If you are asking the question, can you charge a 6 volt battery with a 12 volt charger, the answer is no.
With any 12 volt battery charger.
You do not charge a 7.2 volt battery with a 9.6 volt charger period unless you want to ruin the battery. You charge it with a 7.2 volt charger.
No, you cannot charge an 8 volt battery with a 6 volt charger. The voltage of the charger must match the voltage of the battery.
Yes, an 18 volt charger can damage a 14 volt battery. This is because the wattage for the battery needs to be equal to the wattage of the charger.
No, a 12 volt charger will overcharge a 8 volt battery and destroy it.
A 12 volt battery charger is designed to charge 12 volt batteries.The answer to the Related Question explains how any battery charger works.
Yes, a 12 volt battery will be damaged if charged with a 24 volt charger.
No, an automobile battery charger outputs 12 Volts. This is far too many volts to charge a 5 Volt battery. You would destroy the 5 Volt battery with this charger.
No, the battery charger has to match the voltage of the battery it is to charge.
No, it will overcharge the 6 volt battery.
Charge it with a 12 volt battery charger.
This is not advised! The 9-volt charger might have a current limiter so that nothing burns up, but it any case if left on it will destroy the 6 volt battery by overcharging. A 6-volt charger is not expensive.