Nissan Murano Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
466 Posts
Discussion Starter #1
Has anybody ran some power wire from the battery yet? I'm trying to find the easiest route to run it.
 

·
Nissan Enthusiast
Joined
·
197 Posts
There is a small rubber grommet beneath the brake cylinder assembly that is not used. I used a wire hanger to poke a hole into the grommet and fished a wire thru it. The rubber formed a tight seal around my wire.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #3
Hmmm....I'm gonna have to take another look....I didn't see a small grommet, just a big a$$ one in the upper left hand side of the engine bay. Thanks!
 

·
Registered
Joined
·
129 Posts
Wire to where ?

If you want to run an amp in the back.


There is a 30 amp circuit that runs to the spare tire area left side back that is suposed to be used for the trailer harness but for some reason I think most dealers just run a new wire back from the battery for this pupose. The bozos that put mine in did anyway, not to mention they used the wrong size blue snap on wire splices so that my trailer lights failed on a road trip. A very understanding state trooper in Pasco Washington gave me a by on a ticket and I fixed it the next morning but I decided there and then that the dealer in question would never touch my MO again.

Fuse for this circuit is in the small panel to the right of the air box under the hood.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #5
I'll need more than a 30 amp circuit. I will be running at least a 2AWG wire, if not 0. Two amps total putting out around 1,100 watts RMS.

Anyway, I will look for the plug just below the brake cylinder tonight. I was going to the other night and was side-tracked. I have decided to swap out everything except the head unit (of course.) I will let you know all the tricks I learn while doing this that are specific to the Murano as well. If you know some, PLEASE POST so it can be easier on me. I have installed systems before in the past, so I know the basics of audio installation, but I've never ripped apart a Murano. :)
 

·
Nissan Enthusiast
Joined
·
197 Posts
Number "0" wire? Hold on...Zero guage wire can handle 800-1200 amps of current @ 36 volts. You aint gonna be anywhere near 300 amps at 12volts. If you are pulling down 800 amps I guarantee you are melting a cell in that Nissan battery and the alternator is going next.......I am sure the warranty folks are gonna have a good laugh at that one. Good look though. I like your style. Make sure you put some large capacitors in the power line.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #8
generator said:
Number "0" wire? Hold on...Zero guage wire can handle 800-1200 amps of current @ 36 volts. You aint gonna be anywhere near 300 amps at 12volts. If you are pulling down 800 amps I guarantee you are melting a cell in that Nissan battery and the alternator is going next.......I am sure the warranty folks are gonna have a good laugh at that one. Good look though. I like your style. Make sure you put some large capacitors in the power line.
Well, with my experience in the past, capacitors do not do well with Class D amps, which I have one of for the subs. This amp is supposed to be extremely efficient--somewhere around 83%. In any event, if I am pulling 1,100 watts constant power, what size wire do you think I should install from the battery? I know 0 or 2 AWG seems like a lot, but remember the longer the wire, the harder it is to draw power from, thus creating a bottleneck effect in terms of how much power the amps will be able to draw from the battery.
 

·
Nissan Enthusiast
Joined
·
197 Posts
Honestly if you are pulling that kind of amperage you shoudnt be doing directly off of your primary battery. You should be running a time/voltage splitting isolation block (available at any Motorhome supplier) to a marine/deep cycle battery in the rear. The isolation block usaully splits the availably current from your alternator in a 60 / 40 ratio. It also isolates your main battery from the others when the cars is not running so no need to worry about dead main battery after listening to 5 hours of music at the beach.


And the caps will work. I need one to keep my dashboard lights from dimming. Worst case you run 1 or 2 guage. Look at all your amps. The fuse on them will tell their tale. You probably have a main slow blow fuse of 30-50 amps on each amp. So that means if you have three amps running your average consumption may be around 150 amps. If your amps are efficient the transients may temporarily double that figure. 2 guage wire for 150 average and 300 peak amps @ 12 volts is more than adequate.
 

·
Nissan Enthusiast
Joined
·
197 Posts
I am really curious how much current you will be pulling....If you know anyone with an amp clamp tell them to check the draw while coinnected to a battery and speakers.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #11
I'll be using MTX amps. The 801D for the subs (800 x 1 dynamic power @ 14.4 volts), and the 684 for the mids/highs (85 x 4 Dynamic @ 14.4 volts).

The 801D has three 25 amp fuses and the 684 has three 30 amp fuses. I can see using around 60 amps of draw from the 801D, and roughly 45 amps from the 684 because I won't be lowering the impedance on the 684.

Do you think this is a good guestimate?
 

·
Registered
Joined
·
466 Posts
Discussion Starter #13
generator said:
Sounds like you will be under 300 amps during transients.
What size power wire do you think I should run? I would think hat 4AWG would be too small. What size main fuse should I run also?
 

