I put mine on a charger for about 10 minutes at 6 amps until it showed nearly done, then 2 amps for about half hour. This morning started at 11.7 volts. Yesterday - same time, same temp - it was at 11.1 volts. Maybe 4 miles isn't enough to charge back the energy used for one start cycle? I looked at the manual's battery section again and it does state that if you have lots of short trips you may need to visit the dealer more often to have the charge checked. Maybe I need one of those solar trickle chargers... 5 watts oughta do it, right? It's a small car.