What type relay

[hobbit]

Ok here's oen for you sparky's

Trying to wire a recover light beacon in at the mo, no probs, but
needs powering on one switch, but the unit has 2 circuits to run, one full power to run with the engine running, and a low power circuit for when the engine is off

I know it needs an auto switching relay but cant think of the type, one that will automatically switch the power from a charging circuit(high powered) to battery (low powered)

and also be able to be turned off on one overall switch

Just cant get my head round this at the mo

Hope this makes sense :?

[ChrisW]

Is it two circuits in the light bar or one?

Engine running - circuit one on / circuit two off
Engine off - circuit one off / circuit two on

OR

Engine running - circuit on supplied from alternator
Engine off - circuit on supplied from standby battery

[Hissy]

Lights, Switches, Relays Mmmmm  :shock:  :shock:  :shock:
Now that sounds complicated  :?  :?  :?  :?
You'll be needing an electrician then      

[hobbit]

Is it two circuits in the light bar or one?

Engine running - circuit one on / circuit two off
Engine off - circuit one off / circuit two on

Yes Chris

This one, the bar has two feeds in

[Elmo]

If I'm understanding your requirement properly, you need a 5 blade switchover relay.

Vehicle wiring products do them for £3.13 +VAT +postage which can handle 20 amps, if you need more they are probably available but I can't give you a link.

http://www.vehicle-wiring-products.co.uk/VWPweb2000/relays/relays.html

Piccy attached.

Basically attach one circuit to the 87 output, another to 87A.

Force the relay to switch on engine running by firing it from the alternator warning light feed to the dash.

You'll need an override switch as in this scenario the "engine off" feed will run regardless i.e. always.

best guess as to actual connections (without seeing bar or car :) ):

Battery - fuse - override switch - terminal 30
Output to beacons (low) - 87A
Output to beacons (high) - 87
Alternator sense (tap from alternator brown/yellow wire or intercept under dashboard/column) - 85
Earth - 86

Hope this is (a) right and (b) helps

[gtomo2]

top tip time
most 1990 rrc have these relays fitted as standerd (small metel cased ones) with 5 pins

[hobbit]

sounds about right.
I was looking at them but just couldn't get my head round it, got to be worth a punt though

VWP is on my doorstep, mind you so is a man with lots of landy parts too, so more than likely to there first

Will have a go after the weekend and try the layout

Thanks for that :lol:

[imspanners]

Just to throw a spanner in the works, the low power version is for night-time use. So you don't blind people with 55w bulbs flashing round.  8)

[hobbit]

Hmmm spanners and electrics, oh yeah that the slow blow fuses aren't they :lol: I find a nail a good remedy for that though :?

Just wired a 12 to 24v charging unit in the motor yesterday, found the aux battery flat this morning, turned out the aux charging relay for that battery had a bad connection on it too

All good fun arn't they :lol:

The only worry was flattening the battery with the top lights on when parked up, they have a reducer to cut the power drain down if you are not running on tickover, good thing as they run 2x50w halogens in the beacons on high power