as long as the battery fits it will work just fine
No. The 12V supply will overcharge the 9.6V pack. However, my Drillmaster 18v cordless drill has a charger that reads output 22v.
Yes. The voltage of charger has to be slightly higher than the battery for it to be able to charge the battery.
Current will go up by a factor of 6 times in that scenario.
If your load runs on 6 volts, you cannot replace it with a 12 volt battery. You will be exceeding the voltage rating of your load and will start a fire.If you want more amps (capacity) then you can wire more 6 volt batteries in parallel with the first.
It depends upon the amp hours of the 6 volt battery. The higher the ampacity of the battery the longer it would take. I hope that this is a hypothetical question because why would one want to fry a battery.
Yes.
No. It requires more that 8.4 volts to charge a 8.4 volt battery. If the 8.4 volt battery is discharged to less than 7.2 volts then it might charge up to 7.2 volts but no higher. Once the voltages are the same then current stops flowing and charging stops.
NO, a 12 volt battery cannot be charged with a 6 volt charger. To charge any battery, the charging voltage has to be, at least, slightly higher than higher than the voltage of the battery. Current flowing through the battery is what accomplishes the charging, and no current will flow at or below the voltage of the battery to be charged.
Power or energy cannot be measured in volts. The only thing you can say is one - the 9 volt battery - has a higher voltage than the other, the 6 volt battery. If you are asking about the power or energy contained in a battery, then the amount iof energy it can supply depends mostly on its physical size that is determined by the battery "type".
get a higher volt battery
Remove Phillips screw in hand control and replace 9 volt battery
well, i don't really get your mean, if your lithium battery declines, you can replace it for a same capacity, working volt, and the part number.