wiring a 2nd battery relay??

[iceteebone 5,000+ posts]

A true ignition switch is any wire that gets power when the car is turned on... get out a DMM and start searching... my scheme is actually quite simple btw //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

then the red acc. wire is a true ignition source then?

 

[jujumantb 10+ year member]

Here is a simpler version skipping the first relay, this does the exact same thing, but risks frying the deck's REM wire.

 

[jujumantb 10+ year member]

then the red acc. wire is a true ignition source then?

If it gets power when the car is turned on, yes. Again, get out a test light or DMM and test it out.

 

[iceteebone 5,000+ posts]

Here is a simpler version skipping the first relay, this does the exact same thing, but risks frying the deck's REM wire.

that's what i said in like my very first post and people said it wouldn't work.

 

[iceteebone 5,000+ posts]

If it gets power when the car is turned on, yes. Again, get out a test light or DMM and test it out.

if it gets power when the car is off, the radio would never shut off. i'll get out my light and make sure.

**edit** read post wrong

 

[jujumantb 10+ year member]

that's what i said in like my very first post and people said it wouldn't work.

The problem is that most deck's REM wires arent able to carry enough current to turn on that big relay, along with several amps, thats why I have that second relay you see in the first pic, they are like $2 at radio shack.

 

[djman37 5,000+ posts]

it's just that if you have enough gear in your car to WARRANT a second battery, you might run the risk of pulling too much current throught that little REM wire from your head unit, possibly causing MAJOR HU damage, or fire. A relay is a sure way that all audio equipment that requires a remote line will get enough current to turn on.

 

[djman37 5,000+ posts]

beat me to it.

 

[iceteebone 5,000+ posts]

but couldn't i tap into the red acc. wire in the car? not the rem on the headunit.

 

[djman37 5,000+ posts]

i've used a switched cig. lighter wire before. MUCH heavier than rem leads out of HU and would qualify as ignition source.

 

[OKLAGMCRUISER 10+ year member]

but couldn't i tap into the red acc. wire in the car? not the rem on the headunit.

by using the red acc wire the relay is activated when the car is on...

by using the remote turn on the relay is only activated with the stereo is on.

It really depends upon what you are hooking to the second battery as to whether you want the battery to be charging when the car or radio is on.

Pat