charging lithium batteries

[icarus4586]

Nickel-based batteries are charged basically with straight DC, obviously at different currents and voltages based on size and type.
My brother flies RC planes and has several electric ones that use Li-Poly batteries. To charge these, a "charger" is attached to a power supply (basically converts 120V AC to 12V DC).
Basically my question is what does that bunch of circuitry do to the straight DC current coming in, and why does it need to do this for lithium batteries?

 

[Varun]

Good question.

I did a quick google and found this

 

[Lynx516]

Li-Ion/Poly batteries have a habit of exploding if they are overcharged so the circuitry is there to prevent overcharging.

 

[Bassyhead]

The method for charing Li-Ion batteries is much different. They don't take straight DC like NiCd or NiMH. Unless you're knowledgeable on how to charge Li-Ions, don't try it. Devices like laptops have sophisicated microprocessor-controlled circuits that monitor how the battery is charged, the rate at which it charges, and the temperature(s) inside the battery.

 

[DaSaint]

just think if someone had the notion to render that chip useless u could have exploding laptops... lil freakay