# 18650 Lithium/Li-Po Cells over 3000mah



## brainzel (Jun 15, 2009)

I bought six UltraFire 4000mah cells from an ebay trader from china three weeks ago, just for testing.
Payed US$ 3,34/pcs. including shipping to germany.

Once they have arrived I want to discharge and charge them to get the real capacity and test my experimental environment, before connect it to the "great LiFePos" ... so it is worth to me 

I will report my experiences if it's interesting for anyone?.

edit:
just found on ebay: http://www.ebay.co.uk/itm/290539058085
Look at the graphs and testingdiagramms.


----------



## aeroscott (Jan 5, 2008)

I want to here.


----------



## lithiumlogic (Aug 24, 2011)

I found a few online tests of flashlight batteries and it seems lithium cobalt cells all fall in the 2200-2400 range, the claimed rating having little relation to reality.

As far as i'm aware only the Panasonic NNP cells (lithium cobalt, with a bit of Al and Nickel in the mix) are true 3000mah 18650s. These are used on the Tesla model S.

Panasonic have made available a pretty nice PDF about these cells. 

There's a heat resistant layer on the separator film. If metal particle contaimination in the manufacturing process causes a tiny puncture in the separator, the heat generated by the short causes melting of the separator and the hole to get bigger and bigger, a chain reaction. The heat resistant separator prevents the hole expanding.

It also shows a pack design they've come up with. They've worked out a cell layout that prevents a fire in one cell spreading to the next, without wasting all that much space.

Now, if pre-assembled battery modules in different shape and size were available, or at least, mounting hardware to build your own packs with this spacing, you'd have an option to compete with LFP prismatics..


----------



## cruisin (Jun 3, 2009)

COS said:


> Anyone know where one can acquire such cells?
> Most I can find are 3000mah UltraFire flashlight cells. The ebay sellers, well, I don't really trust.
> 
> Thanks


I have Sanyo and Panasonic Li-ion 2.7 ah 18650 cells, removed from unused laptop batteries that had a bad BMS, for as little as $1 each in quantitys. Most have solderable tabs which is a must. PM me for more details.


----------

