Running multiple 12v accessories off one power source?

[GlanzaAtHeart]

Hey everyone,

I'm looking at wiring up 3 gauges (Air Fuel Ratio, Oil Pressure, and one other), and possibly another lighting accessory which will all need a constant 12v circuit.

Is it possible to wire them all into the 12V accessory socket? Or should I wire them in a different place, like the radio power? Or will I have to wire each 12V accessory to a different 12v power source?

Unsure what I can and can't do. I still want to use the 12V accessory socket as normal for USB stuff.

Any insight would be greatly appreciated.

[Mr-Paulio]

You can run as many accessories as you want off one circuit as long as the total current of all those items isn't more than the fuse for the circuit. And you can't just put a bigger fuse in as the fuse protects the wiring from melting under high load. And you don't want more melted wiring aye?
So just total up the running amps of each. If its new they should be supplied with that data. If not you might have to mesure them when on.
Hope that helps

[GDII]

What he said!

[GlanzaAtHeart]

You can run as many accessories as you want off one circuit as long as the total current of all those items isn't more than the fuse for the circuit. And you can't just put a bigger fuse in as the fuse protects the wiring from melting under high load. And you don't want more melted wiring aye?
So just total up the running amps of each. If its new they should be supplied with that data. If not you might have to mesure them when on.
Hope that helps

Oh please no more melted wiring, especially under the dashboard

Oh okay, so I would be safe, provided that the accessories I'm wiring in aren't overdoing it in terms of current draw. All but 1 of the accessories are new, but one of them isn't provided with an amp draw.

Would I just be best off running a secondary power wire from the battery, like car stereo amp wiring kits in most cars? Get one of those for ~ $30 and then use the power wire with an inline fuse? Probably the best way to do it now that I see that the wires behind the 12V socket aren't exactly thick. Just gotta figure out how i'd run it from there to only turn on when the car is running.

Thanks for the help - Didn't know it was only current that is the killer!

[Benckj]

What you need is a standard 12v 20amp relay. They will have 4 pins;
1/ Battery power +12v
2/ Ground
3/ Trigger ( use 12v that comes on with ignition like cig plug )
4/ 12v supply to all your accessories.

Make sure you install an in-line fuse to the 12 v supply rated to your wire gauge. I’m sure Phil can post up a link and pics on hi to do.

[GlanzaAtHeart]

What you need is a standard 12v 20amp relay. They will have 4 pins;
1/ Battery power +12v
2/ Ground
3/ Trigger ( use 12v that comes on with ignition like cig plug )
4/ 12v supply to all your accessories.

Make sure you install an in-line fuse to the 12 v supply rated to your wire gauge. I’m sure Phil can post up a link and pics on hi to do.

Ahh doing some research, this is perfect! Thank you!

Something like this will be exactly what I need.

I have some supercheap auto credit too, so I'll get one of these: https://www.supercheapauto.co.nz/p/trid ... CN01060705

I'm sure I can figure out how to wire it all up - Phil has been helping me more than enough already

Thanks Jim, this has been a huge help.

I'll post up some pics in the next week or so when I get all wired up.

One last quesiton however, the trigger - I presume I splice into the positive 12v source of the ciggarette lighter?

[Benckj]

Yes, that will work fine. Never seen one with a fuse included with relay. Hooking trigger to cig lighter is fine as I’m pretty sure this is energised with ACC rather than IGN. Just depends on what you want as can always pick a fused supply in kick panel to use. Just make sure you get a couple of insulated spade connectors to terminate into relay.

[GlanzaAtHeart]

Yes, that will work fine. Never seen one with a fuse included with relay. Hooking trigger to cig lighter is fine as I’m pretty sure this is energised with ACC rather than IGN. Just depends on what you want as can always pick a fused supply in kick panel to use. Just make sure you get a couple of insulated spade connectors to terminate into relay.

Yeah female spade connectors will probably be the go. I might solder in the 12V supply to the accessories as I might wire in a few.

Thanks for the advice Appreciate it! Answered all my questions perfectly