Electric fan

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moparwedden

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Ok I have already upgraded to the Mad dog wiring upgrade. All after market stuff like gauges and fuel pump are running off a relay switch to a separate fuse box on its own. I am getting to upgrade too an 300cfm electric fan, single. Will I need to upgrade my alternator. I am using the 60 amp stock. Lights are still hooked up threw existing wiring.
Thanks.
 
Well I reckon you'll find out when you hook up that fan? LOL
You know if you wanted to get real crafty you could just remotely hook up the fan while the car is running right now and see how much of a draw it puts on it?
 
300cfm? I hope that’s a typo. Should be more like 3,000 cfm.

All depends on the draw from the fan. It’s not unusual for fans of the right size to pull 40 amps on start up. That’s a short term problem of course, the running draw is lower. If you’re running all the accessories though 60 amps can go away pretty fast. People have done it, it’ll just depend on how much the fans run and how many other accessories you’re running.
 
300cfm? I hope that’s a typo. Should be more like 3,000 cfm.

All depends on the draw from the fan. It’s not unusual for fans of the right size to pull 40 amps on start up. That’s a short term problem of course, the running draw is lower. If you’re running all the accessories though 60 amps can go away pretty fast. People have done it, it’ll just depend on how much the fans run and how many other accessories you’re running.
Yes a typo. 3000 cfm
 
You should be able to run the fans with your existing alternator. It does not draw enough power to bother it
 
You should be able to run the fans with your existing alternator. It does not draw enough power to bother it

He says without having any idea of what fan is being used or how much it draws. Ok, your crystal ball must work better than mine, because some of those fans vary quite a bit in how much they draw, especially at start up.
 
Definitely run it off a relay. The secondary fuse block is a great idea.

Unfortunately with mopars fantastic approach to wiring the charging system, please not sarcasm..., There is no perfect place to pull power with an item that may run in both engine on and off configurations.

If you have a wire around set up in place, I'd tend to run the power off the alternator. The alternator powers the car with your engine running and most likely when the fan will be running.
 
Not much help John, but you mentioned original wiring for lights? Do the HL relay upgrade. I did it last year and a noticeable improvement.
 
Absolutley mine works better than yours. You are getting into specsmanship instead of the real world
I AGREE W/ STANSBLU, a lot of variance in elec. fans and loads on alternators ! What other loads does he have on it?
 
...your crystal ball must work better than mine.........

Lol...........
Eenie meenie chili beanie, the spirits are about to speak.
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No wipers,horn, or heater. Just lights, gas gauge. All other are on a different fuse box run threw a relay.

One thing to keep in mind is that hopefully the fan will only be running when the car is stopped or going real slow.
The down side is that the fan will only be running when the car is stopped or going real slow.
See what I mean there?
Normal running of the fan will usually be at real low RPM's where the alternator doesn't help a lot anyway.
I pull in and shut the engine down and maybe 30 seconds later the fan comes on to compensate for the climb in temp from not circulating the coolant, and brings it back down.
The next time I start the car the alternator replaces what was used out of the battery from the fan running after shutdown and restarting the engine.
When this is happening the electric fan isn't running because the temps are already a lot lower.

I can tell you I run a stock 60 amp alternator with a thermally controlled fan that comes on and goes off even if the car is turned off and I don't have any problems with it.
The controller is set to turn the fan on at 210 and back off at 195 so it never really comes on until I shut the car off or sit at a stoplight long enough for it to get up to 210.
If it is already on and I pull in and shut the car off the fan keeps running until the coolant in my motor gets back down to 195.
I actually like this, because it takes that recent shut down higher temps and pressures off the system real quick.

Hope I explained that ok. :D
 
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Absolutley mine works better than yours. You are getting into specsmanship instead of the real world

Well bud, here in the real world if the draw from the fans and accessories pulls more than the alternator puts out your battery doesn’t charge. That’s how it works.

A fan that pulls 30 amps isn’t hard at all to find, and it doesn’t take many accessories to pull another 30. And yeah, 60 amps is the rating, not what it puts out at idle or low rpm when the fan will be running. You want your crap to work in the real world, knowing a couple specs is pretty handy.

Or just make crap up and hope for the best I suppose. Or maybe burn up your harness or kill your battery.

No wipers,horn, or heater. Just lights, gas gauge. All other are on a different fuse box run threw a relay.

See, now that’s useful!

