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Author Topic: Big 3 Upgrade  (Read 585 times)


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Big 3 Upgrade
« on: April 02, 2019, 05:47:09 pm »
Hey guys so I have installed a JL Audio 1200/1v3 and 2x 12w3v3 (this is getting swapped for a single Sundown SA12) in a 30hz tuned box with a Pioneer system.

I get dimming of my headlights when the bass drops or pounds hard, I have gone ahead and done the Big 3 using 0 gauge/awg wires, found it strange doing the big 3 as the wire from the alternator does not go to the starter then battery but in the mk5 gti case it goes straight from the alternator to the front fuse box and then from there is goes to the battery.

So the way I have done the big 3 is as followed;

0 awg alternator to fuse box
0 awg starter to battery terminal
0 awg from fuse box to battery positive terminal
0 awg negative battery terminal to chassis
0 awg ground engine/gearbox to chassis

Now the wierd thing is, usually how the big 3 works is alternator to starter then from starter to the battery positive terminal but this is wired different from factory.

Anyways long story short, I still get headlight dimming but my sound system sounds a hell of a lot better, but I'm also thinking of upgrading from the factory battery to a Stinger spv70 to help with the load, I really don't want to add a second battery all the way in the back of the car.

What can be my solution?
Can I upgrade the battery and add a second 0 awg all the from the alternator to the battery positive?

any helps and input will be much appreciated.

Offline mod_junkee

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Re: Big 3 Upgrade
« Reply #1 on: May 07, 2021, 10:09:20 pm »
I need pics , trying to do the same thing to my mk5 Gti