thumb nail is? How many times is a fingernail the only thing that will work? Why can’t someone invent a scraping tool that works as well?
You tore off all the protection circuitry off of the pack anyway I'm sure the fault wasn't with the cells themselves ,,Do a search on blf for info on tearing packs apart and how people clean them up afterwards . I use a piece of the plastic as a scraper to help get the glue off cells .The Panasonics and Sanyos both have very tough heatshrink so you won't hurt them .Be careful when scraping Samsungs their heatshrink is terribly thin ... I use a small file or a dremel on the weld tabs on the bottom.and on the top I leave them rough and add a solder blob using lots of flux .
My guess is the recall is meaningless....In fact it might mean the cells have been used less ..could be a plus
This looks very good: consistent results and low IR.
About the spot weld remaining, I just used a hammer (and very little force) to press them down so that the remaining bits don’t scratch anything. Or you could file them down…
BTW, you state that the small pack looks healthy because it showed 4 green LED. But storing a battery at full charge is worst than storing it at 25%.
You can see some nice studies on that point on battery university.
I recently got a never used laptop battery pack that was stored for 2 years fully charged. The cells are not very good anymore. I don’t have a cell stored at 20-60% to compare but you can trust battery university…
See table 3:
If the glue doesn't peel off easily, I just rewrap my cells using the shrink wrap from FastTech. Get different colors and you can sort them into sets, or use the clear, and you can mark the cells under the wrap to keep them sorted.
I use a small dremel-type tool to buff the metal burs from the ends after using pliers to remove as much as possible...
as the ammount of batteries in my cellar grows i have to reconsider my decision to store them full (at arround 10-15°C) because if i need one i take it from the shelf…
on the other hand:
using the full capacity gives lower cycles (300-500) instead 1000+
storing full kills them 15% faster
so maybe 3 years of use possible instead of 4 or 5?
i dont mind…
the comfort of using them when i want to play with my lights is worth more than extending cell life
.
i will store “Backup” Batteries at 3,7V and the others full.
That’s a good strategy. Keep a few cells fully charged for the times when you need one “right now” and the others at 3.7V. That’s what I do anyway.
Jut out of curiosity: where do you get your cells? In France it’s quite difficult to get some old battery packs. There is a place were you can put all the garbage that needs to be recycled and can’t go in the normal trash but they don’t want people to take things out of that. They even locked the battery compartment and placed cameras everywhere.
When I pull cells (about once or twice a week, I pick up tons of packs from the recycling bin at home depot) I R&R the wrapper to take care of the glue and quickly sand down the bottoms to take care of the spot welds, then on the top I add solder blob buttons to cover them.
Make sure you test the voltage with a DMM to check for any below 2.7 and throw them away, using a charger with a display isnt the best way to go about it because insoon as you put them in they start applying current throwing the voltage reading off and you wont know if they were low enough to cause damage. With free pack pull cells there is absolutely no reason to put yourself or your family at risk, even going below 2.5v one time will cause damage and can lead to the cell eventually venting.
My favorite packs to find are Ridgid brand, they contain either 5 or 10 sanyo 15M’s, 1500mAh high drain cells like the 25R’s.
