Ugh, this is so not fair, there are no good deals like this in europe :_(
i would love to get one of those cells to test here.
10 year old nos?
would be interesting to know how they held up.
i can test ir and capacity.
pm me if you want to mail me one.
the fact that they are not rapidly self discharging and can do useful work(running a 3a light)is encouraging.
What is the sony method? I have collected 12 Sony cells also from and old Toshiba laptop, the code is G5141ML13k. My multimeter says 2,8v, is there still hope?
My first laptop pulls, 6x Samsung 4.3v 2800mAh, initially all read about 2.1v. The first charge took about 12 hrs w/ 250mAh charger to about 4.24v. Been using/discharging them to about 3.9v and then recharge w/500 mAh for about 2 hrs to about 4.24v. So far so good. Based on my experience, the “2.5v rule” does not hold water.
I’ve had pulled-out 8 years-old cells as low as .72V and tested it and until now still doing fine, although its capacity is already about 1/3 of its original rating. It’s a Panasonic CGR from laptop batt packs.
not sure how bad overdischarge is to more modern cells but the few i tried to charge for a test hit nearly 4.0 and then started heating.
if pushed they may have gone into thermal runaway.but other junk cells we played with on bsu day were not very willing to vent with flame,roman candle,or rocket when overcharged.seems the better condition they are in the more likely they are to put on a show!
bsu day=blow shit up.
When charging doubtful cells, extra care should be taken like watching out for sudden heating up.
Hey cpfdaniel, sorry I have been moving this past week so not much time to answer stuff. Here is the link I used to determine my sony batteries date code https://budgetlightforum.com/t/-/1746#comment-143122
Basically:
on Sony lithium ion cells look at the first two digits in the second row.
8A = 2600mAh
G7= 2400mAh
G6, 6A, 6B= 2200mAh
G5= 2150mAh
G4= 1950mAh
The last 5 digits of that row tell the manufacturing date.
digit 1: year. Q=2008, R=2009, S=2010 and so on
digit 2: month. A=Jan, B=Feb, ...J= Oct
digit 3+4: day
digit 5: electrode history
Battery Status Update: I have had all 12 of these sony 18650's battery stored in my gadget box for the past 2 months since I initially recharged them to full capacity, and have been untouched since then. I have tested each and every one just now, and they are all measuring this:
3/28/2014: 4.23-4.24V - initial charge
5/25/2014: 4.20-4.22V - after 2 months in storage
As you can see, I am blown away by how good these batteries seem to hold a charge, even for being 10 years old, new old stock. Now time to find a good home for them, as I seem to have an over abundance of 18650 batteries at the moment!. I just tested them in all my lights and so far I can tell no difference between these and my samsung icr18650-28A in performance or runtime.
Thanks a million, hope mine are as good as yours.