Electric fan bypass switch

[84cutspreme]

Okay I have a question or two with wiring dual electric fans. I have both fans wired through individual relays. relays are powered from electric junction and have 30amp Maxi fuses in between. my question is whether to hook 12 volt source to keyed on ignition or constant? I like the idea of fans running after shutdown to cool motor however my fans draw a total of 44amp together. If I wire it to constant how long can fans run before they would drain battery and have restart issues? Battery is 120 reserve and 55 Ah @ 20hr rate

 

[pontiacgp]

If you wire it constant and that wears down the battery then you need a new battery. The battery that you have should have no problem running the fans after the car is shut off

 

[fleming442]

Do you have a timer to turn them off?

 

[airboatgreg]

I would wire ignition, that way you know you will not run the battery down. Think about running one fan with a timer after engine shut down. I see no need to run two. As far as to how long you can run both fans with the engine off depends on the minimum volt/amp required to crank and start the car but not as long as you may think. 44 amps is a bunch and the engine probably won't crank under 9 volts with the starter load.

 

[UNGN]

44 amps is probably what they draw at start, which is usually 2X - 3X what they draw when already spinning near their rpm/volt speed.

I don"t see much value in cooling off a radiator on a parked car, but then I put low temp thermostats in all of my performance cars, so the posibility of an overtemp overpressure puke session is about nil. Your results may vary.

 

[pontiacgp]

I would think that 44 amp is the spike when the fans turn on and would draw less than half of that when running. The intreped fans pull about 10 amps when running

I have to start checking with UNGN before I post anything so I don't duplicate his posts....I type slow....

 

[84cutspreme]

I wish 44 amo was spike but each fan draws 22-23 amp while running and I have checked it. They are the high performce spal 13” with s-blade fans. How would I wire in a timer? Only ever seen that on GN but controlled by ecm

 

[pontiacgp]

If they draw 44 amps then what is the amps at spike?

 

[TURNA]

So if you wire them constant what will turn them off?


A dead battery????

 

[UNGN]

That is a lot of amps. I would run them in series and only switch the to parrallel above 200 degrees.

Ideally, when cruising they should draw zero amps, because they are off. In Series, they will draw about 1/4 the amps. Of course they won"t cool as well, which is why the switch to parallel above 200 degrees.