I have realized that lead acid battery is way too heavy for Alfred’s body. However, I have to make a comparison and find a better way to have high density battery. Also price is another concern.
I have made some tests and concluded the battery comparison chart below:
3S4P Li-Ion battery set will need to be regulated to 5 volts. I also created below diagram to reduce the voltage from 12 V to 5 volts.
I think this power system will support the Alfred’s RPI systems. Next step is to design the battery charge / discharge module for Li-Ion. In a way back to square one from charger perspective.