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Re: Mercedes fan upgrade [Re: DaveRS23] #838250
11/12/10 10:28 PM
11/12/10 10:28 PM
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ky hills
thehemikid Offline
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Quote:

WOW!!! I was just hoping to get a fan controller here, but I am getting an education to boot. Keep up the brain storming guys.






...Dave are you still looking/leaning towards variable speed or high & low by temp switch.
...

Re: Mercedes fan upgrade [Re: thehemikid] #838251
11/13/10 02:06 AM
11/13/10 02:06 AM
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Oregon
hooziewhatsit Offline
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Alrighty, I first tested by giving the trigger wire a variable voltage. It wouldn't turn on until I hit right near the battery voltage (12.7ish on this one). It didn't turn off again until I hit about 9.5v while slowly decreasing the voltage on the trigger wire. I didn't hear any difference in the fan speed between giving the trigger 12.3v or 9.5v.

It was the same thing when I fed that voltage through the controller; with an 8v PWM it did not come on. With a 12v PWM, I couldn't hear a difference in speed between a 95% and 85% PWM.

Sooooo, it appears that the fan is on/off only. I guess that makes the controller easier.

Although with an HHR type fan, if there isn't a fancy controller onboard, I could switch the main current with a PWM to control its speed


If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: DaveRS23] #838252
11/13/10 09:21 AM
11/13/10 09:21 AM
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San Jose, California
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DennisH Offline
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Baloney. Clutch fan. Copper rad. MaMopar knew what to do.

Re: Mercedes fan upgrade [Re: DennisH ] #838253
11/13/10 02:09 PM
11/13/10 02:09 PM
Joined: Jan 2003
Posts: 28,063
Irving, TX
feets Offline
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feets  Offline
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Thanks, Dennis. That whole points and condenser thing worked out well too, didn't it? Now please go stand in the corner for sticking your nose where it doesn't belong.

Dave, can you fire up the fan and let it run until the battery voltage will no longer support it?
If the controller will run the fan for a long time without letting the smoke out then I believe your job is done. It makes for a cheap controller too.
Adding variable speeds and other fun stuff is simply icing on the cake.
I know the Mercedes fans fire up on a high speed then drop to a lower speed. I see and hear that happen in the shop all day long. Maybe MB drops the voltage after the fan hits it's top speed. Feel free to explore that if you like.
I still would like to know if that 4th line is simply a feedback for the fan motor tachometer or if that is used for other purposes. Is it possible to dig into that when you have time?

You can play with the HHR fan beside the MB fan and find out for yourself that it doesn't come close to moving the same air. The MB fan is also a better fit.


We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: Mercedes fan upgrade [Re: feets] #838254
11/13/10 10:51 PM
11/13/10 10:51 PM
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Oregon
hooziewhatsit Offline
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Well, it ran for 22 minutes, until the voltage on the battery dropped to 10.2ish. 90% of that is about the 9.5v I observed earlier where it turned off. After a couple minutes for the battery to temporarily recover it started right back up (albeit with the voltage dropping quickly).

I was going to do some more research on the controller itself, and then try some different frequencies and see if I can make anything work.

Otherwise, it looks like the controller will be just be an on/off deal, driving the fan at 90%.


If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838255
11/13/10 10:54 PM
11/13/10 10:54 PM
Joined: Jan 2003
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Irving, TX
feets Offline
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That's good enough for most folks. Some of us (read: Andrewh, me, and other EFI guys) would keep digging for more.

Making it on/off at a user adjustable temperature setting would make for an easily built and cheap controller.


We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: Mercedes fan upgrade [Re: feets] #838256
11/13/10 11:05 PM
11/13/10 11:05 PM
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gtx69 Offline
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Have you tryed to leave the charger hooked up to the battery while the fan is running to keep the battery charged up.That is how i was able to keep fan running for hours.

6300596-HPIM0413.JPG (78 downloads)
Re: Mercedes fan upgrade [Re: thehemikid] #838257
11/13/10 11:36 PM
11/13/10 11:36 PM
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Benton, IL.
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DaveRS23 Offline
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Quote:

Quote:

WOW!!! I was just hoping to get a fan controller here, but I am getting an education to boot. Keep up the brain storming guys.






...Dave are you still looking/leaning towards variable speed or high & low by temp switch.
...




