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Electric car air condition system

Golfelectric on Sun June 26, 2011 1:52 PM User is offline

Year: 1999.5
Make: VW
Model: Golf
Engine Size: Electric
Refrigerant Type: R-12
Ambient Temp: 90F
Pressure Low: 40
Pressure High: 125
Country of Origin: United States

I have an all electric conversion that I have added AC using a unit supplied by Electric Blue motors. It is essentially a 120V window unit that has the evaporator cut off and hoses added to allow for connection of hoses to the car evaporator.
The problem I am having is the unit is not cooling very well. I have taken the car to a conventional auto shop and had Freeze 12 added (the recommended coolant for the unit) and am having problems getting the head pressure above 150. Right now the high pressure was at 125 and low was at 40. Recommended setting for the unit are 30-40 on the low side, no recommendations for the high side.
My thought was that the evaporator is clogged and I just realized that the connections at the firewall include an expansion valve, could that be restricting the flow of coolant and causing the lack of cool air in the car? The connectors under the hood on the low side are cold to the touch and the compressor is running. Should I pull the second expansion valve and just drill it open to clear the restriction?
Any help would be appreciated

1999.5 VW Golf IV
All Electric conversion

JJM on Sun June 26, 2011 3:20 PM User is offline

Two things come to mind:

First, Most window units have a fixed orifice, so if the fixed orifice was not removed, you're going to have a problem with the TXV. Probably better off keeping the TXV rather fixed orifice, since modulated refrigerant flow provides the best performance.

Second, and most important, most window A/C units are not going to have enough BTU capacity for a vehicle. Unless that former window A/C had some 20,000 to 24,000 BTU - which would likely require 240VAC - you're not going to have sufficient cooling.

I'll reserve my comments on the folly of electric vehicles for another discussion.


When considering your next auto A/C purchase, please consider the site that supports you:

Golfelectric on Sun June 26, 2011 3:56 PM User is offline

So you are saying that the expansion valve in the car will not make a difference. The new unit does have its own expansion valve at the compressor. Of course the one in the car was designed to work with R132a. I know that there is a difference in the capacity of the two units. I am just trying to maximize the performance of the replacement unit. I had the option of a 8000BTU unit, but the footprint was too large.

I won't fight you about EVs, I have a believe they are not for everyone, but some type of hybrid or electric car will extend the life of the existing fuel reserves that we have.
We are using too much too fast. The window is closing on oil. If we changed our primary fuel source today, it would take 15 years to replace the current fleet of existing cars.
We are currently using 85 million barrels of oil every day.
Sorry this is not the forum for this discussion. Just stating current facts.

Thanks for the reply. I wont argue that AC in my ICE is way better than the EV conversion. My new Leaf on the other hand has no problem staying cool.

1999.5 VW Golf IV
All Electric conversion

mk378 on Sun June 26, 2011 4:27 PM User is offline

Any non antique window unit would be designed for R-22, the latest ones are R-410a. Freeze-12, R-12, or R-134a are not suitable substitutes for either of those refrigerants. Like JJM said you probably have nowhere near enough compressor for the necessary BTU. Air infiltration and solar heat gain are huge on a car compared to a house.

NickD on Sun June 26, 2011 7:21 PM User is offline

Seems like these guys should have the answers to your questions.

"Island Green Motors wanted a car that is fully equipped. We put in all the extras, air conditioning (using our Cool Blue air conditioner and Blue Flash inverter), power steering and power brakes. These extras make the car drive just as if it were powered with gas. As a bonus, the air conditioner can run even when the car is stopped. The Blue Flash inverter has 2KW capacity and can also be used to power other things like power tools or lights. "

See their vehicles use 34 each 160AH LiFePO4 Batteries

Weight:7.00Kg Price:$248.00

1. Nominal voltage : 3.2V
2. Nominal capacity(C/3, 20 ??: 160Ah

Discharge@ 23?
3. Max. Cont Current : 1C
4. Max. 30 sec. Pulse : 3C
5. Cut-off Voltage : 2.5V

Standard Charge (CC/CV)
6. Charge Voltage : 3.65V
7. Charge Current : 0.2C
8. Charge Time : 5.5 hrs

With all 34 in series for a 108 DC voltage output, so the resultant capacity would still be 160 AH with a battery cost of 8,500 bucks.

