Why aren't all 1.5V batteries the same size?

Question

It annoys me! My kids have battery operated toys, almost all using mutiples of 1.5V. Oh good - I have AAs and Cs! Oh wait - it needs AAAs....

Why not make the battery compartments all the same size, probably AAA so they fit smaller toys?? What is the reason for having the same voltage in different sized batteries?? Sales only?

Answer 1

Not quite. Apart from having differently sized toys (big toy cars have more space than a small handheld Game), the batteries have different "lasting Times" (mAh = milliAmpere Hours. For example, a toy car using 100 mA can run roughly 6 hours, if the batteries have 600 mAh), and toys have different power requirements (toy cars need a lot of Power for accelerating a great mass, whereas a Gameboy needs not that much power, but has a steady power consumption for a long time).

For example: Take your car. It has a 12 Volt lead battery. It's a huge massive block.
If you daisy-chain 8 AAA batteries together, you also get 12 Volts.

However your car needs a lot of power to turn the engine and get the spark plugs to spark. Therefore the car's battery has several Ampere of power, whereas the AAA batteries have only a few milliamperes.
And larger Power requirements require larger batteries. Regardless of their Voltage.

It's not always the Voltage, that's important with electronics, but the amount of current that is needed.

A great analogy is a water tube.
Volts is equivalent to the speed wich the water runs through the tube.
Ampere is the pressure of the water.
And Wattage, is the diameter of the tube.

If you have a set "speed" (the batteries Voltage), you need a bigger Tube to get more water at a constant speed.

Answer 2

No. Bigger batteries have higher capacity (Ampere Hours). So a remote control that takes a low current can get away with AAA. A powerful torch that takes a high current and is expected to last more than 2 minutes takes D