·
Nissan Enthusiast
Joined
·
197 Posts
Based on my calculations you should not need more than 2 guage. Voltage drop on 2 guage cable over 12 feet is negligable.
and it can handle some monster current. You have to beat the crap out of that wire to get it to get warm. Trust me I know. I am a tech for electric vehicles, and it is not unusual for me to see 300 amps going thru a 2 guage cable.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #15
Great. I think I have decided to use different amp because of certain features I need. That being said, the max RMS power consumed would be around 1,000 watts, with brief surges at no more than 2,000 watts. I am looking into getting Kicker amps, and I spoke with a rep today from their company. The Class D amp that I spoke about, is roughly 85% efficient at 1/3 volume, unlike Class A/B amps, which are around 50%. The more volume is turned up, the less efficient the Class D amp is, eventually getting to become the same efficiency of a Class A/B amp at FULL power.

Also, Kicker has, in their owner's manuals, recommended power wire for the specific amps. The only problem is they don't provide what the power wire should be when using more than any one amp.

For my sub amp, it is the 600.1 in which they recommend 4 AWG wire, with a 60 amp main fuse. For my mids/highs amp, it is the 600.4 in which they recommend an 80 amp main fuse and 4AWG. With this amp, it will be only running at 4ohms stereo, so this will definately not draw the power it's capable of.

So, I guess the main fuse would be 140 amps, while the power wire will be 2AWG? Could I get away with 4AWG?
 

·
Nissan Enthusiast
Joined
·
197 Posts
I stole the following text from a Kenwood Website for your pleasure. Looking at a reference table for wire guages I see that 2 guage is recommended for 1000-1100 watt applications (continuous; you aint listening to a continuous stream of 1kilowatt music dude). If what you say is true then I would be going with 2 guage and running two monster caps.


**************************************


You need enough power cable to run from your car battery's positive terminal through the engine bay to the amplifier. Make sure you fit an in-line fuse or circuit breaker near the battery. Without one, an accidental short circuit could damage your amplifier, not to mention the possible fire hazard.

You also need another length of the same grade of cable to serve as your earth wire. This should be kept as short as possible by making your earthing point as close to the amplifier as possible.

The final power connection you need is a 'turn-on lead'. This one does not need to be as thick as the power and earth wires (6 amp wire should be fine). It runs from the remote turn-on outlet at the back of your radio to the remote terminal on the amplifier. When connecting these wires, be sure to use crimp-on blade or eyelet terminals to make the tightest, lowest resistance connection.

The audio signal travels from the back of your radio to your amplifier through an RCA signal cable. Your signal cable should be long enough to reach the amplifier but not too long, as this will tend to become damaged and pick up interference and electrical noise.

At the output side of the amplifier, you'll need speaker wire. Generally the thicker this wire is, the better. Keep in mind that the thicker the wire, the less of your signal will be absorbed by the copper.

What size power and earth wires do I need for my amplifier?

Before you can determine the appropriate grade of wire for your system's needs, you need to calculate the current demand of your equipment.

To do that, you must determine the approximate current draw (in amps) of your amplifier(s). To do this:

*

Calculate the total power of each amplifier (multiply the number of channels by the number of RMS watts per channel)
*

If you have multiple amplifiers, add up the total power figures for each amplifier to arrive at a grand total
*

Next, double this total power figure to arrive at a peak power figure (RMS gives you an average figure)
*

Finally, divide by the 13.8 volts of your vehicle's battery - the result is your system's approximate current draw in amps.

Make sure the cable you use can easily carry the maximum total current drain of your system.

Where should I earth my amplifier?

Your earth wire should be of the same gauge as your power wire and must make direct contact with the body of the car. Look for an existing bolt or screw that makes contact with the car body near the amplifier. Remove the bolt or screw, and scrape away any paint or grease.

A star washer will help your earth wire maintain tight contact with the car body. Use a eyelet terminal on the end of the earth wire, to keep it securely fastened to the bolt or screw.

If you can't find a convenient earth screw or bolt, drill a hole for one. Be careful not to drill into the petrol tank, a petrol pipe, or a brake pipe!

If you're earthing multiple components, try to earth each one separately, with about a half-inch of space between each of the earthing points. If you'd rather use a single bolt, place the earth for the most current-hungry component (probably the biggest amplifier) closest to the body of the car. Put the earth for the component that draws the least current (probably the electronic crossover) on the top.

*******************************************
 

·
Registered
Joined
·
466 Posts
Discussion Starter #17
It's been a while since your last post....I've been kinda busy trying to figure out the size wire

As far as the RMS wattage....

MTX 801D is rated at 500 watts RMS @ 12.5DVC
MTX 684 is rated at 240 watts RMS @ 12.5DVC

Total wattage = 740 watts RMS

Dynamic power (brief music peaks) is 1,140 watts.

If I use the formula for estimated current draw, I come up with 107 amps. (Using RMS wattage above.)

I think I should be okay using 4AWG wire.
 

·
Registered
Joined
·
466 Posts
Discussion Starter #18
I ended up using 1/0 guage. It's on order and will probably install it next weekend...
 
1 - 18 of 18 Posts
Top