I am planning a device consisting of a load, a battery, and an external power source.
The idea is that the battery powers the system until the external power is plugged in — then, the external source provides the power and charges the battery.
I am working with a 8.2V battery pack, and would like to add an auto charging circuit to this battery, such that it start charging when the battery has been discharged a certain amount, and stops charging when the battery is fully charged.
I would like to know what is a good way to accomplish this, and what voltage source/level I should be using to charge the battery safely.
Best Answer
Please provide FAR MORE detail.
Do you have a specific battery in mind?
What is your application?
If 8.2= 8.2V it implies 2 x 4.15V cells = (probably) two x Lithium Ion (LiIon) cells in series. If so, use of a LiIon charger or a LiIon charger IC is required.
2 x LiIon in series should never be exposed to more than 8.4V but 8.2V is safer.
BUT there can be quite a lot more than that to LiIon charging.
Please provide details - What mAh, cell type, use, ...?