Sure, it happens… making it wrong sure takes to that scenario. And without considering the correct loads handled on every spot at certain stages.

I guess it got a 8 gauge wire or so to source it? LOL.

Most fans are wired into 14-16 gauge wire rate. Sure the start up instant would require thicker wire if the load for it was constant, but the start up high peaks are not larger than 1/4 of second or so, then the decay is abrupt once the fan stopped inertia is beaten

Correct fan wiring.

You are not understanding.

NOT WITH AMMETER EQUIPPED CARS,

I fully understand. I would bypass the ammeter and install a voltmeter. I would also install a fused larger gauge wire at the alternator to either a buss terminal, relay stud or battery, large enough to support the alternators maximum output.

Thats a DIFFERENT STUFF. All my explanation is based on cars still with ammeters in working order and also explaining how ammeter can be kept in place still with upgrades and safe.

The installation you posted is exactly the kind one which, on stock setup, acelerated the bulkhead burning process along the years and get ammeters out of their limits, being constantly stressed.

Now, bypassing ammeter and bulkhead at the same time with the tipical batt/alt jumper wire is, as told by John is a matter of prefferences, but even this must be made on the right way.

What happens when you are 50 miles from home and the alternator quits. Where does the load go then?

It comes from batt to feed fan, ammeter will show discharge. Sure, bulkhead and ammeter will get the fan loads.

Are we assuming the fan is replacing the stock fan clutch? Or being added to reinforce it?

But if alt quits the right thing is take the car appart and wait for tow, just like if brakes fail or Ign module.

In any case, that’s the exception, not the rule. If we think on every “WHAT IF” posible then don’t try to live.

You can also disconect the fan, and drive back home. Just 50 miles.

Also, if you think on every “what if” well, the same than get small spare parts on trunk, a piece of wire to jump out batt and alt and bypass the amm and bulkhead.

If you are driving at night, lights also will be affected, then the ammeter too.

Alt can fail also with belt broken… which is maybe easier than an alt fail itself.

What about if fan fails?

P.S.:
That’s why I’m fan of the stock fan clutch.

How many modern cars have an engine-driven fan?

It should not be forgotten that the silicone fluid in viscous or lock up fan clutches can be changed
so that the unlocked fan rpm can be varied - less to save horsepower or improve fuel economy,
but also more viscous to move more air.

Realize that fan designs done by CAD have greatly improved in the past 15 years - quieter and use less power to move more air.

Today’s best fans “look like mean Klingon weapons”
with sharp points, edges and creases that both stiffen and improve aero
but the blade positions around the hub are not always symmetrically arranged

If you are a bit shocked,
and think:
“I would really hate to stick my hand down into that”
it is probably an improved design.

John, how many cars still have carburetors? How many got ammeters? How many have a single coil or even a distributor? That premise doesn’t have sense my friend about the cars we are talking and working.

But it does reply to the question "what about if the fan fails". The same as if your fan belt breaks, s**t happens and that's no reason to reject a modern upgrade.

Well, yes… but at the end is cheaper and easier to replace the belt than the fan LOL. And you can get a spare on trunk

Yes, because OEM electric fans have such a failure rate that it is an issue

If you use a non OEM style fan, well you take your chances.

I put an electric fan on my 51 Plymouth. Several reasons why. I watched an engine masters dyno test where the fixed style fan my 51 had used approximately 30 hp to run, on a 97 hp (when new, lol) engine. So that was a cheap and easy 30+% increase in HP to the wheel. Not to mention it's quieter and fuel economy improved without that fixed fan running all the time.

If you're driving down the road and your fan belt breaks it usually drives something else as well. So not only have you lost the cooling effect of the fan but you're no longer pumping coolant through the motor. And quite likely you've lost power from the alternator as well.

On the other hand, if your electric fan bites the bullet you'll still have coolant flow, power, etc. and the airflow through the rad just might be sufficient enough for you to limp home.

Guys, I just said and fan of the stock fan clutch, not saying anything againts the electric fans LOL.

About what I’m not agree is getting the power to the fans from battery without take in mind you have an ammeter, which is a wrong procedement. This is the deal on the thread. Aside the alternator must be upgraded accordingly for it/them.