Gitten close, gitten close!

Hooked the fan up to the car today and ran it for about 30 minutes before it got too cold and had to retreat. Even the car was having trouble keeping the voltage up when it was running

The mercedes fan seemed to run just fine with a 90% pwm at 100Hz. It's not a 'true' test either, since the radiator it was strapped to was empty, and not dumping heat on the controller.

So, at this point, I'll finish up the code and do some more testing, then ship it off to Andrew for more in car testing.

One question though: with the 5 minute ignore button, what do you want to happen if the AC comes on 3 minutes later? 8 minutes later? I assume we'd turn the fan on in both cases, and let the AC override the other command?

so you are going to have a seperate input for the trinary?
if so then yes, that would be fine, but my guess is, that the car would be overheating too if you got an a/c signal to start the fan.

Perhaps the momentary isn't a great idea. or 5 min is too long.
The fan barely gets spun up before the trinary kicks it off based on only a/c input, so it doesn't take a lot of air flow to keep the a/c working.

perhaps one min is a better delay, or just leave it off if it is too much trouble. very few people will probably use it. the car doesn't over heat with the fan running. just thought I could save a bit of energy and heat by giving it a chance to shut off after I get to highway speeds.

Yes, I was thinking separate inputs for AC and the 5 minute ignore. This is still the prototype, so features are 'fluid'.

I guess for now we just want to verify that the 90% pwm keeps the fan from dieing, so that's what we'll focus on.

I'll see if I have time tomorrow to finish it up, then send it out early next week.

Sorry about being out of this thread for so long. I took the week off work to concentrate on building the hot rod.
Andrewh came over last night to finish up the wiring and help be drop the engine in.
I won't have it running this week. There simply isn't time.
Once it's up and alive, we can either test the fan controller on his car or the hot rod. Both of us have charging systems that can easily handle running the fans.

I'll dig around and see if I can come up with another old style fan.

What was the longest you were able to run the fan?
If you still have the 30 or 40 amp alternator in your truck it will definately have a hard time. You will need to keep the RPM up.

its been awfull quiet,are you guys still workin on sumthin us elektronical chalenged can hook up?

Quiet? Me?

I was hoping to send it off before thanksgiving, but then we got 1.5 feet of snow, and 10* temps since then

I'm still waiting for the temperature sensor pigtail to show up. If Andrew just wants to ground the sensor input to turn the fan on, I can probably send it out tomorrow. Otherwise it'll take a little longer to get the temp sensor mapped out.

I can just ground it, but if you complete it and send a sensor with it, I can plug it in to my car and test the whole thing I guess.

It depends on how thoroughly you want it tested.
Slap it on a fan and let it run all day or put it in the car and drive a few hundred miles?

Andrewh has a new style fan in his car. It's also a different shroud so the fans we use won't bolt up. We would have to test the controller on his existing fan.
I can change to an old style on the hot rod but it's not running yet. Close, but not there.

My concern is powering the fan for a long time without burning it out. I think that if you can get it to run more than 5 or 6 hours straight then it's done.

If you can't supply that kind of amperage, I guess we can slap it on the hot rod and try to fire it up ASAP. If it'll run all day long we'll be set.

If your temp sensor lead is something common or easy to tap then we can do it now.

This is a great thread. It needs to go in the archives when it's done.

Doesn't Andrews fan work fine with a constant 12v? If so, ideally, we'd find a fan that needs the PWM. If the fan works fine with a constant 12v, it should still work fine with the PWM, so we haven't really proven that the PWM keeps the controller from dieing.

I don't want to make you rush to finish the hotrod, but sometimes a kick in the rear is handy


I'm about to go ahead and get a 175A tuff stuff alt. Then I could actually install this fan and test it. It also started snowing again tonight, soo...I really need a garage

I did get the sensor tested and mapped out today, so about all I need to do now is add that to the code, then make the prototype more rugged, and send it to someone.

That is correct. The fan I have wired up runs fine on 12 volts.
My plan was to get another fan from feets, and wire that up to my car and your controler.
I just unplug mine and plug in the other.

I would at first just set it to ground so the fan came on full time and just leave my car idling in the driveway for a while. I can place the loose fan in front of the rad to pull air to keep the car cool and monitor temps with the computer.
Have some tuning to do anyway.
Based on the other threads, if it lives an hour or 2, it means it is working better than 12 volts straight.

Once we have that down I verify your controler works in running driving conditions with my fan till feets gets his car running and can run both on the street at the same time.

And in the off time, I can hook yours back up with a charger or idle in my driveway to make sure it lasts more than a couple of hours.

Depends on how impatient people get to have one, and your lead time on boards as to how much time we have.

I figure a month to be sure everything works as expected. But that is based on using feets car too. if the indivdual pieces check out, over the next week or two, it could be just that long.

I have an old style fan available for use.

Unless you're concerned with heat being a factor, I don't see the reason for shipping it to us.

Can you run it on your truck with a battery charger helping the alternator carry the load?
If not, can you simply have the fan suck the air out of a space heater for a couple hours?

I still think that if the controller can run the fan for a few hours without either of them failing the job is done.
The only concern left is making sure the controller will not fall off the car.

Since you're only using the controller as a trigger it can be mounted anywhere in the car. People could stuff it in the trunk under the package tray if they wanted to. It only needs a few small wires. All the big power will run straight to the fan.

Once Tuff Stuff gets back to me, I'll probably just buy the high amp alternator. Then I can do a proper test here. My charger is only 10A, which still may not be enough with the truck to power it

The heat I was wondering about was the heat on the fans controller from sitting on the hot radiator, not my board. The microcontroller I got is good to 300*F, so it should be just fine under the hood

I was under the impression that the fan I have is a (damaged) OEM Mercedes one, and that it would work fine with a constant 12v? And if so, I'd prefer to test on a fan that requires the PWM.

damaged maybe. as in the shroud might have cracks or a piece broken off.
but that is the style that requires a controler to not die.

so that will be the type to run your test on.
it will not handle a full 12 volts with 40 amps supplied.
someone ran it for a long time as long as the supply was less than 40 amps. his charger has a variable out put, so supplying 20 and 30 amps was fine. but it burned out after supplying 40amps.

I ran the test with the charger it would not run with the 40 amps for long. Anything less it would run for hours but it never reached full speed.

The fan I sent you has a metal heat sink. That is the type of fan that will fail.

well it is an either or thing not both.

A dip switch would be fine, marked ground on one side sensor on the other, OR
can you have an extra lead for ground instead of wiring through the sensor wires?

so if the extra wire sees ground fan comes on.

Not sure what you are getting from the sensor though. If it is resistance or some voltage, so not sure what you would do with the empty leads.