Retrofit Electric Engine Cooling Fans

[gmachinz]

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....and then it all stays nice and sneaky and nobody really notices it.

 

[gmachinz]

....now I mount a 3-speed fan conversion relay harness I designed to the Motorcraft fan assembly and then there is only a 6-wire fan control harness that pops theough the side of the truck shroud and those wires get routed and it all retains a factory look.

 

[74 Shortbed]

Hmmmm, a **** load of options here, good thing I have a long ways to go before I get to this point, gives me a lot of time to make a decision, lol..

 

[notime2d8]

I'm also using the Windstar fans. My TBI 16197427 computer turns them both on. I have the computer switching a mini relay which switches on 2 40amp relays with 2 40amp breakers. I think I did 2 6 gauge wires to the junction and 4 gauge running from the alternator and battery to the junction with a 140amp alternator. No real drain with them both coming on. They were causing me to stall out when my battery was bad. My computer has the option to control one on high and one on low temps. I may do that in the future. I have the 454 radiator...I mounted the fans with 8 zip ties. Need to figure out a mount at​ some point.

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[gmachinz]

Ive built a few of these 6000 CFM dual 14" fan assemblies for BB and 6.2L diesel radiators. These fans require serious relay control power-running amps at full speed is 32-34!!

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[HotRodPC]

We'll call that set up Hurricane !!!

 

[Camar068]

Thought I'd post some results for the windstar fan here as well since it's a sticky.

Measured current flow on the fan. It's a 98 windstar fan made by TYC (part # 620270).

-small fan = (start spike/running) 29/7 amps @ 12.5V (amps will go down when running)
-large fan = (start spike/running) 34/15 amps @ 12.5V (amps will go down when running)

Last week I compared relays looking for voltage spikes when power was removed. I compared the 35 amp relays, out of a 2006 w/ built in varistor and the cheapo's from amazon (5 for ~$10).

The cheapo's did have a larger spike....but not as large as I expected. They had a ~8v spike. The 2006 relays cut it down to about a 2v spike. It didn't spike every time, I had to be quick hitting the freeze button on the o-scope to catch it.

[edit] I should mention the spike only happens when turning off the fan. The varistor helps protect your fan and relay from this spike.

 

[HotRodPC]

Good, I was going to copy that post over here too. You beat me !!! Rep Given

 

[Camar068]

I'm going to edit the above post again, but those amps were on a battery out of the vehicle. It was reading 12.5v. If you throw the 13.5-13.8V to it, the amperage will go down.

 

[Camar068]

The wire size on the fan relay box for a 2006 LS is 12 Awg. Should be fine as I over estimated for initial spike in the calculations below, running amps are way lower than shown. Also, this is at 12V, not your running voltage of ~13.5V. Copy and paste any over HR lol.

 

[74 Shortbed]

Great info thanks for posting that.

 

[gmachinz]

Ive built a few of these 6000 CFM dual 14" fan assemblies for BB and 6.2L diesel radiators. These fans require serious relay control power-running amps at full speed is 32-34!!

These fans NEW I've measured using my inductive amp probe as:

low speed 11A

medium speed 23A

high speed 34A

This is of course using a fixed resistorized circuit too so there is no high inrush current on any speed and the voltage spiking isnt an issue with the parallel diode equipped TYCO 100A load relays. The 3-speed conversion harness with fans wired in parallel (not series wired) can be setup on the positive or negative to control the fans-I just opt to use the positive side.

 

[Camar068]

high speed 34A

is that both fans running drawing 34 amps? If so, obviously more efficient/higher cfm than the TYC fan I have lol. Actually about the same now that I do the math (TYC ~21 amps both running). Yours guessing higher due to CFM. LOL wish I could afford it.

 

[1987 GMC Jimmy]

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....and then it all stays nice and sneaky and nobody really notices it.

I really like how nice and clean that looks. You might be onto something there, bud.

 

[Camar068]

ok we finally got the larger relays in to utilize the '06 silverado cooling fan relay box. More importantly I got the recommended size thermistors to eliminate the inrush current. I'll be damned it they don't work. I tested them on the battery I had laying around and THERE WAS NO CURRENT SPIKE! I've got pics of it, but so it's apples to apples as I posted earlier, I'll do it on the truck tomorrow at 14.5V and update.
lol screw it....here's what I've got on a 12.26V battery. I used the DC shunt I built and calibrated with a Fluke clamp meter that was calibrated last month. For every mV displayed = 1 amp.

This is the TYC 620270 98 windstar aftermarket fan. I'll update tomorrow with results of it running off the truck running at 14.5V.

[edit] ~35 amp inrush then down to about 8-10 amps constant:

pretty solid 8'ish amps....no inrush!

added the pics back:

without thermistor....notice it took about 2 seconds to get to normal-running amperage:

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With Thermistor:

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