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Discussion Starter · #1 ·
I have several projects going on at the moment. One of them, I'd like to keep a clean look under hood and also not rob power from the already not so very powerful engine. I looked into robbing an electric A/C compressor unit off one of these newer hybrids or all electric cars, but finding info on voltages to run it, and wiring them, seems to be nearly impossible. Most shops, including dealers, don't even understand them. While searching eBay for a cheap candidate to do surgery on, I came across this unit. (Link and pic below) It seems simple enough and uses standard Asian style fittings for the A/C lines. I have done my own A/C work on my vehicles for nearly 30 years. I don't see any issues with installing it and making it work. My idea of trunk mounting or possible chassis mounting is unknown. The eBay seller doesn't respond to my questions other than to quote the info in the eBay listing. Has anyone done this conversion? How did it turn out? What is the noise level, and where is the compressor unit mounted?


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Down in flames.
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Discussion Starter · #3 · (Edited)
I just found this on Amazon and it requires 80 amps at max load using the same compressor in my first post. :oops:



 

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The compressors in hybrids ,like a prius, run on 300 volts or around that .

Te 12 volt job you posted looks good.
They are now making 12 volt refrigerators. The compresors are 12 volt, and that is huge for us RV ers
 

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And, Thank you for posting that litle tid bit with the 12 volt compressors.
I am sure they will catch on as guys want to keep the underhood clean (uncluttered) plus less drive belts. win win(y)
 

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Discussion Starter · #6 ·
The compressors in hybrids ,like a prius, run on 300 volts or around that .

Te 12 volt job you posted looks good.
They are now making 12 volt refrigerators. The compresors are 12 volt, and that is huge for us RV ers
Some of them are 300-700 volts DC. A few are actually 12v @80-90 amps. I just can't get confirmation on which models use the 12v compressors.
 

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It would be best to by something like the one you posted.
Look at it this way. Say you spend time fabbing mounts and wiring and get some junkyard POS electric compressor to fit.
Then, you find out it is junk, or works long enough to grenade into your system.
Then you are stuck messing around trying to find another,flushing out your system only to risk similar things happening again.
Build your setup with the new 12 volt job,and be done. If it fails, a replacement is easy to find and you know it will fit.
 

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also not rob power from the already not so very powerful engine.
You do realize that the power comes from the engine either way, right? Turning a larger alternator to power higher electrical loads still robs engine HP. The difference is that with an electric compressor, you have efficiency losses going from mechanical to electric and back to mechanical vs just driving the compressor directly from the engine.
 

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Another thing to consider is a lot of the generic "hot rod" style compressors are only 5000 BTU, whereas a OEM electric compressor is way more. Most car ac systems need to be 20000 BTU or higher due to overcoming the green house effect and to actually cool the car in a reasonable amount of time when you get in it. They are way oversized for the space they condition vs what you'd put in a house, because unlike a house system, it needs to cool quickly and won't run all the time.

Most hybrid or electric car compressors factory now run off the high voltage system which is as stated 300 to 900 volts, three phase ac voltage. They use the inverter in the car to convert from DC battery to AC voltage. None of which is a feasible swap. I'm sure there may have been some 12v compressors, but I don't know what used them, most modern ones have gone 3 phase ac for efficiency.

Also oil is critical with electric compressors. Most use a poe oil vs PAG like belt drive compressors. PAG is conductive which will ruin an electric compressor, and it doesn't take much PAG to contaminate the system. Unless you're starting with all brand new components, it'll be very difficult to flush 100% of the old PAG oil out of all the driers and coils, adding expense.
 

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Personally I’m not much into air conditioning but my wife has a Prius, that compressor runs off the prime mover battery which is way bigger than 12 volt system. Albeit you can trade volts for amps with enough wire gauge.

Bogie
 

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Discussion Starter · #11 ·
Personally I’m not much into air conditioning but my wife has a Prius, that compressor runs off the prime mover battery which is way bigger than 12 volt system. Albeit you can trade volts for amps with enough wire gauge.

Bogie
Yes, all the Toyotas run off the drive battery. They are either the 300v older models or 700v newer models from my understanding.
 

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As noted above, changing any accy to electric just means you're now running that system off the alternator belt instead of where it was run from before, at the cost of a further transition between electric and mechanical, so at-least don't do it in the name of efficiency. Furthermore...and this is just me now...I never "got" the idea of cleaning up under the hood if it meant hiding things further than they already are by being under the hood. Like with inside a closet, items should be neat and organized but all out there and accessible once the door is opened, that's what the space under the hood is for. And again, that just me.
 

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Let's just do a little simple math here before you decide what you want to do. Let's assume a compressor draws 3HP. I think most would draw more but let's just use 3 for an example. Our 12 volt system is the killer of this deal.

1 HP = 745 watts: therefore 3 HP = 2,235 watts
To calculate amps we divide Power (watts) by volts. Therefore, 2,235/12 = 186 amps! :oops:

You can use smaller compressors but still you are not going to adequately cool your car with a 1HP compressor which will still use 62 amps continuously. Noise is the least of your worries.
 

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Discussion Starter · #14 ·
Let's just do a little simple math here before you decide what you want to do. Let's assume a compressor draws 3HP. I think most would draw more but let's just use 3 for an example. Our 12 volt system is the killer of this deal.

1 HP = 745 watts: therefore 3 HP = 2,235 watts
To calculate amps we divide Power (watts) by volts. Therefore, 2,235/12 = 186 amps! :oops:

You can use smaller compressors but still you are not going to adequately cool your car with a 1HP compressor which will still use 62 amps continuously. Noise is the least of your worries.
The unit I posted is used in heavy equipment with no issues. Sanden comps that most aftermarket systems use, are rated at 7.5 kilowats at 3500rpm.

 

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Power = work. You won't get the same amount of work out of it as a Sanden compressor system, either. I used a very conservative number on my assumption,as you can see. The system you listed is way under that. I am willing to bet it won't adequately cool a cars interior in hot weather.
 
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