Anyone have any comment on this?
What do we think is inside? It lists 3400mah - am i thinking incorrectly they could be true panasonics?
Or is it more likely two cells that equal 3400mah?
6 cells, 1700mAh each.
I don’t fully understand the calculation for the laptops.
Capacity: 10.8V x 3400mAh
Number of battery cells: 6
So it sounds like its 3S 2P
I think.
How do you figure out what batteries might be inside?
Once you figure the wiring configuration from the voltage and number of cells, look at the capacity and parrallel cells.
2 Cells 3400
1 cell 3400/2
1 cell == 1700
>>>>>>My understanding was that this voltage is so low
>>>>>as to cause copper shunts inside making the cell
>>>>>>potentially very unsafe - a decent charger probably rejected them for good reason.
It is my understanding that in order for the copper shunts to grow the pack must be REPEATEDLY over-discharged. There should be absolutely no problem with a new pack. In fact, if copper shunts were a problem with borderline low-voltage packs, computer battery packs would be blowing up with alarming regularity — as many laptop users are buying these borderline-low-voltage packs.
If this was a USED pack with that voltage, I might think twice about it. Then again, the laptop pack owner would have to charge up the pack and then wait realistically over a year, maybe two years, for it to drop too low. And then he would have to do that 10-15 times to cause shunt growth, or also crystal growth in the “jellyroll” pack, which is also a problem. So, extrapolating, to really abuse a laptop pack with over-discharge even 10 times would take 10-20 years, a situation I doubt would happen.
(The only way to get the laptop pack to “overdischarge” is to let it sit for a year or more. The circuitry — as we all know — will shut the pack off before an overdischarge state occurs. So the only way — again — to achieve overdischarge is to let the pack sit. And since a typical 18650 only loses .5 - .10 volts a month when sitting on a shelf, overdischarging can take a seriously long time!)
But I am just theorectically speaking here. If I get a pack where the cells have really low voltage, I just toss it. There are too many packs around with great cells.
Those of you interested in the dangers of overdischarge (and overcharging) should read the NASA white paper. For whatever reason, once the cells are charged/discharged individually and removed from a pack environment, overdischarge is less an issue.
This isn’t to belittle the dangers of overdischarge, overcharging and other li-ion dangers. Li-ion cells can come back to seriously bite you if mistreated, so they should be used with extreme care.
The rings around the top of Sanyo cells almost always can tell you the type of cell.
Some of the more popular colors:
4.2 volt cells
Sanyo UR18650SA 1500mah pink ring (tool batteries)
Sanyo UR18650F 2200mAh red ring
Sanyo UR18650A 2250mAh violet ring
Sanyo UR18650F 2400mAh green ring
Sanyo UR18650F 2600mAh teal blue ring
New 4.35V cells:
Sanyo UR18650ZT 2800mAh violet (orange cell cover) 4.35V
Sanyo UR18650ZTA 3000mAh yellow (violet cell cover) 4.35V
Hi All,
Ok, I don’t get any of this.
I started this thread to share what I thought was a good deal. Per the thread subject, I thought that it was a good thing to share, and I’ve followed up on everything that I said I’d do, and more, presenting the test results from all of the tests I’ve done, as quickly as I could (I was up for 24+ hours straight to do all of that, charging the 12 batteries I got as quickly as I could, and running the 2 discharge tests, as quickly as possible).
As I said in an earlier post, after that, it’s out of my hands…
Maybe you all think I’m a shill for the Ebay seller (I’m NOT), or maybe you all think that I’m just lying (I’m NOT), or maybe my equipment is bad (I don’t know), but all I can say is that I’ve put in a lot of effort to get as accurate info as I could out to you all, and it’s the best that I can do.
You all can do what you want with the info that I’ve provided, but I think that I’m done with this whole situation, as I don’t see any point in doing anymore with it.
Full disclosure: In case anyone is wondering, I’m happy with the one pack that I got originally, and have purchased another 2 packs for my own use (even though I have no idea at the moment what I’m going to do with 36 new batteries :laughing:, so I’m “putting my money where my mouth is”.
Good luck,
Jim
What happened?
If it matters at all I really enjoy these threads. This is Budget light forum after all.
Those are Sanyo red tops. I have a bunch of them. Very robust cells. Not the highest capacity but some of the most reliable pulls I have tried. I like Sanyo reds.
Thanks for sharing Jim !
Great source of cheap cells.
Please keep us updated in your findings…
Thanks for posting this deal. If I didn't just buy 3 of the Acer packs I'd probably get some.
I guess I just bought the last 3. 
I looked at this thread when you first posted it and thought to myself 'This guys only ~20-25min. away from me.I should see if I can buy these for $6.99 and go pick them up.' I finally looked closer. There was an option for local pick-up!
Now I have to look into 4.3v chargers.
OMG! 63 cents per cell! Thanks Jim!
Hi Jim,
Not sure what has upset you but I'd also like to say thanks for the info you are providing.
This whole thread has been a very interesting discussion to me and has encouraged me to consider keeping an eye out for never used, old stock laptop packs - something I probably wouldn't have thought to try otherwise.
People will always have different opinions but nothing I've read seemed to me to be questioning your motives.
Cheers
Make sure to get a positive ID on exactly which cells you get and find official documentation on them before trying to charge them to 4.30v anything other than 4.20v...
I picked up my batteries.
A strange 'hole-in-the-wall place behind a dry cleaners. No indication they're there except the '665R' on a mailbox.
I just opened the first battery, got Kelly green cells, ~2.21-2.26V. Labeled:
SF US18650GR
K G511MMD25C
Kelly Green Cells?
The US18650GR is a Sony model number and color.
The box says “Brand: SONY” on it, which suggests, along with the wrapper color and code, that they are indeed Sony cells.
I was just surprised after seeing Ohaya's from the same small lot. Fantastic deal, 58 cents each before sales tax!
