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Discussion Starter · #1 ·
So out cruising last night about 80° outside car is running good, with the stereo on so my 100w amp and sub are on but not bumping, 16" puller fan running 15amp draw, and parking lights...I notice my volt meter is at 13v now I usually don't have the radio and parking lights on so ok getting into some stop and go traffic the temp gets up to 190-195° I flip on the two pusher fans @ 8amps each and the headlights voltage still at 13v but increases to 14v with more rpms ok...stop for a bite to eat pull the key out and it's warm (never had that happen) so I feel the ignition switch and it's warm maybe 85-90 ° idk. So I use my battery disconnect go eat for an hour drive home about 5-6 miles all the same things on except the pusher fans voltage is at about 14 get in the garage the key and switch are fine not warm at all. I'm running a 100amp Tuff Stuff 3 wire alternator and new regulator...do I have a problem, do I need a bigger alternator or is this a normal happening because I've never had it happen before and this is the third summer with all these components except the pusher fans were added this winter. Just don't want a fire while driving I hear that's a bad thing.
 

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Discussion Starter · #2 ·
....I should add that I have a new engine harness and stock size battery cables but the original three alternator wires and I did laser temp the alternator after I got in the garage and it was between 140 and 165° depending where I pointed it but it always seems like you can't touch it after running for while but maybe some of that is engine heat, I did not feel the wires from it or the regulator.
 

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If you still have stock battery / charging wires than you need to upgrade. Stock alt was what 40amps? Short length of 10gauge took care of that. Now you have 100amps trying to run thru that same 10guage. You need to upgrade to at least a 4gauge (i prefer 2awg) for the alternator to battery and ground from battery to chassis.

Your ignition switch getting hot is a different thing. If you’re running the radio, amp, and electric fans off the stock fuse block then that extra draw is going thru the ignition switch. If it was rated for 40-50amps but now you pushing more current thru it than it will heat up. That’s why its always a good idea to use the ‘acc’ taps on the fuse block to trigger relays that are feeding direct battery power to the devices.

On another note, from my experience all pusher fans do is block incoming air. I would ditch those and get a better puller fan setup that will get the job done. We like to see at least 4,000 cfm from puller fans with a sealed shroud to cool properly. Its also handy to have a controller that can shut those electric fans off above lets say 50mph so the fans arent slowing down the incoming air at that speed.
 
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Discussion Starter · #4 ·
Ok bare with me because electrical isn't my strong suit but I understand most things, you say upgrade the cable from the battery to the alternator but I only have a 4awg negative battery to engine, a 4awg positive directly to the starter then the 12awg? from the alternator into the loom which plugs into the fire wall block. So which one am I supposed to upgrade? And I do have my stereo and fans into the auxiliary terminals on the fuse block just never had this issue before but maybe I was running more than usual. As far as the fans I'm not running much of a shroud I know that's the problem but I don't like the looks of the bulky plastic shroud so I'm dealing with it for now, I have a 16" puller fan that's about 3000 cfms because the belt driven fan put to much drag on my serpentine belt and it would squeal, then I put two 13" pusher fans(1000cfms each) at the bottom of the radiator for when I get into traffic and it seems to be working well, stays at 200° on a 90° day in traffic
Motor vehicle Hood Automotive fuel system Automotive design Automotive tire
and they don't have much restriction as going down the road on a cooler day sometimes I don't have any of the fans on.
 

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Discussion Starter · #5 ·
Ok so I searched some posts here about an alternator upgrade and all agree I need a bigger gauge wire to the battery, question is can I or do I have to leave the smaller wire going down to the starter connected or do I have to disconnect it?
 

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#4 will be hard to work. Not to mention it is pure overkill

The real problem here is that the alternator large red wire runs through the ignition switch from the alternator then to the battery
It is NOT made to handle 60 + amps , at least not for long.

Run a #10 Ga AWG from the alternator straight to the battery . Then it will cool your switch down Ha Ha
seriously , I have checked this out on my 64 and the charge wire goes through the ignition switch then to the battery.That is the root of the problem

Leave the small wire and everything else intact
 

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Discussion Starter · #7 ·
Ok, I could probably deal with a #6 or #8 pretty well unless that's still overkill? I didn't have any of the fans when I bought the alternator so now I'm thinking I should get a 140 amp because I forgot or didn't realize I'm not getting 100 amps at idle, so then with the 140 amp alternator I would probably need a 6 or 8 cable. I'm glad you said I could just add a wire because to replace the wire going to the starter would be a nightmare.
 

