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View Full Version : Using a relay for remote turn on

jessewilliams
08-23-2012, 06:39 PM
In my car stereo system that is currently in work, I have 2 amplifiers, a Bluetooth adapter, and a backup camera that all require the remote turn on coming from the head unit.


I couldn't find a definitive answer on the current draw for the remote turn on for the amplifiers but the general consensus is that its around 50mA. 2 amplifiers = 100mA.


With the Bluetooth adapter once again, I am not entirely sure what the current draw is and am waiting for JVC customer service to get back to me.


Finally, the backup camera that I plan on getting has a current draw of 300mA.


So my JVC KW-AV50 remote output is only rated at 400mA... with only the amplifiers and the camera I am already approaching the limit of my head unit.


My idea is to use the remote out on the HU to simply switch a relay that would in turn switch a direct 12V to the amp remote turn on's and the devices...


Any thoughts? ideas?


Also, I realize now that I need a power supply so that I can test these items on the bench in order to determine things like current draw!
derickveliz2
08-25-2012, 02:24 AM
I may be wrong, but you can use the same remote for more than 2, 3 or 4 devices. It's only to turn them on/off. The power comes from a separete 12v wire from Battery for each device!

D.
jessewilliams
08-25-2012, 09:34 PM
Nope, the Bluetooth adapter and camera each have a single 12v lead, no remote turn on...
CTScott
08-25-2012, 09:46 PM
You could use a relay and connect the output of the HU to one side of the coil and the other side of the relay coil to ground. Then you take the common terminal of the relay and connect that to the ACC power wire of the radio harness and connect the normally open terminal of the relay to your three devices.
jessewilliams
08-25-2012, 10:56 PM
Any idea on a brand? part number?
CTScott
08-25-2012, 11:02 PM
Any idea on a brand? part number?

Any relay with a 12 VDC coil will do. The simplest thing is to pick up a "standard automotive relay" with a wired socket from your local auto parts store.

It will look like this:

http://www.tmrmzine.com/ebay/images/12vp-rsoe.gif
derickveliz2
08-26-2012, 02:27 AM
Nope, the Bluetooth adapter and camera each have a single 12v lead, no remote turn on...

Then you can't use the remote directly from HU, follow CTScott's suggestions.

In my case the remote from HU turns on 3 amps and a CD charger. But each one has a separate 12V input for power.

D.