The best way is to use LI ION cells,
You can get easily 3.7v li-ion cells from the old Laptop batteries.
Just Like the Once in the IMage.
Now you need to find out which one is working.
Check the Voltage of each cell if it is 4.2v it is fine.
(first try to charge it by a 4.2v charger or 5V is also good or one time)
Now connect all the Cells in parallel so if you have 2 cells 2600mA +2600mA = 5200mA Power Bank !
Now you need a Boost Circuit for 3.7v to 5v this you can easily get from TI or you can build you own.
IF you are not able to make a boost circuit than connect 2 cells in series and you will get 3.7v +3.7v = 7.2v 260mA and connect a LM7805 and a USB socket DONE. But Linear regulators waste lot of energy in the form of heat. You will also need a Charging circuit for series cells which you can use 9v adapter(ideally 8.4V)
You can get easily 3.7v li-ion cells from the old Laptop batteries.
Just Like the Once in the IMage.
Now you need to find out which one is working.
Check the Voltage of each cell if it is 4.2v it is fine.
(first try to charge it by a 4.2v charger or 5V is also good or one time)
Now connect all the Cells in parallel so if you have 2 cells 2600mA +2600mA = 5200mA Power Bank !
Now you need a Boost Circuit for 3.7v to 5v this you can easily get from TI or you can build you own.
IF you are not able to make a boost circuit than connect 2 cells in series and you will get 3.7v +3.7v = 7.2v 260mA and connect a LM7805 and a USB socket DONE. But Linear regulators waste lot of energy in the form of heat. You will also need a Charging circuit for series cells which you can use 9v adapter(ideally 8.4V)
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