Abstract: A battery monitoring method and apparatus are used for monitoring the charge level of a rechargeable electric storage battery, for example a lead acid battery. The counter-voltage of the battery is monitored by continuously monitoring the actual terminal voltage of the battery. When the battery is fully charged, the monitor provides a "DO NOT CHARGE" signal, for example a green light. When the charge level has dropped to a point that there may be some value in recharging the battery, the "DO NOT CHARGE" signal is replaced with an "OK TO CHARGE" signal, for example a yellow light. When the battery has discharged to the point where the battery must be recharged in order to avoid damage, the "OK TO CHARGE" signal is replaced with a "MUST CHARGE" signal, for example a red light. Audible signals may accompany the "OK TO CHARGE" and "MUST CHARGE" signals. The monitor is self-testing when turned on. It automatically recognizes the charge level of a battery to which it is connected.