How many watts does a computer fan draw.

I took a fan out of the packet at Tricky's and clearly didn't mention watts drawn.

Perhaps I need to shop elsewhere?

Sounds like Trickys have got a bit slack since Woolies took them over.
Jaycars still give the good info.

Tricky Dicky's has been owned by Woolies for many years Phil.

do you have a pic of this installation thinking of fitting one to my 32l Engel?

Interesting, I was not aware these fridge compressors run on 12V DC. The old Engel fridge I have uses 20V AC for the compressor, the fancy Danfoss compressor on my boat uses 3 phase AC of some kind, never measured it.

It may be saver to use a current sensing relay to turn on the fan, this would not interfere with the fridge wiring in any way.

Klaus

Dunno Troopie.

I just hooked it up and away she went ? all day long ? must be a tough fan ?
cheers

You must have the 24v engel ?

I located the power wire in my engel while it was running with a 12v dc light tester.

But WHY do you want to keep the compressor cool?? lol It's the condenser (the bit that converts hot refrigerant gas to liquid that needs ventilation. By the way my fridge works a treat in all conditions - adding a fan is absolutely unnecessary - just the boys and toys syndrome which of course is very common in four wheel drivers. Another classic example is solar panels. I've known people who go to great expense and effort to buy and then transport and set up a solar panel which produces in a day the same amount of electricity as running the car (or truck as four wheel drivers call their station wagons) for 5 minutes.

Aandy,

I agree with you its the condenser that needs cooling, thats why Engel now put a fan in there, which draws so little current, and is offset by a lesser duty cycle of the compressor, giving a saving in overall power consumption, which is the aim.

I would have to disagree with your solar panel theory, to camp in the bush for any length of time running a fridge on battery power, you WILL need to charge the battery, and the most common way of doing so is a panel. Without this you need to run your vehicle not just for 5mins, but about 30mins above 2000rpm, and possibly twice a day....I used to do this and its a P.I.T.A. or carry a generator which makes noise and uses fuel.

My camping experiences have become so much better since getting my panel, which puts out up to 3.5amps, which is more than my fridge draw current, which allows me to camp in one place with freezing cold beer / fresh food for a week.

Tell us your setup and how you camp when not on a powered site then, as you dont seem to sound like a panel owner?

Ron

Ron,
your information is worthwhile reading !!

Aandy it has nothing to do with "boys and toys syndrome". It is just plain logical to remove the hot air from around the condenser etc ASAP, which in turn increases the heat dissipation and hence reduces the amount of time the compressor has to run to achieve maximum cooling, with the least amount of power consumption. I know for a fact that it works. When in the Simpson last Feb I had to add a computer fan to my Engel to help keep it cool. As I have a wagon (Frontera) the hot air in the rear is trapped even if A/C is on. By adding a fan to sit under the Engel bag at the top of the vents and rotated so it SUCKS, I was able to reduce the INSIDE temp of the Engel by THREE Deg's. Blowing into there was less efficient at only 1 deg less. I did not bother wiring it in so just made up a lead with ciggie plug on the end and plug it in as required. Sure I agree if the ambient temp is moderate or even hot, the Engel is very efficient, but the Simpson in the middle of summer. Nah, that is bloody hot.

Strawb

Hey Strawb,

What a bloody top idea mate!! instead of stuffin with the 24v etc, just slip a 12v under the cover at the grill, like you say tween the bag and grill, take in and out as reqd, no need to carry in winter.

Thats the go, I'm makin it up now.

I got my 2nd battery in back of dual cab, sits next to Engel, short wire from battery terminals, fit in a small connector, so just plug / unplug as reqd, give it the flick in winter.

Nice one.

The simplest ideas are always the best ones eh?

Ron

Strawb you went to the Simpson Desert in February .... not a good move ... I crossed in June and it was warm then!!

Hi Mick

Yes it was very hot, about 40+ in the car, hence the extra fan. Did not bother with A/C as my cars sucks fuel too much when A/C is on and in 4wd. Funny though the heat did not bother my brother and I, but the bloody flies did!!!! Breakfast was easy though. Plain bread turned into raisin bread in about 10 secs. Must have been magic I reckon.
A hint - Buy a 12V oscillating fan and hang it by the fan cage above you in the tent (used it at Uluru) by ocky straps. The jump start pack ran it most of the night. As it oscillates it jumps around and the breeze covers most of the tent area.

BTW. Laying in a swag under the Simpson night sky is the absolute best. If anyone has not done that, they have not lived.

Strawb

Just to add a little more. I have glued a fan to a piece of perspex which is the size of the rear window (it gets held in place by the real window pushing it up). The fan also sucks the hot air out of the car and seems to work reasonably ecomically.