With no other big accessories you’re probably going to be fine. The draw from the fan would still be good to know to be positive, but it sounds like the fan is going to be the only major draw. A 60amp should be enough to deal with that in most conditions.

Doesn’t sound like you’ll be stuck in traffic with the fans, headlights, heater, wipers and stereo going at the same time.:D
 
The only issue with the lack of accessories is the shitty low rpm performance of most every OEM period correct alternator.

Put a Denso style on it from a late 80's Dodge van or pickup and the idle/low RPM performance is much better
 
The only issue with the lack of accessories is the shitty low rpm performance of most every OEM period correct alternator.

Put a Denso style on it from a late 80's Dodge van or pickup and the idle/low RPM performance is much better

An even better idea! :thumbsup:

Because yeah, an OE style 60 amp alternator doesn't put out anywhere near 60 amp at idle. Another reason to know the draw from that particular fan to be sure if it will work.
 
Found out fan draws 7-10 amps. 120 watts

Is that running or at start up? I’m guessing running considering how low that draw seems. Start up is less important anyway, since it’s a long term deficit that will cause problems.

With those numbers I don’t imagine you’ll have any issues, although, those numbers seem very low for a 3000 cfm capable fan.
 
A few basics (IMHO):

If your battery stays charged over a week of driving, your alternator is doing its job. It doesn't have to meet the peak load, which is why your car has a battery (unlike some 1970's 2-stroke motorcycles).

If you install a bigger alternator, design so your wires won't melt.

Mechanical clutch-fans work better and continued for a long time in longitudinal engines. The best electric fan is the Taurus 2-spd which hot rodders like. You can buy integrated fan controllers w/ relay and temp sensor fairly cheap, which beats "roll your own" design.
 
A few basics (IMHO):
Mechanical clutch-fans work better and continued for a long time in longitudinal engines. The best electric fan is the Taurus 2-spd which hot rodders like. You can buy integrated fan controllers w/ relay and temp sensor fairly cheap, which beats "roll your own" design.

Better? I don't think you can go that far anymore. None of the clutch fans will work as accurately as an electric fan with a programmable controller, which means with an electric you're losing less horsepower because you're not spinning a fan when you don't need one. And of course with a mechanical as soon as you shut the engine down you lose your fan, which doesn't have to be the case with an electric. You won't beat the efficiency of an electric fan with a good programmable controller with a mechanical clutch fan. Any losses you get from using electricity to drive the fan can be more than made up for by using a good controller.

As far as long term reliability, electric fans are much improved today. And mechanical fans fail too, the aren't indestructible. The clutches go bad, the water pump shaft/bearings go bad, fan belts can break or get thrown, heck depending on the fan the fan blades themselves can come off. They're not entirely problem free, although most of those problems should be fairly rare or preventable with proper maintenance. With the electrics there's just stuff that quits, so an inspection won't tell you something is about to go usually.

Pretty much all new vehicles, including those with longitudinal engines, come with electric fans now. And 100k mile warranties, so using an OE designed fan like the Taurus or Contour fans should give you pretty darn good reliability. So, "better" isn't a slam dunk for mechanical vs electric fans anymore. The mechanical fan with a clutch is still the most simple way to go though, because setting the electric fan up right means a good controller, relays, an alternator that can meet the new electrical demand, and some wiring upgrades to handle the extra current. Granted, most of these cars could use a good portion of those upgrades anyway, so, it's not like you can avoid all of those upgrades just by keeping a mechanical fan either.

Also the Chevy HHR fan works well.View attachment 1715142315

I have seen those used, seems like they're getting more use lately. The Taurus fans were the standby for a long time, and they work well for a 22" radiator. Looks like the HHR fans would be for a 22" core as well. I haven't seen CFM ratings for those, I know the Taurus fans are capable of over 3000 cfm and I believe that's on the lower speed of two.

For the 26" radiators, the Ford Contour dual speed, dual fan set ups are hard to beat. I love the one on my Duster, it works great. 3,000 cfm on the low speed, close to 5,000 cfm on the high speed. On my car the high speed rarely ever even kicks in, only on the 100+ degree days if I'm in town or in traffic. With the Dakota digital controller I can set the fan on/off temps by a degree at a time, same for the high speed, and even program a shut down timer to keep the fans spinning even after I shut down the car so it has better overheat protection and that will shut itself down for low voltage too so it won't kill the battery. It was a little bit of effort getting everything set up, but IMHO it was worth it compared to the simplicity of a mechanical fan.
 
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