"Big 3" Grounding Questions

[Oldbasshead]

I've got the 1/0 OFC wires to do my Big 3 on a 2019 Mazda 3 sedan with a stock 130A alternator and new battery. As it sits now, I'm getting some pretty severe voltage drops, dropping below 11V at full-tilt, which is causing my cap/amps to go into protect. I'm running 4G OFC power/ground to my amp board and probably pulling somewhere around 1500W RMS between two amps. I'll replace the 4G power/ground if I absolutely need to, but I've read that many people have no issues with 1500-2000 RMS on 4G wire, so the plan is to leave it for now and see if I still have voltage drop issues after I do the Big 3.

Which brings me to my questions. Both the engine block and the battery negative terminal are running through some stupidly thin wire (10G maybe?) straight to a flimsy piece of sheet metal that's been spot welded to the strut housings under the hood. Should I use those same grounding points for the Big 3 upgrade? Seems like it wouldn't give the best ground since it's essentially only grounded at those two spot welds. It would be a lot easier if I sanded down the paint on the strut housings and grounded to those larger bolts. I have other options, but those are the most accessible. As long as I'm metal-to-metal, those strut towers should be a good ground point, correct?

With that in mind, I was also considering grounding the engine block to the battery negative terminal itself. Are there any pros/cons to running that ground to the battery instead of to the chassis? I mean, it's all going to be grounded to the chassis from the battery negative anyway.

Thanks in advance for any help.

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[Bass Addict 10+ year member]

I've got the 1/0 OFC wires to do my Big 3 on a 2019 Mazda 3 sedan with a stock 130A alternator and new battery. As it sits now, I'm getting some pretty severe voltage drops, dropping below 11V at full-tilt, which is causing my cap/amps to go into protect. I'm running 4G OFC power/ground to my amp board and probably pulling somewhere around 1500W RMS between two amps. I'll replace the 4G power/ground if I absolutely need to, but I've read that many people have no issues with 1500-2000 RMS on 4G wire, so the plan is to leave it for now and see if I still have voltage drop issues after I do the Big 3.

Which brings me to my questions. Both the engine block and the battery negative terminal are running through some stupidly thin wire (10G maybe?) straight to a flimsy piece of sheet metal that's been spot welded to the strut housings under the hood. Should I use those same grounding points for the Big 3 upgrade? Seems like it wouldn't give the best ground since it's essentially only grounded at those two spot welds. It would be a lot easier if I sanded down the paint on the strut housings and grounded to those larger bolts. I have other options, but those are the most accessible. As long as I'm metal-to-metal, those strut towers should be a good ground point, correct?

With that in mind, I was also considering grounding the engine block to the battery negative terminal itself. Are there any pros/cons to running that ground to the battery instead of to the chassis? I mean, it's all going to be grounded to the chassis from the battery negative anyway.

Thanks in advance for any help.

I would definitely replace the 4awg power and ground to 1/0 and put a extra batt in the vehicle.run main power wire to batt in vehicle.from batt in vehicle to amps.if the strut tower was the only place that looked solid,then yes i would do it.i had a 110 amp alt running a door speaker amp and a 2500 rms amp.i used 1/0 awg power wire to batt in back then to amps except i used a splitter in cab for my door speaker amp.the 1/0 wire i changed out in place of the original 4 awg i had made a difference.then when i added a second batt,it made even bigger.difference.thats my experience.

 

[Oldbasshead]

I would definitely replace the 4awg power and ground to 1/0 and put a extra batt in the vehicle.run main power wire to batt in vehicle.from batt in vehicle to amps.if the strut tower was the only place that looked solid,then yes i would do it.i had a 110 amp alt running a door speaker amp and a 2500 rms amp.i used 1/0 awg power wire to batt in back then to amps except i used a splitter in cab for my door speaker amp.the 1/0 wire i changed out in place of the original 4 awg i had made a difference.then when i added a second batt,it made even bigger.difference.thats my experience.

Thanks for the feedback! The ultimate goal is going to be building a custom enclosure for my 2 Skar EVL 12's (or possibly some Sundowns) and adding a 3k amp to power them. I'll definitely be upgrading all wiring to 1/0 at that point along with a spare battery and alternator upgrade. For now, I really just want to stabilize the voltage best I can with my current setup.

I'll get the big 3 wired up in the next day or two, see what I'm dealing with voltage-wise, and go from there, but I'm really regretting wiring it up with the 4g to begin with. My dumbass should have known that 1k watts would never be enough for my old deaf ears.

 

[Bass Addict 10+ year member]

Thanks for the feedback! The ultimate goal is going to be building a custom enclosure for my 2 Skar EVL 12's (or possibly some Sundowns) and adding a 3k amp to power them. I'll definitely be upgrading all wiring to 1/0 at that point along with a spare battery and alternator upgrade. For now, I really just want to stabilize the voltage best I can with my current setup.

I'll get the big 3 wired up in the next day or two, see what I'm dealing with voltage-wise, and go from there, but I'm really regretting wiring it up with the 4g to begin with. My dumbass should have known that 1k watts would never be enough for my old deaf ears.

It took around 3500 for me lol

 

[Bass Addict 10+ year member]

Bought these for my new setup.1/0 awg power wire and grounds fit perfect.