With standard efficiency of a 2 KW inverter, and since you can run your vehicles' AC with the motor off, should keep you cool for a day with a full charge. Course, you won't be going anywhere.

Really don't know if their AC unit is based on HVAC or MVAC standards, but Freeze12 for either seems to be a very poor choice of either application, R-134a would be far superior as Freeze 12 is 80% R-134a anyway. The other 20% is R-142B that is supposed to make it compatible with R-12 or at least that is what the manufacturers claim.
Really doubt if Electric Blue Motors is using an old R-12 AC system.

Also a green person, how about a methane external combustion equipped powered vehicle with 90% overall efficiency? Never see that with an oil controlled congress, that is the first objective. With all the engineering that went into the Chevy Volt, the heating and AC system in that vehicle is killing any thoughts of saving energy. Converting electrical to chemical energy then back again, just is not efficient. Using plastic on bumpers to save a couple of ounces, then add over 600 pounds of batteries.

Golfelectric on Sun June 26, 2011 10:20 PM User is offline

I am using the same unit as the one pictured, just smaller. The one in the photo is the 8000 BTU unit. Their installation manual clearly states using R-12 or Freeze 12.
I agree that there are better coolants out there and I questioned them from the beginning before installing the unit. It seems that when I first had it in the car it was cooling better. The car sat for the entire summer last year because of some issues with other faulty components, so this is the first hot summer with the car actually driving everyday.
I spent 2 hours adding freon and messing with the unit with a guy at the auto shop.
I am happy driving my EV and not buying gas. If I am the only one in the car it is not too bad. It is better than most of the guys that do conversions, they just forgo the AC completely, that is painful here in Texas during the summer.
I have a message into these guys that built the unit. I will let you guys know what they say about what they did. I am tempted to remove the Expansion valve to at least reduce the constriction and allow the freon to travel into the Evaporator.
Thanks for all of the quick responses.
Details of my car are
144V 90ah LiFe04 battery back. About 13KW (the Volt is 14KW)
40-50 mile range
Charge voltage can be 120V or 240V. Charge time on 120v about 4-5 hours.
Electric heat
Driving is totally normal. I can adjust the acceleration of the controller for normal or more aggressive driving.
Took about 6 months to get the car on the road, then switched to LiFe batteries and took some time to get Battery Management System in order and working properly. When I added the batteries there wasn't a real BMS system available to the public for controlling them. I took 6 months of searching to find the proper system.
Car is now a daily driver for a 30 mile daily commute.
You can see the car and AC at
Thanks again

1999.5 VW Golf IV
All Electric conversion

JJM on Sun June 26, 2011 10:25 PM User is offline

Do you realize this irrational fear that the world is running out of oil goes back more than 100 years? And guess what has happened in the last 100 years? Oil production is at an all time high. The only reasons oil is relatively expensive now is because the value of the US dollar is falling, the US tying it's own hands behind it's back over superfluous environmental concerns, and speculation pricing in potential flare-ups in the Middle East.

Don't know how old you are, but I'm 45 and have heard all the fear mongering over and over again. In the 1970s the fear de jour was we were headed for another Ice Age due to pollution drowning out the sun, and of course, overpopulation. In the 1980s it was acid rain and the ozone hole. In the 1990s through present it's global warming - though now the experts are covering their asses by calling it climate change... how can anyone ever be wrong about that, given the climate has been changing since the Earth began.

In 1972, the "Club of Rome" published a book "Limits to Growth" which created a lot of fear that the world would run out of gold by 1979, silver and mercury by 1983, tin by 1985, zinc by 1988, petroleum by 1990, copper and lead by 1991, and natural gas by 1992. Has any of this happened? And despite persistently wrong predictions for more than 100 years, people still fear we're running out of these resources.

