Is the a/c designed most efficient when permanently on?

I believe that the Prius uses LESS energy whenever the A/C compressor is turned off. Since it does run off of the traction battery, it ultimately will use more fuel which will lower MPG.

I keep ours turned off unless I want actual A/C.

 

Martin, I think there is an option on the gen2 via Techstream to turn the AC off by default when you demist the screen instead of it coming on all the while. If I get chance in the next couple of days I will check it out and advise.
If this is possible I will be doing this to my car.

John (Britprius)

 

Another thing to look at in the way of modifications is to fit heated mirrors. This is not difficult or expensive. If you are interested let me know.

John (Britprius)

 

All the power for the car comes from gasoline, so the AC will lower your mileage. I would use it as little as possible. However, safety comes first. If your windows fog up without the AC, you should use it.

 

Martin.
There is a setting for the AC as I thought if you have the Mini VCI and Techstream or other suitable device.
Go to AC / utilities / compressor, choices are "auto or manual" default is auto change to manual and save.
This setting may revert to auto if you disconnect the 12 volt battery (have not tried this).
This stops the compressor starting unless you select AC on the touch screen.

John (Britprius)

 

Anybody know the actual codes that Techstream is sending to achieve this? I would love to use Torque to change the setting. I have successfully used Torque to disable the reverse beep in a gen3 Prius I was renting. I would suspect this would be similar.

 

Just to mention, it's worthwhile running the a/c at least a few minutes, say once a month: to keep oil in the circuits circulated.

 

I did notice that on the climate screen, while on AUTO, the A/C button is lit even if I am running the heater. Is the compressor actually running or is the computer just telling me that it will run if I ask for cold air, or turn on the defroster?

 

It runs even if you are asking for heat. It is there to remove moisture from the air.

John (Britprius)

 

Yes, that's the idea John. You got it.!!!

 

Yup, it will run at the most efficient load. Since it is electric, the compressor can run at any speed, therefore only at the required load. It can run full blast even with the gas engine off.

This is superior to any belt driven compressor chained to a combustion engine.

 

I've been following this thread and I'm now puzzled about something - my Prius used to turn on the A/C by default when ever I hit the front windscreen demisters. Though I was not happy about the resultant MPG I perceived, I was grateful for it on those few frosty mornings recently when I needed to defog my front windows, however, I digress.

On one such occasion while commuting to work, I was pleased with the powerfully efficient way the Climate Control had rid the interior of the windows of all traces of fogging, I then disabled the A/C side of the equation by turning it off from the screen - apparently while the front demisters were still lit.

I turned that off from the steering independently sometime after that. And here's the curiosity; since then, when I press the front demister switch on the steering, the A/C doesn't come on! I must however concede, this might be because I already have the standard blower (without A/C) on - before I lit front and rear demisters.

Anyway, all of this week - the A/C hasn't come on - and yes, I've been using that front windscreen demist button. I'm surmising that some how I've turned it off from being initialised by the front demister button on the steering wheel. I'm sure my A/C still works though. I'll check it on the way home in a moment.

I am still discovering the complexities of my wonderful "Futurama-esque" Prius II T Spirit, suffice to say it never ceases to impress me, even after 5 months and 4,700 miles of ownership. It has easily surpassed all the positive expectations I ever had for it. Impressed, I definitely am


iPad ? HD

 

Data, I've turned off the A/C while using the "demister".... turned the car off then back on, and the A/C comes right back on.
How was yours working yesterday?

 

When I want to manually cycle the A/C for demisting, I turn AUTO on using the wheel control, go to the screen and turn A/C OFF. Then when I hit the defrost button on the steering wheel, it turns the compressor on. hit the defrosts button again and the compressor goes off with the air being redirected back to VENT. That way, I can keep the windows clear by running it for fifteen seconds or so every couple of minutes, at least until the car interior is warmer, at least in cooler weather.

 

My front defrost used to turn on the AC by default as well, but I disabled it the other day and this morning the AC didn't turn on when I turned on the defrost. I thought it was kind of funny that it happened after reading your post yesterday. I'll let you know how it acts the next few times I use defrost.