Autometer Gauges Flashing When Taurus Fan Comes On - Alternator?

[73azbronco]

you need more horsepower ie amps. Get a 200A alternator, or more and rewire the output as required.

130a is fine for basic EFI, but fans add another 100A on the safe side.

a 76-93 mustang used a 200A alternator

https://www.americanmuscle.com/powe...0KkguSTxnqisSjwvCM3rsUK92QBufBTIaAjcgEALw_wcB

 

[ntsqd]

I must be missing something. We know that the fan doesn't draw anything close to 100A.

 

[73azbronco]

on startup maybe it does. Jeep world guys are using 800-900cfm fans drawing 90-100A running not startup surge. 2024 JEEP USES A 240A ALT.

 

[Timmy390]

I know the Taurus fan is a beast but I run this fan with a cheap eBay Rad and it keeps my W running cool and no flickering issues with a 90Amp Alt.
https://www.wildhorses4x4.com/high-...01wVZAsDfQJlcRJmKejarjHiUvxZdIAEaAtt2EALw_wcB

Tim

 

[DirtDonk]

And this doesn’t have anything to do with your issue, but are you calling an “internally regulated” alternator, a “one wire” alternator? Or has it actually been converted to a one wire voltage regulator?
If it has, why are you running a trigger/exciter wire?
Is it disconnected in the harness, or is it actually a typical three wire, internally regulated, 4G Explorer alternator?

 

[ntsqd]

on startup maybe it does. Jeep world guys are using 800-900cfm fans drawing 90-100A running not startup surge. 2024 JEEP USES A 240A ALT.

It normally draws ~22.5 amps by my math. I've never seen an in-rush current with a that much higher percentage than the steady-state current.
One electric HP needs 746 Watts, at 12.0 Volts that's only 62.2 amps. Guessing the in-rush current could be 100% that finally breaks 100A. I've not seen a fan motor anywhere near that big. This is how big a 3/4HP 12VDC electric motor is, it's not small:
https://www.amazon.com/dp/B00W1TNO6U/?tag=classicbroncos-20
I start one of these every morning and it doesn't pop a 60A breaker.


Those are Jeep guys, I wouldn't put much faith in anything that they do.

 

[Yeller]

When I was testing a thunderbird fan, Taurus 2 speed motor with the Mark VIII fan and shroud, I was getting in rush at 55 amps starting on high but only lasted a few milliseconds and then dropped to 28. I can see the inrush being a little more on this set up, the fan is larger and heavier. For reference same fan in a Mark VIII uses a PWM motor. I too feel your alternator is not an issue and that @jamesroney is on the right path of a weak ground to the gauges.

That fan is a beast, moves a noticeable amount more air and is quieter than a taurus. I was all set up to put it in my bronco and then figured out I was getting a steam pocket in the head and pushing the coolant out...... still on the shelf. Never installed due to needing an NOS water pump to clear the fan housing. Solving the air pocket issue solved the overheat issue. Just needed a bigger recirculation tank.

 

[EFI Guy]

Here's my .02. I measured right around 25-28 amp draw from the Taurus/Volvo fan, but on the initial spike, I have measured as high as 110 amps. I also have had it trip the 150amp circuit breaker that I was using on the output of the alternator. After switching to 175a Mega fuse, it was fine, but I eventually went to a PWM controller that I programmed to take 7 seconds before getting up to 100% DC.

I have seen people lately using the large car audio capacitors to feed the fan and that seems like a cheaper way to smooth the initial hit.
I have never used one of the one-wire converted 3 or 4 G alternators. But my experience has been that anything self-energizing often fails to energize properly at idle.

My final rant is just aftermarket electronics in general. When that circuit breaker popped, the car continued running off of the battery until it started acting real weird at 6 volts. I was surprised the factory EFI still ran with that low of voltage and I'm lucky it didn't cause damage because 1/2 the voltage doubles the amp draw.

Anything digital runs off of 5V maximum for the logic portion, so I can see why it still ran. However, aftermarket stuff doesn't seem to be able to step the voltage down if the input voltage is low, they just fail instead. My dataloggers, digital gauges, and such freak out at anything lower than 12 volts. So starting after sitting a while can play havoc with aftermarket electronics. I have a buddy who is running an aftermarket TBI setup that was given to him. Every time he starts the vehicle, the handheld resets and throws errors, even if it's on the charger, it has to be unplugged and reconnected every time. I've been over his wiring, it's solid. I think the old school starter just draws enough to cause problems.

The solution I'm going to try for my gauges and loggers is just a simple buck/boost converter on the circuit feeding those things. You set the constant voltage output that you want from 0-30V, and whether the input voltage is low or high, it kicks out the voltage that it was set to. If the wiring and ground for your gauges are solid, it might be something to consider.

 

[DanWheeler]

Great stuff and ideas, guys. Thank you and thank you James for the list of test points above, I should be able to work that tonight and report back. It takes a lot of brainpower to keep an old Bronco running and that's what I love about this board and the community - a lot of smart brains in the room who know what to do.

