I have purchased a circuit that operates in an unusual way. This circuit firstly only as a 5V DC input terminal to power the 5V components. in addition, the 5V DC input voltage is also fed to a 12V DC boost converter. This 12V powers the 12V components.
My problem is this. I am currently running the circuit via the mains (the power supply outputs 5V DC which goes to the input terminals of the circuit). I would also like the option of running this circuit via a portal power supply such as an SLA battery. However, I only have the option of using a 12V 7Ahr DC SLA battery. (the entire circuit pulls about 840mA/hr)
First I would use a buck converter to step down from 12V DC to 5V DC then input to the circuit.
My question is, will the battery get drained quicker if use so many voltage converters i.e. I step down the voltage to 5V using a buck converter, then using the boost converter on the circuit to step the voltage back to 12V DC to power the respective components?