Now adays about 36 - 48 months is all you get from one.
if you mean shelf life they last for years if stored properly
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.
Stock battery is a 6-volt unit. check VW specialty shops for replacement.
This will depend on the size of the 12 v battery.
No set answer to that. Depends on the power rating of the motor and how hard you're running it.
The answer is going to depend on the size of the battery and what you are mowing. 12-volt batteries provide 30 - 40 minutes of mowing time; 24-volt mowers last 40 - 75 minutes; and 36-volt mowers run for up to 90 minutes. If your lawn is thick, lush or tall then the charge may not last as long.
Absolutely not! It is a 14 volt drill. Use a 16 or 18 volt battery will destroy the drill in short order. It will run but not for long.
3 hours
As long as the ATV is wired 12 volt, not 6.
It takes about 6 hours to charge a 7.4 volt battery when using a 5 volt charge. For the best results try charging it over night.
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.
6 hours