6 2900mah 18650's for $16.50

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wiljen
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I’ve seen that happen with the I4 on a few I had. Try putting them in another charger like a wf-139 first and get them up over 2.4 then the i4 will work. For whatever reason if the voltage is below that the i4 refuses to charge them.

FMcamaroZ28
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Because the i4 thinks its a NiMH til you get the voltage up to 2.0 or 2.5. taking them out and putting them in a bunch of times might be enough but I’m not sure.

DayLighter
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Thanks for all sugestions.. it works now, i charged the batteries using cheap generic chargers.. then after1 hr , i took it out and put it on I4 charger.. now it’s charging.. cool Smile
now the question is.. should i get more laptop batteries? Big Smile
PS: only buy laptop battery for Acer or Fujitsu which consistently contain Panys batteries

The only way to do a great work is to love what you do.

moderator007
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You might try two cells in series hooked up to only one bay in the charger. It should get them up to 2.1v each, they might charge individually then.
.
I see you got them charging now. You might considering getting a hobby charger to do actually capacity test to see what kind of performance you getting out of the laptop pulls. A lot of information about the cell’s health can be obtained from a discharge test. Smile

xevious
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ImA4Wheelr wrote:
Correct. Cell capacity (mah) is multiples by the number of parallel banks. Voltage is cell nominal voltage times number of cells in series. The the second battery you mentioned is most likely 2s2p (3.7v*2=7.4v, 2900mah*2=5800mah). Maybe it looked fat because the cells are arranged sideways?

Thanks for that… I think I get it now. Smile The cells are definitely not arranged sideways, as the container is long rather than square. Here’s an example on eBay: link.

I just noticed in this particular auction that they revealed the number of cells—there are six of them. So, given 7.4v, there would have to be only 2 cells in series, split into 3 banks… meaning 2600mAh cells. On top of that, the battery is only 5.4” long according to the posted dimensions… images can be deceiving without anything to compare. Wink

ImA4Wheelr
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Thank makes sense. Thanks for the follow up. If you haven’t purchase it, I would probably hold off. That about $3.67 per cell. At that point, I think I would just buy known new, high quality cells from FT or some one. If you have purchased, you probably will be getting good cells since that is an original equipment type battery.

xevious
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^ Yeah, while the 18650 lottery can be fun, I’m not someone who is draining 18650 cells on a daily/weekly basis and needs to have a stock pile. I think I’ll just stick to cannibalizing my own laptop battery packs once they’ve expired (got 3 great 2600mAh Samsung 18650’s from my last one), and buying quality protected 18650’s when needed.

B42
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Ty for the heads up, 6 nice 18650s. I will test them all later today. One has a light scratch in the grey exposing metal though.

ImA4Wheelr
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You’re very welcome. Thank you for the feedback. Mine have been doing great. Some charge up to 4.25 and hold at 4.21 after about a month sitting.

Yeah, I just clear tape the wrapper nicks. I got some shrink wrap for when they get too bad.

Aftrburnr
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Been looking at some of these packs. It looks like the same seller has like 2-3 different ebay accts. So, do you think these are going to have the Panasonic 2900 mah batteries in them? I’m thinking about getting a couple.

Acer 10.8V 5800mAh ebay battery pack

Thanks!

Ubehebe
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Panasonic is the only manufacturer that makes 2900mah li-ion 18650s, as fas as I know. So +IF++ it is a 5800mah pack, I would think the chance of them being 2900s is about 99%, but you never know. Be sure and check the pack label before ripping them open. I got some 2400s, but it was partially my fault. The pack said 4800 NOT 5800. I should have returned the pack, but by the time I saw it was 4800, it was too late and had ripped the pack open.

Good luck!!!!!

ImA4Wheelr
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Yes, that pack would have 6 Panasonic 2900mAh cells. I have purchase 2 of those. In post 11, I show a tip on how to break open that specific pack.

Aftrburnr
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@Ubehebe Thanks for the insight, I’ll be sure to have a look before I tear into the packs!

@ImA4Wheelr Thanks for your info as well! I did read about your findings and about cracking open the pack. I’ve cracked open a few packs now and I’m pretty good at it! Usually I can crack one open in less than a minute Smile Then, I take my time removing the tabs from the batteries so as to not distort the ends.

I guess I shouldn’t have posted the link to that auction. I came back to it tonight and it was sold out! lol I went to another different seller but I believe that the same seller has like 3 or more identities as the listings looked the same and was shipping from the same place. Texas to AZ, I should have them by Thursday or Friday. On another note, I thought I saw a thread here where these Acer packs were going for something like $9-$10 but I think those were mebbe used. So, I’ll let you all know how I make out.

scaru
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@aftrburnr, yeah those sold out pretty quickly. I also went and bought another 2 from one of the other auctions. Wink It is just such a great deal. 

B42
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I think you guys caused a run on Acer battery packs…oh wait, I guess I participated too Wink

texaspyro
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These are, without a doubt, the best deal in laptop packs to salvage (it was even better when they were $10). The cases are snapped together and not glued and are trivial to open. The cells are not overly aggressively attached to the case, they come out without peeling off the labels. The goo/tape left behind on the cells rolls off rather easily. The spot welds are small and come of rather cleanly (two per cell).

I salvaged a Dell pack that was a horror to open. Then the cells were so firmly taped into the case that the labels ripped off getting them out. Then the tabs had four huge welds on each cell that left behind about a pound of tab material.

