New purple Samsung 2800mah unprotected 18650 batteries for $2.68 each

I positively 100% figured out the samsung date code mystery if anyone cares.

And I am a dummy. I looked in the wrong place!!!

When cleaning up another six cells today, I noticed that there are BARELY LEGIBLE numbers UNDERNEATH the wrapper, printed on the actual metal battery can. DUH!!! as you may remember, that’s exactly what the Samsung date code explanation says: “There are two lines +ON THE CELL METAL CAN as follows…” DUH!!! The caps are mine. It’s on THE CAN. NOT on the wrapper.

These are barely readable through the wrapper but they are definitely TWO lines in the the exact format cited in the explanation, and they are now easily translated. Here are the two lines from one of today’s batteries:

G099
5O9D2

Okay, so the last number in the first line is the year. in this case 2009. That’s the important one. These batteries are from 2009, not the best date possible, but not the worst.

Second line:

First digit = 5 is the month, so May.

Second digit is “O” (not a zero, but the letter “O”), which is 25 (directions say “E=15, so count up from there: F=16; G=17, H=etc.).

So it’s May 25, 2009!!!

HOORAY!!! I figured it out.

the 3rd, 4th and 5th digits don’t really concern us. But they mean: 3rd digit (serial number of winding = 9); 4th (Reel Number = D); And 5th number is the winder machine used, number 2 in this case.

Man, you need a degree in cryptology to figure this out.

Good show, Ubehebe !

Wonder how good 4-year old Samsung is.

(No Eneloop warranty information at Amazon.)

[EDIT]
Sanyo Eneloop warranty is 1 year.

>>>>>Wonder how good 4-year old Samsung is.

Good point.

Before I knew what the dates were, I took these; put em in a light with a 4-amp driver and shined the light on my lux meter to see how well the light output held up. Did the same with the new 2012 ones from FT. I can see no difference. After a minute, both had settled in at 48k lux and were hanging on.

After 30 minutes in my test light …. The 2009 Samsung was actually slightly higher than the 2012 Samsung at 3.94 volts vs 3.89 for the 2012 one. So I am sure there is a difference. How can a 4-year-old battery work as good as a new one? But I can’t see any difference. Maybe they drop in voltage quicker in the lower range that we don’t use in lights? Say, down around the 3.50v area? Got me.

Remember now that I have 300 batteries here and have probably processed 500 batteries over the past year, 200 of which I didn’t keep because they didn’t hold a charge or the votage dropped too fast under load. So I kinda have a feeling for bum batteries. As far as I can see, these are not bum cells. But I DEFINITELY would add a YMMV. Maybe I got the three best 2009 Samsung battery packs and all the rest are junk? Be interesting to hear what the others who bought them think.

Well I decided to order one of Fasttech’s cheap 4.35v chargers and a pair of LG18650D1 batteries ………These Samsungs should be fine at 4.35

>>>>Well I decided to order one of Fasttech’s cheap 4.35v chargers

Let us know how it works.

Man, that extra .15 would take some of my lights into the stratosphere, especially the L2s. I can really tell the diff in output in many of my L2s when voltage is 4.2 vs 4.0 and lower.

Will most single-cell li-ion lights handle 4.35 volts? I have so many (and also many modded), I wouldn’t even know where to look for trustworthy specs on my lights for top voltage.

bdiddle - Youd be overcharging the cells by a good amount @4.35V and with an uncertain outcome. If it were me, Id probably rethink your recharging strategy.

Ubehebe - As with all 18650’s, the voltage sag is nearly immediate above 1A, so you probably wont notice any differences.

Check out HKJ’s excellent cell comparator:
http://lygte-info.dk/review/batteries2012/Common18650comparator.php

General opinion seems to be that lithium cells usually go around 5 years (if well taken care of) before they might possibly take a turn for the grave. Some go longer, others not. Id say that @$2.68 each, and given Ubehebe assessment, they seem to be a great buy.

It would be nice if someone could discharge test a few of these with a hobby charger to confirm capacity. Id love to see a 3A discharge curve.

