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Inverter cooling worklog (PICS)

M

miazmaticdotcom

Gawd
Joined
May 3, 2003
Messages
545
This is my Wagan-Tech 75W inverter that I use to run my iBook, iPod, cell phone etc. off the car's power.
inverter1.jpg

However, when you use it for 3+ hours its protection kicks in at ~150F and shuts it off. I have a 5 hour car trip on Wednesday, and my brother wants to run Starcraft on my old Toshiba, in which the battery is shot.

The thing takes 12V DC input from the car, and so do case fans...

1. Make a nice big hole in the top.
inverter2.jpg


2. Connect the fan to the power... I traced the DC +/- to make sure the fan spins in the right direction.
inverter3.jpg

inverter4.jpg


3. Duct tape connected fan over hole, blowing in.
inverter5.jpg


I haven't had a chance to test it yet, but once I take it on my long trip on Wednesday I will post back.

What do you guys think, should the fan be blowing in or out?
 
Might wanna make sure there is a way for the air to vent out on the other side (can't tell from your pics)
 
Originally posted by __Maad__
Might wanna make sure there is a way for the air to vent out on the other side (can't tell from your pics)
Click to expand...
I was thinking the same thing. Airflow requires a relief from the pressure, not just pushing the air into a sealed container.
 
lol yeah..you would probably get 2x as much cooling using half the size fan and letting air escape around the edge.
 
*lol* why not just put a tornado on there! heh, Serriously, though. A single 40mm would have probably been sufficant and looked a little nicer. But other than that, props for taking care of a problem (hopefully) most people would have "just lived with".

:)
 
Well, the thing is rated for 75W, but we're usually pulling more like ~120W between all the laptops and phones and stuff. I'm sure if we only used 75, it wouldn't overheat.

What can I say, overclocked inverters need extra cooling! :D

As far as putting a Tornado on it - I'm not into using anything conductive, 'cause somewhere on that PCB is 120v. I've shorted out a 120v outlet before, and it was not pretty. Almost set the building on fire.
 
all I can say is...Finger guard! lol... the long trip is bad enough, dont add injury to the list. :)

Anyways, I agree with a couple of the other people. Could've gone with one of those slim 40mm fans to make it look better, but that should keep everything nice and cool. :)
 
I have a 400w (rms) inverter that has active cooling on it, i have xbox in my car (ask for pics) and I have driven 8 hrs without a single problem.
 
Cool! Gimme pics.

See, we're driving a Toyota Sienna minivan, which warns us not to take the load past 120W to avoid running down the battery. I'm guessing you have a big truck with insane amounts of horsepower (and therefore alternator wattage). Plus, 400W inverters are expensive, this is just something I picked up for thirty bucks at Fry's before my last long trip.

I plugged it in just now and it works, the fan spins up and the inverter light turns green. I'll see how it goes on the trip tommorow. Last time I built a heatsink out of AOL CDs ;) and that kept it going for about three hours. This time we'll try for five.
 
Originally posted by miazmaticdotcom
Cool! Gimme pics.

See, we're driving a Toyota Sienna minivan, which warns us not to take the load past 120W to avoid running down the battery. I'm guessing you have a big truck with insane amounts of horsepower (and therefore alternator wattage). Plus, 400W inverters are expensive, this is just something I picked up for thirty bucks at Fry's before my last long trip.

I plugged it in just now and it works, the fan spins up and the inverter light turns green. I'll see how it goes on the trip tommorow. Last time I built a heatsink out of AOL CDs ;) and that kept it going for about three hours. This time we'll try for five.
Click to expand...

1Horsepower equates to over 700Watts, so the engine is not the issue. The warning is probably referring to use while the van isn't running, because otherwise there's no danger of killing your battery with an extra 120Watts - while the car is running the inverter shouldn't even be drawing from the battery, the alternator supplies all the current.
 
That's quite a ratio. I was wondering if I would be able to run my 420w desktop computer off the car sometime. Looks like it shouldn't be a problem if I can get a macho enough inverter. Maybe for our next trip (although then I'd have to mount a flat panel on the back of my mom's drivers seat.)
 
Originally posted by zer0signal667
1Horsepower equates to over 700Watts, so the engine is not the issue. The warning is probably referring to use while the van isn't running, because otherwise there's no danger of killing your battery with an extra 120Watts - while the car is running the inverter shouldn't even be drawing from the battery, the alternator supplies all the current.
Click to expand...

I think, actually, thats precicely the issue. An alternator cannot supply an infinant amount of wattage based on horsepower. I think thats why people with like thousand watt subwoofers need two+ alternators... I think.
 
Originally posted by 8Complex
I was thinking the same thing. Airflow requires a relief from the pressure, not just pushing the air into a sealed container.
Click to expand...

yea i agree....you need to relieve the pressure


hey 8complex....you live in schaumburg so do i! :D :cool:
 
I would have it sucking out, like a power supply. Cooling mosfets and stuff works better when you suck heat away.
 
Originally posted by Shinare
I think, actually, thats precicely the issue. An alternator cannot supply an infinant amount of wattage based on horsepower. I think thats why people with like thousand watt subwoofers need two+ alternators... I think.
Click to expand...

Assuming an alternator voltage output of 14V and 60Amps (a low estimate) the alternator should be able to supply well over 800W. Most newer alternators pump out alot more current than that too. But yes, there is a point where you'd need a larger one, or another one.
 
i have a 1200 watt Rockford Fossgate amp that i payed 200 dollars for on ebay.

i spent 400 dollars on a 200 amp alternator to run it:(
 
Originally posted by zer0signal667
Assuming an alternator voltage output of 14V and 60Amps (a low estimate) the alternator should be able to supply well over 800W. Most newer alternators pump out alot more current than that too. But yes, there is a point where you'd need a larger one, or another one.
Click to expand...

I think that point may come sooner than you think. Dont forget about your headlights (big drain), dash lights, sterio (could be huge too), electronic ignition, heater/AC fan, and everything else electric in your car. I'd say that if your alternator is pumping out 800W and your inverter is using 400W then you are probably going to overwhelm your alternator and start pullin juice from the battery right off the bat to power everything else electric in your car. Thats why it drains down your car if you run that 400W inverter at max load for very long.
 
you guys are also forgetting the wear and tear that the extra stress put on the alternator will have. Usually alternators last a good while, but if you're sucking more than average watts from it then you're cutting down the lifespan of it. I don't think ~200w drain would be that bad, but if you get to 400w+ then you're cutting into the life of the alternator. Although I'm not an expert in the field of alternators, so take my words for whatever they're worth.
 
Originally posted by Shinare
Why do that call it an alternator if it produces direct current? :)
Click to expand...

It produces alternating current, and has a circuit that rectifies it and smooths it into nice DC power.
 
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