C5 X7 amplifier power cables, trunk ground point

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raqall
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Joined: 02 Feb 2020, 10:14
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C5 X7 amplifier power cables, trunk ground point

Post by raqall »

Hello fellas!

I am building a custom car audio system in my 2008 C5 X7. I installed the JL Audio's e6450 6-channel amplifier in the trunk where that "cloth-basket" was initially, on the left side. Now it is time to power it. The thickest power cable that fits into amp's socket is 25 mm² - that's what I bought (100% Copper cable, OFC, not CCA). The amp requires a 60 A fuse.

I am going to pull the positive wire through the firewall using a water-sealed grommet and install a 60A fuse near the positive terminal of the battery. Now the question I have is:
Shall I:
A) pull another (negative) wire through the firewall straight to the amplifier at the back
or
B) use a factory grounding point (I located one near the seat-belt tensioner at that top shelf of my Saloon)?

Will B) impact the electronics in the car somehow? The obvious drawback of A) is that I would have to fish 2 wires instead one. #-o

wheeler
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Re: C5 X7 amplifier power cables, trunk ground point

Post by wheeler »

I haven't had a close look but im sure there will be an earth point near to where you are installing, probably for the rear lights. If not you would be far better off making your own earth point rather than run a separate cable from the battery.

Also be very careful where you pass the wiring through, I've seen may BSI units written off due to water ingress caused by poor installation of wiring through the bulkhead, The favourite on the Mk1 C5 was wiring for taxi meters being passed through the rubber grommet for the main wiring harness which was located right above the BSI.
EDIT: Original earth location picture added. This is for a saloon model, let me know if it's an estate.
Attachments
X7 Earths.jpg

raqall
Posts: 16
Joined: 02 Feb 2020, 10:14
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Re: C5 X7 amplifier power cables, trunk ground point

Post by raqall »

wheeler wrote:
04 May 2020, 13:57
I haven't had a close look but im sure there will be an earth point near to where you are installing, probably for the rear lights. If not you would be far better off making your own earth point rather than run a separate cable from the battery.

Also be very careful where you pass the wiring through, I've seen may BSI units written off due to water ingress caused by poor installation of wiring through the bulkhead, The favourite on the Mk1 C5 was wiring for taxi meters being passed through the rubber grommet for the main wiring harness which was located right above the BSI.
EDIT: Original earth location picture added. This is for a saloon model, let me know if it's an estate.
Image
Thanks, great image!
My car is LHD, though I believe those locations are the same, especially at the trunk.

I have already made use of MC40 ground point, I installed the DSP there :D

On the other hand, why would they fish new wiring for those taxi-meters? I would just use a fuse-tap.

wheeler
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Re: C5 X7 amplifier power cables, trunk ground point

Post by wheeler »

raqall wrote:
04 May 2020, 15:52
My car is LHD, though I believe those locations are the same, especially at the trunk.

I have already made use of MC40 ground point, I installed the DSP there :D
I Selected LHD when I got the diagram, but I imagine they would be the same.
raqall wrote:
04 May 2020, 15:52
On the other hand, why would they fish new wiring for those taxi-meters?
Good question, I would use a feed inside the car too. The Mk1 C5 has been around since 2001 thought & piggy back fuses weren't that popular back then.

raqall
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Re: C5 X7 amplifier power cables, trunk ground point

Post by raqall »

Actually my parents have the mark 1 since brand new in 2004, I'll be installing some aftermarket rear-view camera and parking sensors real soon :D

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white exec
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Re: C5 X7 amplifier power cables, trunk ground point

Post by white exec »

If I read you right (and I might have misunderstood)...
25mm²/60A-fusing for the power cable, and original cabling for 100mm/4-inch door speakers?
#-o

raqall
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Joined: 02 Feb 2020, 10:14
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Re: C5 X7 amplifier power cables, trunk ground point

Post by raqall »

Well, yes. Actually those speakers are 165 mm.

I initially planed to go with some smaller/cheaper amp but I needed 6-channel amplification and that JL Audio was at a bargain price, so I bought it. Now I need to power it :P and it requires such power, that's why such a cable is needed.

I have everything done by now except for fishing that power wire, which I feel is the most cumbersome task of the entire process :/.

Already done: (RNEG2 install, car audio upgrade):
  • RNEG2 screen with its bezel and head-unit installed
  • roof console fitted with FAKRA GPS antena, USB extension cable for a soon-to-be-installed dash cam and mic for RNEG2
  • custom harness made so not to cut the OEM cables
  • Pioneer DSP installed and wired: two fuse-taps used (one for power, one for ignition-only power), custom harness utilised to receive the RNEG2's audio signal
  • audio cables wrapped in protective loom and fished through the headliner away from the airbags, extra cables wired for additional speakers at the back shelf (for audible parking sensors)
  • tweeters replaced with Clarion tweeters
  • crossovers installed behind the glove box (LHD) and connected
  • door pockets in all 4 doors treated with sound dampening butyl/aluminium mats, OEM moisture-barrier also replaced with butyl mats
  • Clarion speakers installed on aftermarket rings (separated set for the front, coaxials in the back doors)
  • custom-made sub-woofer enclosure fitted to the trunk's right pocket and shallow-mount subwoofer installed
  • amplifier mounted into the trunk's left pocket
a lot of work! :P I will visit a car mechanic to ask for help fishing that power wire through.

Some photos I took throughout the process:
Attachments
IMG_4257.jpg
IMG_4276.jpg
IMG_4237.jpg
IMG_4207.jpg
IMG_4205.jpg
IMG_4203.jpg
IMG_4253.jpg

raqall
Posts: 16
Joined: 02 Feb 2020, 10:14
x 2

Re: C5 X7 amplifier power cables, trunk ground point

Post by raqall »

Thank you for your answers, the amp is finally installed!

I fished the hot-wire from the battery to the trunk going under left doors' kick-panels. There is just a perfect factory grommet, goes right through the firewall, more/less on the level where the steering wheel (LHD) is. One needs to look from below the steering wheel rack. I can post some pics if anyone interested.
I grounded the amp using factory ground location MC61 used for tail lights.

I've been listening for some time - no issues with the electronics of the car.