I’ll just remove the batteries at 4.3v

But don’t the companies normally say 4.2v +–5?

>>>>As with all 18650’s, the voltage sag is nearly immediate above 1A, so you probably wont notice any differences.

Still, I would like to try a 4.3 or 4.35 battery actually charged to those specs to see if they do make any perceivable difference in light output. Have you tried one yet?

Yes, and there is no difference in the initial turn-on that I have observed with any of my flashlights. Voltage drops almost immediately while under load. Have you had a chance to check out HKJ’s comparator that I linked? Check out the discharge curves of the Sanyo UR18650FM and the higher voltage ZT’s. They sustain voltage the longest above the critical 3.5V demarcation throughout the discharge curve. Most single celled flashlights will benefit from these cells. Still, the price of the Samsung 2800’s is amazing; considering that for their age, they still seem to sustain high amperage demands.

Has anyone had a chance to discharge test these for capacity yet?

Was it this one?

http://www.fasttech.com/products/1421/10000969/1343600-polar-435v-21865017670-lithium-li-ion-battery-char

Sort of depends on how the batteries were stored etc. A new unused pack that has 3.8 volts and is stored correctly My guess is it will be perfectly fine , My revrend jim panasonics are still great batteries and they are much older than 2009.. I'm guessing that 5 years from the date you start using them is a more acurate assumption .

i have some very old batteries that came from a very old laptop that still suprise me how strong they are ( orange panasonics ) i think they just were from an old unused pack .

Pack in the OP has been relisted at a higher price, $24.98... guess it was getting too popular. :)

Any idea if these have the same cells?

http://www.ebay.com/itm/370749477282

http://www.ebay.com/itm/370749474174

http://www.ebay.com/itm/330866686790

http://www.ebay.com/itm/370739547155

They're all using the exact same pics, I'm assuming they're all the same but just listed at different prices hoping someone buys without finding the cheaper ones?

In for 4. http://www.ebay.com/itm/370739547155?ssPageName=STRK:MEWAX:IT&\_trksid=p3984.m1438.l2649

I would suspect that all the Acer packs from this seller would be the same or comparable. The stock photo shows a 2010 mfg date. If they dont perform, they will get sent back or PP dispute.

Thanks for all the research and trials guys. I need 24 cells for a large remote pack to hang on my next bike light build.

Could you give the source of the information?

+1

>>>>>>Any idea if these have the same cells?

If they are six cells, 56wh and made in Korea, they should be either Samsungs or maybe (cross your fingers) LGs, which for me would be even better. +BUT+ in cracking many many packs, just because the label says one thing, doesn’t necessarily mean that’s what you’ll find inside. I have never found cells that were less mah than advertised, but I have found ones that were more than the label says, so maybe Samsung 3000mah could be in there? Or the pink 3000 LGs? Wouldn’t that be nice?

I got one pack similar to your link, also ACER, but is 5800mah, from another vendor. It contained grey Panasonic NCRs, lowest at 1.72V out of the pack but I have all of them discharge-capacity tested in my iCharger and all even exceeded its 2900mah rating. (if indeed they are 2900mah cells)

I have incoming 2 packs from this OP’s item, will be tested when it arrives.

Just got the pack.
How and where do you start cracking it open?

If you’ve got a Swiss knife, use the CAN opener’s squared edge by pressing it in-between the halves of the pack, then twist. When you do it right the two halves will slowly split. When the halves are a little bit opened, you may use the CAP opener’s flat edge to split it wider. You may start at either side of the left or right side of the pack.

You should always see is peeling the labels off first helps .Some packs have just a thin plastic covering cells on one side and peeling back the label that has all the writting on it reveals the cells . i'm probably thinking of a dell pack or something else .. but since ubehebe said they were an easy pack to open maybe I just made that assumption ....wait and ask "the king of pulls "

>>>>>How and where do you start cracking it open?
.
This is how I do it —- VERY carefully. The batteries are thin and the plastic is sharp. It isn’t a race. Just take it slow, and it’ll be a breeze. Feel any battery getting hot during the process; toss the whole thing outside and leave it alone for at least 15 minutes or so. If you feel heat, you probably short circuited it and that’s the end of it. But fortunately this rarely happens.

