Quesions about Grounding a 3500 wRMS amp and running speaker wire

[MackMurder]

So. My cresend 3500 wrms amp has 2 power inputs and 2 ground inputs. I have 2/0 gauge power and ground runs I'll be doing. 

 

Question 1- should I ground back to the battery? Ive heard its a  better ground. If so I'd like to do that. But fuck me including my 4 channel amp that will be 5 runs of 2/0 gauge through that hole in my firewall. I won't have a grommet to fit that shit. So do I cut out the old grommet to fit the 5.runs of wire and then silicone the piss out of it? I also have that rubber sticky electrician wrap for bare wiresults I could rap around as well where it sits in the firewall.

 

Question 2- I'm redoing all My speaker wire rn..does it matter ifbmy speaker wire is next to my power wires. Noise wise? I was gonna run rcas down the middle of the truck. Power down drivers side. And speaker down driver and passenger side? Thoughts?

 

Any help is appreciated. 

 

 

 

[snafu]

The short answer is that running cable the length of the vehicle to the battery negative terminal is never a better solution.  Your 3,500 Watt amplifier and any 4 channel amplifier making less than 2,000 Watts requires at most a single 1/0 AWG power cable to supply both.

3,500 Watts / 75% amplifier efficiency = 4666.67 Watts Input 
4666.67W / 13.8V = 338.16A
338.16A x 50% duty cycle (playing music at clipping) = 170A

2,000 Watts / 60% amplifier efficiency = 3333.33 Watts Input
3333.33W / 13.8V = 241.55A
241.55A x 50% duty cycle (playing music at clipping) = 120A

So, 290A of combined current required for this combo.  That's a single run of 1/0 AWG Power Cable from the front, grounding both amps to the frame rail in the rear via 1/0 AWG (and a distribution block to split between the amps), and a Big 3 Upgrade Kit.  So, instead of using a 6" holesaw to cut a ginormous hole in your firewall, we put science to work for us and now we can run one 1/0 AWG cable through the firewall.  A single run of 2/0 AWG would be overkill and wouldn't add any measurable performance but if it made you sleep better at night, got for it.

OTOH, if you want to reproduce sine waves at full output with minimal voltage drop, current consumption would double (at least for the sub amplifier).  Even yet, a single run of 2/0 AWG would more than cover that.  Your bigger problem would be maintaining voltage.

You may find the following beneficial:  https://ceautoelectricsupply.com/wp-content/uploads/2016/05/The_Truth_about_the_Big_3_Upgrade.pdf

[Mack187Murder]

 

 

2 hours ago, snafu said:

The short answer is that running cable the length of the vehicle to the battery negative terminal is never a better solution.  Your 3,500 Watt amplifier and any 4 channel amplifier making less than 2,000 Watts requires at most a single 1/0 AWG power cable to supply both.

3,500 Watts / 75% amplifier efficiency = 4666.67 Watts Input 
4666.67W / 13.8V = 338.16A
338.16A x 50% duty cycle (playing music at clipping) = 170A

2,000 Watts / 60% amplifier efficiency = 3333.33 Watts Input
3333.33W / 13.8V = 241.55A
241.55A x 50% duty cycle (playing music at clipping) = 120A

So, 290A of combined current required for this combo.  That's a single run of 1/0 AWG Power Cable from the front, grounding both amps to the frame rail in the rear via 1/0 AWG (and a distribution block to split between the amps), and a Big 3 Upgrade Kit.  So, instead of using a 6" holesaw to cut a ginormous hole in your firewall, we put science to work for us and now we can run one 1/0 AWG cable through the firewall.  A single run of 2/0 AWG would be overkill and wouldn't add any measurable performance but if it made you sleep better at night, got for it.

OTOH, if you want to reproduce sine waves at full output with minimal voltage drop, current consumption would double (at least for the sub amplifier).  Even yet, a single run of 2/0 AWG would more than cover that.  Your bigger problem would be maintaining voltage.

You may find the following beneficial:  https://ceautoelectricsupply.com/wp-content/uploads/2016/05/The_Truth_about_the_Big_3_Upgrade.pdf

Snafu thanks for the taking the time to go through all that.  It definitely makes sense. I was waiting for 2 days for a replyso I just kinda went and did it andy ways.  

 

I had a 50 foot  chunk of 2/0 gauge welding cable and a 100 foot chunk of 2/0 green ground cable ( with insulation in side the rubber) all brand new from the rig. So I had the materials and the cost me nothing.  I did end up.running the 2 power and 2 grounds back to the battery. ( andactctually ran them threw the firewall grommet quite cleanly after an hour of cursing my self

 However for my 4 channel I ran some new 2 awg for that. I have two XS power batteries 3300 amps a piece  and  a  MECHMAN 370 amp alternator .

I have my MECHMAN fused with a 400 amp fuse.

And my bateries wirred in paralell. The power wire for those.is 200 amps on each end 

Maybe I ran some overkill but i dont plan on having some a sysstem that plays 3 songs and has to charge back up 

My biggest question now is my amplifier suggests a 450 amp fuse. Do I split the difference between each power wire. So 225 per run. Or do I put a 450 amp fuse on each power wire. 

And if that is the case since I only have 400 amp fuses. Coud I get away with running those instead of the 450 the amp suggest. Is that a maximum recommended? 

 

Also if u see any other problems with size of fuse I used on my batteries and alternator let me know. Pretty sure I followed the instruction manual but I can't seem to find them

[Mack187Murder]

Oh and jungle is mack. Just ouldnt remember my old password for.jungle 

 

[snafu]

Science is your friend in car audio.  Your two runs of 2/0 AWG likely have more resistance than using the frame / frame rails as the return path.

[MackMurder]

Well iI guess it's not too late to pull out the 2 ground wire runs it only requires me.to take out my.drivers seat.

 

. What about grounding the amps in between the chasis and a seat belt bolt? If I grind down the surface so it's Shiny

 

And what are your thoughts on fusing my power wires.