Circuit for power bank? Answered
Hello, Need a circuit design for the following requirement. Checked online available circuit designs but not sure if they meet all needs.
Looking for circuit design as per following details.
1. It will have one or two, 3.7 volts 2600 mah 18650 lithium batteries
2. Batteries will be charged using smart phone mobile charger or solar panel 10 to 20 volts and around 500 mah to 1 ah input
3. Will have mini usb connection for the same on pcb
4. Circuit should have battery level indication. While being charged, when they are fully charged LED should turn on indicating battery full. Also there should be one LED to show that the charging is in progress. When the battery charge drops below specific level another LED should turn on.
5. If we use 2 batteries then they will be connected parallel
6. Output voltage of the batteries should be 5 volts (so step up is required) and current should be appropriate for mobile charging
7. There should be provision for 2 USB connections. Load can be mobile charging / USB mini fan / USB mini keyboard LED (could be 2 at a time)
8. Circuit should be safe enough so no damage is caused to batteries / load etc.