Hello, i want to add an extra cooling fan into the engine bay for better cooling of the engine.
I have a 10" 12V 6A fan for the job but will the fan survive if i attach it directly to the car battery which i assume is over 12V and 6A? It will only be turned on 30 seconds at the time by the way so it's not over a longer period of time.
Thanks!
The fan will draw only the current it requires.
The voltage of a typical lead acid car battery is normally between about 12 and 13.8 volts, but the bit extra should not hurt the fan.
Do install a fuse, greater than 6 amps and less than the capacity of the copper wire that you choose to use. Plan on severe vibration, road salt, water, and high ambient heat.
Thanks! Will vibration, heat and so on effect how well power comes through the wire?
No, it will effect if the fan will survive for more then a week....
If you are fitting a second fan, presumably you will be powering it along with the first and providing (relay) switching.
You need to know what fuse is powering the current fan - if it is adequate for both, you can just connect the new fan in parallel with the original.
Of course, you do not connect a new circuit directly across the battery (except for a communications radio) - you want to make it convenient to disconnect the battery wires for replacement, so you want to connect the new circuit in at the main fuse block and the chassis grounding point of the negative cable.
The thing is that the built in fan not always turn on thanks to a loose wire somewhere.. So i might just use a ATTINY85, a relay and a waterproof temperature sensor inside the thermostat and instead of adding a fan more i'll just use the built in fan and wire the 12v from the battery to the the existing wires so the fan still kicks in when the A/C is turned on.