LIMnPO4?

[themotorman]

No Joke, they are listed. the question is are they what they say they are.
3 amps out of these cells
http://cgi.ebay.com/24-x-18650-GTL-Li-ion-3000mAh-Rechargeable-Battery-3-7v-/110538726410?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item19bc9f1c0a at what c rate? Sure wish there was more data. REAL DATA!
Dan

I bought one to look at and it is 18 mm dia. x 65 mm long , It does charge to 4.2 volts and delivers about 800 mA-Hrs after two cycles, it also will dump nearly 25 amps into a short. I did accidentally let it discharge to zero, and with much surprise, it recharged OK! This is a long way from the 2800 mAHrs as marked and advertised l!! I did find a reference to someone who has tested all the li-ion of this size he could find including this one but I cannot locate the link.. sorry. Some of the of the cells in the same size did deliver nearly 3000Ma-Hrs and according to the tests, and are LiMnPO4. They are listed on line by battery websites and cost as much as $12/cell. If in fact you can let them go to zero without having a dead cell ( like LiFePO4 's ) then that would be a real advantage as it makes them usable in places where a BMS is impractical like flashlights. I will try and look through my old history and if i find the reports on the testing I'll post it here.

 

[katou]

pm sent

 

[themotorman]

I found the site with testing info, it looks like he knows what he is doing.: The GTL results are about the same as mine..
http://www.candlepowerforums.com/vb/showthread.php?t=255943
Hope this throws some light on these cells.

 

[texaspyro]

If I was going to make a big pack out of those small cells, I would probably glue them together in something like a 6 wide by 4 deep brick (24 p). Then weld a single piece tab (5 mil nickel sheet?) across all the cells with the tab extending out about 1/2" the full wdith of the 6 cells. To series the bricks, clamp or solder those full width tabs together. YGMV (your geometry may vary).

You would need to check your cells very well before grouping them. One nice thing about a big parallel group is a single high resistance or open cell won't cause much grief. One bad thing is a single shorted cell will cause a lot of grief.

Another thing to look out for is the "+" terminal. Button top cells don't have much area to weld... Smaller low aH/low C cells would not be as big an issue.

 

[fairlyfaded]

I got a batch of these cells (8) http://cgi.ebay.com/6-x-18650-GTL-2800mAh-Rechargeable-Battery-3-7v-Li-ion-/190421148578?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2c55fc23a2

And got 1.3ah out of them cutting off at 3v... A bit... Lackluster...

Michael

 

[DAND214]

Has anyone tried these http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140427102816&ssPageName=STRK:MEWAX:IT ? Seller claims 10c for these cells. Don't know why I keep looking at batteries, why do I keep looking at women? I guess it's always a gamble. Win some, you loose some.
Dan