A/C Wattage vs lights

[thorn]

I had downloaded some of the Prius manuals and found that the A/C (Page BE-30) power consumption is 200W. Does not seem like it would cause a big drop in MPG. The lights are 35w each plus tails & front lights (what, 15w each?) so say 130 watts total? Seems like if the A/C at 200w causes a reduced MPG what about the lights? I usually leave mine on during the day.

[KMO]

That doesn't sound right. I can't find any figures, but I would have thought that the A/C would be more like a couple of kilowatts.

[Marlin]

Are you sure that's not the wattage of the blower fans? Toyota seems to use the term "air conditioning" in the most generic sense at times. I could certainly believe that the blower fans consume 200 Watts.

[kirbinster]

Has to be much much more than that. A car requires a lot of BTUs due to the metal and glass making the thing act like a greenhouse with no insulation. A home wall unit that is rated at 12,000 btu/hr uses something like 12-14 amps at 120 volts - that is something like 1440 to 1680 watts. Is it possible they were saying 2,000 watts and a zero got dropped?

[thorn]

<div class='quotetop'>QUOTE(Marlin\";p=\"110467)</div>

Are you sure that's not the wattage of the blower fans?  Toyota seems to use the term \"air conditioning\" in the most generic sense at times.  I could certainly believe that the blower fans consume 200 Watts.
[/b]

It says 200w. 170 for the heater. Cooling cap. is 4500W. That seems like a lot for a car AC! And 200w seems like a lot for a car fan.


Here is a copy of the manual page:

[kirbinster]

That sounds more reasonable. Just remember that when you regenerate through braking you earn a little gold star for each 50 Watt-Hours you produce. Well for each hour you run the AC you need to generate 90 of those little stars, so yes it is quite a bit of energy.

[seasalsa]

Not really on subject but a lot of Prius AC info:

http://www.denso.co.jp/AR-e/1998/TW/climate.html

[jamarimutt]

Seems to me that anything that consumes electricity will lower mpgs because the ICE will have to run longer to maintain the same charge level in the battery. The air conditioner has a definite toll on mpgs, and leaving the lights on all the time should do too, although to a lesser extent.

[Marlin]

<div class='quotetop'>QUOTE(thorn\";p=\"110481)</div>

It says 200w. 170 for the heater. Cooling cap. is 4500W. That seems like a lot for a car AC! And 200w seems like a lot for a car fan.[/b]

Not really.

450 cubic meters per hour is a lot of air. It works out to 264 cubic feet per minute(CFM).
It's not a perfect comparison, but I looked up the specs of fairly beefy ventilation fan that is rated at 300 CFM. It's like the kind of fan you would put in a bathroom, but at 300 CFM, it would need to be a big bathroom. Anyhow, that fan was rated at 300W. So, a 264 CFM fan in the car, could concievably consume 200W.

That chart you posted kind of sucks in my opinion, because it's not real clear. I suspect the actual power consumption of the compressor is 4500 watts.

First off, look at the heating section. The Prius has an electric heater in addition to using the heat from the engine. If the 200W number was the total power consumption of the A/C, then the 170W number would be the power consumption of the heater. A 170W heater is too small to be worth installing in anything, particularly a vehicle that might have an interior temperature of 10 degrees when you start it. A 5300W heater sounds more reasonable. With that, you really could heat a car from 10 degrees to 65 degrees in five minutes or so.

Secondly, I belive I've read that the Prius battery is a 1.5 kWH battery, meaning to could supply 1.5 kW of power for an hour. That is probably the rating if the entire capacity of the battery is use, however the Prius uses only about 60% of the capacity to prolong the lifespan of the battery. So for practical purposes, lets call it a 1 kWH battery.

If you start with a full charge, and ran the A/C at full power, consuming 4500W, then your battery SOC would go from 8 green bars to 2 pink bars in about 10 minutes. This matches the observed behavior of the car.

[thorn]

450 cubic meters per hour is a lot of air. It works out to 264 cubic feet per minute(CFM).
It's not a perfect comparison, but I looked up the specs of fairly beefy ventilation fan that is rated at 300 CFM. It's like the kind of fan you would put in a bathroom, but at 300 CFM, it would need to be a big bathroom. Anyhow, that fan was rated at 300W. So, a 264 CFM fan in the car, could concievably consume 200W.

I guess you are right, at first it seemed like a lot of power. ops:

That chart you posted kind of sucks in my opinion, because it's not real clear. I suspect the actual power consumption of the compressor is 4500 watts.

I does really cool that car down fast so it could be using 4500W.
It is a terrible chart. I have not seem any other data on the AC. I guess I could call/email Toyota?