What should a truck battery read while running?
What should a truck battery read while running? Fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts. If they are dim, that indicates the lights are running off the battery and that little or no charge is being produced by the alternator. What do the numbers on a battery charger meter mean? At the bottom of the meter is the charge rate. The numbers shown will depend on your battery charger. In the image above they represent the number of amps flowing into the battery...