Is it possible to set up a 12v socket so it will only be live when the car is switched off? I'm guessing I'll need to take a perm feed live as per various threads on here and then have a relay triggered from a switched supply that will only move to the "on" state when the switched supply is off. Do such relays exist? I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
22nd Jun 2009 1:12 pm
Bodsy Site Sponsor
Member Since: 06 Nov 2006
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Yes they do, you need a switching relay as opposed to a switched relay.
Switching relay will have power coming through one output when off and through another output when on. so you just have one of the outputs wired up Bodsys Brake Bible
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22nd Jun 2009 1:14 pm
PaulP
Member Since: 04 May 2007
Location: Barcelona
Posts: 4317
Or in other words, you need to ask for a Single Pole Double Throw (SPDT) relay
You need to connect the new 'only on when ign off' power socket (or whatever) to the Normally Closed (NC) contact so that it allows current to pass when the relay coil is not 'excited'.
When power is applied to the relay coil (probably taken from another ign switched socket), it will switch over to the other pole (which you probably won't connect anything to) and therefore disconnect the power to your new socket.2006 Discovery 3 TDV6 SE AutoBuckingham Blue 2007 Golf GT DSG
22nd Jun 2009 1:24 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
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No Del, this is to wire up two solar panels so that they only connect to the battery when the car is switched off.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
22nd Jun 2009 1:28 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72787
That's the kiss of death for a sunny summer down souff!!!
22nd Jun 2009 1:31 pm
jkp
Member Since: 17 Sep 2005
Location: Living among Bawbags
Posts: 4528
Do these panels not have a gate/diode in line, so if the engine is running/ignition on, nothing will flow 'up' to the panels, but only allow current to flow down to the battery when ignition off ??
Although my basic education in electronics is a bit rusty, so may be talking complete drivel, as usual.
Only reason I say that is I seem to remember someone on here doing that a while ago. Kit from Maplins or the like, which just plugged in and left all the time
Yeah, it has a diode to prevent reverse flow, but it also has a warning in the bilge that comes with it stating that you shouldn't leave them connected when the engine is running.
Not being an electrickeral jeenyus I presume this is because your diode will explode into a million razor-sharp shards, each as hot as the sun, all off their heads on WKD and spoiling for a fight. Or something.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
ND - probaby the "or something" option - hope this helps "To finish first, one first has to finish ...."
22nd Jun 2009 7:49 pm
XX03
Member Since: 03 Sep 2006
Location: London
Posts: 474
At £9.99 Alan....try blowing one up , it might be cheaper to see than buy and wire the relay. It will save us all having to do the experiment.Formerly Blakey
You've both been an enormous help. Either of you want to sling me £12 for a solar panel so you can test them in your cars? Not sure an 08 SE in Zermatt is "typical" enough to provide valid results in this experiment. Something a little older in a higher spec or perhaps fractionally newer, but a little darker will provide more a more appropriate basis methinks?I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
I've bought the bits and everything. I would say - "I'll fetch my coat . . . . . " but that will start a whole new line of abuse "To finish first, one first has to finish ...."
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, it might be cheaper to see than buy and wire the relay. It will save us all having to do the experiment.
