300 watt-hours per mile seems to be a common number thrown around.
If you charge at 12V times 1.5 amps, that's 18 watts. Do that for an hour and that's 18 watt-hours. Do that for 10 hours, and it's 180 watt hours. Now you have enough power to push your car for about half a mile!
You are going to want a higher amperage chargers than that. Typical is an amp rating on the charger about one tenth the capacity of the battery. For example, if you have a 100AH capacity battery, and a charger that charges at a rate of 10 amps, it will take 10 hours for a complete recharge. (You should never run the battery all the way down. No more than 80%. If you never go deeper than 50%, they are really happy and will live a long time.) Even without the battery being completely discharged, the charger slows down as the battery charges, so 1/10 the battery capacity still seems like a good ballpark for a charger.
Then that charger either needs to be of a voltage to charge the entire battery pack, or you need one charger PER battery.
For a while, I had a 48V charger on my motorcycle, which was supposed to be 5 amps. The bike had 55 amp hour capacity batteries. So, in THEORY, the most it should ever take is 10 hours to recharge. But it was a crummy little made-in-china charger that never put out as much power as advertised. Taking 20 hours to recharge a half-empty battery pack was not fun. At that point, any time I would ride the cycle, I would have to wait an entire 'nother day to ride it again.
DON'T use starter batteries. They are NOT designed for electric car use. You want batteries designed for deep cycling. Flooded 6V deep cycle will be the best for cost and durability (but not for weight and bulk) and there are various AGM and Gel 12V batteries that might cost more but get you to to higher voltage faster.