Here is a simple LED emergency light circuit that you can implement for home lighting during power failures. We know that LED bulbs consume very less power and hence they have a much longer life. This LED lighting circuit design is intended to light automatically during main power failures. So here we are going to help you with the building of cheap emergency lights. The main part of this led light schematic is a relay, which automatically connects DC voltage to the battery when main power is present and connect LEDs to the battery in the absence of main power supply.Upon request from our readers, we have integrated this with an automatic battery charger circuit. See our updated emergency with automatic charge controller.
- How to connect relay: Relays working with animation
- Simple battery charger circuit and battery level indicator with low battery recharge alarm
Emergency light circuit board diagram
Click on the image for enlarged view
- Step down transformer-1 (230V to 12V or 110V to 12V)
- Diodes-5 (1N4007)
- Capacitor-1 (470µF)
- Led-1 (Red)
- Resistors-2 (1K)
- Relay-1 (12V)
- Rechargeable Battery-1 (12V)
- Switch LED Array (Group of LEDs, See my prototype )
Working of Emergency light charger circuit
- The step down transformer and the diode bridge rectifier steps down and convert the high AC (in the range of 110V or 230V) voltage to low (12V) DC voltage.
- The diode D2 prevents the battery charge from flowing back, it acts as a free wheeling diode too.
- In the presence of electricity, the relay contact connects the NO (Normally Open) terminal to battery. Thus battery charges during this time.
- We are using a red LED as the charging indicator which glows when the emergency light battery is charging.
- When supply failure occurs, relay connects the NC (Normally Closed) terminal to the battery.
- The LED arrays are connected to NC terminal, thus they glow by using the charge stored in the battery.
Above shows our prototype (Look inside the case, it is very simple.We are using two 6V batteries in series to get 12V.)