Two way relay?

[Nij]

Hey.

Just wondering if there is such a thing as a two way relay (2 input 1 output).
I want to put a 12v socket that when the ignition is on (engine running) it runs from the cranking battery, when parked up it will run from the leisure battery.

Hope that makes sense.

Nij

[bigherb]

You just need a changeover relay.
Connect pin 87 to the starter battery via a fuse
87A to the leisure battery via a fuse
30 to the socket
85 & 86 to earth and an ignition switched live.

[syncroandy]

You need a 'single pole double throw' relay. See here. They have 5 pins vs the usual 4 for 'single throw' ones, 85 & 86 (coil), 30 (input), 87 (normally open output), 87a (normally closed output).
An example of a VW SPDT relay is 321 919 505 A.

[California Dreamin]

Seems to be a pointless modification: If you have the normal split charge setup? connect this socket to the leisure battery and you will have the same result ie:
Engine running will take it's power from the both batteries/alternator AND THEN.... with the engine turned off....it will be taking it's power from JUST the leisure battery.
I take it the whole point of this is so you don't flatten the starter battery whilst camping? thats why you have a split charge relay......

YEAH!

Martin

[Nij]

Cheers people

Martin, I thought that......thats the new plan