DIYMobileAudio.com Car Stereo Forum banner

Big 3 conundrum

1017 Views 16 Replies 8 Participants Last post by  ckirocz28
5
Hi folks, how's it going?

So I'm having an issue with the big 3 on my car. I have a 60ah lithium battery and an Autotech 320A HO alternator so obviously better wire is next. I'm planning on running 2/0 OFC welding wire and it looks like it won't be a problem except the firewall. I have a post through on the firewall that connects both sides. Here are some pictures so you can see what I'm talking about:

Hood Automotive tire Bumper Automotive lighting Vehicle door

Motor vehicle Tread Automotive tire Tire Automotive exterior


When I removed the stuff, this is what I found:

Hood Automotive tire Trunk Automotive exterior Gas

Automotive tire Wood Bumper Wall Fender


Now as far as the wire from the alternator to the firewall, it is not just one wire, its a bunch. It looks like this:

Automotive lighting Automotive design Map Automotive tire Automotive exterior


So here is my question: Am I going to need to drill a new hole in the firewall, put in a rubber grommet, and run the cable from the alt to the battery? I thought about adding a wire to the alternator and having it attach to the post through but since it would be touching metal, I think that would be really bad.

So what do you think, do I need to drill a new hole or is there something I can do that doesn't require that?
See less See more
1 - 17 of 17 Posts
Measure the OD of the welding cable insulation and get the proper size strain relief for the cable and then enlarge the hole to mount the strain relief.
strain relief
  • Like
  • Helpful
Reactions: 3
These type of grommets are really good. Cut the hole to the appropriate size, prime the bare metal, and install.

  • Like
  • Helpful
Reactions: 3
I agree. Those are excellent.
  • Helpful
Reactions: 1
These type of grommets are really good. Cut the hole to the appropriate size, prime the bare metal, and install.

I agree. Those are excellent.
+1
  • Helpful
Reactions: 1
Oh man never seen those before, I want to redo my wiring now 😂
  • Like
Reactions: 2
Oh man never seen those before, I want to redo my wiring now 😂
The only issue with them is that once that collar squeezes down on the insulation there's not much leeway to bend the wire very close to whatever bulkhead you are going through, but as long as you've got some space on each side they great. We use them on off road vehicles and have confirmed they are watertight with no leakage when installed properly.
  • Helpful
Reactions: 2
Hi folks, how's it going?

So I'm having an issue with the big 3 on my car. I have a 60ah lithium battery and an Autotech 320A HO alternator so obviously better wire is next. I'm planning on running 2/0 OFC welding wire and it looks like it won't be a problem except the firewall. I have a post through on the firewall that connects both sides. Here are some pictures so you can see what I'm talking about:

View attachment 372245
View attachment 372246

When I removed the stuff, this is what I found:

View attachment 372247
View attachment 372248

Now as far as the wire from the alternator to the firewall, it is not just one wire, its a bunch. It looks like this:

View attachment 372249

So here is my question: Am I going to need to drill a new hole in the firewall, put in a rubber grommet, and run the cable from the alt to the battery? I thought about adding a wire to the alternator and having it attach to the post through but since it would be touching metal, I think that would be really bad.

So what do you think, do I need to drill a new hole or is there something I can do that doesn't require that?
View attachment 372836
  • Like
  • Helpful
Reactions: 2
Oh ****...that rules!!! That is even better than the grommet...I can connect a 4/0 welding wire to that. I think we have a winner!!! Thank you so much ckirocz28!!! By the way, what does your name mean?? I've never seen the word ckirocz before.
Just to note, a 3/8" brass stud is good for 400A while a steel 3/8" stud is only good for 250A...
  • Helpful
Reactions: 1
Just to note, a 3/8" brass stud is good for 400A while a steel 3/8" stud is only good for 250A...
Yeah, I just read that they are only good for 100A which is not enough since I have a 320A HO alternator. However, I found one on Amazon rated at 440A continuous with peaks at 550A, so I'll probably go with that since my alternator is High Output. I can also go from 2/0 welding wire to 4/0 welding wire. I could even do the big 4 and drill two holes...one from alternator to battery positive and one from the alternator frame to the battery negative. This is a game changer for me.

