8 amp draw too much?

   / 8 amp draw too much? #1  
M

MuncyBob

Platinum Member
Joined
Mar 17, 2004
Messages
868
Location
N Central PA
Tractor
PT 422
My side exhaust fan needs to be replaced. I can't seem to find the exact model I have from one of previous emails but have found a decent fan on Amazon. Is the 7" fan I found with an 8 amp draw too much for my PT422?
 
   / 8 amp draw too much? #3  
Find out the amperage output of your charging system on your engine. If, for example, it's 15 amps, and your fan pulls 8, you're good. But if you have two fans, and they both pull 8, that's 16 and your battery won't charge. Then turn on the head lights....
 
   / 8 amp draw too much? #4  
And after you add in the headlights, you need some more to charge the battery and don't forget any other electric draws (PTO toggle switch controlling electromagnetic hydraulic valve). AND if it is 15 amp charging system, that makes the 15 amps at 3/4 to full throttle with the alternator cool. If the engine running at a lower RPM, it is less then 15 amps and when the alternator gets hot, the efficiency drops.
 
   / 8 amp draw too much?
  • Thread Starter
#5  
No label on the battery showing specs. Called the store where I got it and all they could tell me is it's 330 cold cranking amps and the reserve is 34 minutes at 25 amps. Not sure if this tells me what I need to know?
 
   / 8 amp draw too much? #6  
Farmall140 said:
Not sure if this tells me what I need to know?
Click to expand...
Not really. That's a tiny battery. What you need to know is the Charging Rate of the Engine. Since it's a 0.64L gas engine, I'm guessing it has a built-in alternator. I would be surprised if it put out more than 15A.

You want to keep the total accessory current draw below about 75% of the charging rate of the engine or your battery will be dead by the time you finish mowing grass.
 
   / 8 amp draw too much? #7  
The short answer is yes, 8 amps is too much for an aux cooling fan.
 
   / 8 amp draw too much?
  • Thread Starter
#8  
Found a fan with much higher cfm, only 6 amp draw. Gonna give it a shot. Wish there some markings on the old fan as it worked great.
 
   / 8 amp draw too much? #9  
Farmall140 said:
No label on the battery showing specs. Called the store where I got it and all they could tell me is it's 330 cold cranking amps and the reserve is 34 minutes at 25 amps. Not sure if this tells me what I need to know?
Click to expand...
Battery size has almost nothing to do with the ability to source 8A to run a fan.

You said the fan on one side failed. Is there another on the other side? If so, then put your meter inline on that fan and measure the current draw.

Could also check the fuse on the circuit the failed fan used. Is anything else on that circuit? Would expect to see at least a 10A fuse for an 8A fan.

What markings, P/N, etc, on the failed fan? Maybe somebody knows what it is and knows it's CFM and power consumption?
 
   / 8 amp draw too much?
  • Thread Starter
#10  
Just the 1 fan, although I have thought about adding another. The fan has no markings at all, failure is in the wiring. Last year one of the wires broke but enough wire out of the housing wass exposed so I was able to solder that. Now the other wire has broken off too from inside the housing and I just cannot repair it. New fan should be here in 2 days.
 
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