Timer Relays

**101RRS** · 8th January 2018, 04:10 PM

I might have asked this before but I cannot remember and search does not throw anything up - old age is the culprit

.

The cubby fridge in my RRS gets its power from an unswitched source and on a couple of occasions I have left it on over night but thankfully not completely discharged the battery. Now I could change it to a switched power source but that means the fridge will only run when the ignition is on.

Ideally I would like to have an arrangement where the fridge will keep running for say 2 hours after I turn the car off then switch itself off. This will cover times when I am travelling and am away from the car or I just forget to turn it off. I could use a battery low voltage cutout but this means the car battery would have to drain down a fair bit before the fridge switches off and I would prefer not to do that.

So does anyone know of a 12v relay that has a timer function inbuilt so that when switched power is removed the relay still allows unswitched 12v to stay on for a pre determined time (preferably adjustable) then switches the power off.

Thanks

Garry

**austastar** · 8th January 2018, 05:23 PM

Hi,
Better still, a voltage sensitive relay. It will turn off at a voltage that you can restart with.
Redarc make one that is not expensive, as nodoubt do some others.
Cheers

**trout1105** · 8th January 2018, 05:31 PM

Most modern 12v fridges come with a built in voltage cutoff with 2-3 settings, These will stop the fridge from drawing power below a certain voltage

**101RRS** · 8th January 2018, 05:48 PM

Originally Posted by austastar

Hi,
Better still, a voltage sensitive relay. It will turn off at a voltage that you can restart with.
Redarc make one that is not expensive, as nodoubt do some others.
Cheers

Thanks - but as I said " I could use a battery low voltage cutout but this means the car battery would have to drain down a fair bit before the fridge switches off and I would prefer not to do that."

Cheers

Garry

**Tins** · 8th January 2018, 06:04 PM

Something like this?

BU_ DC 12V Digital LCD Programmable Timer Relay Switch for Power Equipment Uniqu | eBay

Not sure if it will do exactly what you need as I haven't really researched it.

Or, are you near a jaycar? They would probably sell you a kit to build one.

**Homestar** · 8th January 2018, 06:07 PM

Hi Garry, not sure about automotive timers, but I've used dozens of industrial timers on gensets and ATS's, etc. Usually use the Carlo Gavazzi units available from NHP - https://portal.nhp.com.au/Auto%20Pro...download&lg=EN

Data sheet here - http://www.productselection.net/Pdf/UK/DMB51CM.pdf

Using the Delay on Release function and the ignition supply to trigger it - ie, when the ignition goes off you can set the delay from a efw milli seconds to 100 hours.

Not sure of the price though, IIRC they were around $70 but I could be waaay off. There are probably cheapy Chinese knock offs for a quarter of the price if you wanted to test it - we've used some Chinese 7 day timers in light towers with no drama (similar to what John has posted above, but this particular unit isn't suitable for what you need, but I bet there's something out there that is.

**bee utey** · 8th January 2018, 06:20 PM

This might do it:

Adjustable Time Turn On/off Switch Trigger Delay Timing Control Relay Board | eBay

**101RRS** · 8th January 2018, 06:21 PM

Originally Posted by trout1105

Most modern 12v fridges come with a built in voltage cutoff with 2-3 settings, These will stop the fridge from drawing power below a certain voltage

Hmm not the cubby fridge in a D3/D4/RRS

Cheers

Garry

Tombie · 9th January 2018, 10:51 AM

Garry... my D4 shuts it down after a few minutes normally.
As does the old boys D3..

Sounds like someone did the bypass on yours!

**101RRS** · 9th January 2018, 11:03 AM

Originally Posted by Tombie

Garry... my D4 shuts it down after a few minutes normally.
As does the old boys D3..

Sounds like someone did the bypass on yours!

Yes I have heard some are switched and some not - I bought mine a few years back in a group buy over on the D3 UK site - just plugged it in to the standard loom already there so hasn't been bypassed.

I am surprised that an auto timer relay is not available - I will take a closer at a few of the suggestions and links provided above to see if I can modify to make work as I want. If not I might just run it from a switched source on the fuse box so it works like yours.

As I have a new battery it will probably take a few days to run down if I left it on but I just dont want to get caught out if out somewhere. It did run my old dying battery down in about 12 hours - it still managed 13v but Ah and CCAs were right down.

Cheers

Garry

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