Movement cutoff

Submitted: Sunday, Apr 25, 2010 at 22:27
ThreadID: 78001 Views:2872 Replies:5 FollowUps:6
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Gidday all,

I have a electrical cable that runs direct from the battery to the back of the ute where I have the fridge and also I have it running to the camper. I also have two switches located in the back of the ute to turn the power off when I stop and switch the motor off. If I leave the switches on, running the fridge etc, naturally it will run the battery flat. I have been lucky so far that every time I have stopped I have turned the switches off but there will be a day when I will forget and run the cranking battery dead (do not have a second battery).
What I want to know is there a movement sensor that can be hooked up so that it will automatically turn the power off to the fridge/camper and when I move on, turns the power back on again?

Cheers

Greg
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Reply By: Member - Allan B (QLD) - Sunday, Apr 25, 2010 at 22:53

Sunday, Apr 25, 2010 at 22:53
Better still Greg, make it so that the power is de-energised when you turn the engine off.

Put a 30 amp relay in the +ve cable from the battery with the relay coil controlled by the ignition circuit. When the engine is running = power to fridge, when engine is off = no power to fridge. Therefore no forgetting to turn it on or off.

Cheers
Allan

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Follow Up By: Member - Greg H (NT) - Monday, Apr 26, 2010 at 08:05

Monday, Apr 26, 2010 at 08:05
Cheers.

The old KISS principle again.

Greg
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Reply By: Member - bungarra (WA) - Sunday, Apr 25, 2010 at 22:58

Sunday, Apr 25, 2010 at 22:58
Install a VSR (Voltage sensitive relay) between the battery and your cable heading to the rear.

The VSR will sense the alternator voltage (higher than the battery at rest) and activate (close the contacts)when the alternator is charging and disconnect (open) when the engine is off...(alternator not charging)

The will be a few minutes at the most when it (the VSR) remains closed whilst the battery voltage drops below the set level......typicaly the VSR will close its contatcs at around 13.8 V from memory....just check the charging specs of your vehicle alternators as some of the recent vehicles have a lower charging voltage............there are a number of these VSR around and one will suit your vehicle alternator charging specs
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Follow Up By: Member - bungarra (WA) - Sunday, Apr 25, 2010 at 23:11

Sunday, Apr 25, 2010 at 23:11
Have a look at one here

http://www.keoghsmarine.com.au/product_details.php?g_ProductID=847

plenty of dealers around selling them that site is of no particular significance or recomendation ,it just came up on Google.....

This is the type of device you need........just instead of connecting the second battery via cable.........it simply allows current through to your devices in the rear instead of
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Follow Up By: Member - bungarra (WA) - Sunday, Apr 25, 2010 at 23:11

Sunday, Apr 25, 2010 at 23:11
Have a look at one here

http://www.keoghsmarine.com.au/product_details.php?g_ProductID=847

plenty of dealers around selling them that site is of no particular significance or recomendation ,it just came up on Google.....

This is the type of device you need........just instead of connecting the second battery via cable.........it simply allows current through to your devices in the rear instead of
Life is a journey, it is not how we fall down, it is how we get up.
VKS 1341

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Reply By: Nomadic Navara - Monday, Apr 26, 2010 at 01:22

Monday, Apr 26, 2010 at 01:22
If you are looking for something simple to wire in try a Fridge Switch - at $62 its much cheaper than a VSR

PeterD
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Reply By: feathery - Monday, Apr 26, 2010 at 06:36

Monday, Apr 26, 2010 at 06:36
I am looking at this it might do the job

http://www.engelaustralia.com.au/cgi-bin/products.cgi?category=Fridge%20Accessories&sub_category=Battery%20Monitors

feathery
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Reply By: Member - John and Val - Monday, Apr 26, 2010 at 07:52

Monday, Apr 26, 2010 at 07:52
Greg,

Allan's is the simplest cheapest solution. Use a 30A headlight relay in the engine bay to switch the fridge line when the ignition is on, or better when the auxilliary is on. Using the auxilliary will allow you to deliberately run the fridge with the engine off if you want to, but disconnect it when starting.

The next cheapest option is a motion sensitive switch as suggested above, then comes the VSR that will leave the fridge turned off until the cranking battery has recovered from starting the engine.... Lots of options, but I'd go with KISS - keep it simple!

Cheers

John
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Follow Up By: Member - John and Val - Monday, Apr 26, 2010 at 07:55

Monday, Apr 26, 2010 at 07:55
Forgot to mention - you say that the line running to the fridge is connected directly to the battery. Very important to have a fuse (say 20A) close to the battery. I'd run through a fuse to a relay to the fridge line - simple, cheap.

HTH

John
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Follow Up By: Member - Allan B (QLD) - Monday, Apr 26, 2010 at 08:49

Monday, Apr 26, 2010 at 08:49
Thanks John, methinks you and I see eye-to-eye on these matters. Great!

Cheers
Allan

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Follow Up By: Member -Dodger - Monday, Apr 26, 2010 at 16:41

Monday, Apr 26, 2010 at 16:41
Another vote for Allans solution.
Very simple and reliable.
I used to have a handle on life, but it broke.

Cheers Dodg.

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