Given the volume of air that this bad boy pushes, I thought the variable speed would be nice. But, the important thing is that is that it moves that much air. So on and off is fine. I am just real happy that someone is taking the time to do this for us electricityly challenged folks.


Master, again and still
Re: Mercedes fan upgrade [Re: DaveRS23] #838258
11/14/10 01:32 AM
11/14/10 01:32 AM
Joined: Sep 2009
Posts: 1,805
ky hills
thehemikid Offline
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ky hills
Quote:

Quote:

Quote:

WOW!!! I was just hoping to get a fan controller here, but I am getting an education to boot. Keep up the brain storming guys.






...Dave are you still looking/leaning towards variable speed or high & low by temp switch.
...




Given the volume of air that this bad boy pushes, I thought the variable speed would be nice. But, the important thing is that is that it moves that much air. So on and off is fine. I am just real happy that someone is taking the time to do this for us electricityly challenged folks.




...I agree on/off is fine, to be able to have & run that Monster and live for a long time. I hope its not to loud that it would drown out a small roller cam'd Hemi with 3" exhaust but sounds like it might. That may be the price of having a little over kill in the cooling department. I like over kill. I heard it in the video, but I haven't heard this thing in person yet either. That's the only drawback I see. ...well it might be a little hard on batteries & alternators.
...still
...& thankful for their efforts.

Last edited by thehemikid; 11/14/10 01:42 AM.
Re: Mercedes fan upgrade [Re: thehemikid] #838259
11/16/10 03:08 AM
11/16/10 03:08 AM
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Oregon
hooziewhatsit Offline
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I've tried drive frequencies from 30Hz, to 22kHz. At the higher frequencies, it still runs with a 10% PWM, but the fan speed doesn't change from the max.

Without getting a mercedes on my Oscope, or getting documentation outlining how to control the fan, or even a wiring diagram, it looks like we'll be stuck with on/off

However, since it will have a microcontroller in it, if I figure it out eventually, you can just send it back to me, I'll update the code, and you'll have variable speed

Edit: I just shoved some wire into the plug to go to the 4th terminal. On the oscilloscope, it just goes high (12v) the entire time the fan is running. Usually, a circuit like this would have a resistor pulling it to 12v, then a switch to pull it to ground for each rotation. I'm not seeing anything like that.

Last edited by hooziewhatsit; 11/16/10 03:22 AM.

If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838260
11/17/10 01:43 PM
11/17/10 01:43 PM
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s.w.fl
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bonefish Offline OP
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OK,i scored this fan locally for cheap so i picked it up,its from a 2001 c320,its obviously not the ideal wire fan,how close are we to making it work for a sinple hot rod carberated application,no efi or ac.

6306227-fan(Small).jpg (73 downloads)
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838261
11/17/10 10:57 PM
11/17/10 10:57 PM
Joined: Oct 2004
Posts: 132
Colorado Springs
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Bens_Coronets Offline
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hooziewhatsit,

Are you testing w/o the blades? If so the PWM might not lower the RPM due to not having a load/drag on the motor. It could simply be that the internal magnets can run the motor at the full speed with lots of PWM (lower % on time) with no fan dragging it down.

Another test I can think of is to just add a resistor inline to lower the voltage. It'd be interesting what it's output is at 6 Volts.

But then I run into the problem of how to get 6 volts. I thought I'd easily find a 12V to 6V 'box' for use on pre-50's cars with a mixed power system. However I can't seem to find such an animal...

too bad the batteryies don't have a 6V tap on them.

Ben

Re: Mercedes fan upgrade [Re: Bens_Coronets] #838262
11/18/10 02:16 AM
11/18/10 02:16 AM
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Oregon
hooziewhatsit Offline
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Yea, the fan has the blades installed. It's also strapped to the old radiator out of my truck, so it has to pull air through that as well.

At this point, I just need to do the circuit board layout and have those made (will take a couple weeks to turn around), then assemble, test, and ship

And they'll be re-programmable on my end, so if we get variable speed working, they can be sent back for an upgrade.

The fan itself is 600w. To put a resistor inline, it would have to burn off 300w in heat To make a power converter, it would also have to support about 300w, which is quite a bit. Since MB has variable speeds, I know it's possible; I just haven't figured out how (yet).


At this point I'm contemplating only having one knob to select a target temperature. It will likely turn on a few degrees above that, and turn off a few below it. Thoughts?


