6 2900mah 18650's for $16.50

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.

Quick question, seen this pack listed at 7200mah http://www.ebay.com/itm/11-1V-7200mAh-Battery-For-Acer-TM07B41-/261127278644?pt=LH_DefaultDomain_0&hash=item3ccc661034
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
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And has anyone seen the any more of the 2900mah packs???

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=p3984.m1438.l2649

http://www.ebay.com/itm/400478669310?ssPageName=STRK:MEWAX:IT&\_trksid=p3984.m1438.l2649

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-rechargeable-lithium.
Just a guess. :stuck_out_tongue:

Those have very low mah

Yea i think you’re right since the pack looked like 3x3 configuration anyway.

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?

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?

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 :frowning:

@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.

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.

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.

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 :slight_smile:
now the question is… should i get more laptop batteries? :smiley:
PS: only buy laptop battery for Acer or Fujitsu which consistently contain Panys batteries

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.
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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. :slight_smile:

Thanks for that… I think I get it now. :slight_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:

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.

^ 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.

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.

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.

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!

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!!!