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[ian warren]

I am looking to install a new ICE system in the car but a bit different from the norm. The idea is to have a mac mini in it.
My problem is the power, this is some time away but I am trying to get my head completely round it, soon it will be looking at exactly how to wire it up (although I do have an idea or two).
I am thinking of putting in the mac (85 watts continuous power)
FLI 800 AMP (4*100) to power 17cm in front and 6*9S
FLI 10 or 12" active sub 250 watts
screen (at a guess 50 watts)

So this is a total of about 800 watts (not massive I know but their is a bit of thinking to do yet)

Ok first things first, not the best sound system but I do not have a shed load of money to put to this and speakers/amps can be upgraded in the future if wanted, this i am sure will be better then what i have at the moment which is 13cm infinitys in rear and Fusion speakers in the front.

I am thinking the alternator (75A by the info on this site) will probably just be big enough to power the lot making me happy although if you think different and a bigger alternator is needed please tell me.

Aas I am whipping out the head unit I currently have I am sure i will be able to power the screen from the cables in the dash so that should be fine.

The next part is the size of wires.
Right now I am thinking of running one main cable from the battery to the boot where the install will be, computer amp and sub. From here I can split the cables and I am happy to use the recommended sizes to go from a distributer to the devices (6 for the amp and sub, 8 for the comp)
My question is what size cable will be needed to go from the battery to the boot?

Something to take into consideration is on the battery too. The mac goes into sleep mode and draws a constant power, apparently people have has their macs on for two weeks in sleep mode though (without starting the car) with no problems. It has me a little worried and starting to think if a second battery even though the power supply (carnetix 1900) does have a cut out switch. I will probably try just one battery first and have a look at a second if needed (prefer not to do this due to finding a secure way of storing the battery.

So to summarize do you think the stock alternator will be fine and what size cable do you reckon will be needed to run from the battery to the boot?

Is their anything else I need to take into consideration that I have missed?

thanks for any help and sorry for the long post. This is not a throw away idea, I have thought about this for a while so I do have most things sussed (in my head anyway), powering it from a car is new to me though

 

[Jayfish]

can't answer all your questions but running a second battery is definitely in your favour, a relay to ignition live can cut the circuit from the main battery to the second, so it will charge with ignition on and with ignition off it will only drain power from the second battery. if you are putting a battery inside the car it has to be a dry cell battery as lead acid batteries give off hydrogen whilst charging, explosive gases in confined spaces are not recommended

I ran a PC in car for sometime and used a similar setup to the one you are proposing, the current alternator will do the job, but the draw will be fairly close to it's limits, if you do lots of short trips you may find you end up with a flat battery, an upgraded alternator might be wise.
I wired my touch screen into the wiring for the cigarette lighter as the power draw is low and it is already an ignition live circuit.

Hope this helps.

 

[ian warren]

thanks, it does help. Looks like second battery meaning I will have to re thing wiring a bit. I take it I would hook up the battery into the electrical system and then connect all the parts to the second battery?