Can you use 7.5 volt charger for 6 battery?

It is not recommended to use a 7.5-volt charger for 6 batteries. Batteries are usually rated for a specific voltage, and using a charger with a higher voltage can damage the batteries or cause them to overheat.

For example, if the 6 batteries are rated for 1.5 volts each, then the total voltage of the battery pack would be 9 volts. Using a 7.5-volt charger would provide a higher voltage than the batteries are rated for, which could cause them to overheat or damage the battery cells.

It is important to use a charger that is specifically designed for the type and voltage of batteries that you are using. Using an incorrect charger can be dangerous and can damage your batteries.