How many volts does the GEN III AC Compressor run at?

What you presumably want is the number of amps out of the battery, right? In that case, you don't even need the compressor's voltage - you need the battery's voltage! Otherwise, you're getting the amps to the compressor, not the amps out of the battery.

You could use the battery's nominal voltage (201.6V) as a starting point. A different number might be more accurate considering that the voltage can vary, but I don't know what it would be. I'll assume that you know how to fiddle with the MTH field for the ScanGauge to get the right values...

 

Unlike MG2/MG1, the A/C compressor is driven by DC-AC inverter from HV battery directly.

Ken@Japan

 

OK, so what's the voltage?

 

So does this amp reading include the blower motor or not?

 

You misunderstood me. What I meant is this: you already have the battery current gauge, telling you that it's drawing, say, 5 amps. What you want is an AC current gauge that tells you that 3.5 of those amps are going to the AC compressor, or whatever. For this, you want 201.6 (or even better, the actual battery voltage), regardless of what the AC compressor runs at. Otherwise, say the AC were a 100 Volt system, then 1000 Watts would be 10 Amps, yet the battery amp gauge would only be 5 Amps. So the AC compressor voltage doesn't matter one bit.

Glad you figured something out. I long ago decided that the AC watts gauge wasn't very useful for me. The exact amount isn't terribly important to me, I just want to minimize it - and I know exactly how to do so without a gauge; if it's not too unpleasant, I leave AC off. If it is, then I put it on set to as high a temperature as tolerable. Unless of course I'm going down a mountain and have more regen than I know what to do with, and then I'm happy to turn it down to 65°.

 

Yes, the nominal voltage is 201.6V, or 1.2V/cell.
However, the battery voltage depends on charge/discharge current and SOC.
Please refer to following graph taken by myself sometime ago.

	time	ICE rpm	accelerator (%)	current	volt	SOC
1	4:03:35-4:03:37	2240rpm	68(34%)	-4.8/+3.0A	230-231V	62.5%
2	4:03:37-4:03:54	max 5024rpm	200(100%)	max 154.3A	min 181V	min 59.5%
3	4:03:54-4:03:55	960rpm	0(0%)	min -25.6A	228V	59.5%

Ken@Japan

 

People are usually surprised when they find out how powerful car ACs are.

1750 Watts = 2.3 HP, that's very reasonable for initial cool down power draw on an automotive AC. Car ACs commonly run 20k BTU to 35k BTU cooling capacity, about the capacity of a really big wall unit or small whole house unit. The Prius unit is probably somewhat smaller capacity since they have more control over it because of the electric motor driven compressor instead of a belt drive off the engine.

 

Hello,

I'm trying to use the 2011 Prius refrigerant compressor to make a stand alone air conditioner and I would like to send the correct signals to the built in inverter to make the compressor run. This seems to be a 4 wire Serial Peripheral Interface (SPI) bus running at 12 Volts DC. Can anyone please help me find the correct protocol to use to communicate with the compressor? In the Prius, the Power Management module is the master that talks to the compressor as the slave and sends the required RPM. The Power Management module communicates via the CAN bus.

Does the CAN bus run on 12 Volts DC?

Thanks for any help you can offer.

 

Did you find out any more regarding and make any theoretical or applied progress?

I'm starting to see these parts cost effectively worth investing in for studying, learning and practical applications. Now that I own two inverter/converters and a CVT that I picked for an amazing price just to disassemble and learn what I can make from them along with learning the associated design paradigms of thinking, I'm ready to start studying the designs more. I plan to first read and watch some Weber State University videos regarding.

Would be nice if there was an itemized source. I'm guessing there are details in the open source inverter/converter controllers documents or at least code that will elucidate some info that can be itemized for easy design planning.

Anyone know of any other possible references?

While on the AC compressor topic; what's the operating potential and current range of the Gen 3 AC compressor and the control signals details?

 

As mentioned upthread, it has the traction battery voltage coming in, which is nominally 201.6 VDC but can move around rather a lot, from up to 240ish during regen braking or heavy charging down to 190ish or maybe even lower under heavy loads and low state of charge.

Values I've seen of the "AC watts" PID have been up around 2 kW during initial cooling of a hot car, so that would indicate a maximum current of ten-ish amps.

The most info I've ever seen about the control signals is what you'll find in the repair manual (more info) section for the trouble code B1498, which includes a diagram of the connections between the compressor and the power management control ECU.

Seeing that the connections are called CLK, DIN, DOUT, and STBI allows you to do some not-completely-wild-guessing, but beyond that, I haven't seen more documentation. A lazy afternoon with a four-channel scope might bring some insights.