Why are two or more batteries sometimes needed?
Answers
Explanation:
Older equipment typically using junction transistors would need at least 3 volts to work. TTL-series chips need 5V. Since most battery chemistries give about 1.5V (2V for lead-acid), you need at least two AA cells in series to get 3V. Many years ago, before transistors were invented, people had battery-powered valve (tube) radios. Those needed 100V batteries. (a battery is technically a number of cells wired in series; an AA cell is just one cell but a 9V battery is six 1.5V cells stacked up in an outer case).
Often, more batteries are used to get more voltage to give more power. A higher voltage means that the wires can be thinner and cheaper compared to a lower-voltage flashlight of the same power.
Sometimes, two batteries are used for redundancy - a second one can be switched in if the first one fails or is drained. Many sailboats have two batteries; one for starting the engine and one for running the lights and radios, with a changeover switch.
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Answer:
to provide more voltage for high power consuming activities