Electrical E-fan... Pulls Sooo Much Amperage. Help?

[Adams91LX]

This weekend I installed my Mk8 fan.. I made a relay harness myself, installed the new timing cover, water pump, p/s pump, alternator, and a/c compressor (94-95 accessory swap)..

When my fan kicks on it pulls so much amperage. I have a 130a 3g alt already..

I was wondering if I could hook up a capacitor to help even out the drop... i got a 1 farad cap for free. But, I'm not sure where to put it the circuit. My battery is in the trunk, and I definitely need to keep the capacitor inside the car (trunk or cabin). I thought about putting a short 0/1 ga stint between the positive post and the capacitor, then hooking up the cap straight to the current battery cable.. opinions?

 

[fiveohwblow]

I know it may seem annoying, but my first question is; "what" is happening when it kicks on and the current draws?

I ask because if nothing is happening you just dont like seeing a needle dip than it might be something you can put your OCD on the shelf for...

 

[RangerJoe]

I don't know anything about capacitors. Alot of people like to use the DC Controllers, Spal Controllers, and I'm sure there are a few others out there. They turn the fans on at 50% or so and then gradually speed them up to avoid the amp spike. I burned up a cheap AutoZone fan controller with my dual Focus Fans. After that I made my own controller using a painless temp switch and put each fan on its own relay. It did nothing for the power spikes, but two relays handle the power just fine.

I recently swapped out my radiator for a Mitsimosho 3 row with their dual fan setup. The fans suck....well, not enough actually. I loved that they drew very little amperage, but they couldn't keep my car cool in this 95+ degree heat around town. I swapped back to my focus setup, and it sucks tons of amps, but I can't get the thing to overheat. I hotrodded it around town the other day, red light to red light, in 91 degree heat. It never even sweated it. I guess I will put up with the amp spikes.

On a side note, I may get shot for saying this, I was looking into a DC controller before I built my own relay one, but I couldn't get the guy to return my emails regarding questions I had about it. I know he makes them at home, on the side, but I'm not going to spend my money on something that I'm not totally clear on and can't get any customer support on. JMO.

Joe

 

[Noobz347]

I don't know anything about capacitors. Alot of people like to use the DC Controllers, Spal Controllers, and I'm sure there are a few others out there. They turn the fans on at 50% or so and then gradually speed them up to avoid the amp spike. I burned up a cheap AutoZone fan controller with my dual Focus Fans. After that I made my own controller using a painless temp switch and put each fan on its own relay. It did nothing for the power spikes, but two relays handle the power just fine.

I recently swapped out my radiator for a Mitsimosho 3 row with their dual fan setup. The fans suck....well, not enough actually. I loved that they drew very little amperage, but they couldn't keep my car cool in this 95+ degree heat around town. I swapped back to my focus setup, and it sucks tons of amps, but I can't get the thing to overheat. I hotrodded it around town the other day, red light to red light, in 91 degree heat. It never even sweated it. I guess I will put up with the amp spikes.

On a side note, I may get shot for saying this, I was looking into a DC controller before I built my own relay one, but I couldn't get the guy to return my emails regarding questions I had about it. I know he makes them at home, on the side, but I'm not going to spend my money on something that I'm not totally clear on and can't get any customer support on. JMO.

Joe

I've heard that a number of times about him. The DC Controlers are more than just a relay though. No spikes, no nothing. It ramps up slowly to avoid that.

 

[jrichker]

Some explanation of what PWM is and how it works would be helpful. Both the SPAL and DC Control fan controllers use PWM to vary the fan speed according to engine coolant temperature.

Any fan controller that uses a relay to directly control the main fan cannot use PWM. The relay will not switch on and off quickly enough to make PWM work correctly.

Some units may use a relay to turn on the auxiliary fan used for the A/C condenser or some purpose other than controlling the main fan.

 

[Gearbanger 101]

I've heard that a number of times about him. The DC Controlers are more than just a relay though. No spikes, no nothing. It ramps up slowly to avoid that.

I get the initial needle dip with my DC fan controller, but it quickly recovers. I am however running underdrive pulleys....but I'm also running an overdriven 150a 3G unit.

 

[stang&2Birds]

Summary: Get a DCC controller and leave me alone.

More info:
1) Your POS 1F cap isn't going to do squat to lessen the start-up load from the fan.
2) @gearbanger-101: Yea, but what voltages are you talking about and for how long. If you go from 13.8V to 13.4V back to 13.8V, then BFD.

Feel free to see how much an Electrical Engineer with 5+ years of experience makes. And, if you think that you "know everything" from the quick first level approx that I'm going to go over, and the POS simple *ss (and often incorrect) info you find on the interweb, then WTF didn't you became an Elec Engr right from HS?