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I believe that changed in 65 LATECH. Alternator output to starter. Starter to battery. Red wire to ignition switch is spliced to the alternator-starter wire as part of the engine harness wiring. You can add a # 6 or 8 wire directly to the battery from the alternator but leave the original wire in place. You will then have two wires in parallel feeding the battery.
In regards to the ignition switch getting hot have you added anything to the ignition circuit such as the aux panel you installed?
 

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Discussion Starter · #9 ·
Haven't added anything since the two pusher fans last winter so been running all spring and summer like this, added it to the same auxiliary terminal the pusher fan was hooked to and all separately fused with one switch for the pushers one switch for the pullers. The small wire theory makes sense as you can't hook a garden hose to a fire hydrant and expect it to work, plus I probably never had that many things turned on at once....perfect storm. I guess I should try the bigger wire first before buying a bigger alternator unless there's a formula of adding up amperage loads of items to calculate what I need.
 

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#4 will be hard to work. Not to mention it is pure overkill

The real problem here is that the alternator large red wire runs through the ignition switch from the alternator then to the battery
It is NOT made to handle 60 + amps , at least not for long.

Run a #10 Ga AWG from the alternator straight to the battery . Then it will cool your switch down Ha Ha
seriously , I have checked this out on my 64 and the charge wire goes through the ignition switch then to the battery.That is the root of the problem

Leave the small wire and everything else intact
Your’re saying NOT to upgrade to a 4awg for a high amp alt?? Ok ill make sure you never wire any of my cars LoL. Keep in mind i do this for a living.
 

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Your’re saying NOT to upgrade to a 4awg for a high amp alt?? Ok ill make sure you never wire any of my cars LoL. Keep in mind i do this for a living.
Kiss my A S S
If you are running 24 feet of wire then a 4 AWG would be needed
Get a grip

A 3 foot run of #10 is fine. It is not like the alternator is going to be used for welding,Even if you think it is too small...
the original wiring for the alternator is still present along with the added wire being discussed. And you want to add a 4 gauge ?
Remind me not to let you bill me for work done on my car

I swear the more common sense I post the more BS i get from trolls and know it alls
 

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Op im done. If you want real advice PM me. There is no circumstance inwhich a 10awg wire is acceptable for 100amp alternator.

To LAtech, im wrapping up a 200k restomod chevelle for an NBA player and the shop is completely full of high end wiring jobs. Do you boo. Wire your cars however you want. When you start giving BS advice to random people is where i have a problem.
 

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Discussion Starter · #14 ·
Whoa guys, didn't want to start a pissing contest but LA has a point the longer the run the more resistance = heat and loss of signal, I'm only talking about a 16" wire plus like stated I still have the original wire I believe looks and feels like a 12# based on me wiring enough 110-240v commercial stuff. So what's everyone's opinion on upgrading to a 140 amp alternator without starting another war? Aslo remember everything is rated for cover your ass lawsuit, I've rented to mold making machine shops that were running locked rotor ratings of 400 amps on everything totaled up out of a 200 amp 3 phase box that they could hardly get the cover bolted on with no problems, but I know the inspector would never pass it because you're only supposed to use 80% of the total amperage so they're just covering there ass to avoid a lawsuit that's all. Thanks for everyone's advice I do take all of it in 👍
 

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ooooo. That kinda explains a lot.

Can you provide a picture of the fuse box with your connections. It sounds like you may be running everything off the ignition circuit and accessory circuits which would explain why the switch is so hot.

if this is the case you MUST run your amp and fans off a separate panel powered directly off the battery and controlled by relays.

I’ll refrain from any more conjecture until I get a look at the fusebox.
 

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Op im done. If you want real advice PM me. There is no circumstance inwhich a 10awg wire is acceptable for 100amp alternator.

To LAtech, im wrapping up a 200k restomod chevelle for an NBA player and the shop is completely full of high end wiring jobs. Do you boo. Wire your cars however you want. When you start giving BS advice to random people is where i have a problem.
I have been working on cars as a profession for 38 years. Master certified.
You arent teaching me anything
 
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