What is exactly A/C Load Ratio

Just to add to @Tideland Prius comment. A/C Load is only for HVAC utilizing the heat pump. Heated seat, heated sterling wheel, and rear defroster (which turns on heated side mirrors) do not get counted into this equation, even though they too use the traction battery power AFAIK. On the other hand, turning on windshield defroster will force the A/C to run at full blast, thus taxes the A/C load heavily.

 

What does "A/C Load Ratio" even mean? In everyday English, is it "the effect of air conditioning on miles per gallon"?

For another layer of complexity: the Toyota Owner's Manual seem to describe any-and-all usage of the cabin's ventilation system as A/C, not just usage where the freon variant compressor is mechanically/chemically cooling the air.

For what it's worth, I've found if I've rolled up to a red light with a partially warmed engine, I can get that engine to turn on or off, by either raising/lower the cabin temperature setting, or in some cases by shutting the system right off. That would have some impact on mpg I think.

 

That brings a new question. I have not tried driving EV using just ventilation fun ON, but with A/C turned OFF. Would that be counted as A/C load? I don't know. I will give it a try tomorrow and report back here unless someone already knows the answer. I drove in 4WD SUV today. The road was still full of ice and snow this morning and I no longer have snow tires on my PRIME.

 

I've done that quite a bit. I suspect that it does count, but so far in my case it hasn't been enough to earn a "1" in the percent column.

Edit to add: At least I don't remember it being above 0. The old gray cells aren't what they used to be. I might be able to check it again coming to work tomorrow.

 

That means fan motors use far less amount of electricity than the heat pump. I usually leave my A/C setting on AUTO for I usually have the 11.6 inch display turned off. I can control the A/C Auto temp from MID using just wheel buttons. During winter, my A/C load ratio is anywhere from 15%-30% with A/C (heat) on. That really eats up my EV range.

 

Did that frequently in my Gen II's. Can't stand to have an engine running when the vehicle isn't moving (*). So turn the climate control off while at a red light, back on when moving again. Car doesn't cool down noticeably.

* daughter has driven only Prii until her car got hit last summer and she needed a rental. She only drove it when I needed my car, otherwise she drove my '09. Engine running at red lights drove her nuts. Keys that must be stuck in slots and turned drove her nuts. Gated shifter going through reverse to get to drive drove her nuts. Having to shift to park before the car could be shut off drove her nuts. Smart girl

 

I kinda like gate shifter, keeps you more cognizant of what gear your in, reverse vs drive.

 

Has anyone figured out a way to use AUTO without the car switching from recirculate to "fresh" air seemingly at random? In my PiP and my Prime I can't use AUTO because invariably it will just decide to switch to "fresh" air right at the worst time and suck a bunch of Diesel fumes from the highway into the car.

For cleaner air, set car vents to 'recirculate' study says - LA Times

 

xo xo xo

 

Sorry, I have no idea how to change that behavior. I have to admit that have not experimented much with HVAC on my PRIME. My goal was to use the 11.6 inch display as little as possible. I usually keep the display off and leaving the setting at AUTO. I use MID and wheel button to control the temperature, and voice control to turn it on and off. Now outside temp is getting warmer, I will likely to leave it OFF most of the time until it gets really cold.

 

I don't know if this has changed for the Prime, but the way AUTO works in my Gen 3 is, if I push the AUTO button, that means "auto everything". After that, if I touch the fresh/recirc, or the fan speed, or the outlet setting, it continues to mean "auto everything except what you just touched". If I end up touching all three things, after that it's "auto nothing much at all". Until I press AUTO again.

 

I had to use the defrosters may times on my drive from Bangor home today. Tons of fog. Even though the climate control system was initially off, when I turned off the front defroster the system went to Auto. I find that unfortunate, it should go back to whatever it was when I pushed the front defrost button.

 

You keep the display off... because? energy use? distraction? I just got a new prime, and it seems more work to adjust the temp via the steering wheel, or at least its much different from my older Priuses.

 

Yeah, wheel switch is cumbersome not the best solution, but I hate touch screen operation so much so that I don't want it to stay on. It is a distraction while driving. I don't get tactile feedback from the screen touch. And the screen is at a location that requires to take my eyes off the road and my right hand off from the wheel, thus not safe. Less I have to use the screen the better my driving experience will be.

 

The steering wheel climate controls on the Gen II were much more ergonomically friendly. One touch auto, temp up/down, recirculate, front and rear defrost all without moving your hands nor your eyes off the road.