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Needing advice Wiring head unit to leisure battery

Posted: 15 Jul 2006, 22:51
by weejoe
Gidday all :)

Just getting the van the way I need it for my trip at the end of the month.

WRT hooking up the head unit to the leisure battery

1. Can I simply run a live cable (Fused) to the H.U from the battery ?

What my thinking is, it would run off the battery when the van is parked up.

When the van is on the move and the alternator is charging the L.B, power to the H.U would still come from this cable but would infact be routed from the alternator as source.

Oh and I guess yee olde wiring won't have a constant live cable for the H.U memory, again can this be sourced of the same cable ?

Does that sound about right or is there a simpler means of hooking up the H.U to the L.B ?


Cheers 8)

In my best Oirish accent

"There's more".............



On a similar note I've bought a flush mounted Cigar lighter type socket to wire into my L.B

My plan is to Charge/power my Laptop and/or Mobile phone when on the move or when stationary.

I have an car adaptor for the laptop, it steps the voltage up to 19V 3500mA

What size of fuse would ya'll recommend in this circuit. ?

Anyone with a similar set-up ?

I'm sure my L.B is a 70aH one

Any idea how long a Laptop can be run on this without damaging the battery by draining it too much. ?

So many questions in one thread

Sorry I'm a Newbie :oops:

:wink:

Posted: 16 Jul 2006, 00:45
by Hacksawbob
Howdee Joe
as for your HU Q yes that all seems OK. fused (near battery) run the cable to HU all good.
However there is a slight suggestion that if you run the "ignition live" signal to your switched live ignition wire ( in a standard ISO plug) you could potentially be "leaking" good volts from your driving/leisure battery via head unit without realising it. (cos the engines not running you think the batteries are separated by your alternator switched solenoidbut they are linked via the HU.) just make sure you get ALL the positives going to your LB from your HU + AMP. That way you can drive away even if you have no tunes.

Posted: 16 Jul 2006, 02:59
by weejoe
Cheers Mucka :D

So I'm right in saying that as long as my alternator-to-LB charge circuit works fine (ie isolates the LB from the Starter Battery via the relay) and I run both the +12V power to HU and the memory power strictly from the LB then all should be well.

Posted: 16 Jul 2006, 07:53
by DiscoDave
yeah, if your running the heed unit from the leisure batt you'll want to join out the red and yellow wires, this way you only have to run one cable to the head unit. for your cig lighter arrangement you'll be needing some nice big fat wire and then try a 10a fuws. if the charger has an out put of 3.5 amps i would guess that the input will be slightly higher on the 12v side!

good luck

Posted: 16 Jul 2006, 14:28
by weejoe
Cheers Dave :)

I'm strugglin to think of anywhere local that I can pick up any decent cable

Any suggestions anyone ?