I've seen a couple short articles on these in Flying Models and a couple of other places, but not too much real info.  Apparently DeWalt is using them for their high tech power packs.  Each cell is a sealed metal can.  It apparently uses different chemistry than the LiPo, which is safer and less likely to catch fire/explode, but has a similar energy density.  You can find the DeWalt packs on sale and get 2300 mah cells out of them for $10 apiece, which is a pretty good price.

Actually, these are lithium ion cells from A123 Systems.  http://www.modelelectronicscorp.com/products/SPTs/loose-cells.php
http://www.a123systems.com/html/company.html

The A123 cells have great potential. I don't think they will catch on in PA models just yet because they have a lower energy density than Lipo's (we look for any advantage we can get). They are however a good lower cost (about $90 for 10 cells) and safer (aluminum case rather than foil bag) alternative to Lipo's. There is no reason they can't be used in lower skill level events or sport flying. To give you an idea of performance, they are better than NiMH, but not as good as Lipo's.   

One drawback is the need for a separate charger. A Lipo charger will not charge A123 cells because of the voltage difference, 3.6 volts for the A123 cell and 4.2 volts for a Lipo cell. For this reason we will also need different pack configurations. A123 cells have a capacity of 2300mah ONLY and a weight of ~2.5oz ONLY. Lipo's on the other hand have MANY capacities and weights to choose from.

If you feel up to the task you can modify your Astro Flight 109 charger to charge A123 cells (thanks to Pat Mackenzie). The mods are very simple and only require a capacitor, wire and a spdt on/on switch (oh yea, and the risk of voiding your warranty or ruining your charger). Once you are able to charge them they can be charged at greater than 1C  , so flight to flight turn around will no longer be ~ 1 hour like Lipo's. 


I think A123 cells have a bright future (or new batteries that are developed from their technology). I would like to use A123 cells and see what the highest attainable performance is and stay on a tight budget. I have thought about using NiMH cells again at some point, just to see what can be done for cheap. At any rate I am keeping an eye on them.     

Emoli cells are another alternative not talked about. 

Hi Igor,
The running voltage is lower, though. On the other hand, they don't vent with flame!
For competition RC annd CL the weight/voltage penalty is a bummer, but for Sport flying, this safety factor makes it hard to justify any other battery.
Then again, they can be charged in 20 minutes!
later,
Dean

Yes Fernando,
And it's a fast charger too!
If you go to A123 batteries website they have a line of product for RC under the name A123 Racing.
The balancing charger they offer can do very fast charge cycles.
Dean

Hi Gang,
Here's a data sheet for the cell.
Dean

Thanks Dean et al:
 I found this forum  discussion on 123 batteries http://www.rcuniverse.com/forum/m_4667844/tm.htm might be useful.  It's onR/C Universe.
Haven't gotten into it yet.
Fet

So I did it after all:

Battery 6s1p A123
Motor PJS 1900 ... kv=1038rpm/v, 33mohm, 140g (5oz)
folding prop aeronaut 11x6
model weight 54oz span 55"
TO rpm 10000
lap time on 60ft lines 5,2s
needs 2100mah for 5 minutes

the motor was very hot, it is too small for such a power, so I used spinner with cooling vent, but epoxy smell was clear after every flights. (the producer says no problem while magnets are under boiling point).
I had problems with CG so I did not want to use heavier one.

The weight handicap was clear, the battery weight is 15oz. But I was able to charge it in 15 minutes (charging current is 10A), it allows next flight after 20 minutes break, what allows to use only one battery pack. I did flights as often as possible and found that the battery is coldest part of the whole powertrain.

So my conclusion is that A123 IS usefull, but need really light model which will not feel that extra weight.

The model is old IC type (for FP .40) reworked for lectric. Cells are moved as back as possible. But it needed 2oz tailweight anyway.

hmmmm ... yes, may be the 3s2p will work better with actualy available motors, but problem is with chargers, 3s2p will take twice the charging time at the same charging current. Most of available chargers are limited to 10A. I have ballancing charger FMA Balancepro HD 6s and also Pulsar2 - boths are alimited to 10A but can make enough voltage for charging.

Also ESC for 1s is smaller, this setup will work well with Jeti Spin44.