Lipos are very easy to charge. They are usually charged at a constant current ( usually the current numerically equal to the 1 hour discharge capacity) until a certain voltage is reached (usually 4.2v per cell).

The charge process is commonly described as a constant current phase followed by a constant voltage phase. This sounds as if the charger has to make some sort of decision as when to change modes.

This is misleading as although it may seem like that the reality is quite different. All that is necessary is for the charger to apply two limits all of the time.

One is a current limit, the other a voltage limit. Applying these limits results in two phases. An initial phase in which voltage increases with current limited to the maximum desired value until the voltage reaches the maximum value at which point the current is reduced to the value required to maintain that maximum voltage.