So, from a MILLION MILE SUPER MEGA HIGH-LEVEL VIEW:
A 1F cap has enough charge for 1amp @ 1V for 1 second.
For the fan, you would need ~70amps at 13V for ~4 seconds. In other words, very roughly 70 * 13 * 4 Farads = 3,500F.
Note: In real life, that's not accurate - it would be much more. But, it gives a very very rough "first level approximation".

A super quick google search found:
http://forum.onlineconversion.com/showthread.php?t=4848
http://www.candlepowerforums.com/vb/showthread.php?210264-on-supercaps
NOTE: I did not look at detail at the info. But, it seems close and on the right track.


So, if you want a real life cap that that could reduce some of the instantaneous current draw (very very very roughly ~80 amps for ~0.1 seconds) in an automotive application, then you're in luck! In fact, it's even in stock!

View attachment 146262
PDF: http://www.maxwell.com/products/ultracapacitors/docs/datasheet_48v_series_1009365.pdf
Link: http://www.digikey.com/product-detail/en/BMOD0165 P048 B01/1182-1031-ND/3079295
Digi-Key Part Number 1182-1031-ND
Price: $1,729
Quantity Available 28
Maxwell Technologies Inc
Manufacturer Part Number: BMOD0165 P048 B01
Capacitance: 165F
Voltage - Rated: 48V
ESR (Equivalent Series Resistance): 6.3 mOhm
Lifetime @ Temp: 1500 Hrs @ 65°C
Size / Dimension: 16.457" L x 7.638" W (418.00mm x 194.00mm)
Operating Temperature: -40°C ~ 65°C


Oh yea, you'll likely need a few thousand dollars of stuff to properly switch the cap in and to charge it and for a diode, etc, etc. Or, take a sawsall to the rear side of a nearby Prius, and yank all of that stuff out.


IMHO, all of the SPAL and other "big company" cr*p is just that - CR*P! I've had a POS "big company" fan controller go on me during the summer (when else - duh), and I was "lucky" in that I had an iron block and heads in that car, and I didn't drive far. So, it was "only" replacing the blown head gaskets.

For my money and for my engine, I went with a DCC.


[on soapbox]
Note: It takes 3+ MONTHS TO GET A DCC CONTROLLER - PERIOD END OF DISCUSSION!
So, STFU about "It's been a month and I haven't gotten mine yet".
DO A *****ING SEARCH!!! :search:
[off soapbox]

 

[Gearbanger 101]

Note: It takes 3+ MONTHS TO GET A DCC CONTROLLER - PERIOD END OF DISCUSSION!
So, STFU about "It's been a month and I haven't gotten mine yet".

Really....I got mine in about 3 1/2-weeks....and that was shipped to Canada?


BTW.....why are you so angry all of the time?

 

[RacEoHolic330]

My DCcontroller also only took about 4 weeks to show up. I'm sure he has busy and slow seasons.
I was also going to comment on how a cap will not help the "across the line" current draw from the fan, but 2birds did it with a level of sarcasm that I could never match!

 

[Adams91LX]

I tried to find this thread again, it turns out it was moved to tech... seems reasonable.

If my headlights are on, and the fan kicks on, it may/may not stall.

It is drawing a ton of amps, for less than .5 seconds.... I know the DCC and SPAL current ramp, and in fact, the Lincoln Mk8 used the ECU to PWM the fan on so it wouldn't spike amperage draw.

I was hoping a 1 farad cap would help.

I think I am going to try it, see how well it does... worst case I'll either swap the fan... or... cough up the DCC funds... which I would hate to do.

 

[fiveohwblow]

First time I've liked a Brian post.

Write that down.

 

[RangerJoe]

Really....I got mine in about 3 1/2-weeks....and that was shipped to Canada?


BTW.....why are you so angry all of the time?

This was what I meant when I said, "I may get shot for saying this."

 

[stang&2Birds]

but 2birds did it with a level of sarcasm that I could never match!

Somebody gets my posts. Actually, many people do. Some people do not.
Gee you'd think that with all of the smilies, it'd be clear.
I do not get paid for my time or for my posts. So, if I can't have some fun in my posts, screw it!

 

[stang&2Birds]

BTW:
To be clear, *I* think that the OP and orig question was very good!

My comment about people trying to do electrical engineering design was to head off someone from quoting some BS web page or post. I don't have the time or desire to argue about electrical design.

Often people read web pages that go over simple ideal theory, don't even think about how that does or does not fit their exact application, and often completely ignore the issues of real life design.

It's similar to how when people read the info on:
http://www.miracerros.com/mustang/
and, they all of a sudden "know everything there is to know about coils, suspension design, etc".
Gee, I guess those mechanical engineers are also idiots for spending 4-5 years in collage when everything they need to know can be summed up in a dozen or so web pages.
Wow, people blab off about coils/height/etc don't even think back to the fact that since the front coils are in an arc, that alone invalidates a lot of their calculations and assumptions.

