It’s a simple 5v battery backup circuit with constant slow charging facility. Its mostly suitable for microcontroller projects where we need constant current source without any cut-out. Whenever mains fails the battery takes the load without any delay again when mains restores batter goes to charging mode again. Its not just a idea or diagram I developed this circuit for my own (my digital clock need’s constant 5v power supply) and still using this, till now without any problem.
![Backup Backup](http://www.circuitdiagram.org/images/6V-battery-backup-circuit.gif)
Make the circuit and if you face any difficulties just give me a call. Did you use the resistor 680 kohms or 680ohms and what if use 6v battery instead of 5 v wht u used in your diagram.should i change any components or it will work in this diagram and whats the purpose of the led?? Is it for showing the battery is on while ac power fails?? And when ac power is on and this led will stop?? And also is there any chances to get the battery over charging or it will break the charging when it will be full charged and separetly my load can get from the constant power from ac until it it gone by loadsheding?? Plzzz reply.thanks for your tutorial it helps me much.
Coin cell battery recharging circuit for RTC backup power. My first thought is to just use a rechargeable coin cell battery, with a small charging circuit. This should theoretically never require a battery replacement, unless the battery itself is malfunctioning. If the current source can supply a voltage higher than 3.6v. 6volt backup battery circuit with auto charger Thread starter saad ahmed khan; Start date Jun 15, 2008. What i want is a circuit that runs of ac and charges a 6v dc battery while simultaneously running the 6 volt switch. When the light goes out the battery then should power the switch. 6volt backup battery circuit with auto charger G.