The cells are great and deliver their rated capacity (I even ran a couple with 10 amps J) pulses for a discharge test), but will probably arrive at an uncomfortably low voltage. In an I4 charger, they start off being recognized at NiMh/NiCad cells and the charger will quickly (30 seconds) indicate that they are fully charged. This gets the voltage up high enough so that if you re-insert the cells that they will be recognized as LiIon cells and should charge normally.

One thing is that the voltage rather quickly drops after charging into the 4.16 volt range and stabilizes, no biggie… it doesn’t affect the capacity/runtime. I cycled a bunch of them a couple of dozen times with my battery analyzer and this did not change. Then I ran them in my SRK with my custom driver. This got them rather warm. This seemed to stop that behavior and they now hold their full voltage after charging.

B42
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texaspyro wrote:
These are, without a doubt, the best deal in laptop packs to salvage (it was even better when they were $10). The cases are snapped together and not glued and are trivial to open. The cells are not overly aggressively attached to the case, they come out without peeling off the labels. The goo/tape left behind on the cells rolls off rather easily. The spot welds are small and come of rather cleanly (two per cell).

I salvaged a Dell pack that was a horror to open. Then the cells were so firmly taped into the case that the labels ripped off getting them out. Then the tabs had four huge welds on each cell that left behind about a pound of tab material.

The cells are great and deliver their rated capacity (I even ran a couple with 10 amps J) pulses for a discharge test), but will probably arrive at an uncomfortably low voltage. In an I4 charger, they start off being recognized at NiMh/NiCad cells and the charger will quickly (30 seconds) indicate that they are fully charged. This gets the voltage up high enough so that if you re-insert the cells that they will be recognized as LiIon cells and should charge normally.

One thing is that the voltage rather quickly drops after charging into the 4.16 volt range and stabilizes, no biggie… it doesn’t affect the capacity/runtime. I cycled a bunch of them a couple of dozen times with my battery analyzer and this did not change. Then I ran them in my SRK with my custom driver. This got them rather warm. This seemed to stop that behavior and they now hold their full voltage after charging.

I’m curious, how low of a voltage did they arrive at, and do you still charge them up from?

texaspyro
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B42 wrote:
I’m curious, how low of a voltage did they arrive at, and do you still charge them up from?

Mine were at around 2.1V Most people seem to get them at around 1.8V I use the I4 charger. If the voltage is too low, it thinks that they are almost fully charged NiMH cells and tops up the voltage enough so that after 30 seconds it says they are fully charged. Re-insert the cells and it then recognizes them as lithium cells.

B42
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texaspyro wrote:
B42 wrote:
I’m curious, how low of a voltage did they arrive at, and do you still charge them up from?

Mine were at around 2.1V Most people seem to get them at around 1.8V I use the I4 charger. If the voltage is too low, it thinks that they are almost fully charged NiMH cells and tops up the voltage enough so that after 30 seconds it says they are fully charged. Re-insert the cells and it then recognizes them as lithium cells.

I got another pack reading 1.6V, supposedly new….would have to be a long sit around to get that low Sad

Aftrburnr
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I ordered mine Monday night. They shipped Tuesday and got them 11:30am today Smile Popped the pack open in like 10 seconds! Hit the Panasonic lottery!! Tested voltages of cells. They were @ 1.72 volts. Ok, so I’ve got 2 on a cheap Trustfire TR-001 for the last 10 hours now. Charger is slow but mebbe they’ll be done in 3-6 more hours. I’ve had used pack pulls w/low voltage sometimes take 20 hours to charge the first time. Some pics! You’ll see that these cells are from late 2008…

Ubehebe
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Many new computer power packs ship with batteries around 1.9-2.5 volts. I had a white paper from panasonic or samsung why they’re shipped that way, but of course I have neatly lost it. I need to troll the web and find it again.

Anyway, crystals forming in the battery catalyst and causing an explosion when they rip through the plastic liner happens after REPEATED charging from a depleted state (see the Nasa white paper on li-ion cells). So if you charge the batteries once or twice from 1.9-2.2 volts, the chance of an explosion should be next to nil because charging once or twice from an over-discarged state should not be enough to cause crystal growth (again see the nasa white paper).

But I sure wouldn’t make a habit of discharging them that low because cystals CAN and will form, and could result in an explosion. And obviously, if you get a USED pack with batteries that low, I would toss the pack because you have no idea how many times the cells have been overdischarged that low. I think nasa said that problems can develop around 25-50 instances of overdischarge. And they definitely said that it is much more prevealent in PACK batteries that are wired together. For some reason single batteries can take much more over-discharge abuse than multi-cell packs.

This is my understanding of the danger of over-discharging li-ion batteries, but I am not a battery scientist nor a degreed expert on it. Just have done a lot of reading on it. But who really knows how accurate any of these studies are since most come from the manufacturers themselves.

Hope this helps!

Aftrburnr
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Just checked google & ebay and I see these cells being sold for $11.00-16.00 + shipping for just 2! Good catch this was!

tatasal
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Aftrburnr: I have also ordered the cell Acer battpack everyone here is talking about. How do you pop it open? I have opened quite a number of different packs and until now I haven’t got the hang of popping open one.

Aftrburnr
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Try this tip below…

ImA4Wheelr wrote:
Yes, that pack would have 6 Panasonic 2900mAh cells. I have purchase 2 of those. In post 11, I show a tip on how to break open that specific pack.
ImA4Wheelr
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Nice score and pics Aftrburnr. Thank you for sharing. That cracked open pack with those pana’s just waiting to be freed is a thing of beauty.

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