High current through panel battery connectors

I ****ing love this place...thank God for DIYMA!!!
Another thing to note is that between the two crimps and the two bolted joints, you're adding 20,30,50 ft of 4 ga wire to the circuit, voltage drop wise. Running a single piece of wire will always be better than having connections, if you can do it. I should have 4 of the pass-thru connectors discussed just before this for 1/0. I'll send you one, if you want...

  • Helpful
Reactions: 1
Yeah, I just read that they are only good for 100A which is not enough since I have a 320A HO alternator. However, I found one on Amazon rated at 440A continuous with peaks at 550A, so I'll probably go with that since my alternator is High Output. I can also go from 2/0 welding wire to 4/0 welding wire. I could even do the big 4 and drill two holes...one from alternator to battery positive and one from the alternator frame to the battery negative. This is a game changer for me.

High current through panel battery connectors

I ****ing love this place...thank God for DIYMA!!!
As @Slave2myXJ pointed out above; you will be much better off with the only connections in the wire at either end. The 2/0 wire is plenty for any reasonable distance and you still need proper tools to make those connections on each end. The tools for 4/0 are starting to get into the size where you have to purchase separate dies for each wire size and use hydraulic crimpers (unless you intend to solder the ends on and that's a whole 'other' ball of wax)... additionally, that through post uses stainless nuts on an unknown metal plated copper post so if your wire end is brass then you've got copper to brass to stainless to mystery metal to copper and back again in dissimilar metals to cause dielectric changes, corrosion, resistance and noise.

Sent from my SM-G965U using Tapatalk
  • Helpful
Reactions: 1
As @Slave2myXJ pointed out above; you will be much better off with the only connections in the wire at either end. The 2/0 wire is plenty for any reasonable distance and you still need proper tools to make those connections on each end. The tools for 4/0 are starting to get into the size where you have to purchase separate dies for each wire size and use hydraulic crimpers (unless you intend to solder the ends on and that's a whole 'other' ball of wax)... additionally, that through post uses stainless nuts on an unknown metal plated copper post so if your wire end is brass then you've got copper to brass to stainless to mystery metal to copper and back again in dissimilar metals to cause dielectric changes, corrosion, resistance and noise.

Sent from my SM-G965U using Tapatalk
Luckily I have a 16 ton hydraulic crimper so that won't be a problem. Well, back to the grommet...I can forget about the big 4. Running one run of 2/0 or 4/0 wire will be difficult but two runs is going to be a pain in the ass. Thanks for the advice.
Luckily I have a 16 ton hydraulic crimper so that won't be a problem. Well, back to the grommet...I can forget about the big 4. Running one run of 2/0 or 4/0 wire will be difficult but two runs is going to be a pain in the ass. Thanks for the advice.
The rule of thumb (unless your cable mfr says otherwise) is 2/0 is good for 400 Amps up to 50 feet.

Sent from my SM-G965U using Tapatalk
  • Helpful
Reactions: 1
The rule of thumb (unless your cable mfr says otherwise) is 2/0 is good for 400 Amps up to 50 feet.

Sent from my SM-G965U using Tapatalk
That is why I was originally planning on using 2/0 welding wire. With my subwoofer amp, I'm going to use 2/0 instead of 1/0 because of the amount of current I'll be pulling. The wire that connects my battery negative to the chassis is still going to be 4/0...you can't overdo grounds.
Oh ****...that rules!!! That is even better than the grommet...I can connect a 4/0 welding wire to that. I think we have a winner!!! Thank you so much ckirocz28!!! By the way, what does your name mean?? I've never seen the word ckirocz before.
My first initial, my second initial, then irocz (IROC-Z).
  • Helpful
Reactions: 1
1 - 17 of 17 Posts
Top