View Full Version : battery to fuse box wire. (thicknesses)

11-16-2011, 08:31 PM
Hey guys.

I've had problems with corrosion on my positive terminal a little bit down the cable run, not very far. i did some cleaning and had it working good all summer. as the winter time has run in im getting some moisture or something making the startup not the best. I bought a replacement side post cable with 2 AUX wires (IE would go to the fuse box and whatnot)

heres my issue.

the cable from the battery to the fuse box right now is a good thickness.

the cables on this new patch kit have 2x 6 gauge wires. ones black ones red (color doesn't really matter to me as the whole patch itself is black and its for the positive post.

can i strip the wire coming from the fuse box and crimp it onto this 6 gauge wire without running into problems?

or can i crimp it onto both 6 gauge wires hooked together to better distribute the load?

Thanks for the read.


11-17-2011, 03:19 AM
upon closer inspection , one aux wire is 6 and one is 4 gauge.

11-17-2011, 10:45 AM
If you bought an OEM cable then this should be a straight forward replacement without needing to crimp onto old wiring. The service manual describes disconnecting the cables and cutting them 3" back from the ends and leaving the main harness as is while running the replacement cables alongside the old set with room on both ends for slack.

If this is a store replacement without the terminals on the ends (fuse box) then you'll have to carefully consider some options. One would be to strip and crimp similar sized terminals onto the fuse cable to connect directly to the fuse box or if splicing onto the existing fuse cable, butt connecting/crimping/soldering the ends together for the best electrical connection possible to ensure full current carrying capability. Hand crimping has only one advantage - a mechanical lock to hold cables together to a terminal but doesn't ensure full conductivity. A machine crimp applies more force to crimp and tightly squeeze wires together that allows full current carrying capability hand crimping may not approach, especially a fuse box cable crimp. A fuse cable termination using a splice should involve soldering - using a propane torch, resin and electrical solder if necessary for the large gauge wires used. A crimp may not work unless you can ensure that this crimp can carry the full current needed to the fuse box. Splicing a single wire is easy when one wire carries a maximum of say 10 amps but when wiring a replacement battery cable with a run to the fuse box, considerations must be made involving the large currents carried from the battery to the fuse box. Much more than 10 amps. Do everything to make this replacement as good as the factory connection otherwise you'll find out down the road at the worst possible moment when you least expect it. Freezing cold/rainy/wet snow/winds above 30mph......................with nothing working.

Water didn't do any damage. That's battery acid in the wiring. Make up a warm solution of water and baking soda and use a tooth brush to dab this solution onto the area you think is soaked from water. If you see immediate bubbling, baking soda is neutralizing battery acid, not water. Either the previous battery suffered a broken side terminal or the present battery has a broken side terminal. Once broken, the small amount of battery fluid leaches out onto the battery cables to eventually corrode and eat away copper. The blue-green powdery deposit is dried battery acid, neutralized with the solution. Replacing the battery is the only choice with careful tightening and adequate cable slack to prevent future side terminal damage.

11-17-2011, 12:56 PM
I didnt buy a OEM per say replacement, i bought a universal one.

http://www.autozone.com/autozone/parts/_/N-5yc1s;jsessionid=3D35EC2E57A4E3A78D244CEE787DB168. diyprod3-b2c13?itemIdentifier=831028

The battery isnt the original one as the cars over 10 yrs old. this new battery hasnt leaked as far as i can see but the old battery did considerable damage as ive cleaned it with the hot water / baking soda solution once in the past and it took the problem away. i'm just curious to see if using this "side terminal battery harness repair splice" will get it better then another baking soda scrub.

on the pic at autozone it looks like both aux wires are the same but on the actual product theres 2, ones thicker then the other but still smaller then the fuse box wire.

if i strip the fuse box wiring a few inches back and the battery cable a few inches back. bolt it to the battery cable with its screwdown connector and crimp it to the fuse box with its 4 gauge wire. will it fry the 4 gauge?

11-17-2011, 12:57 PM
i looked on a website


says 4 gauge you can run 60 amps and 6 gauge you can run 37 amps.

would that be correct?

11-17-2011, 01:32 PM
Using references is fine but not a guarantee that a manmade mechanical splice will translate to meet actual specifications. Remember, those are published references for solid wires (not spliced) without any basis on actual use - engineering terms for maximum current capability, not actual use in specific circumstances like splicing that breaks and voids specifications.

When all is said and done you ultimately inherit any and all mistakes as well as any good repair. It always your choice on how this repair ends. All I'm suggesting are the possibilities that exists in reality against published specs (that do not apply here) that are used for reference only and sometimes do not translate to actual numbers. That would have to be proven with test equipment that's outside our discussion.

A splice means wires are joined so current becomes limited/lowered from those specs that are for continuous unbroken wiring. Ensuring a good splice electrically allows the most current to conduct without causing any resistance - resistance to current translates to heat that can cause many issues on a main power line not repaired correctly.