Automatic battery charger automatically starts the charging procedure when battery voltage drops below a certain predefined value and stops after the voltage has risen above the maximum allowed value. Setup can’t be easier, just connect two alligator clips to battery terminals and plug the device in mains. This way it can stay connected for months and the battery will never overcharge. This comes very very handy when you have a scooter or a real motorcycle that you don’t drive during the winter time. Because we all know what happens to a battery when not used and especially during the winter.

Device consists of two main parts; power supply with current and voltage regulation (2 x LM317) and voltage monitoring circuit with switching relay. The charging procedure starts when voltage drops below 12.6V, and finishes when it gets to 13.8V. These values are not fixed and can be adjusted with trim-pots. The maximum charge current can also be adjusted with DIP switches. Voltage is not that critical but it must not be below 13.85V so that the charging procedure can stop.