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using multiple 4 gauge instead of 1/0 gauge?

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Old 10-17-2022, 10:48 PM
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Default using multiple 4 gauge instead of 1/0 gauge?

Curious if anyone has tried to run multiple 4 gauge wires, instead of one 1/0 gauge wire? I think that 4 gauge will fit under the carpet quite a bit better than 1/0 will.
Old 10-17-2022, 11:17 PM
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how many amps exactly are you trying to feed? adding extra smaller runs doesn't work out usually due to the amount needed to add up to the larger size. example (2) #4 runs doesn't double the amp rating, it only adds like 2-3amps. I can't find the exact chart at the moment, but yes its that low from what I remember. you'd end up running 10+ runs of #4 to feed the same as 1 #1/0
Old 10-17-2022, 11:45 PM
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Originally Posted by bthomas
how many amps exactly are you trying to feed? adding extra smaller runs doesn't work out usually due to the amount needed to add up to the larger size. example (2) #4 runs doesn't double the amp rating, it only adds like 2-3amps. I can't find the exact chart at the moment, but yes its that low from what I remember. you'd end up running 10+ runs of #4 to feed the same as 1 #1/0
This is for moving the battery to the back. Four 4 gauge cables will be easier to run under the carpet than one 1/0. Four 4gauge should be more total than one 1/0.
Old 10-18-2022, 09:09 AM
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4 AWG cable is about 42,000 circular mils.
0 AWG cable is about 105,000 circular mils.
00 AWG cable is about 140,000 circular mils.

Three 4 AWG cables is right in between 0 and 00 AWG size cable, and exceeds ampacity of 0 AWG cable (related to the amount of copper in the bundle). However, it may be a bit difficult to make the physical crimp to bring those cables together. You're good to go if you can get that figured out.
Old 10-18-2022, 09:19 AM
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Here is a technical document how to calculate circular mils by TE Connectivity, https://www.te.com/commerce/Document...=SS&DocLang=EN
Old 10-18-2022, 10:53 AM
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Originally Posted by QwkTrip
4 AWG cable is about 42,000 circular mils.
0 AWG cable is about 105,000 circular mils.
00 AWG cable is about 140,000 circular mils.

Three 4 AWG cables is right in between 0 and 00 AWG size cable, and exceeds ampacity of 0 AWG cable (related to the amount of copper in the bundle). However, it may be a bit difficult to make the physical crimp to bring those cables together. You're good to go if you can get that figured out.
I figured I would use distribution blocks on both sides, instead of trying to crimp.
Old 10-18-2022, 02:29 PM
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You can, but from an engineering perspective it is undesirable to have more than 2 large ring terminals at a junction block, and definitely no more than 3. Main reason is resistance in the stack-up, and tendency of bolts/nuts to loosen with the soft copper materials. Just sharing so you can make well informed choices.

Places like CE Auto Electric have presses than can make these 3 cable crimps and you can have them do it before sending you the cables. Although they use PVC insulation on their battery cables which is not desirable. Best to use SGX insulation because it's tougher to rubbing / abrasion. Most the safety in battery cables is careful cable routing, clipping, and choosing tough insulation material. SGX is pretty stiff, doesn't turn corners very easy, but it's the right stuff from a safety perspective.

Last edited by QwkTrip; 10-18-2022 at 02:39 PM.
Old 10-18-2022, 02:34 PM
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Originally Posted by QwkTrip
You can, but from an engineering perspective it is undesirable to have more than 2 large ring terminals at a junction block, and definitely no more than 3. Main reason is resistance in the stack-up, and tendency of bolts/nuts to loosen after the soft copper crushes. Just sharing so you can make well informed choices.
ahhh. I had not considered the added resistance. Maybe I will just figure out a way to run the 1/0 gauge cable.
Old 10-18-2022, 02:41 PM
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Sorry, I tried to do a ninja edit of my last response with more info that might be helpful but didn't get it done before you replied.
Old 10-19-2022, 02:43 PM
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Originally Posted by QwkTrip
Sorry, I tried to do a ninja edit of my last response with more info that might be helpful but didn't get it done before you replied.
Still, might be better for me to try to figure out a route for the 1/0 cables. I don't know if running them under the car is a good idea or not. I can likely get away with running them along the driveshaft hump, under the carpet.
Old 10-19-2022, 03:23 PM
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I ran a 1/0-gauge amplifier wiring kit through the car from the firewall to the spare tire area. I will be zip-tying it next to the OEM cable channel (removed the factory speaker wires) and will be securing it along the sail and into the trunk with the OEM speaker/amp cable management and 3M adhesive cable managers. The firewall transition was the hardest part. I removed the 2 computers to have better access and once I got the right amount of length through I had to put 2 holes in the wheel well to secure the fuse block to at the battery end. I am putting in new mass backing carpet so it shouldn't be an issue with the extra space the wire is taking up. As the OEM placement is already there it shouldn't get pinched or crimped by anything there. This is a different application but its how I ran the wire to get juice to the rear.


