Ted Baldwin

.............An interesting thing happened to me. I mistakenly left my lights on overnight and by morning, I could not start my car. It was then I discovered that my headlight switch was left on. By this time there was no light at call coming from the headlighs or dome lights and as I stated, the car would not start. I turned the headlight switch to off and left the car alone and went to work. later in the evening when I returned, I put the key in the ignition and was suprised that the car started immediately. This happened one month ago and since then the car starts and drives just fine. Has this ever happened to anyone and what is the explanation? I was pretty certain that leaving the headlights on had drained the batteries but why did the car start later? Did turning the headlight switch off cause the battery to recharge somehow? I know I shouldn't care but I feel like this is like the movie "Chucky"


Ted

Lynn

The battery was warmer in the afternoon than it was in the morning. Most, if not all, batteries will produce more current when warm. This is why poeple in the northern climes put battery warmers in their cars.

You can demonstrate this using a flashlight. Place some used batteries in the refrigerator overnight. When placed in the flashlight, the light will be dim. Now heat the batteries with a hair dryer, heat lamp, etc (not in the microwave!) to somewhat more than room temperature. The light will be much brighter.

sosh

They will regernerate to a small extent and temp does have an effect. Its would be unusual that after being completely dead that the regeneration alone would provide enough juice to start the car, but between the warmer temp and a bit of generation it could and obviously did. This holds true to an extent for all lead acid batteries. I bet though that if the car did not start on the first crank over that there was not enough to provide a second try