Just brought a relay

[albertramsbottom]

From Motorworld (Disney World), as we dont have any shops where i live in the sticks.

Now im a bit confused by this relay as it says on the packet that it is a 20/30amp relay and on the back it says that the extra 87b is for an auxillary item. So will this relay be good for my lesure battery and my fridge?

I know there isnt much to go on here but I thought that someone might already be using a relay with an 87 and a 87b on it

Cheers

[albertramsbottom]

Make that 87 and 87a.

I suspect that the 87a is just another 87. Just like wiring up two wires from one 87 pin. If so would this be OK to feed my fridge?

Im just guessing here but I would have thought that when the engine is off the relay would discontect the 87 and 87a so the electirics would only take power from the LB. When running then the relay would switch so the power from the alternator would charge both batteries.

So I think I have answered my own question here as if I used the 87a for the fridge and didnt turn the frinde switch to hookup position it would run from the LB and flatten it. I really only need the fridge to use the alternator power when the engine is running.

So no the extra 87a would be no good for my fridge? Is that right

Paul

[bigherb]

Looks like you have bought a change over relay which has through connections between 30 and 87a when off and 30 and 87 when on. The two amp ratings are 30Amp for 30 and 87a and 20Amp for 30 and 87

[Red Westie]

That relay isn't ideal for a split charging (not really rated high enough at 30amps) and you won't use it as a change over.
Look at this page: with a standard (75amp/hr) single battery leisure (7 down will just about cover it, 40amp relay) if you want to use a large leisure/multiple batteries or connect the fridge diectly through a relay so it only works on 12v when the engine is running then relay (5 down, 70amp) or even 3 down (a bit over the top perhaps, 100amp but you might find it easier connecting multiple eyelets to a post rather than putting two wires in a large spade connector)

http://www.autoelectricsupplies.co.uk/product_list/36" onclick="window.open(this.href);return false;
Martin

[albertramsbottom]

Change over relay?

Well I am not sure what that is but yes it does look a bit flimsey. OK so I guess the 87a is the change over part and thats the bit that I wouldnt be using.

OK that sguys im gonna order a 70amp one, 4 terminals

Cheers

[albertramsbottom]

Do i need two if I am gonna have the fridge in this electical nightmare?

Most diagrams and advice seems to suggest that you need to two relays but I have just had a look at this diagram and it suggest just one

http://www.keithandsylvia.co.uk/tech%20 ... charge.htm" onclick="window.open(this.href);return false;

Any ideas

Thanks guys you have been more than helpful

[AngeloEvs]

Deleted as I missed the 70A upgrade but for reference...........

I would use these ....absolute doddle to wire up ...........http://www.towsure.com/product/1828-Sel ... tion_Relay

[Red Westie]

Nope....as it's a 70amp relay it's well up to delivering the 10-12 amps your fridge needs and the possible 30-40amps your leisure may draw. It will require two wires soldering or otherwise onto one large spade connector (one wire thick enought to handle upto 20amps the other upto 50 (both with seperate fuse holders (15 and 30 should do it but if you find the 30 blows you will need to up it to a 40) so you are going to need something like 2/2.5mm cable for the fridge (17/22amp) and 6mm (42amp) for the leisure. Thats quite large wire for the leisure (because of the current it is having to carry) so make sure the connections are up to the job. Personally I solder all my terminal joints.
Martin

[Oldiebut goodie]

Nope....as it's a 70amp relay it's well up to delivering the 10-12 amps your fridge needs and the possible 30-40amps your leisure may draw.
Martin

errrr.....

"it says on the packet that it is a 20/30amp relay "

[Red Westie]

Quote: OK that sguys im gonna order a 70amp one, 4 terminals... and... Do i need two if I am gonna have the fridge in this electical nightmare?
Is that alright for you?
Martin

[AngeloEvs]

I missed that 70 amp upgrade too.......wheres me specs.........

[tonytech]

Do i need two if I am gonna have the fridge in this electical nightmare?

Most diagrams and advice seems to suggest that you need to two relays but I have just had a look at this diagram and it suggest just one

http://www.keithandsylvia.co.uk/tech%20 ... charge.htm" onclick="window.open(this.href);return false;

Any ideas

Thanks guys you have been more than helpful

This circuit will charge the leisure battery and supply the fridge, BUT If the fridge is ON while the engine is OFF the fridge will run from the leisure battery, drawing up to 10A.
Most Batteries will only manage to supply a fridge for 4 hours or so. and seriously shorten your camping expeirience.

2 relays is the way to go.
T

[Oldiebut goodie]

oooerrrr

gallows[1].gif

Use the original for the fridge and the other for the leisure, pity it wasn't a voltage sensitive one.

[AngeloEvs]

It will at that (wot Tony spotted)....just looked at it.........

[albertramsbottom]

Do i need two if I am gonna have the fridge in this electical nightmare?

Most diagrams and advice seems to suggest that you need to two relays but I have just had a look at this diagram and it suggest just one

http://www.keithandsylvia.co.uk/tech%20 ... charge.htm" onclick="window.open(this.href);return false;

Any ideas

Thanks guys you have been more than helpful

This circuit will charge the leisure battery and supply the fridge, BUT If the fridge is ON while the engine is OFF the fridge will run from the leisure battery, drawing up to 10A.
Most Batteries will only manage to supply a fridge for 4 hours or so. and seriously shorten your camping expeirience.

2 relays is the way to go.
T

#

Bloody hell I nearly lost the thread here. Right so I def need two relays becuase I only want the fridge running when the engine is on. Thanks to everyone who has helped on this matter.

Sorry another question if I need two relays is the original 5 connector one I brought good enough for the fridge. ITS 30AMP so I WOULD HAVE THOUGHT SO - Sorry caps lock on

thanks