power for electric radiator fan?

[Tom]

True Bruce, they do draw 4-5 amps of power, but they will only run long enough to cool the engine then shut off. They are nicely ducted to ensure the air flows through the radiator too. And at 14" diameter they are the right size for smaller radiators. They are commonly available and low cost too.

[Sfene]

Try surplus city, all kinds of ac and dc fans. I use 225 cfm ac fan with a medium size radiator, 3500 watts normal load, 190f temp sender to relay which picks up fan. 2nd sender 210f to 2nd relay picks up taco circ pump.

[ronmar]

How about multiple 4" computer fans.  Available about anywhere, very robust, multiple fans leaves out single failures, Add in two small power supplies and a set of snap switches for a redundant system...

[BruceM]

I really like Ronmar's  computer type box fan(s)  idea, but I think I'd go with the AC version for simplicity.  Very low power, redundancy by design, and a good match for our very limited airflow needs. You could consider eliminating the thermostat switch, also.  If you had 3 set close to the radiator, I don't think you'd even have to make a simple shroud, and any one failing would still leave you with plenty of airflow.  They are available for 120 or 240VAC.  mpja.com has had them cheap, surplus, in the past.

I woudn't want the 1500+ watt start surge of a 500 watt attic fan that happens just as my water well submersible pump tries to start, but then I've only got a 3KW ST generator head.  The DC auto fan would be better as far as start surge issues, though again it is way more fan than we need.

[Tom]

Yes Murphy will make sure that anything that has a start surge will start all at once, usually at the most inconvenient time. Computer fans and a computer power supply would be an inexpensive way to go. One could even use it to charge a small 12v battery too.

[LowGear]

Hi ronmar,

Did you know you can use most any PC power supply to run these really quiet fans?  I too am fascinated by these couple of watt workhorses.  Don't forget a used laptop / printer brick that has the right voltage (or close and you can series them for different voltage needs).

Casey

[ronmar]

Hi ronmar,

Did you know you can use most any PC power supply to run these really quiet fans?  I too am fascinated by these couple of watt workhorses.  Don't forget a used laptop / printer brick that has the right voltage (or close and you can series them for different voltage needs).

Casey

Yes, you can:)  12V wallwart P/S's are also inexpensive and readilly available, and perhaps a bit simpler...

[bandmiller2]

Carpenter,I'am in a little late on this fray but I believe multiple ac computer fans is the way to go.They could be staged on to regulate engine temp.and lets face it when the engine needs cooling you have ac power. Frank C.

[cujet]

I use a 12V power supply from  www.mpja.com

"Marlin P. Jones" electronics in West Palm Beach has an incredible supply of power supplies. Many of them are quite inexpensive.

[BruceM]

There are lots of 12V supplies on ebay sold for LCD monitor replacement power supplies.  Typically $10 including shipping.  I still prefer the AC muffin fans- less hardware to fail.

[deeiche]

Not the cheapest solution but perhaps you could use the waste exhaust heat to run a thermoelectric generator.  There are links in the wiki page to various manufacturers.

[ronmar]

Not the cheapest solution but perhaps you could use the waste exhaust heat to run a thermoelectric generator.  There are links in the wiki page to various manufacturers.

If I was going to do anything with exhaust, I would go Bruce M's route and use it to induce a draft to pull air thru the radiator.  WAAAY old school, but well proven, dead simple with no moving parts, and almost zero chance to fail...

[BruceM]

It's true, with induced draft loss of cooling  means the engine must have stopped.

[Stan]

Using the thermoelectric generator on the exhaust is the only system that will not rob horsepower from the engine.  Penelope has the fixed radiator and it robs 1/3 hp from the engine to run the fan, using power from the alternator to run a 110 or 220v fan also robs power from the engine.  Using an electric fan with heat sensor on/off perhaps will be a bit more efficient but there's no defeating physics when you need to power a fan from an engine.  Even systems to put vanes on the flywheels to blow air through a fan rob power.

Stan in Kimberley

[ronmar]

Using the thermoelectric generator on the exhaust is the only system that will not rob horsepower from the engine.  Penelope has the fixed radiator and it robs 1/3 hp from the engine to run the fan, using power from the alternator to run a 110 or 220v fan also robs power from the engine.  Using an electric fan with heat sensor on/off perhaps will be a bit more efficient but there's no defeating physics when you need to power a fan from an engine.  Even systems to put vanes on the flywheels to blow air through a fan rob power.

Stan in Kimberley

Stan
  Induced draft won't rob any HP from the engine either:)