Effects of relays in fan circuits? - ponderings needed

[davecymru]

Just a quick bit of auto-electrical pondering i'd appreciate your thoughts on.....

I've been having cooling issues with the Countach and I found that the 3 cooling fans were all powered directly from a single 12v feed coming from the ignition switch and the thermostat was triggering them via a joint negative.


I have now completely re-wired them so that the switched 12v is going to the thermostat.
When the thermostat switches-on then it triggers 2 fused relays.
The feed to those relays is then coming via a large gauge wire directly from the battery main distribution point.
When the thermostat is triggered, that large gauge feed is then sent to the 12" fan by one relay and to the pair of 9" fans by the other relay.

So while this new setup is obviously more stable and safe, "to me" it also seems as though the fans are running much faster now as well

I could understand this difference if I'd switched from having them in series to be in parallel. But would also going from a shared, switched single supply to this new setup also have a difference?

I "think" the answer is yes, but i'd appreciate hearing the thoughts and ponderings of you lot.

[woodsmith]

The previous set up was supplying power to the fans via a small wire running a long way. That would have added a lot of resistance to the current flow reducing the voltage getting to the fans and making the wire get hot.

The new set up has a larger wire with a more direct path and so there is less resistance to the current flow. The voltage at the fans will be higher and the cable will not be heating up (much if at all).

It is like imagining water flowing through a hose pipe and a drain pipe. If you need a lot of water flow you will get it through the drain pipe more easily then you would through the hose pipe.

A good modification, and safer too!