 

[Kalex]

I am running a fan out of a 1993 Mark VIII and have been since 2006. Mine was programmed to come on at 197 and go off at 203. Worked flawlessly for those 20 years with the exception of it when it cycled on you could feel the rig basically shudder. It came on at 100 percent once activated. It also ran through 2 relays in series. I was always worried a relay would fail. Anyway, I recently installed A PWM box with and inline 40 or 50 amp circuit breaker. Don't remember whether it was 40 or 50. . Anyway, again if memory serves correct is has 10 internal transistors at 110 amps each. It can control dual or a single fan. It has a soft start and you don't even know it's running. It also runs for about 10 seconds after shutdown for cooling. I bet it has never even caused my fan to run at over 30 or 40 percent of capacity as it only speeds up the fan if needed. You set the temperature on the control box to basically what you want your engine temperature to be based on your thermostat. I actually need to change my thermostat as my motor will now not get above 181 or so and that is with the control box on the hottest setting.

Before installing this current set up I spoke to someone at Derale about their control boxes and they said their boxes will not work with the Taurus, Mark VIII, and one other popular electric fan as the initial draw is too high. Or basically they wouldn't warranty the control box if you do hook it up one of those fans. There are a lot more options now than when I was doing this in 2006 as far as fans that move a lot of air.

 

[DanWheeler]

I am running a fan out of a 1993 Mark VIII and have been since 2006. Mine was programmed to come on at 197 and go off at 203. Worked flawlessly for those 20 years with the exception of it when it cycled on you could feel the rig basically shudder. It came on at 100 percent once activated. It also ran through 2 relays in series. I was always worried a relay would fail. Anyway, I recently installed A PWM box with and inline 40 or 50 amp circuit breaker. Don't remember whether it was 40 or 50. . Anyway, again if memory serves correct is has 10 internal transistors at 110 amps each. It can control dual or a single fan. It has a soft start and you don't even know it's running. It also runs for about 10 seconds after shutdown for cooling. I bet it has never even caused my fan to run at over 30 or 40 percent of capacity as it only speeds up the fan if needed. You set the temperature on the control box to basically what you want your engine temperature to be based on your thermostat. I actually need to change my thermostat as my motor will now not get above 181 or so and that is with the control box on the hottest setting.

Before installing this current set up I spoke to someone at Derale about their control boxes and they said their boxes will not work with the Taurus, Mark VIII, and one other popular electric fan as the initial draw is too high. Or basically they wouldn't warranty the control box if you do hook it up one of those fans. There are a lot more options now than when I was doing this in 2006 as far as fans that move a lot of air.

I spoke to Derale about this too and they would not give me technical details about why they don't support the Taurus fan for their controllers but I think I eventually I figured it out... I believe it's because their controllers/relays switch the ground for the fan instead of the positive. I actually have their controllers with temp controller for my low-speed control on the Taurus and I had to double relay it because their controller has the relay output switching ground instead of positive. Was too difficult to re-wire it so I just used another relay downstream switched on ground. But I'm kind of assuming their other controllers are set up the same to switch ground.

 

[DanWheeler]

And this doesn’t have anything to do with your issue, but are you calling an “internally regulated” alternator, a “one wire” alternator? Or has it actually been converted to a one wire voltage regulator?
If it has, why are you running a trigger/exciter wire?
Is it disconnected in the harness, or is it actually a typical three wire, internally regulated, 4G Explorer alternator?

Mine is internally regulated, yes, and has a single wire coming from the top post to the rest of the system. The trigger wire is jumpered to the top post so it tells it to turn on when the alternator starts spinning. I really thought that's what everyone was doing these days.

 

[ntsqd]

One wire alts are still popular in hot rods where its fewer wires to hide.

 

[MD]

I spoke to Derale about this too and they would not give me technical details about why they don't support the Taurus fan for their controllers but I think I eventually I figured it out... I believe it's because their controllers/relays switch the ground for the fan instead of the positive. I actually have their controllers with temp controller for my low-speed control on the Taurus and I had to double relay it because their controller has the relay output switching ground instead of positive. Was too difficult to re-wire it so I just used another relay downstream switched on ground. But I'm kind of assuming their other controllers are set up the same to switch ground.

Dan, Derale has a PWM controller which will work with the Taurus fan, and I highly recommend that along with others here.
There is only one type of Derale fan controller which switches on the ground side. The reason it will not work with the Taurus fan is for two reasons:
1. Limited to only 25 amps which the Taurus high speed circuit exceeds.
2. Taurus two speed has a common ground for both speeds, so you can't use a ground switched relay.

Can you clarify how you previously had the RED, YELLOW & BLACK wires connected from their wiring diagram?
(Sorry can't include a cropped image here from some reason, here is the link to the doc with the diagram)
https://derale.com/images/stories/virtuemart/product/pdfs/16759.pdf

 

[Kalex]

Mine also switches on the ground side. Don’t think I mentioned that. It also has a fail safe that you can wire a switch to turn on the fan at 100 percent to override the controller. Has an A/C pin as well if you have air conditioning. I don’t, so I didn’t use that pin.

