6 2900mah 18650's for $16.50

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texaspyro
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ImA4Wheelr wrote:
Plus shipping. Starting to get to a point where I would consider buying new, new from FT at $11+ for a pair.

The listing that I posted is from a different seller than the original posting…

Ubehebe
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This guy has two left for 16.50. They appear to be the same, but you better double check me.

http://www.ebay.com/itm/New-Genuine-Acer-10-8V-5800mAh-White-Laptop-Batt...

Ubehebe
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Hey, how are the batteries doing that everyone got out of the first packs of 2900s? The ones that were charged to like 1.9 volts?

Mine are not holding a charge so great.

A full 4.20 charge slides back to 4.16-4.17 after a couple days. Not great in my experience …. ALTHOUGH some of the new Panasonics seem to slide back a little to like 4.17 or so and hold that charge for a month or so. Hope that’s the case. Plus I have only cycled them a couple times. Sometimes 10 cycles are needed to hold 4.2 in my experience. Then again, I have had many new batteries hold a 4.2 charge for amonth after the first charge.

ImA4Wheelr
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I see. It just said “Calculate Shipping” for me. But after I plugged in my zip code, it then said indicated shipping was free. That’s a pretty good deal. I was thinking shipping within the US would be a pretty good size charge.

Yeah Ubehebe, that looks like the same battery to me too.

texaspyro
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Ubehebe wrote:
A full 4.20 charge slides back to 4.16-4.17 after a couple days. Not great in my experience …. ALTHOUGH some of the new Panasonics seem to slide back a little to like 4.17 or so and hold that charge for a month or so.

I have some new, fresh, unused versions of these cells and they do the same thing. Only one of the 24 recycled cells that I have behaves differently. It drops to 4.10V after a week or so. All the others are at 4.18 to 4.19V That seems to apply to all types of cells that my I4 charges.

Ubehebe
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>>>>>I have some new, fresh, unused versions of these cells and they do the same thing.

Yeah, like I said, the newer higher-capacity Panasonics don’t seem to hold a charge like the old ones. I have like 25 Panasonic CGR18650D 2400-mah pulled cells that hold a solid 4.2 volts for 2 months or longer. And work like workhorses; can’t tell the diff in runtime in or output between them and the 2900s. Really.

Ditto for the newer samsung pinks (2600) and purples (2800 I think). Ditto for even the ancient Panasonic lime-green 2000s or CGR18650CE (2250 mah). Hold a solid 4.2 volts for months. And those latter two be OLD. In fact, the runtime isn’t so great. I suspect they have been beat to heck and back, but they still hold that 4.20 volts for 30 days or more.

I mean the panasonics are great cells and all, but that’s why I have been shying away from them and liking the samsungs more. What’s the sense of charging a battery and going to use it 30 days later and finding it at 4.05 or lower?

Having said that, I have found with panasonics 2600 and higher, if you cycle them 10-20 times, they seem to hold a chrge mUCH better. But not one cycle, wait a week, then another cycle, wait a week. What seems to work is run it down to 3.75 volts; charge it again; run it down the next day; charge it up; run it down the next day. Then they seem to hold it okay.

The 2200 (light green) and gray (2400) samsungs have the same problem. In fact, maybe only 5 out of 30 gray samsungs I have found were worth keeping. But then I don’t know their life history as I pulled ‘em from packs.

I’m finding that samsung pinks and purples and panasonic 2600s are my best performers. I know that may not be what the charts and tests say, but when I get back home after about six months of my usual nightly desert walks, those are the cells that always read the highest remaining voltages in all kinds of lights. That’s a mix of new and pulled cells.

