So I pulled 12 Sony SF US18650GR cells rated at 2200mah each from a new old stock Toshiba laptop battery that was about 10 years old. Using the sony date code method, I have determined they were manufactured in October of 2004. When I first extracted them, they all read between 1.18v-1.2v on my DMM. So I put them on my Nitecore Intellimax i4 charger and within about 20 seconds of putting them on the charger they all read fully charged, which they really were not. So I took them off and let them sit overnight, thinking I would properly dispose of them tomorrow.
Well, the next morning, for some reason I put them back in the i4, and sure enough, it started to charge them. It took around 10-12 hours for each set of 4 cells for them to read fully charged. Yesterday, I topped off all 12 cells within 2-4 hours. Doing a reading gave me 4.23-4.24v for each cell.
It has been about 24 hours now and just checked them again and they are reading 4.23-4.24v still, I checked the voltage with my DMM and my voltmeter. They have not dropped at all in the last 24 hours.
From what I have read on here, supposedly anything discharged below 2.5v is reportedly worthless and should be tossed in the trash. Are you guys sure this rule is solid?
Mjêh, some may say I’m crazy, but just charge ’em and see what will happen.
I have brought a few with similar low voltages back to life myself.
It takes time and current.
Just stop charging at 4.3 Volts.
Accidents happen with extreme over charge and / or extreme discharge (as in short circuit…)
Watch the temperature when charging old cells though.
Don’t let them get too warm.
I left them on the charger for a few hours after showing fully charged, and they don't seem to go any higher than the 4.23-4.24v they are now, and no they never got hot at all while on the charger. I plan on using them to build a 12x18650 7.4v battery pack, so just wondering how most people would gauge these batteries to see if they are worth using or not.
Sounds like they’re still okay.
You want to make a 2s6p pack then.
As long as you charge that balanced, what could go wrong?
You should plot a diagram of Voltage vs time, under a given discharge current (1A Constant Curent LED driver for example) for each cell to be sure if they’re still good. (or good enough )
What others have said is that at below 2.5V crystals start growing inside the battery that you can’t see without taking it apart, the battery may work fine but if the crystals grow and cause an internal short someday in the future (even after working normally for months or years after the low voltage event) it can lead to fiery results and that there is no way to predict if a specific battery will experience this or not.
Yes, it will be 2s6p. Just wondering how can I test it against an exact current, as I only havews nanj 3.04A drivers and XM-L2, so if I just put one battery in there now and will see how long it last on high, it should tell me the capacity when it starts cutting out? I'm a newbie when it comes to determining capacity, so might need some help.
I just put one of these batteries in my solarforce and seeing how long it runs with it on high. We shall see!
Hmm, interesting. So should it be fine being used in a 2s6p battery pack, or would I be creating a ticking time bomb? And isn't this a risk inherent to all li-ion batteries?
2.5V or less per cell is the danger, so if you have many cells put together that does not make one cell have more volts.
And yes this is be a risk to any li ion batteries, some devices are designed to not let the battery charge again if the voltage drops too low
I was wrong, it’s even simpler, as you want to know Ah (or mAh).
So you just watch how long it takes at that 3.04A before it drops to 3 Volts.
As current would be 3A, you can multiply time by 3 and there you have your Ampere-hours (Ah) @ 3A and 4.2 to 3.0 Volts.
(Don’t forget to make decimals of the minutes!)
But there must be folks here with more experience and knowledge on this subject than me.
Also, when you have a 6p configuration, you will probably hardly ever will draw 18A.
I don’t know at what current they usually measure the capacity.
1 Ampere ?
When you first inserted them in the charger, because of the low voltage i4 recognised them as ordinary NiMH AA batteries, started charging up to ~1,5V and indicated they are full…
Hi BLFD. My understanding is that the reports (weren't they from NASA) said they had to be taken low repeatedly. Don't remember how low and how many times before failures started happening.
I wouldn't jump right into going to a 2S arrangement. I would run them through a couple cycles to see how they act. I definitely wouldn't combine them into 2S packs until you capacity test them to make sure they match. You absolutely don't want a cell draining and then reverse charging. The parallel cells should reduce the risk of that if they are parallel at the cell level, but I wouldn't count on that alone.
Genius. Never thought of that, but makes sense. I have been using one of the cells in my solarforce for the last hour and a half now on high at 3.04A an it's still going. Did a voltage check and it's down to 3.86v now. I'm very impressed to say the least. I really need to figure out how to put the other 11 cells through there paces to make sure they are on par with the cell I tested.
If anyone knows an easy way to gauge the capacity of the cells, by the batch instead of individually please chime in! Running each cell in my solarforce one by one, seems like it will take a very long time based on the way the 1st cell I tested is going.Plus I just got another Anker 12 cell laptop battery, and they came with BAK 18650's.