 

[Kalex]

In the right hand, driver's side you will see the control box and the associated wiring. From the top #7 is ground, Fail safe, A/C, Sensors, Ign, Bat. On the right of the box you can see that you can wire two fans or they are internally connected so you can just use one and run one fan which is what I am doing. I should not have said it won't work with the Derale or other boxes, but rather they won't warranty it if you use one of their list of fans that are a no go. It does say diesel radiator on the fan controller, but clearly doesn't matter. For a 25 dollar difference I bought the most robust box he made. There are quite a few install videos on youtube and he includes very good instructions. I am terrible at wiring and all associated and I figured it out.

 

[DanWheeler]

OK did some poking around with the voltmeter tonight...

per jamesroney's questions - answers are listed as: at battery / at gauge post / Summit voltmeter itself

1. Ignition off? - 12.5 / 12.4 / 11.6
2. Ignition off, headlamps on? - 12.4 / 12.18 / 11.6
3. Engine on, headlights off, at idle? - 14.46 / 14.15 / 13.5
4. Engine on, headlights off at 2k rpm? - 14.5 / 14.05 / 13.5
5. Engine on, headlights on, at 2k ? - 14.49 / 13.96 / 13.4
6. Engine on, headlights on back at idle. - 14.49 / 13.98 / 13.4
7. Ignition off again. - forgot to do this one

From this, we can conclude the Summit Racing volt meter reads a little low which is fine and not indicative of an issue by itself.

I also did a bunch of checking between the + lug on the in-cab fuse block which is fed by about 6' of 4GA battery cable and multiple points on the chassis. I get a little voltage drop, maybe .3 or .4 volts on the chassis compared to right at the battery but I think that's to be expected. Doesn't seem like a ground issue.

Here's two things I thought were strange:

1) My initial engine-off voltage reading at the battery was 13.2 which was taken right after removing the trickle charger but dropped to 12.5 after a few minutes. Can't remember if that was ignition on or off but it was dropping way faster than I'd expect. This either tells me I have a parasitic draw or there was just some residual current in the system from the trickle charger. (no idea if that even makes sense electrically) I don't think it was dropping further than 12.5 other than what you might expect from having the ignition and lights on for 10-15 minutes taking the readings above.

2) Right after taking the trickle charger off and starting the engine and running the taurus fan on high, there are zero issues with the Autometer gauges coming on and off. It's not until I go for a 5-10 minute drive (which gets it hot and runs the fan) that my voltage starts dropping down to a level where the Autometer gauges start getting unhappy.

I noticed my idle vs 2k rpm results for questions 3 and 4 seemed to show that the alternator was putting out slightly LESS voltage at 2k RPM than it was at idle. That's interesting.

I also observed my voltage going back UP after returning from my drive and letting it sit in idle without the fan running.

It really seems like the alternator is just not keeping up with the fan. I know the Taurus fans don't draw enough to max out my alternator but maybe with everything combined (fan, fuel pump, ignition, coil, gauges, lights, etc.) the alternator isn't keeping up? Is it possible the alternator is tired and is just barely hanging in there?

 

[DanWheeler]

Dan, Derale has a PWM controller which will work with the Taurus fan, and I highly recommend that along with others here.
There is only one type of Derale fan controller which switches on the ground side. The reason it will not work with the Taurus fan is for two reasons:
1. Limited to only 25 amps which the Taurus high speed circuit exceeds.
2. Taurus two speed has a common ground for both speeds, so you can't use a ground switched relay.

Can you clarify how you previously had the RED, YELLOW & BLACK wires connected from their wiring diagram?
(Sorry can't include a cropped image here from some reason, here is the link to the doc with the diagram)
https://derale.com/images/stories/virtuemart/product/pdfs/16759.pdf

The way I have the fan wired is working great, so I don't want to mess with that but thank you for the suggestion, I'll still check it out. I'm using a simple high-amp relay for the fan high speed and a standard relay for the low speed which is triggered by the ground switched relay on the Derale controller (yes, the one you linked the PDF for) Not sure about the colors but basically the large black wire is normally the output for that Derale fan controller and I just run that into pin 85 or 86 on the relay switching +12v for the low speed on the fan.

I'm using this 3 position residential A/C switch to allow me to set the Taurus fan to OFF / AUTO / ON / HIGH. Works great.
https://www.amazon.com/dp/B0899XCWKW/?tag=classicbroncos-20

 

[ntsqd]

To get real, steady-state readings from strictly a battery it needs to 'rest' for a little while after any outside voltage source is removed before taking any measurements.

 

[DanWheeler]

To get real, steady-state readings from strictly a battery it needs to 'rest' for a little while after any outside voltage source is removed before taking any measurements.

got it, thanks. Guess that explains the initial drop.

Unrelated to that - just another data point, the alternator is making a slight clicking or ticking noise. I think it's been doing this for years.

I think my next steps will be to try a temporary jumper wire from ignition +12v to the alternator then maybe get some current draw readings with a clamp meter to see what my total draw is with fans, lights, fuel pump, radio, etc. before I go waste money on a 200 amp alternator vs a stock 130 amp. 200A seems like a LOT. That's 2400 watts at 12v right? That's like 40 incandescent light bulbs! Does anyone's rig really use that much?