I am quite new to batteries and charging them. I have a Polymer Lithium Ion battery (7.4V) and am about to attempt to charge it with a battery charger. The charger has a myriad of options from battery type, charge voltage, and current. I do not want to destroy the battery by attempting to over or under charge it. I peeked at a generic datasheet for LiO batteries and found an interesting charging plot.
The datasheet can be found here: DataSheet - see page 19.
What is going on here? The description of this plot writes that the maximum charging voltage is 4.2V (which presumably is for the battery they were using to collect this data).
Is this plot showing that at a charge voltage of 4.2V, the charge increases linearly for the first hour or so and then tapers off and the charge capacity of the battery is reached? Is this type of behavior governed by the controller inside the battery or does the battery suppress input current (like a charging a capacitor in an RC network)?
For a 7.4V battery, do we charge it at 7.4V? What are the differences between slow and fast charging (i.e. high or low input current)?
What are the side effects of charging at high current? Of course the battery would charge much faster, but does that shorten the life of the device?