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A123s are designed to be charged to 3.6v per cell. Lipo chargers charge to 4.2 so they must not be used (directly) with these cells. Dont be misled by the fact that your lipo charger is designed for 3.6 or 3.7v lithiums (learn the difference between nominal and charge voltages). Your options for charging (from 12v) are as follows:

1) Upgrade or buy a new charger that can do A123s
2) Make or buy a Dapter - this allows you to use a nicad or lipo charger with A123 packs (it regulates the voltage correctly)
3) Make a cheap and very effective charger yourself...

A123 cells have a 3.3V nominal voltage, instead of the 3.6V and 3.7V for Li-Ion or LiPo. Should you put 4.2V into your A123 cells they will go bad. They will not explode but they will deteriate quickly.