Also, all 20 of the Panasonic CGR18650CG batteries I ordered just came in. Each and every cell measured exactly, and I mean exactly 3.63V on the dot. Plus, they work flawlessly in my SRK and my TM26... But that's for another thread...
But as you can see, I definitely a way to gauge all my batteries. Whats the best, cheap equipment most here on BLF use to gauge there cells capacity?
Just my two cents to add: If they really are NOS cells I wouldn't worry about it if they hold around 4.2v after they've been charged. If they got hot during charging or had a high self-discharge rate I would worry, otherwise don't sweat it.
That's a good question and I look forward to hearing the responses. I use and Accucel 6 from Hobby King. It is limited to 1 amp discharge rate. I would like something that can go up to 10 amps, but everything I know is expensive.
I have no idea what an NOS cell is. Care to enlighten me?
After doing a little bit of searching, would this charger work for what we are trying to do: SkyRC T6200 Touch Screen Charger from T-mart with 5A/40W discharge for $80.99. If I use coupon code "SPRING6" it brings it down to $76.94 shipped. Is this a good deal and would it work? Plus, it looks amazing to me, lol, from a battery charger POV! Here's the official specs straight from SKYRC website: SKYRC T6200 Battery Charger. I didn't want to spend this much, but might just for everything it seems to do. I'm not even sure if I know how to hook this up to my 18650 batteries to be honest.
Would the battery charger I linked above work to balance the batteries? I am new to this kind of charger so please let me know. Thanks!
First off, “NOS” is an acronym for “New Old Stock”, meaning some item that sat on a shelf until it was no longer needed, but was never used. As Robert Hunter said, “the bottle was dusty but the liquor was clean”…
As to that wonderful machine…
The word “overkill” springs lightly to mind… I’ll continue looking into it, but there are many people here who have “just the charger you need” — I am not one — and will pipe up soon I’m sure.
As to “balance”, in essence “balancing” (in my own words) means to keep sets of cells together, electrically, by discharging and then charging them together to the same levels.
The key point is, in laptop pulls, the factory balanced the cells for you, by buying the best they could afford in tractor-trailer-load batches, then loading the packs with the sequentially delivered 18650s. If the pack is NOS, the initial charge will be the last current those batteries will have seen until you get them. Even it it has been used, the set(s) of 18650s inside will tend to remain “balanced” as they age.
When you discharge one 18650 of a set, it’s a little like putting one new tire on your car, driving awhile, then replacing the rest of the set. The “try” one has more wear & will fail sooner. In tires, that’s not such a big deal; but in batteries (especially ones that can push 8A or more through that one bad battery), the problems can cause you some grief.
(PS: SWMBO’s nickname since childhood is “Peanut”. I LOLed at your “Twerking Mr. Peanut” Avatar!!)
As an update to how the 12 batteries are doing so far. The date code on these batteries are from 2004, so exactly 10 years old as New, Old Stock. I fully charged all cells on 3-28-14 and today is 4-5-14, so it has been approximately 1 week.
After 1 weeks, here are the results:
1st column, initial full charge - 2nd column, charge after 1 week
4.24 - 4.24
4.24 - 4.23
4.23 - 4.23
4.23 - 4.23
4.24 - 4.23
4.24 - 4.24
4.24 - 4.24
4.23 - 4.22
4.23 - 4.23
4.24 - 4.23
4.23 - 4.23
4.23 - 4.23
So as you can see I am very, very surprised at how well these batteries have been holding there charge. So far, I can't complain.
I have some of the same batteries that came out of an old dell pack left over from my corporate days. I remember retiring this laptop around 2004-05 so those cells were at least 10 years old. The starting voltage was a bit higher than yours, the from 2.3v to 3.1v.
I was amazed those old Sony’s charged up without heating up, but I also charged them 4 at a time in the intellicharger which takes 2x as long. Then I put them in a good flashlight and measured the amp draw at the tail and got ~2.5A. A freshly charged recently made LG cell would give me ~3.3A on the same light.
I’m guessing this has something to do with increased internal resistance in the older cells. Do a search here at BLF and you’ll find plenty of info about this, and how to check for internal resistance with your DMM. I’m going to keep these cells for my colored lights that don’t pull a lot of amps, but I have also marked them all as CAUTION.
Be very careful when charging questionable cells, they can heat up very fast and if not caught eventually go BOOM! I’ve had questionable cells charge up fine as sets of 4, but then when I put them in single or 2 in alternate bays of the charger have them heat up. This happens fast without any previous notice, they can be chugging along fine and then all of a sudden start heating up. If you do charge questionable cells keep a close eye on them and if they start getting hot unplug the charger immediately an move it to a safe location.
BTW, if you like to hunt for NOS laptop pulls a trick I do is to search the model number of the computer it fits. You’ll find a bunch of reviews posted online from when it was new giving you an idea of it’s age before buying.
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