Relay Switch for 12v Fridge

[Rob Dean]

Hi,

My trusty 12v fridge has been wired with 10mm cable through a domestic cooker switch. This works well enough and has given me 4 years good service.

 

I'm now replacing the whole galley and am tempted to do away with the bulky cooker switch and replace it with a relay switched from a spare switch on the main DC fuse panel.

 

Question: What relay should I use? And is this more hassle than it's worth? I quite like simple and the current system works. But if others use a relay without problems, it could be a neater solution.

 

thanks

 

Rob

Edited February 8, 2010 by Rob Dean

[steelaway]

Hi,

My trusty 12v fridge has been wired with 10mm cable through a domestic cooker switch. This works well enough and has given me 4 years good service.

 

I'm now replacing the whole galley and am tempted to do away with the bulky cooker switch and replace it with a relay switched from a spare switch on the main DC fuse panel.

 

Question: What relay should I use? And is this more hassle than it's worth? I quite like simple and the current system works. But if others use a relay without problems, it could be a neater solution.

 

thanks

 

Rob

 

 

Hi

 

Why have a switch at all.

The small amount of times you need to switch it on/off could be done by the switch on the fuse panel.

 

Alex

[Nickhlx]

Hi,

My trusty 12v fridge has been wired with 10mm cable through a domestic cooker switch. This works well enough and has given me 4 years good service.

 

I'm now replacing the whole galley and am tempted to do away with the bulky cooker switch and replace it with a relay switched from a spare switch on the main DC fuse panel.

 

Question: What relay should I use? And is this more hassle than it's worth? I quite like simple and the current system works. But if others use a relay without problems, it could be a neater solution.

 

thanks

 

Rob

 

Hi Rob,

 

The fridge will probably take about 5 amps and relays are easy to find rated with 10 amp contacts. It would definitely be a good idea to use a spare breaker to energise the relay, if local to the fridge, if only to save the voltage drop of the doubtless smaller cable running all that way to the fridge from the breaker.

 

Bear in mind though that all the time the relay is energised it too will be taking a small current, and so will get warm - can you not fit a conventional switch near to the fridge to save this loss ? Lots of small currents make up a bigger current and whilst its not perhaps meaningful if it's the only one, a local switch might be the better solution

 

Nick

[Rob Dean]

Hi

 

Why have a switch at all.

The small amount of times you need to switch it on/off could be done by the switch on the fuse panel.

 

Alex

 

Because the fuse panel switch is not heavy duty enough to switch without creating volt drop. The Fridge cable connects direct to the battery bank (through an in-line fuse)

 

I need a method of switch that doesn't introduce volt drop. You can see from other posting here that this is a big issue with these fridges. Using a domestic cooker switch is a good solution but fairly bulky.

 

Rob

 

The fridge will probably take about 5 amps and relays are easy to find rated with 10 amp contacts. It would definitely be a good idea to use a spare breaker to energise the relay, if local to the fridge, if only to save the voltage drop of the doubtless smaller cable running all that way to the fridge from the breaker.

 

I thought I'd put the relay at the fuse panel. There's a dedicated 10mm cable for the fridge so it doesn't matter where in the line it is switched.

 

 

can you not fit a conventional switch near to the fridge to save this loss ?

 

That's the solution I have at present

 

 

Rob

[Nickhlx]

Can you not replace the fuse panel switch with a heavier duty switch ? It seems that using a relay is not really getting to the source of the issue, rather a work-around with possible new disadvantages... I don't know your switch panel so can't recommend but if its a standard toggle switch I would be pleased to find some suggestions for you if electrics is not really your favourite subject.

 

Nick

[steelaway]

These take up to 15A complete with fuses. Clicky

 

Alex

[WotEver]

The Fridge cable connects direct to the battery bank (through an in-line fuse)

Exactly the same as ours.

 

I need a method of switch that doesn't introduce volt drop.

Why not just remove the fuse on the odd occasions you don't want the fridge powered?

 

Tony

 

edit to change "on" to "powered" as you can switch the fridge off locally if you just don't want it... umm, 'on'

Edited February 9, 2010 by WotEver