Electric fans

[cycleguy55]

Originally Posted by 66AC

One thing to note, as the rated CFM of the fan goes up so will its corresponding amperage draw. So if you are ever going to replace a fan you could kind of over do it if you choose a much higher CFM replacement fan which could put a serious burden on your alternator and battery.

A solution to this perhaps would be a fan and thermo switch device which gradually speeds up the fan as the water temperature increases and likewise slows the fan down as the water cools. This would require some amount of
"smarts" in the fan circuit. Mitsubishi and others have this figured out in their mini-split air conditioning compressors. However I have yet to see this fan feature in an automotive application.

While current draw and their effect upon alternator and battery are considerations, I'd be more concerned about whether the installed wiring was sufficient for a higher draw fan. Yes, the fuse(s) or circuit breaker (preferred) should protect the circuit, you don't want the fan(s) cutting out when you need it/them most. If a replacement fan has a higher rated current draw, make sure the circuit can handle it, including wiring, relay(s), fuse and/or circuit breaker.

BTW, after a cooling fan relay failure in my car, I installed a pair of relays in parallel - each is sufficient to handle the load should one fail, but as they're sharing it I doubt (hope?) I'll ever see another failure.

BTW, variable speed controllers are available from Flex-a-lite and PROFORM. Both are rated at 45 amps and available with either / both temperature probe (insert in radiator fins) or threaded sensor. They're about the same price too.

Flex-a-lite description:
The Flex-a-lite® Variable Speed Controller turns the electric fan on and off at the desired temperature. Fans turn on at 60-percent power and fan speed increases as the temperature rises. You can easily adjust the activation temperature between approximately 160-240 degrees Fahrenheit. It also turns the electric fan on when the vehicle air conditioner is engaged. Fan will run for up to 25 seconds after the vehicle is turned off.

From PROFORM:
This variable speed fan controller makes the fan or fans run at whatever speed is needed to maintain a consistent temperature. The controller receives a temperature signal from the radiator through either a push-in, or thread-in brass probe (both included). The fan controller processes this signal and runs the fan(s) at the correct speed needed to maintain the desired temperature. The weather resistant billet aluminum housing with bright digital display ensures easy setting by simply pushing + or - to set the temperature. By simply pressing the Mode button, the digital display will show temperature in F or C. As a bonus, the display screen will also show live amp use, so you know how many amps your fan configuration is chewing up.

I really like the PROFORM model - may have to add that to the to-do list...

https://www.flex-a-lite.com/accessor...re-sensor.html

https://www.proformparts.com/product...read-in-probes