i bought a ipod interface that automatically charges the ipod when you turn off the car for about 20 mins.

is charging your ipod several times a day bad for the battery on the ipod?

 

A unique drawback of the Li-ion battery is that its life span is dependent upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles. So an older battery will not last as long as a new battery due solely to its age, unlike other batteries. This drawback is not widely publicized.

Try to avoid frequent full discharging of the Lithium battery.

For lithium battery meter calibration, periodically do a full battery discharge, every 30 charges, to increase meter accuracy.

Avoid heat, heat is the Lithium battery