Here are a few reasons why:
1. Safety risks: Connecting batteries in series or parallel can be dangerous if done incorrectly. If the batteries are not properly balanced, they can overheat, catch fire, or explode.
2. Power limitations: Disposable and rechargeable batteries typically have a lower capacity than a car battery. Connecting multiple batteries together may not provide enough power to run the air pump effectively.
3. Damage to the air pump: Using batteries that are not designed for the air pump can damage the internal components. The air pump may not function properly or may even be permanently damaged.
It is always best to use the power source that is recommended by the manufacturer of the air pump. In this case, it is recommended to plug the air pump into a car plug or use a 12v battery that is specifically designed for powering the pump.