An electronic system for a battery comprises a charging circuit (20) for the battery connected to a connector powering the charging circuit (15), a control and monitoring circuit (30) for the operation of the battery, and a discharge circuit connected to power connectors (2) of the battery. The control and monitoring circuit (30) interrupts battery charging when there is a call for current via the power connectors (2) of the battery. The electronic system has application to rechargeable batteries used to provide back up power.