Head unit: Ignition or Battery

[Andyman]

To cut a long story short a ice company told me i should power the head unit from the battery not the ignition cos i wont get full power to the head unit if i run it direct off the ignition !!

Now everyone else iv spoken too, 2 of which are in the electrical / motor trade have never heard about this and say running off the ignition is fine.

So should my head unit be run off the battery or is the ignition fine to use ???

Oh yeah ive got a Alpine head unit



Cheers

 

[Dink]

battery.

people say its fine of the iso block but id rather be safe than sorry.

 

[Andyman]

What do you mean by safe ??? Is there a fire risk linking it up to the ignition ?? Soz im new to all this ice lark !! HeHe

 

[Dink]

well there is a good chance of you melting all of the cables in the loom together

 

[case]

the yellow wire should go striaght to the battery and the red to the ignition. the yellow wire draws all the current for the head unit then from the battery, and the red on the ignition will mean the head unit will only work with the ignition on. the red only draws a small current, it only acts as a trigger.

I know with my alphine head unit the manual and even the writting on the yellow wire said to go striaght to the battery.

Mark

 

[case]

if you did conect the yellow to an ignition wire behind the dash the wire probably would be able to cope with the current draw from the head unit and whatever its linked too, so neither would preform to there best and the wire would get very hot.

Mark

 

[case]

also dosnt the yellow wire provide a constant feed to the unit so it can store the settings, other wise everytime you turned the ignition off youd lose all your settings.

 

[Andyman]

Well at the mow its linked to the ignition but im not losing any settings when the ingnition is turned off

 

[Pete]

Depends on what power the unit is, some of the better alpine units need a direct feed from the battery.

 

[Dink]

yeah the yellow in the iso block is a perm +ve but i wouldnt like to connect my alpine to it

also you need to connect the negative from the hu to a metal part of the chassis(sp?)

 

[Andyman]

Quote: Originally posted by Dink on 02 January 2005

yeah the yellow in the iso block is a perm +ve but i wouldnt like to connect my alpine to it

also you need to connect the negative from the hu to a metal part of the chassis(sp?)

What do you mean the metal part of the chassis ?? Do you mean the cage the head unit sits in ??

 

[Dink]

no you need to connect it to a nut/bolt that goes on to the chassis of the car

 

[Andyman]

Im sure when a mate fitted my head unit the cable wouldnt be long enough to stretch to a nut or bolt linking to the chassis though ??

Where abouts have you fastened your negative to Dink ??

 

[Dink]

i installed mine when i had the dash off

so extended the cable to the bolt behind the dash

 

[BRUN]

right, if the Alpine you have, has got a seperate 12v wire on it, this must be connected to the battery, the normal plugs will just plug into the cars wiring plugs

if it hasnt got an extra 12v wire, just plug the wiring loom as normal into the wiring blocks on the car, and forget about it

 

[Lunner]

Quote: Originally posted by Dink on 02 January 2005

i installed mine when i had the dash off

so extended the cable to the bolt behind the dash

There is a -ve in the standrad ISo loom, this connects to earth (car chassis), absoloutly no need to extend the wire etc

 

[Dink]

well if the standard +ve isnt up to the job i doubt the -ve is up to job either

 

[Bryan]

Quote: Originally posted by Dink on 02 January 2005

well if the standard +ve isnt up to the job i doubt the -ve is up to job either

correct

if you uprate the +ve then its essential you uprate the -ve

no point allowing more power in to the unit than you can safely remove