Firewall along door sill

Along sail panel

Power and sail speaker wires
Old 10-19-2022, 07:59 PM
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Originally Posted by jybravo70
I ran a 1/0-gauge amplifier wiring kit through the car from the firewall to the spare tire area. I will be zip-tying it next to the OEM cable channel (removed the factory speaker wires) and will be securing it along the sail and into the trunk with the OEM speaker/amp cable management and 3M adhesive cable managers. The firewall transition was the hardest part. I removed the 2 computers to have better access and once I got the right amount of length through I had to put 2 holes in the wheel well to secure the fuse block to at the battery end. I am putting in new mass backing carpet so it shouldn't be an issue with the extra space the wire is taking up. As the OEM placement is already there it shouldn't get pinched or crimped by anything there. This is a different application but its how I ran the wire to get juice to the rear.


Firewall along door sill

Along sail panel

Power and sail speaker wires
That's not too bad. I doubt it will be noticeable under the carpet.
Old 10-20-2022, 08:45 PM
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Has anyone tried to follow the driveshaft tunnel, maybe tied to the fuel line? I think that two 1/0 cables would fit. One for the distribution block, and one for the alternator. Hell... 2/0 might even fit!
Old 10-26-2022, 12:00 AM
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How does this plan look?


Attached Files
File Type: pdf
battery relocation.pdf (63.3 KB, 30 views)

Last edited by FCar2000TA; 10-26-2022 at 12:16 AM.
Old 10-27-2022, 01:42 PM
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Your alternator wiring needs to be on the switched side of the cut off switch or you'll back feed and the switch won't do anything this is a pretty good video, Devin has some other good videos about power and ground set up, they might be tailored to racecar stuff and Holley ECU's, but the information is still relevant. Also I suggest using quality resettable circuit breakers vs a fuse for your circuit protection.


Last edited by biketopia; 10-27-2022 at 01:52 PM.
Old 10-27-2022, 04:14 PM
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Originally Posted by biketopia
Your alternator wiring needs to be on the switched side of the cut off switch or you'll back feed and the switch won't do anything this is a pretty good video, Devin has some other good videos about power and ground set up, they might be tailored to racecar stuff and Holley ECU's, but the information is still relevant. Also I suggest using quality resettable circuit breakers vs a fuse for your circuit protection.

https://www.youtube.com/watch?v=jy1I1Cbci_o
I thought that NHRA rules stated that the alternator had to be wired directly to the battery?
Old 10-28-2022, 05:45 AM
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There's no specific language in the rules saying the charging cable needs to go directly to the battery, just "it needs to be on the positive side of the electrical system and stop all electrical functions." As long as there's no way for the system to back feed off the excite wires or any accessory wired to the alternator, then direct to the battery is ok. But without it going through the switch even with the switch off, there's still 12v available at the back of the alternator and running through your relocation cable.

Old 10-28-2022, 11:44 AM
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Originally Posted by biketopia
There's no specific language in the rules saying the charging cable needs to go directly to the battery, just "it needs to be on the positive side of the electrical system and stop all electrical functions." As long as there's no way for the system to back feed off the excite wires or any accessory wired to the alternator, then direct to the battery is ok. But without it going through the switch even with the switch off, there's still 12v available at the back of the alternator and running through your relocation cable.
Even if the fuel pump and injectors have no power, so the alternator is not turning?
Old 10-28-2022, 12:15 PM
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With the car off and the cut off "off" if you took at test light to the back of the alternator as wired above you would always have battery voltage on your charge wire is what I'm saying. Weird things happen with back feeding as well. If it was an older SBC set up with just the charge wire off the alternator then the power only has the battery to travel back to, but if there's a wire for the gauge, and an excite wire power can be back fed to an extent through out the system allowing a run on or harming electronics.
Old 10-28-2022, 12:51 PM
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Originally Posted by biketopia
With the car off and the cut off "off" if you took at test light to the back of the alternator as wired above you would always have battery voltage on your charge wire is what I'm saying. Weird things happen with back feeding as well. If it was an older SBC set up with just the charge wire off the alternator then the power only has the battery to travel back to, but if there's a wire for the gauge, and an excite wire power can be back fed to an extent through out the system allowing a run on or harming electronics.
ah. ok. Since the back of the alternator is directly connected to the + of the battery, the wire will have power.



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