Oil might not be finite at all, and could very well be a "renewable resource" after all as some recent science suggests. Oil wells which were capped some 30-40 years ago that have been revisited have "miraculously" been filled with oil. Though the possibility that seismic activity might be partially responsible for these wells being "renewed", it's also possible the Earth continues to produce this resource. The fact is, we still do not know very much about what goes on deep within our planet, or on the surface of our planet, or anywhere else for that matter. What has been is typically accepted as "established science" is often proven wrong. We were told that we have discovered every living creature there is on the planet, and look at how many new species we continue to find in our seas, land, and skies.

So in short, there is no need to adjust our lifestyles in any way, or do with less. America has NEVER been about doing with less. In order for America to remain prosperous we must continue to produce more energy. Granted, the current political climate is antithetical to this, and is it any wonder why we have record unemployment, high inflation, stagnant growth, and the increasing possibility of another recession and possibly depression. On the other side of the globe, China doesn't subscribe to any of this nonsense and look at how exponentially prosperous they're becoming.


When considering your next auto A/C purchase, please consider the site that supports you:

JJM on Sun June 26, 2011 10:43 PM User is offline

I also see from the website this thing only has a top speed of 65 MPH. In your state, the great state of Texas, there's an 80 MPH speed limit in much of the western part of the state, and I understand the legislature is considering raising it to 85 MPH (which is a good thing). This thing is going to be a traffic obstruction, and traffic is huge fuel waster.

Also, once we have more electric only vehicles on the road, guarantee we're going to a have a lot people with discharged batteries in stranded on our roads causing major traffic jams (which will end wasting more fuel for all the other vehicles stuck in traffic), or worse collisions when they're stopped dead in the middle of the highway with no power for lights, nothing. Lives will be lost for the sake of saving a little bit of gas, which is plentiful?

As is now, here in the Northeast, every time the weather gets hot (or very cold), we're told to "conserve" electricity. What's going to happen when we plug all these electric cars in? The no environmental crowd doesn't want us building more power plants, or running more cables, and wants to shut down nuclear plants, so where is all the additional electricity going to come from? The energy fairy?

The majority of electricity generated in the US comes from coal fired power plants. Is the coal that powers these electric vehicles all that green? And won't coal run out one day too?


When considering your next auto A/C purchase, please consider the site that supports you:

mk378 on Mon June 27, 2011 8:06 AM User is offline

That system is only slightly more advanced than the guy who just put a complete household windowshaker through the back window of his car. At the least you should have an auto-style parallel flow condenser mounted directly at the grille for best flow of the "coolest" outdoor air available. The PSC induction motor compressor with 60 Hz inverter is not going to be real efficient on electricity. People have mated auto compressors to brushless DC motors; some hybrid cars have such a compressor stock.

They're telling you to use Freeze 12 because the compressor still has the mineral oil in it from it's original R-22 life. Freeze-12 is just 80% R-134a combined with another ingredient that can push mineral oil around. To use kind words, it is a very sophomoric engineering job. All they have done is take a small cheap window unit, remove the evaporator and capilary tube, and plumb it to an expansion valve and evaporator inside the cab. You do need an expansion valve, some sort of flow restriction is required to develop a pressure difference between the condenser and evaporator.

NickD on Mon June 27, 2011 9:27 AM User is offline

40 years ago, was paying a penny for a KWH, unit of measurement for electrical rates. Was all hydroelectric back then, up to about five years ago, those rates increased by a factor of five while the minimum wage rate only doubled over that time span. In the last five years, electrical rate have more than doubled. Claimed the usage went way up, so instead of paying a penny a KWH, more like 11 cents a KWH now.

Two nuclear power plants were shut down mostly for the Milwaukee area, and all the EPA approved for additional sources of energy for new plants is using natural gas. The reason given for the much greater increase in electrical rates. Six years ago, purchased a Bosch on demand electric water heater that would save me energy cost. Still brand new and in the box. Copper prices skyrocketed, so decided to wait watching the prices, then our electrical rates more than doubled in one monthly billing. It was cheaper for me to buy a energy efficient hot water heater and use that instead.

Also thinking in terms of getting rid of my electric lights and going back to gas lamps, granted using electricity is far more convenient, but also need a gas operated computer, TV, set, at one time, when electric rates were real high, already had gas operated air conditioners and refrigerators. Gas dryers are still common as well as gas ranges.