I sorta think of it like defusing an IED. Someone on BLF said this — not me. But they’re pretty close to the truth.

Get some needle nose pliers and some leather work gloves. Tear the label off. There is also a long thin piece of plastic down a seam. Pull that off. Then start with the tabs. Sometimes, you can get a good grip on one of those and pull back the shell enough to get a gloved finger in. I suggest gloves because this plastic can have edges like razor blades. Trust me on this. I have got some NASTY cuts pulling apart packs without gloves. A couple almost deep enough for stitches.

Okay after the tabs break off and you do all you can do there, start peeling back the edges under the label. Just keep peeling and trying to get the plastic off in as big a pieces as possible. Finally you will get a pretty big hole going in the center. Now go to the rounded ends with the needle nose and sorta grab an edge and see if you can break the ends off and then you can pretty much diassemble it.

It’s not exactly easy, but it’s not exactly hard. These acers are about a 5 in difficulty. There are FAR worse. It is better to twist off little pieces of plastic then to twist a big piece and dent a cell. Once dented, even a small dent, to me the cell is usless and I’ll toss it. If you can cut the label, I’d never use it without a shrink tube over the original label. These cells can arc in a millisecond and tack weld themselves to whatever the arc is jumping to. Once they’re welded to something, you are not going to separate them, and the reaction will continue to its messy smoky and fiery end.

Once you get the battery tree out, twist and pull the tabs off the terminals. Be really careful around the neg poles. The cell-can metal is thin and can be deformed easily, another cause for tossing a cell.

Once you get all the batteries separated, use a chop stick edge to wipe off the crunchy glue. dremel off any weld remnants, especiall VERY carefully on the neg ploes again. The metal is thin and you do NOT want to weaken it. You need a super light touch to do this.

Then use clear 18650 shrink tube — cut to size — to cover any nicks and the whole cell, like a second clear label. Some people don’t do this and I can’t figure out why. The shrink tube costs like 2 cents a cell and protects the label and prevents shorts. Plus it looks totally pro and factory installed. The original label is a stretchy plastic and doesn’t hold up well to use.

I also write battery info on the battery before covering it with the shrink wrap. If you’re using it in a light like the S5 that has a tiny tube, don’t use a second shrink tube. It won’t fit.

Stand cells upright and QUICKLY put an even solder blob on top. Do NOT heat the battery. Once again, you have to be super quick. There’s a thin plastic bag jelly-rolled inside, and if that melts, you’ll get a vent with flames for sure. But you can do the solder so fast that the postive terminal barely gets warm. If you’re unsure of your soldering skills, practice on something first. Magnets will work in a pinch if you’re feeling lucky, but they can migrate and short out. Not a chnace I want to take. Obviously no preheating the tab when soldering. Flux will help it stick better.

Then charge em up.

Maybe there’s a better way to crack a pack, but this is the way I do it. Once you do it a couple times, you’ll do it much faster and be able to do a six-cell pack — from cracking to solder — in about 15 minutes. Charging these in an intellicharger takes about 4-5 hours. Like any new and unknow battery, charge it OUTSIDE. I have had a li-ion blow up inside, and believe me, you don’t want it to happen to you. Not only is it life-threatening dangerous, it leaves a toxic-nightmare mess that will take you and another person DAYS tp clean up.

Oh —- Be careful about twisting the whole pack in a gorilla grip with Hulk strength, thinking your superhuman prowess will bust all the glued plastic seams, and the cell tree will miraculously tumble out unharmed. I have never succeeded in doing anything better than twisting 5 out of 6 cells completely out of round and bulloxing the whole pack. And DON’T use the cells for leverage against your needle-nose pliers. You will dent them for sure. Tear the plastic in peces AWAY from the cells, with a twisting tearing action.

I have also used a dremel cutting wheel to get into some packs, but these acers don’t really have any clearance between plastic and cell, so there’s a good chance you’ll cut the battery AND the plastic.

This all sounds much worse than it is.

Hope this helps!