12VDC to 12VAC

[gregmcc]

I've got a electronic door lock which is powered from a 12VAC transformer. I would like to use a 12VDC backup battery to open the door in case of a power failure. What would be the best way to do this - do I need a 12VDC to 12VAC inverter, or is there an easier way to power the door lock off the battery?

 

[Diver300]

You can probably run the door lock straight from DC.

There might be more current, because the inductance of the coil won't affect the current with DC, but it will with AC.

If it is just a door release that only operates for a few seconds at a time, extra current probably won't hurt.

As a start, measure the current taken at 12V AC and at 12V DC

 

[crutschow]

You can probably run the door lock straight from DC.

There might be more current, because the inductance of the coil won't affect the current with DC, but it will with AC.

If it is just a door release that only operates for a few seconds at a time, extra current probably won't hurt.

As a start, measure the current taken at 12V AC and at 12V DC

You could add a resistor in series with the battery or use a lower voltage to make the DC current the same as the AC current.

 

[gregmcc]

thanks - I'll try that.