Just saying. IMHO. Not my intention to start a big my-battery-is-better-than-yours hoo-hah.

moderator007
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The cells from the other thread that I have are doing great. The 4 I have tested so far have been like new condition. Holding voltage, no heat while charging and discharging almost exactly as Panasonic specified.

texaspyro
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All my Panasonic 2900 mAh cells actually hold their charge quite well. The voltage does drop a little when they come off the charger, but it stabilizes. I just tested a couple of cells that were last charged around 3 months ago and got 2700 mAh out of them. The light they were in had been run for a few minutes during that time.

wiljen
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Another seller has a few left at $16.50 with free shipping here

http://www.ebay.com/itm/360600629939?ssPageName=STRK:MEWNX:IT&_trksid=p3...

got one on the way myself.

Ubehebe
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>>>>> I just tested a couple of cells that were last charged around 3 months ago

What was the voltage after 3 months?

If a cell drops back to 4.10 after a couple of weeks of nonuse (assuming it started at 4.20 volts), it just lost 20% of its capacity for me. And 20% of its BRIGHTEST capacity.

The way I look at it, I can really see a difference in light output when the battery reaches 3.7 volts or so in unprotected cells (from a 4.2-volt starting charge).

If I have a cell that drops to like 4.10 or less after a couple weeks or even a month, I chuck it. I have WAY too many other cells (WAY too many) that hold 4.2 volts for months.

In no way shape or form, am I suggesting that others do this. Nor am I criticizing others who keep cells that drop from 4.2-4.10 after a month. I just have so many batteries (pushing a ridiculous 300 I think at this point) that I need to somehow winnow the best from the less.

ImA4Wheelr
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That seller has a really good track record and is in the US too. I think it’s time for me to recycle all my poor performing used laptop pulls (most of them) and use the remaining used pulls in cars during the summer months.

ImA4Wheelr
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Are you saying the couple cells you tested had dropped to 4.10?

ImA4Wheelr
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Thank you wiljen. I just bought one of those batteries.

Ubehebe
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>>>>>Are you saying the couple cells you tested had dropped to 4.10?

No, no ,no …. I’m just saying in general. That’s one of my main ways of judging whether to keep a battery or chuck it. I haven’t had these long enough to see how they’ll do. Talking more about pack pulls. These 2900s are new (supposedly) and should be fine.

A couple did drop to 4.16 over the first couple days, but that was on the first charge.

Except for protected cells to use in my very few multi-cell lights, I use almost exclusively pack pulls. Although since I am a battery nut (hoarder might be a better description), I do buy a few of the more interesting cells to see how they do.

But I didn’t have enough batteries that were +++exactly+++ positively the same to judge light intensity between lights simultaneously. So I got three of the 2900-mah packs for that end, but that’s really unusual. I find so many GREAT batteries in used packs, it kills me to pay for ‘em.

There is this home depot in a town close to Death valley, and it’s like people buy NEW computer packs and throw them in the recycling bin there. It’s like Christmas every two weeks when I go there to town to do my food shopping (180 miles round trip). The guys at that home depot are so totally nice that they open up the recycle bin so I can look better. Last time I had three guys helping me dig through the mountain of dead duracells to find the good stuff. Best home depot i ever went to.

Metalophile
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I ordered the item in the original post and it arrived yesterday. Cells were at about 1.78V. Charging one up now. My cells also have 9511 code.

The Metalophile —-

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ImA4Wheelr
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I opened up another pack and had 4 cells at 1.91 and 2 at 1.72. I checked again in the morning and the 2 1.72 bounced up to 1.84. I probably won’t get around to charging them till this weekend.

ImA4Wheelr
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Thanks for the clarification Ubehebe. Sounds like a good approach. Good job on building repore with your HD recycle bin folks.

PyTech
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Yea them HD guys can be pretty cool sometimes. Must get good benefits.

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scaru
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Just got in my 2 packs, already got one apart and it had the 2900s. Big Smile They are all charging up now. 

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Well done scaru, now you have even more redundant cells ;P
Seriously though, nice score. Smile

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wiljen
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Mine came in. Cells are all marked 9511 (same batch reported in others). All were 1.78-1.80 Volts on arrival. Charged all at .5C to 4.2v to start them off easily. Ran one on the CBA this evening and discharging at 2A gave a total capacity of 2917 mAh. I’ll run a few more on the CBA after a few cycles but they look to be perfectly good cells on first test.

