Hi all
Yesterday put a sub under my bed an amp run the power from the battery through the loom into the cab done the wires behind the headunit then got to the earth wire an that’s when I came to a stop where do people earth or where is a 12v Earth this is the first time trying to put this in a wagon done loads of cars just struggling with this bit it a 105 daf xf thanks for your answers
Can you not run the earth cable under the floor mat and screw it into the floor?
Or across the cab and onto the door hinge?
Did try the hinge as in a car it’s a earth tryed it in the truck an no joy is this because it’s 24?
Are you running the power for the amp direct from one of the batteries?
If so is that likely to cause an imbalance over time, leading to one flattish battery and one getting charged too much?
Yes running it direct from one battery,is there another way?
It used to be frowned upon when running a standard Motorola or Radiomobile radio, 5w max per its single channel, from one of the pair of batteries.
I’d rather run it through a 24 to 12v dropper, or buy a 24 volt amp if such a thing is available.
Hopefully one of the regular mechanics here will spot this thread, and either advise you accordingly or tell me i’m talking out me arse, usually the latter… 
Ok mate nice one I will see if a 24v amp is about but ain’t holding my breath I’ve been reading about these droppers how do these work?
Bulldog1986:
Did try the hinge as in a car it’s a earth tryed it in the truck an no joy is this because it’s 24?
Im auto electrician so dont take my word for it but I think earth is earth, regardless of a 12v amp running off a 24v system as the earth is just needed to complete the circuit.
Was the paint fully scraped off to give a good connection?
I just put the earth wire on the door lock just to make sure it was all working,as I was told that it’s a deffant earth
earth is earth, it doesn’t matter the voltage
Bloody hello OP are you partially deaf, how much volume do you need. 
That said im guilty of whacking up the volume to 11 when a banging track comes on (especially 80’s disco tunes), so is the sound quality good with a sub woofer under the bunk. Im interested coz I wouldnt mind spending a few quid on a few extras in the truck for entertainment purposes.
what sub do you have ? .
As far as earth goes, just splice into another earth cable.
Ok mate will ave another look when I’m parked tomorrow see if I can get it going where is the best place to get the earth?
Dipper_Dave:
Bloody hello OP are you partially deaf, how much volume do you need.That said im guilty of whacking up the volume to 11 when a banging track comes on (especially 80’s disco tunes), so is the sound quality good with a sub woofer under the bunk. Im interested coz I wouldnt mind spending a few quid on a few extras in the truck for entertainment purposes.
what sub do you have ? .
No Dipper. He`s talking about a sub woofer not the sort of “sub” you use for entertainment purposes. Or does woof mean summat else again?
It’s a pioneer 1400w sub an 1600 watt amp it makes the sound of music a 100 times better if you like bass that is
And where would I splice into a earth cable
Bulldog1986:
And where would I splice into a earth cable
Firstly, I wouldnt recommend doing too much without clearing it with your boss. Many will pay for equipment to be fitted rather than have the drivers DIY it. Safer for them, easier for you. If not the obvious earth point is where the batteries earth strap is. Youve said you have a cable running into the battery box already ? If doing that then ensure youre using suitable cable diameter and that its fully fused. Cable for a 1600w amp is gonna be thick and may be capable of igniting any thing stored under the bunk if it shorts.
Tbh I’ve already send to myself let the pros do it my boss is alright with that sort of stuff
Bulldog1986:
Tbh I’ve already send to myself let the pros do it my boss is alright with that sort of stuff
Fine, no offence etc. You`ve obviously thought of that, but I would have felt guilty not pointing out the idea.
Yeah sure you would mate it’s ■■■■■■■ me off tho because I’ve put loads of sound systems in cars but can’t seem to get it working in a wagon
Think youll find a Hella plug on the passenger side of the floor level tray of a 105. Thatll be 24v so simply plug in on of the 24/12 droppers Juddian mentioned. Assuming its a high enough rating thatll be a fused supply wired thro the key. And easier to remove when moving on. If not a high enough rating, then back to original plan. I would have doubts about that socket`s rating tho, 1600w at 12v seems a big draw??
Stop me if Im wrong here but 1600w at 12 volt would mean drawing a current of 140amps?? That cant be right can it? Someone please tell me where I`m going wrong. Normally enough volunteers to point up mistakes here.