Low Voltage Cut out... Buzzer

[PeterInSa]

I am in the planning stage of helping a friend upgrade his campervan, including a small 12v/240vac Frig, Solar panels, Lithium battery etc.

If the battery gets low on an overcast day etc, I want to warn him with a buzzer when the low voltage cuts out and disconnects the supply to the frig at say11.5v. using a relay and buzzer and the box below.

The circuit I am thinking of is: while the voltage is above the cut-out voltage, a relay is operated. When the battery is below the cut-off voltage the unit below cuts off supply to the frig and the relay. The relay contacts close the circuit to the buzzer with the ( low voltage) battery supplying the power. A switch (with light when activated, lets him know the buzzer is not in circuit) will disconnect the buzzer, pending the battery being charged up.

So, my question is, What’s the best ( low energy) relay for this application? (from Jaycar)



Thanks

Peter

[PeterInSa]

Jaycar all their relays do not seem to be low energy, ie not the best for a nearly flat battery. Have not used MOSFET B4 or reed relays, but easiest solution is a Jaycar relay.

[wotnot]

What we use ->