johnfkimble

Does any know why there is a fusable link on the starter and what purpose it serves? I own a 1998 Corvette.

Also, why is there a red positive wire from the alternator to the starter, then from the starter to the battery?

It seems to me there should be a DIRECT connection between the battery and the alternator, then to the starter.

Why is it wired backwards this way and can I eliminate that fusable wire and run a straight red positive wire?

Thanks for your reply

John

Bill Curlee

John. ANY wire that is connected DIRECTLY to the battery MUST be fused. If that wire shorts, it will catch fire and roast your car.

YES, there are fused links on the alternator wire and the alternator regulator feed back wire. Same reason,, Safety.

The wire directly from the battery to the starter isnt fused because it needs to be capable of supplying full battery current to the starter and its short as possible and routed away from the exhaust.

You can attach a FUSED wire directly from the battery to the alternator but, thats just the way GM designed it.

Look at thread# 5 in this post for your schematic

https://www.corvetteforum.com/forums...lternator.html

BC

johnfkimble

Thanks BC

Why is there a red positive wire from the alternator to the starter, which has the fusable link?
I don' t understand why GM did this when it's NOT the Alternator that turns the starter, it's the battery. So why this wire from the alternator?

I installed in the "Big 4 Wiring System which uses a 300amp fuse on the positive lead. Can I run a "FUSED" pos. lead directly from my battery to the pos. side of my starter as backup in case the fusable link on that alternator wire breaks?

Thanks in advance for your reply

John

johnfkimble

Ok, let me try and make sense of this. I'm in my sixties, old school and I recall building hot rods in my youth. I recall the battery always being DIRECTLY connected to the alternator and the starter, both pos. and neg.

I understand why new cars are wired the way they are with all of the electronics. BUT, I strongly believe the battery should still have a DIRECT connection to the alternator and the starter, both pos. and Neg. I understand there needs to be a ground to the frame for electronics, but NOT for the battery, alternator, and starter.

It seems to me if I install the the Big 4 Wiring System where there is a fuse on the positive leads connecting both the pos. & neg. DIRECTLY to the battery, alternator, and starter, that positive red wire from the alternator to the starter is no longer needed unless it is needed for ther stuff like the electronics.

If there is a fuse at the battery, then why do I need the fusable link on the red alternator wire that goes to the starter? I've had the fusable link break before and the car won't start. I want to eliminate this problem by wiring thing up differently - by-pass surgery.

So, what do you think about this line of reasoning BC?

What I want to accomplish is to eliminate "weak links" via by-pass surgery "adding" DIRECT fused connections where I can. For example, the corvette's negative ground from the battery is connected to the frame, NOT Directly to the starter or the alternator.

This is where I would make DIRECT connections because there is too much resistance on the frame for "free" flow of electrical energy. This is why the Corvette get codes that change from "C" to "H". Some electronics are not getting enough electrical energy, especially when idling. I think this happens because the stock alternator is "under-amped" and should be much higher, like 150 or even 200 amps.

Anyway, I'm going to try this old-school way of DIRECT wiring and see what happens.

Thanks again BC for your thoughts and suggestions

John

lionelhutz

It's just for ease of wiring. It makes very little difference in the big scheme of things. The alternator wire does not have to go directly to the battery.

The wire from the alternator to the solenoid is approximately 6 gauge. Do you really think 2' of about 4 gauge from the solenoid to the battery would cause much of a voltage drop?

The battery is directly connected to the engine block. The heavy cable from the battery connector goes directly to a bolt in the block above the starter.

My personal opinion is that a fusible link with intact insulation and sealed connections (use double wall heat-shrink) is way more reliable than a fuse with exposed connections.

FYI, industrial use does not allow terminals with set-screws on high strand flexible wire and for good reason. The connections fail too easily. But, in car use I see people doing this all the time.

reath1

Run your wires as you plan. Just make sure they are protected from rubbing or damage. You will be fine. I have 0 gauge run this same way in my car.

onspeed

Not to hijack, but anybody know the gauge of the two fusible links?

Just burnt one of mine up, looks like the smaller one is ~16 ga and the larger is 10 or 12ga? Can anyone confirm?

johnfkimble

GREAT! Thanks for your input. To be clear, would it be ok for me to "add" a by-pass red pos. wire from my alternator to the starter? AND since I now have a fuse on the pos. side of the battery to the starter, it won't be necessary to put a fusable link on this by-pass wire from the alternator to the starter. Right?

Would this setup be ok BC?

Thanks again for this priceless service you offer to all of us.👍✊👌👋👊🙏👏😎

johnfkimble

Hey BC, I need to find a hot ignition wire to run a small cooling fan. Where can I make this connection? I was thinking about tapping into the "day-lights"but the wiring is easily assessable.

So, is there a hot wire I can tap into in the engine bay?

Thanks for your expertise.

lionelhutz

You're fusing the starter?

As for power - aren't you adding wires? Tap off of them...

johnfkimble

No. The jumper wire that I would add between the alternator and starter, to by-pass the fusable link, would NOT be fuse because the Big 4 setup already has a fuse from the battery to the starter.

