PWM control for brushless fans - what do you use?

I am helping a friend who doesn't have a standalone ECU in his car.

He wants to make the switch to the super badass brushless fans that can be found from Bosch/Spal that are absolute monsters when it comes to airflow. The issue is, there is really not much choice in the matter for controlling these fans if there is no standalone already installed.

So, is there a controller of sorts that allows control via a Coolant sensor, that also has logic build in to account for AC engage (like AC on triggers a predetermined %duty cycle), but also has a failsafe function.

The Lingenfelter VSFM-002 comes pretty close except it only has 1 override, and it goes to max % once it gets triggered, which when talking for example the SPAL 850W Camaro fan, would be absolutely overkill. I was even considering maybe trying a microsquirt for this, however it seems that the PWM output on FIDLE on the micro is not user definable ?

So, I I figured I would ask here, maybe someone has a neat solution to this! I think the easiest "solution" is to actually have some sort of cheaper/smaller standalone that can just run that stuff, and perhaps do datalogging or also boost control on well to make it worth the effort until a full standalone gets installed.

Thanks in advance!

I may be mistaken, but something like this seems like it could do the job - https://www.autocoolguy.com/pulse-width-modulation

I actually have one of his controller. While it uses PWM strategy to control the fan, it does not control a fan via PWM. The auto cool guy controller is really just for a fan that has power and ground. I am after controlling the c7 vette or Camaro or say a newer bmw fan. They have power, ground and PWM input. Based on that input that will control the fan speed.

good call though on the auto cool guy

Ah, if you haven't done so, might be worth giving him a call - if he can't help, he may know someone that can supply what you need. I'd mention you already had one of his products, and that's why you thought of him, to get him on-side ;-)

Glad I saw this. I'm using the VSM-002 and I agree that 100% is way overkill, and my alternator isn't up to the task. I turn on the A/C and it sounds like a jet spooling up.

I'd like a different solution too, but I've not seen anything else, other than an ECU that can PWM a fan. Delta Pag might be another option.

However, I am considering switching the VSFM-002 from temp mode to percent mode. That would give you two speeds, and you'd have the option of using the primary signal for the A/C and the override for max speed. You could also slow the fan down so that it doesn't use the entire 850 watts.

Are you looking to supply a PWM signal to an internal brushless controller in the fan? If so, would this work?

I've not used this unit, but it seems to be meant to directly drive a brushed fan, so it would be a bit overkill in terms of current it can move, but as long as it generates the signal you need, it may make sense.

https://derale.com/product-footer/electric-fans/fan-controllers/pwm-controller/16797-detail

And I'll just throw in consideration for a PDM.

I just ordered a Haltech Nexus R3 with PD16. Already peaked into the settings and yep, a PDM is far more configurable! Looking forward to finally having complete control over this beast of a fan.

That Derale unit is a to make a regular fan, like a Taurus fan, variable speed. Really cool but same thing as the AutoCool controllers really.

Yeah I am trying to supply just the PWM signal to the fan, the fan itself has all the logic. The easy button of course is go to full standalone and define an output to exactly what I need. I was hoping there is a cheaper way of doing this honestly. The VSFM controller is PERFECT except the AC override would be overkill, just like Ratssled said.

Great ideas from everyone! I will keep on checking around, but it looks like a standalone is the way, curious what the cheapest/smallest option on that is, in case he really doesn't care to get rid of his OEM stuff. Just throwing ideas out, but it would be pretty neat to have a small standalone be able to control the fan, and maybe be a boost controller as well ? just so it has at least some added functionality for the cost.

I will keep peddling the standalone as the best option.

Thanks.

Phil

Phil,

I've seen a few limited functionality units like that over the years, but never tried one so unfortunately I don't have any particular suggestions.

As with any low cost version of another thing, I'd have some reservations and it may come down to how much time you and your friend are willing to invest attempting an option which starts cheaper, but may end up more costly in the end if you have to install/wire it, try it, then buy and install something else you know you can count on.

I'll be curious to hear what you end up with and hopefully it will work out great. Please keep us posted.