In your case, burning natural gas with low efficiency to generate electricity, then changing that to chemical energy, then back to electrical energy to drive a motor to convert that back to mechanical energy, that is six energy conversions! Why not just run your vehicle from natural gas? And develop a high efficiency engine. Efficiencies are already there compared to automotive in industrial applications, its just a question of doing it. We already have a known 4,000 year supply of natural gas, and if a known supply of methane is added to that, brings that total up to 12,000 years!

You would think in that time with the extremely slow development of nuclear fusion, it could be done in 12,000 years. If you really get involved with this, the only thing Washington DC is doing on these subjects is handing out tons of BS on these subjects. The EPA lives on burning HC's, wouldn't have a job if much cleaner fuels like natural gas and methane were used. All this energy stuff is politics.

See your lithium-ion batteries have a 2.5V cutoff, in my opinion that should be raised to 3.0 V. These batteries share that same characteristic as lead acid car batteries, do not like being discharged down to zero, capacity rapidly decreases to nothing, but you are only talking $8,500 or so replacement cost. Had to get on my wife to charge her cell battery every night, was letting it discharge to zero and required new replacement every couple of month. Same with my son with his now six month old Milwaukee lithium-ion battery, already going dead. If your range is 30 miles, would cut that down to 20 miles for a new charge.

Unbelievable they are using an R-12 system, against the law, and was since 1994, did have a delay for R-22 with a theoretical only 5% ozone depletion potential of R-12, but also outlawed for any new systems. Just recently, we have a president that thinks Al Gore is some kind of god. I looked into R-410a systems for my own home, would never see a payback over the life of this equipment. Criticized me if you like, I can take it, but if I don't see a reasonable payback in my investment, its a no-go for me.

With R-12, if you want to see any kind of near efficient cooling, your low side pressure should be a constant 28 psi over the entire operating range. This is not new, been that way for over 70 years, whoops, make that 80 years now.

Anyone want to buy a Bosch whole house on-demand electrical water heater. Still brand new in the box, will let it go for $400.00. One of these days, they will be going back to natural gas AC systems, maybe that is when I will buy one, no compressor, and fairly easy to maintain.

bohica2xo on Tue June 28, 2011 1:26 AM User is offline

Wow. After Nick posted that picture, the first description that came to mind was "Goat Copulation"

I think anybody that calls selling a chinese window shaker with the evaporator discarded "engineering" probably orally copulates with deceased goats on an ongoing basis...

Without getting bogged down in the ooga-booga of electric cars, I can offer this much:

Make sure there is no restriction between the condensor discharge and the TXV in the vehicle. If the window shaker was originally an R22 unit, I would charge it with R290 and evaluate the performance - it either has enough cooling to suit you, or it does not. Simple as that.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Tue June 28, 2011 4:46 AM User is offline

When I first saw that photo, reminded me of the time I hauled a window unit that looked like that in the back of a station wagon over a thousand miles. Drove very carefully, was concerned it would fall apart with all the bumps and pot holes in the roads.

Karl Hofmann on Wed June 29, 2011 7:31 PM User is offlineView users profile

Originally posted by: JJM
On the other side of the globe, China doesn't subscribe to any of this nonsense and look at how exponentially prosperous they're becoming.

Joe it is easy to become prosperous when your workforce work for next to nothing, health and safety are non existant and the effluent from you factory can be dumped into the local river.... Both Britain and the US became rich and powerful using the same methods.

Never knock on deaths door... Ring the doorbell and run away, death really hates that!

NickD on Thu June 30, 2011 6:40 AM User is offline

Many of these industrial pollution problems have never been solved, just exported. But not far enough away, like to another planet, still the same planet, what are they thinking? Like our idiots in Madison, thinking they are going to save the world by super strict refrigeration laws. Just makes a guy drive a couple of miles and cross the state line. Neighboring states get the sales tax, Wisconsin loses out. Major source of pollution in California now is from China. And China is doing an excellent job of polluting the Pacific Ocean.

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