I apologize in advance if this has already been covered, but researching in a thread like this can take hours. I live in Oakland, California, where it's rarely hotter than 80 or colder than 40, and the car is in a garage. My wife's car is a 4 year old Honda CR-V, 30,000 miles, mostly in urban driving, lots of stop and go. The battery can fail to start the car, no crank at all, and actually the car will lose some electronic resets and setting. I use a jump start pack and it starts well, of course, and may continue to start well until one time it just doesn't. Putting it on a trickle charger can help, but it will do it again soon. When I check the voltage with the ignition off it's 12.5. When I tried a 10 amp charger the meter showed a very low amperage going into the battery. I bought a new battery. Happy wife, .... Yesterday after I put the new battery in I hooked the old battery up to the same 10 amp charger and the meter showed a full 10 amps draw for quite a while. It seemed like the old battery was taking a charge better than before. This morning I checked the old battery again and it shows 12.5 volts. I don't have any other testing devices. Is it possible that a battery would charge differently when it's not connected to the car? Is this battery really shot?