New stereo (12v) into 24v - help please

[marmel]

Right I figure the factory reducer isn't got enough guts to power my new head unit which is a double din 7" touch screen model.

I have confirmed it works by running wires direct from one battery.

I guess I need to use a seperate reducer to power it.

I have found one online here:

http://www.precisioncarsound.co.nz/24v.htm

As it is from a car stereo outfit I am assuming you can use the main circuit (10 amps) to hook up to the ignition and the secondary circuit (.1 amp) for the constant connection which only needs to retain the memory etc?

Am I on the right track here?

Also how difficult is it to wire something in through the ignition, I had a bit of a look and it all seems fairly tight in there.

[chevrolux]

chuck the constant on the 10A supply. The 'ignition' wire is just a switching signal for the headunit to turn on. doesnt actually power the sucker.

[marmel]

Will it matter where I take the 24V from?

I was just going to splice into something near the stereo wires.

[chevrolux]

i guess it wouldnt matter too much. but you dont want a pissy little supply. maybe have a look around the fuse box for a feed with a bit of push behind it. im a toyota boy so not too sure. im sure one of the nissan guru's will let you know....

[bobrocket]

I wired my reducer direct to the battery (24v) for the constant and used an old 24v stereo/dash something wire for the ignition switch on the reducer.
I thought the ignition was just a switching wire as well

[marmel]

Don't you run into problems though wiring direct to the battery. I understood it will run one battery flat and can stuff both batteries and the alternator.

I think you can do this if you run a battery equaliser kit but then you are looking at $300 plus.

[DaveM]

Don't you run into problems though wiring direct to the battery. I understood it will run one battery flat and can stuff both batteries and the alternator.

I think you can do this if you run a battery equaliser kit but then you are looking at $300 plus.

I have always run extra reducers from the 24v battery.
You will only run one battery flat if you run a stereo or similar directly off the 12v battery. Hooking a reducer to the 24v is no different to the other factory 24v accessories etc being run off that battery IMO.

Of course, this is based on my very little knowledge of auto electrics, and just going by what I have tried myself, so someone may be able to confirm/deny?

[bobrocket]

If you use one battery as 12v then its bad as you have 2 x 12v batteries getting charged as 24v equally, if one battery is drained more than the other then the charging cycle gets messed up.

If you put a meter on the positive of one battery and the earth to something besides the same battery earth, then one of your batteries will read as 12v and the other as 24v.

I ran my constant from the battery that read 24v (positive) and ran the negative to the other battery (the 12v one).

I figured that if I'm getting 24v then I must be getting current from both batteries therefore draining both equally.

But this just how I did it, I don't if its the best/right way but it seems to work for me with no problems

[marmel]

OK got it sorted today.

went to the auto electrician and purchased a voltage reducer for $100. Provides a constant 10amps so is plenty.

The unit I got was actually a dual channel model which had the second channel for the 'memory' etc but the sparky told me to use the original factory ACC wire and just use the new reducer for the 12v constant. He also said to get the 24v power from somewhere behind the dash so this is what I did. I ended up splicing into the diff lock switch, hopefully this won't cause problems when I get stuck.

Anyway it is in now and working great.