Anonymous

Standards are built on previous standards and convenience, ie two 12V sources. But yes, "24Volts" is actually something between say 22 and 28 Volts. Real world voltage are not at all precise. Appliances are required to accept a wide range of voltage.

Anonymous

Their is a lot of 24 volt stuff about from the commercial truck industry, so you don't have to re design motors, solenoids, actuators and relays.

Anonymous

Because this is coming from the old old day standard removable DC power source original from lead acid battery bank that has standard 24V. Lead acid rechargeable battery was the only practical DC power source in those old days.

Anonymous

Just to add to the other answers about 1.5V cells, it is worth noting that the standard 12V car battery is 6 cells and six is a classic good packing number.