If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838263
11/18/10 09:10 AM
11/18/10 09:10 AM
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s.w.fl
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bonefish Offline OP
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Quote:

Yea, the fan has the blades installed. It's also strapped to the old radiator out of my truck, so it has to pull air through that as well.

At this point, I just need to do the circuit board layout and have those made (will take a couple weeks to turn around), then assemble, test, and ship

And they'll be re-programmable on my end, so if we get variable speed working, they can be sent back for an upgrade.

The fan itself is 600w. To put a resistor inline, it would have to burn off 300w in heat To make a power converter, it would also have to support about 300w, which is quite a bit. Since MB has variable speeds, I know it's possible; I just haven't figured out how (yet).


At this point I'm contemplating only having one knob to select a target temperature. It will likely turn on a few degrees above that, and turn off a few below it. Thoughts?


keep up the good work

Re: Mercedes fan upgrade [Re: hooziewhatsit] #838264
11/18/10 10:58 AM
11/18/10 10:58 AM
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Andrewh Offline
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few things.
I never saw a report on a continous test with something charging the system to show 40 amps to the fan.

can you send the proto type instead of getting boards made? would rather check that out before you outlay money.

The single pot is fine I think, but you probably want a 10 degree spread on the off. maybe even 15.

I have a 195 thermostate in mine, Have the fan come on at 210. Shuts off at 195, but it gets down to 189 before the fan shuts off, and it gets there pretty fast.

Re: Mercedes fan upgrade [Re: Andrewh] #838265
11/18/10 01:34 PM
11/18/10 01:34 PM
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gtx69 Offline
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We do need to know if it's going to be able to run at 40 amps for at least an hour of steady running .In some traffic you are stuck in line and the fan will be cycling on and off.Need an actual test.

Re: Mercedes fan upgrade [Re: Andrewh] #838266
11/18/10 04:45 PM
11/18/10 04:45 PM
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Oregon
hooziewhatsit Offline
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Quote:

few things.
I never saw a report on a continous test with something charging the system to show 40 amps to the fan.

can you send the proto type instead of getting boards made? would rather check that out before you outlay money.



Yea, I can send the prototype first. I'll have to wrap it up since all the pins on the bottom are exposed. The board is roughly 4"x5" (final board will be much smaller). I also need to port the code to the cheaper microcontroller, so sending the prototype will give me time to do that.

Andrew, you're still planning on using an on/off relay to trigger it, correct?

The wider temp spread is a good idea.


When I had it running just off the battery, it should have been pulling its 40A. The battery just didn't last long enough for a proper test.

My battery charger is only good for 10A. I think I can kludge up a way run it off of the truck while it's idling (Then I'll see if my '70s alt can keep up with it , and it just started snowing, and I don't have a garage )


Weird side note: last night I was testing different drive frequencies, and found one frequency, with a specific PWM value, that would make the fan turn on for a second, then turn off. Before it stopped spinning it turned on again for a second, etc. I did quite a bit of testing around those frequencies, but didn't find anything useful


If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838267
11/18/10 04:51 PM
11/18/10 04:51 PM
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Andrewh Offline
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yeah, currently my fan is wired so the trigger wire goes to a relay.
my computer supplies ground to that relay turning on the fan.

You will have to let me know what you need to turn it off and on via your controler instead, and I will rewire accordingly, but my plan was to take the trigger wire off and put it to your controler, and then the ground signal from the computer to your controler, or the power signal from that relay to your controler.

I might be able to wire a temp switch to it,not sure. if you send the one you tested with, I will pull one of my sensors for the dash and put it in to make sure it works.

Re: Mercedes fan upgrade [Re: Andrewh] #838268
11/18/10 05:23 PM
11/18/10 05:23 PM
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Oregon
hooziewhatsit Offline
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Ok, I think I know how to make it work on your system with a minimal amount of changes. It'll be easier to draw a picture. (it'll involve moving one wire to make the relay switch ground, rather than 12v, to my controller).


If you ever find yourself in a fair fight, your tactics suck.
Re: Mercedes fan upgrade [Re: hooziewhatsit] #838269
11/18/10 05:35 PM
11/18/10 05:35 PM
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Andrewh Offline
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I understand how to do that. not an issue. if you just tell me what your inputs are and outputs. I will set it up.

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