As for that "tap in" hot wire. I have two cooling fans that I want to turn on when I start the car. So I need to tap into a ignition wire. The day lights on the front corner of the C5 are on all of the time and I thought this would be a good place to find a hot wire, but are not easily assessable.

So I was asking you where can I tap into my "ignition" under the hood that's closer? Can I tap in via the fuse box? Or do I need to run this little wire all the way inside the under the dash? This is has nothing to do with the Big 4 setup, just trying to connect two little fans like the ones used in computers.

Your thoughts Sir

johnfkimble

Hey BC, you mentioned you used "0" gauge wire in your car. What kind of "0" gauge wire is best? I noticed the "0" gauge wire from car audio store carries this very fine strand wire.

I'm not sure this is the best "0" gauge wire to use. I think the "0" gauge wire used on welding equipment has a thicker strand and may be better.

Your thoughts Sir

onspeed

If you've got a fuse from your battery to starter wire, you should be able to run a direct line from starter to alternator.

As for tapping into an ignition wire, personally I'd tap into something at the fuse box for simplicity reason. Use a fuse tap and you don't have to cut into any wires. There might even be an unused slot although I can't recall for sure.

johnfkimble

Thanks BC

What size fuse should be used with "0" gauge wire? I read somewhere the fuse should 80% of the wire amperage I think. It was suggested I could parallel two 300 AMPS or even two 750 AMPS at the battery. The higher the better he said.

His reasoning is that fuses are very restrictive when used between the battery and the starter, but serve as a safety in case the wire is pinched. So he believes using high amp fuses, even two in parallel, would counter this restriction as the starter requires a lot of energy.

He is using two 750 amps in parallel on his Big 4 setup at the battery.

I'm not sure about this so I'm passing this by you first.

So, what say you BC

onspeed

I'm not Bill Curlee.

Also, I'm not an electrical engineer so take what I say with a grain of salt but a 750 amp fuse sounds almost useless. Don't know the CCA of my battery off the top of my head, but I want to say something around 550-600? So a 750 amp fuse wouldn't blow on a cold day if the terminals were shorted. By having a fuse/link on the alternator > starter side versus battery to starter allows for a much lower amperage fuse to be used since it shouldn't see much more than the output of the alternator which is ~145A I think.

Personally I would not get rid of the fusible links. They shouldn't burn up unless there's something very wrong for several seconds. If you're adding a direct line from the alternator to battery, just add an inline fuse to that, I think mine is 75A, and keep the stock wiring setup as is.

lionelhutz

The car was designed so it would work fine with the wiring that it came with. Don't you think doing things like running a 0 gauge wire in parallel with a 6 gauge wire which is already just fine for the stock vehicle, is a little overkill?

If you just "must" do an upgrade then add another 6 gauge wire with a fusible link in parallel with the existing alternator wire. Install heavier positive and ground cables from the battery to the starter and engine block. I'd say something about 2 gauge would be just fine. Since you seem worried about it, doing these wiring upgrades would be more than enough to ensure the alternator has a good heavy connection for charging the battery and the battery has a good heavy connection for cranking the starter.

I wouldn't put fuses between the battery and starter. There have been 100's of millions of cars manufactured without fuses between the battery and the starter. Just make sure the wire is neatly routed and protected against damage by heat or sharp edges.

Are you running a big stereo or something else that draws a lot more power? If you're not then maybe you should investigate why your system isn't working like it was designed. My car, with 160k mikes and the stock wiring still manages to have >14V at the battery when it is running. The factory fusible links are still in great shape. Adding a bunch of way over sized wires as this "big 4" kit calls for would just be a waste of money.

If you didn't know, the alternator measure the voltage at the starter solenoid so it can compensate for the voltage drop in the alternator to solenoid wire.

johnfkimble

Thanks for your comments

The reason I'm doing this by-pass surgery is because I hate being stranded because of a fusable-link that should have been located at the battery area instead of under the car where I can't easily get to it for easy fuse change and that requires unnecessary maintenance cost.

So, I am by-passing those little fu$kers and installing the fuse at the battery where I can pop the hood and change it out with ease myself. No mechanic needed, money saved.

The first time one of these fusable links broke, it cost me hundreds dollars for towing and mechanic repair just to fix this small little wire on my starter. NEVER again!!

The Big 4 Wiring System and the additional by-passes are well worth the time, money AND peace of mind.

Thanks again for your input👍😎

lionelhutz

The C5 Fusible links are very reliable. Make sure you do a good job with the new wiring install because using any kind of screw-down lug on high strand cable or making poor solder joints will make the car less reliable.

Also, using parallel 750A fuses on the main battery wire is simply dumb.

johnfkimble

You may be right about the 750 fuse. This guy was using 4/0 gauge welding cable for his Big 4 setup. His theory or rather his "experiment" is the bigger the wire, the bigger fuse. He also has a huge car audio system. That may be why he's using a 750amp fuse. It works for him!

I will be using 300amps in my setup. Thanks for the advise.