recovered laptop cells

[asheets]

This weekend I pulled apart a bunch of old laptop batteries that were on their way to the recycle center.  I recovered about 60% good cells, and managed to restore another 15% discharged or reversed cells.

So far I have about 60 3.7V cells of these two types, and I'm going to grab a bunch more batteries to recover cells from over the holidays

http://www.allelectronics.com/cgi-bin/category.cgi?item=LBAT-43T (15 of these)

http://mlftech.en.alibaba.com/product/50032111/50146729/General_Batteries_and_Battery_Packs/Lithium_



Ion_Cylindrical_Batteries.html (45 of these)

Anyhow, what I'm thinking of doing is setting up a battery bank with these cells.  What I'm thinking is putting 15 of these cells together in parallel as a "battery", then hooking up 4 of these batteries in a series battery bank to get 14.8 volts and a decent amount of amps.  As I recover more cells, I'd add them to each battery.  I'd keep the whole bank charged with 1 or more Ametek-based wind gens (or a gen built out of hard drive mags, once I get around to building that).

What I'd like to do is eventually collect enough cells that this battery bank could be used to run a small inverter.  I know that these types of batteries aren't the most ideal for what I'm thinking, but they are free and I can get a lot of them.  The questions I have are:

1. How many cells should I put together in each battery before the bank will have enough ummph to fire off a decent inverter?
   
2. Any problems with mixing the types of cells, or should I just stick to the more plentiful 186650 cylinder cells?
   
3. Any other problems anybody can think of?
   

[maker of toys]

each cell set in a series string MUST have the same total watt-hour rating, otherwise you're going to get into a serious cell reversal situation pretty fast. with Li-Ion, that can be BAD NEWS. (spell that 'B-O-O-M-!')

I would not mix battery types or ratings in a bank. . .  it's conceiveable that you could make a bank of parallel strings of different capacities if you provided a separate charger for each string in the bank, and disconnected the interties during charging.($$$.$$ and hassle)

is it a good idea? NO. Would I do it? Probably not. but it can be done.

-Dan

[asheets]

OK, so what I'm getting out of this is:

1. Assuming that each of the cells I'm using is in good shape, each of the batteries should have the same number of cells in them, and
   
2. I should limit myself to just using the 186650 cells.
   
   

Anything else?

[asheets]

Oh, and I guess I should find a way to isolate each battery from each other in the bank for charging purposes...  I cna't really think of a way to isolate them and still connect them serially to get the required voltage....

[Fiddlehead44]

6. Most important: NEVER PLUG IN A BATTERY AND LEAVE IT TO CHARGE UNATTENDED OVERNIGHT. Serious fires have resulted from this practice.
   
7. Do not attempt to make your own battery packs from individual cells.
   
   

These batteries cannot be handled and charged casually such as has been the practice for years with other types of batteries. The consequence of this practice can be very serious and result in major property damage and/ or personal harm.

- AMA Safety Committee