Alternator Cooling

[BankOfHell]

Anybody found a good way to cool an alternator?

I have a 200A GM type alternator and on warm days I can see the voltage drop to as low as 13v as underhood temperatures climb and the alternator heats up.

I see that BMW ducts air to the back of their alternators and GM has even introduced water cooled alternators.

I thought about cutting a 6" hole next to the alternator in the wheel well and installing a 6" 270cfm fan. But, my hand trembles everytime I pick up the drill to do it--I like to limit my moods on things that can be reversible.

Anybody solve this problem?

 

[Vettehead Mikey]

An alternator will only produce as much energy as the car's electrical system requires at any given moment. Being that car alternators are not all that efficient, a large amount of heat is a major byproduct.

I can't imagine putting enough continuous load on a 200A alternator to cause it to overheat and 'die'. I'd be more suspicious of a defective regulator.

 

[bill81vette]

Why do you even need a 200 amp alternator for?????
This seems like a waste of money and energy..
..jmho

Sent from my DROIDX using Tapatalk

 

[Rod75]

What type of alt are you running? And where's the location of it?

 

[BankOfHell]

200 amp? I'm running a Mark VIII fan, a/c, 1600 watt stereo amp, and a 2000watt power invertor for 120vac to supply studio lights for outdoor photoshoots.

The fan is a CS12 type in standard location--cooling intake clocked away from exhaust mainfold.

 

[Vettehead Mikey]

I'm assuming you don't run the photo lamps while you're driving so there's zero load from that. If the sound system is at legal and sensible sound levels, that's probably drawing maybe 50 watts. The fan might draw a larger amount especially during start up so maybe 200 watts peak, 100watts constant.

That's not enough load to cause the problem you've mentioned. Is this 13V seen with the engine at idle or at normal cruising speeds?

 

[BankOfHell]

A Mark VIII Fan draws 30amps at 100% power --

The car is idling while I'm shooting to power the lights through extension cords--sometimes for an hour or two at a time.

On a nice coolish day under normal load, at road speeds, the alternator voltage is 14.7. On a hot day, it drops to 13 once the car heats up. It's not the fan draw changing because I have a DC Controls PWM controller and that supplies 50% power on demand of trinary switch on condenser coil.

I just feel when it gets too hot, resistance goes way up. I'm sure that's why BMW's and some newer cars have externally cooled alternators. I'm just trying to figure a nifty way to do cool it.

 

[Vettehead Mikey]

On a nice coolish day under normal load, at road speeds, the alternator voltage is 14.7. On a hot day, it drops to 13 once the car heats up. It's not the fan draw changing because I have a DC Controls PWM controller and that supplies 50% power on demand of trinary switch on condenser coil.

So your problem is not due to load which leads to 'overheating' . Again, try a new regulator.

 

[BankOfHell]

I'll try the new regualtor and report back--thanks!

 

[Rod75]

I'll try the new regualtor and report back--thanks!

Found this: What is an "Iceberg" Alternator

Maybe that will help you out...

 

[Tom Bryant]

Now that's interesting. Have you looked into a more efficient type of fan on the pulley? These cars have open blades on the back side where many new cars have a closed back on the fan blades. This would appear to more efficiently move air through the alternator since the air would be routed out of the perimeter of the pulley fan and not be able to fall off of the back side and just swirl around. I have never seen any test results but there must be some reason they have went to the closed design.

Tom

 

[6880 Mike]

Is the stock alternator fan on your unit? Can't really see in your pic, but I'm wondering whether you can have removed it for your pulley set up.

 

[BankOfHell]

Problem solved! I just copied the method BMW uses; I atached a vent pipe to the back.

 

[Rod75]

Problem solved! I just copied the method BMW uses; I atached a vent pipe to the back.

Where did you place front of pipe?

 

[BankOfHell]

Where did you place front of pipe?

I ran it down the back/left side of radiator and out behind the air dam--least chance of dust and debri there was my thinking.

I bent up the pipe well trying locations, so I'm installing a new one to make it pretty.

 

[Rod75]

I ran it down the back/left side of radiator and out behind the air dam--least chance of dust and debri there was my thinking.
I bent up the pipe well trying locations, so I'm installing a new one to make it pretty.

Good creative solution! So did you verify that this cured your voltage output prob?

 

[BankOfHell]

Yes. It was 101F degrees here yesterday. Voltage stayed at 14.5 under full load and stayed over 13.5V at idle.

 

[strokin383-c4]

First of all,

Why do you have "Photo shooting" lights connected to your Corvette?

Second,

Operating voltage range in a car is between 12.5 - 14V

Thirdly,

If you Increase your alternator pulley size, the higher RPM will keep your voltages up. (correct me if im wrong)

-V

 

[JohnZ]

If you Increase your alternator pulley size, the higher RPM will keep your voltages up. (correct me if im wrong)

-V

A larger pulley will turn the alternator slower - you use a smaller pulley to spin it faster.