The car temp was the same as the outside temp after leaving it parked in a sunny position and the fridges were happy. Now of the opinion that the power used by the fan may have been less than that used by the fidges had they been subjected to the hoter air of a closed car.

Kind regards

Hi Beatit

That is a "cool" idea. Is there a problem using something like that with electric windows? Do they stop going up because of a limit switch or is it a clutch / over load thing that stops them? If it stops because of a restriction ie: perspex filler, then I reckon I will do the same. A computer 12v fan draws bugger all power but the benefits are massive if you can equalise the temp. I remember supercheap had those but they were not designed well enough to stop someone removing them from the outside and breaking in.

Strawb

G’day Strawb,

I had no problems with the electric windows I just adjusted the window up until it sat tight. The perspex window is about ¾ the size of the real window and I can slide it in the bottom of the window frame then push it up so it sits nicely in the window tracks. The Perspex is the same thickness as the window also the window is slightly tapered which makes this work. The perspex window has a retaining strip glued on both the inside and outside to receive the window. Made sure that the air flow was “out” and that the vents were open.

Kind regards

Why does it have to be better than no fan basil? If the refrigerant is going through the condensation cycle (as millions of fridges do every day without a fan) then you are simply drawing an unnecessary .35 or .4 amps from your battery. Best you rig up a solar panel to compensate for that!!! lolol

In many cases you're surely right Aandy, but I really think it depends on where the fridge is placed or mounted in your vehicle. You need to get the heat away from the condenser. If for some reason ventilation is poor and you can't find a better place for your fridge, IMHO an extra fan definitely helps.

In our rig, we had the fridge mounted in a sort of a kitchen cabinet. Although the air could flow through large ventilation vents, it always got very hot in there. Adding a computer fan dramatically decreased the power consumption of our fridge. We had a 260 Ah battery and were able to run the fridge for 3 or 4 days without getting the batteries too low. After mounting the fan it was 5 or 6 days! I connected the fan to the power circuit of the compressor, so that it was only running if the compressor was on. Since we've been sleeping in our vehicle, I also added an extra switch to get rid of the fan noise during the night.

Cheers Wolf
www.bush-sweepers.org

Hi All,
I am a fridgy by trade and a fan on the condensor will help. The refrigerant is cooled when it goes throught the condensor by natural air circulation. Adding a fan will speed up the air changeout and will aid in the cooling of the condensor.
Matt

Matt,
In simple terms does this mean your fridge wont use as much power if your condensor has a fan blowing on it?
Cheers

AANDY.
The reason I put the fan in there was because sometimes I carry the engel in the boot of my car along with bags of clothes etc. And during summer the fridge actually stopped due to overheating as we were travelling. I was just trying to get airflow through the condenser and compressor compartment. When we get to our destination I`d plug it into power.
No way would I rely on the car battery when stationary.
cheers

Where does amp hours come into that?

Amp hours is a measurement of current used or current stored, not what is being drawn at any given moment (instantaneously).

Quote taken from Ohio State University dune buggy page listed below:

"Definition - An ampere tells us how much current is flowing in a circuit. Amps multiplied by the time operated in hours is the energy used in Amp-Hours.

Amp-Hours = Amps x On-Time in Hours
For example, we know a No. 1156 12 V bulb draws 2.1 amperes. If it operates for 2 hours, it will use 2.1 amps x 2 hours = 4.2 amp-hours of energy.

Most battery makers recommend that the current draw on the battery, in amperes, not be more than 5 percent of the amp-hr rating of a battery. This means the highest recommended load for a 90 amp-hr battery would be 90 x 0.05 = 4.5 amps. Working the other way, we could calculate the smallest size of battery for a given load. Battery Amp-hrs equals Amps divided by 5 percent.

Battery Amp-hrs = Amps 4 by 0.05"

www.gizmology.net/batteries.htm

ohioline.osu.edu/aex-fact/0596_1.html

P.S. easy to work out in simple current draw items like a light bulb because the current used is constant.

If it is a 3 amp load used for 1 hour, it will be 3 amp-hr

In a fridge the load cycles on and off, so you have to calculate duty time into everything.

i.e. if the fridge draws 3 amps (just to use a number) but is only on 50% of the hour, then you have something akin to a 1.5 amp-hr draw.

I am sure a fridgy or auto elec will have more precise data.

Amp-hours is a stock term, amps is a flow term. Think of it as a dam with a pipe leading out of it and water flowing through. The amount of water held in the dam is "stock" (amp-hours, how much), and the the amount of water coming out of the pipe is "flow" (amps, how fast). They are both called "water".