Car is not in use for long how many minimum hrs should you drive per week to keep car batery healthy?

Diconnect the batttery and it wont matter. Car should be started once a month and idled through the gears if it is an automatic tranny Depends on battery self-discharge, outside temperatures and instruments such as clock that take current constantly. The baterry recharges about twenty minutes after each start to replenish the charge consumed in the starting. In general, it is not good to let the baterry discharde in unused car for longer than 3 months, that would require maybe a 3-5 hours recharge during car drive, but for a 1 month stand with only the clock being active you need about 30-40 minutes drive in mid to high RPM to recharge the battery. If you use the light it might take longer.

In case there is a light being lit in the trunk or storage compartment your battery will be completely discharded in a few days time.