S1 radiator fan current draw

[woozie]

Morning,

I am trying to find the current draw that the radiator fans draw, just so I can select adequate cable.

I've measured resistance across the three fans (wired in) as I don't have an ammeter. I'm getting 1 ohm. Which gives 10amps, and 120watts  (40watts per motor) 

Can anyone confirm if this is to specification. I would look on the motors but they are buried under the car and my jack currently needs replacing....

 

Thanks

J

[drdoom]

Spitball estimate would be 5-10 amps per fan, continuous running, with brief spike well above upon starting.

[AndyPG]

On 25/04/2020 at 10:05, woozie said:

Morning,

I am trying to find the current draw that the radiator fans draw, just so I can select adequate cable.

I've measured resistance across the three fans (wired in) as I don't have an ammeter. I'm getting 1 ohm. Which gives 10amps, and 120watts  (40watts per motor) 

Can anyone confirm if this is to specification. I would look on the motors but they are buried under the car and my jack currently needs replacing....

 

Thanks

J

Hi James,

On my car they each have a 10A fuse so the motors certainly draw less than that. Probably 5 or 6A each.

You need to use wire that is rated above your fuse rating so 15 - 20A automotive wire should be fine for each motor.

Regards, Andy.

[Paul Coleman]

On 25/04/2020 at 10:05, woozie said:

Morning,

I am trying to find the current draw that the radiator fans draw, just so I can select adequate cable.

I've measured resistance across the three fans (wired in) as I don't have an ammeter. I'm getting 1 ohm. Which gives 10amps, and 120watts  (40watts per motor) 

Can anyone confirm if this is to specification. I would look on the motors but they are buried under the car and my jack currently needs replacing....

 

Thanks

J

If I understand this correctly you have measured 1 Ohm for all three fans? If that's so then you have measured the total resistance of 3 fans in parallel which means each fan is 3 Ohms. Assuming the alternator kicks out 14V then each fan would pull 4.667A (and as somebody pointed out more at start up) giving a total of 14A for the three.

Edited April 27, 2020 by Paul Coleman

[woozie]

Thanks you For All for your replies. I’ve noticed they never had relays, which is what I am fitting. Yes Paul,  I've wired them parallel so taking the reciprocal gives 4amps - thanks for confirming! 

cheers all 🤗

[Frank Wissman]

We just repaired the fan wiring after a motor probably stalled and made a mess. A 15A fuse lasts about 1 1/2 seconds and the 25A seems to be fine.