Hi. this is my first post on this group. I drive for DHL in NJ and I get the
same van everyday. It has no AC. It's summer and I'm tired of being hot.
Suppose I connect a 2500 watt inverter directly to the battery and put a
small portable air conditioner between the seats in the cab. (7000BTU, 900
watts, 7.5 amps) The van is running pretty much all day which is 8 hours.
I'll plug the AC into the inverter and turn it on filling my hot van with
nice cool air. Before I spend about $600 too make all this happen I'd just
like to know why this won't work. What could go wrong with this setup? I
don't own the van and cannot make any mods to it. I put it all in the van in
the morning and take it all out at the end of my shift. Please help! Thanks!
900 W, assuming 100% efficiency, will use 75 A (75 A x 12 V = 900 W).
The highest rating I remember on fuses is 30 A. And, the capacity of the
alternator is probably 75 A or so.
In other words, the electrical system is not up for this, most likely.
It's not wired for 75 A, let alone the 100 A or so that the inverter
will most likely need.
Another problem, is that the heat has to go somewhere. You have to have
some sort of setup to get rid of the waste heat from the cab (in most
auto and truck air conditioners, this is into the radiator, and then the
heat goes into the air). I guess the air conditioner would have an air
hose to exhaust the heat. Either that, or some sort of plumbing is needed.
I don't think this is practical.
There you go again, choosing to comment on a subject of which you obviously
have little or no knowledge. :)
Please explain what makes you think, "in most auto and truck air
conditioners, (the heat goes) into the radiator, and then the heat goes into
You might want to search "condenser," "evaporator," "latent heat of
Believe it or not, 7000 BTU isn't enough for a car/Truck/van. You need on the
of 12-15000 BTU. It's due to sun load, poor insulation, lots of glass, etc.
Did the van originally have AC? Vehicles without are pretty rare these days.
did, you could spend the $600 (likely less) to fix what is there. It's not your
but the setup you describe would accomplish the same "loss" of money.
On Mon, 2 Jul 2007 22:15:03 -0400, "Antony Fanelli"
Forget about the air conditioning idea, go to an RV Supply or a good
auto parts and get a 12-volt propeller fan that can plug into the
lighter socket, rig up a simple clamp mount to the doghouse cover, and
start looking for a better job. One where you at least rate a truck
with dash air.
For a dozen different reasons it is not practical to run an AC Unit
off a 12V inverter, and install it in a light truck - the heavy
electrical loads alone are way over what the normal light truck
alternator can provide (typically 80 to 100 amps) and you will kill
the electrical system of the van in short order. Blown alternators,
dead batteries, etc.
You need 100 to 125 amps at 12V just for the AC, not counting the
regular vehicle loads, and a 200A Alternator is $500 to $1000
depending on what you can make fit. A big enough 12V to 120V inverter
to do the job would be $1,500, and you need a $200 Optima battery to
provide the 1000A of DC for the start surge..
(They can get away with a smaller alternator for cars with normal
dash AC because the big load is the compressor, and that runs straight
off the engine. The only added electrical load is the heater blower
in the cab.)
The only possible practical setup would be the inside portable (heat
exhaust duct) style AC unit, and a small 120V gasoline engine
generator like a Honda EU-3000 sitting in a cradle bracket on the back
bumper or a roof rack. You'll spend $400 on the special AC, and $2500
on the generator to run it. And you'll spend a lot of time and/or
money making the mount for the generator.
You can NOT use an undersized 1KW - 2KW portable AC generator for
this because of the compressor starting current surge. Too small a
generator and the engine will stall on a compressor start.
You'll waste an hour a day bare minimum putting it all in and taking
it all out of the truck every day - you won't do it for long.
The first time someone notices that very expensive portable
generator sitting out there, it will be stolen. And any lock you can
device that goes on and off easily can be defeated just as easily -
you damn near have to weld it down to keep it from walking away.
And you'll burn through at least 2 gallons of gasoline a day running
the generator, which the company will notice if you try filling it
from the company gas pumps when you fuel the truck - that's theft, and
you will more than likely be fired.
--<< Bruce >>--
I drive for DHL in NJ. I have to drive all day in a van with no AC.
Suppose I spend about $600 of my own money for a 2500 watt inverter
to connect to the battery, and a small portable air conditioner to put
between the seats in the cab. (7000BTU, 900 watts, 7.5 amps)
I don't own the van and can't make any mods to it. I would install it
in the morning and take it all out at the end of my shift. Before I
spend the money I'd just like to know if this setup will work.
1.) 7.5 amps at 120 vac is about the same as 75 amps at 12 vdc.
The alternator won't stand up to this continuous extra load.
2.) Even if it would, the setup wouldn't work. Part of the air
conditioner must be outside the cab for its heat exchanger to work.
3.) You can try a less expensive evaporative cooler clipped to the
outside of the passenger window. You fill it with water and ram air
is cooled and directed inside as you drive. It works rather poorly
in humid climates like NJ, and when the van stops, the air stops.
Another version has a dc fan to keep the air moving during stops.
It could be connected with a cable to the cigar lighter.
4.) One or two small dc fans in the cab may offer some relief.
5.) Contact the NJ labor Dept regarding these working conditions.
They are certain to have some very productive solutions.
That's pretty funny but I wouldn't go that far!
I want to thank those who replied. I'm gonna save my money and not bother
trying this setup. I had a feeling it wasn't gonna work. I just had to ask
Well, back into the yellow oven on wheels.
On Tue, 3 Jul 2007 07:27:23 -0400, "Antony Fanelli"
Go get a couple of commercial-duty 12V fans - if you keep the air
moving in there it will make it much more comfortable. If the van has
a locked divider screen you can leave the windows halfway down, if not
you can leave them cracked two inches and the cross circulation still
keeps the heat level down.
Do not buy the $12 Taiwan clip-on fan at Pep Boys, they're piles of
utter crap. BT, DT, took it back when it broke inside of a week...
You'll pay roughly $50 each for the good fans they use on school
buses for defrosters, and then have to splice on a lighter socket cord
and make a mounting bracket yourself. But they have real electric
motors (not Mabuchi toy slot-car motors) that will run all day, every
day, for several years without problems.
The other slick solution to get some air if they insist that the van
be secured when unattended is to make an 1/8" aluminum plate filler
panel that clamps into the passenger side window - curved to match the
top of the glass, with a matching curve on the bottom with a channel
on the bottom for the glass. Line the channel with felt or rubber, if
there are any sharp points you can end up with a broken window -
safety glass shatters into little crumbs...
Then you punch several holes in the board (quantity depends on how
wide the board is and the diameter of the fans you get...) and install
12V computer cooling muffin fans with the finger grilles on both
sides. Aim them to exhaust the hot air out.
Roll down the window, pivot and tip fan board into hole, roll window
up to clamp in place. Plug in the power. Leave the heater set on
"vent" so there's a way for cool air to get in.
--<< Bruce >>--
It ain't gonna work. Been in your situation for another Co.
Best bet is to surf around for a 12v fan, they used to make them with
oscillation. Moving hot air is better than nothing. Lighter adapter and vise
grip mounting makes it portable.
Tom and Ray's dad from Car Talk used to deliver ice. Perhaps you can
blow the fan against a huge block of ice on a pan with a drain going
through the floor. Just be careful that when you drill the hole, you
don't drill into something, like a gas line.
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