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Thank you for reporting wiljen. I don’t have discharge testing equipment. So that information is appreciated. My cells have been taking the correct amount of time to charge about 3 amps and have been taking and holding full charges.

PyTech
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Quick question, seen this pack listed at 7200mah http://www.ebay.com/itm/11-1V-7200mAh-Battery-For-Acer-TM07B41-/26112727...
Does that mean that it has 12 cells at 1800mah? since there is no such thing as 3600mah batteries? I would think that would be good deal either way for $19
.
.
And has anyone seen the any more of the 2900mah packs???

-Sean

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What I know about batteries those batts with the voltage that low cant be right…

You can check this packs, are new and working, I think that is a good option;

http://www.ebay.com/itm/400478669912?ssPageName=STRK:MEWAX:IT&_trksid=p3...

http://www.ebay.com/itm/400478669310?ssPageName=STRK:MEWAX:IT&_trksid=p3...

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moderator007
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PyTech wrote:
Quick question, seen this pack listed at 7200mah http://www.ebay.com/itm/11-1V-7200mAh-Battery-For-Acer-TM07B41-/26112727...
Does that mean that it has 12 cells at 1800mah? since there is no such thing as 3600mah batteries? I would think that would be good deal either way for $19
.
.
And has anyone seen the any more of the 2900mah packs???

Just a guess but I think its 9 cells, 3s3p pack. That would mean it contains a 2400mah. Maybe these http://www.fasttech.com/product/1210702-as-is-sanyo-18650-2400mah-36v-re....
Just a guess. Silly
PyTech
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ChangchungLeds wrote:
What I know about batteries those batts with the voltage that low cant be right…

You can check this packs, are new and working, I think that is a good option;

http://www.ebay.com/itm/400478669912?ssPageName=STRK:MEWAX:IT&_trksid=p3...

http://www.ebay.com/itm/400478669310?ssPageName=STRK:MEWAX:IT&_trksid=p3...


Those have very low mah

moderator007 wrote:
PyTech wrote:
Quick question, seen this pack listed at 7200mah http://www.ebay.com/itm/11-1V-7200mAh-Battery-For-Acer-TM07B41-/26112727...
Does that mean that it has 12 cells at 1800mah? since there is no such thing as 3600mah batteries? I would think that would be good deal either way for $19
.
.
And has anyone seen the any more of the 2900mah packs???

Just a guess but I think its 9 cells, 3s3p pack. That would mean it contains a 2400mah. Maybe these http://www.fasttech.com/product/1210702-as-is-sanyo-18650-2400mah-36v-re....
Just a guess. Silly

Yea i think you’re right since the pack looked like 3×3 configuration anyway.

-Sean

xevious
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moderator007 wrote:
Just a guess but I think its 9 cells, 3s3p pack. That would mean it contains a 2400mah. Maybe these http://www.fasttech.com/product/1210702-as-is-sanyo-18650-2400mah-36v-re....
Just a guess. Silly

Interesting. So is the mAh derived from the single battery mAh multiplied by how many are in series, or by how many banks are formed? 9 cells, but divided into 3 per bank means 7200/3=2400. It would seem to work the same way for voltage… as 3.7v x 3 = 11.1v.

I’ve seen some Asus Eee PC cells showing 7.2v or 7.4v and 5800mAh. That means it has to be two banks of batteries in series, but the casing looks very fat like there are 3 rows of cells. Maybe there are 8 cells total, divided into 2 banks of 4 cells?

ImA4Wheelr
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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?

DayLighter
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got 2 Acer battery packs.. they all 2900 CGR panys (?) all of them 1.90V, try to charge them on Nitecore smartcharger.. but after few seconds the lights stay ON.. it won’t charge Sad

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scaru
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@Daylighter, so the I4 refuses to charge yours? Maybe take them out and put them back in? If that doesn't work I have a few more ideas. 

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