 

[stang&2Birds]

I tried to find this thread again, it turns out it was moved to tech... seems reasonable.

If my headlights are on, and the fan kicks on, it may/may not stall.

It is drawing a ton of amps, for less than .5 seconds.... I know the DCC and SPAL current ramp, and in fact, the Lincoln Mk8 used the ECU to PWM the fan on so it wouldn't spike amperage draw.

I was hoping a 1 farad cap would help.

I think I am going to try it, see how well it does... worst case I'll either swap the fan... or... cough up the DCC funds... which I would hate to do.

That sounds like a different issue.
I know. I drove my Stang with a dead alternator and the battery so low that my radio, radar detector, etc wouldn't work. The Fox ECC and TFI don't require a lot of voltage to work.

So, you likely have a grounding/connection issue. Fix that, and, for now, don't worry about getting a DCC.

You need very good grounds and power connections for a MKVIII Fan.
Also, Ford use did the cheap/stupid thing of using a timing cover bolt as the main ground connection. WTF? That would never every get by today. But, it was cheap, and it has "worked". It also helps in electrolysis of every water pump bolt/stud to the cover and block.

First thing to do is to move the ground wire to a nice solid ground on the block. Make sure that the connection is clean and use dielectric grease.

Also, make sure you have good battery cables and dielectric grease on both connection ends of the cable.

Also, you want the power to your fan to come from a separate wire from the battery through a fuse. Also, don't forget to include a good solid ground wire from the battery to the fan ground.

Yea, some people get lucky with poor wiring layouts for their electric fans. Real people also win millions in the lottery! However, the vast majority of people don't get lucky.


BTW: If you order a DCC controller in early March means that you may get one before the summer is finished! But, no guarantees!

 

[rustyruststang5]

is this a dcc http://www.dccontrol.com/selector.htm ?
what one would be good for a 98 v6 contour fan?
im using a spal right now in one of my cars and like it, but it is alittle on the expensive side... but so is that dcc.

 

[blackstangt]

There are a lot of ways to reduce the current or voltage (above stall voltage) available to the fans, with a simple switch controlled by the driver or by sensing the draw one circuit before allowing a second one to come on. Alternatively, if you have a Dual Fan setup, you can have them come on seperately to reduce instantaneous draw by running separate controls or switches.
An easy way (and the cheapest way) to do that would be a separate switch in the car.
Any of these methods would be far cheaper than a capacitor or DC controller, and only require basic wiring knowledge.

 

[Noobz347]

First time I've liked a Brian post.

Write that down.

 

[jrichker]

There are a lot of ways to reduce the current or voltage (above stall voltage) available to the fans, with a simple switch controlled by the driver or by sensing the draw one circuit before allowing a second one to come on. Alternatively, if you have a Dual Fan setup, you can have them come on seperately to reduce instantaneous draw by running separate controls or switches.
An easy way (and the cheapest way) to do that would be a separate switch in the car.
Any of these methods would be far cheaper than a capacitor or DC controller, and only require basic wiring knowledge.

On a good day, there are about 5 people who can do more that spell electricity here on Stangnet. Most of the people here are devoid of electrical knowledge, and shun electrical projects.

Since 2008, I have offered to send a free set of diagrams and a parts list for an prototype analog computer/PWM fan controller to all interested parties. In that time I have gotten maybe 5 requests. No one has ever emailed me back and said that they even tried to build it once they got the diagrams and parts list.

Stang&2Birds, here is your opportunity to be constructive or destructive.

This is a build it, troubleshoot it yourself item. I will not build or troubleshoot units, so it is not suitable for anyone who isn't really good with electronics.

 

[stang&2Birds]

Stang&2Birds, here is your opportunity to be constructive or destructive.

FFRDCs have gotten very strict on other contracts and sources of income. I had to give up my second consulting gig. Well, I guess if I could have gotten the "okay" from President Obama, they may have let me keep my 2nd consulting gig doing electronic controllers for specialized power supplies. So, no way I'd offer competition to Brian. Also, IMHO, the DCC is ~1/3 the cost is really should be, and is far far superior to the CR*P out there!

With the above said....

As Brian has mentioned over the years, there's more involved in the DCC than a simple feedback loop. Fine tuning for the update rate is part science and part art. That's because it's designed to work in many different applications with many different radiators with many different engine heat loads with many different FANs, etc, etc.

Also, the DCC has a fireproof board, the electronics are fully conformal coated ("sealed from moisture"), and Brian has done extensive analysis on not running the components too hot or even close to their power ratings (both kill parts quickly).

I got MEGA ******ed ONCE with a cheap fan controller. Everyone makes mistakes. Smart people learn from their mistakes. Idiots keep repeating the same mistakes over and over. IMHO, if there wasn't the DCC, then *I* would go with simple thermostat/relay based system with a switch backup.