haroldo — No! The A/C uses electrical energy, either from the ICE via MG1, from the battery, from regenation via MG2, or from a combination of these. It doesn't really matter where it comes from. That energy usage represents energy lost to the system. The only case where this energy could be called "free" is when the battery is "full," and where it would otherwise have been lost to heat spinning the ICE in fuel-cut mode. In all other cases this energy has to be made up by the ICE. It's important to understand the physical reasoning involved:

• Energy isn't created from nothing.
• The A/C uses energy.
• That energy has to come from somewhere.
• That somewhere is either the ICE (i.e., the gasoline) or the car's kinetic or potential energy.
• Only when some of the car's kinetic or potential energy was being thrown away as heat anyway (i.e., during fuel-cut spinning of the ICE) can this source of energy be considered "free."

Consequently, while driving on level ground at a steady speed of say 60 mph, the battery does indeed do a good job of maintaining its charge level, but the energy needed to do so, and at the same time power the A/C, comes either directly or indirectly from the gasoline.

Stan

 

Okay, help me understand the following...
During normal highway driving (say a 60 mile trip) I glance at the energy level (non-Nav).
At no time during the trip does the car ever get to a low battery state.
In fact, many times I notice that the charge is almost all the way full...I've never, ever seen it at full charge, so I wonder if that is even a possibility.
Assuming full charge (as shown on the battery graphic) isn't possible, then could it be argued that my car, during normal highway driving, achieves it's maximum charge many times during the trip.
If that is the case (and I'm not saying it is, or isn't) then once I've achieved maximum charge, the extra regenerated energy is lost.
If all this is valid, then could the energy used by the AC reduce my charge state from maximum to some other level, say 70%, but then the normal driving recharges it?
I used the AC for two 90 minute highway trips this weekend. I didn't notice the ICE turn on to recharge, since the level never got low enough.
I guess what I am trying to ask is, if highway driving at 65 miles per hour keeps the battery reasonable charged, does the AC sap enough power that it requires the ICE to run to recharge?

(no, I didn't do well on the English parts of the SATs, why do you ask?)

 

I have seen my battery indicator in the MFD at 100%. This happens when I go down some mountain highways starting off in the Brake position. When I reach 45 miles per hour coasting I shift to Drive. The Brake position will charge the battery quickly and fully if you on a downgrade thats long enough. I have seen the full battery about 5 times now.

Driving like you say at 60 or 65 may provide enough generator to run the AC without bothering the battery. At that speed the generator can easily produce lots of amps if needed.

 

haroldo — Electrical power is constantly flowing between MG1 and MG2 (sometimes in the 1->2 direction, and sometimes in the 2->1 direction — "heretical mode") while the car is being driven, often without battery intervention (i.e., when the MFD does not show an arrow to/from the battery). Indeed, no ICE power at all can get to the wheels unless MG1 is involved. Also bear in mind that the MFD icons only show power flowing to/from the wheels; but power can (and usually is) also flowing to other places; e.g., amongst MG1, MG2, and/or the A/C. If you have the A/C "on," and don't see any change in the battery level, all this means is that the needed electrical power is coming from the ICE via MG1 or MG2. These are powerful motors! They can easily handle the electrical power demand of the A/C. The ICE is actually being run a bit harder than would otherwise be necessary, and this extra power is being converted into electricity to power the A/C. As I've argued above, this extra power has to be coming from somewhere. So, if the battery's charge stays constant, the power is coming from the ICE, which uses more fuel in the process. My calculations give a ballpark estimate of the amount of extra fuel involved.

I can confirm what rburt07 says about the battery showing a "full" charge. Descending the Niagara escarpment near where I live in 'D' is sufficient to boost my battery to read "full."

Stan

 

Yes...........i can agree with SPL on that fact.......Energy has to come from somewhere. Even thought the AC system can run electrically.........is still uses the hybrid inverter/battery power to run it, even in ECO mode. Energy in........energy out. It also will use the ICE to keep the hybrid batteries charged to keep the AC system operating as well.

 

Stan, I think I mentioned we have a rather steep drop over on the east side of the mountain where the city of White Sands, NM is located. I go about 45 miles per hour over the top while in drive. The car coasting quickly speeds up to 60, 70, 80 and it settles at 83/84 miles per hour for about 2 or so miles. At this speed I kept a close eye on the battery as it was charging to see what it's going to do when full. A minute after it was full the line between the battery and wheels went off for about a minute. No ice icon at all. It was like coasting in neutral. I'm sure the ecu was telling the generator that the traction battery is full. Any more charge might overheat the batteries and cause damage. Could also be the generator met its peak rpm and was taken out so it would not over rev.

It is really nice to have the batteries peaked like that occasionally. I noticed once I was back down to 65 miles per hour (cruise on) the motor assist kept kicking in more often for the next 60 miles to home.

I sure wish panasonic or nec would hurry and prefect the lithium traction batteries. I'm anxious to see the estimated mpg improvement when they come out. I read tonight that Exxon/Mobil is also working on a thin film lithium battery. That I would like to see. You would think they would be plenty satisfied with the billions they are now raking in.

The other night we came down our long gravel driveway here in the country. It was quiet outside and we had the windows open from driving slow in the EV mode. I parked and left the car powered up. I decided to turn on the AC set at 80 degrees, low fan. I heard a smooth not that fast hum from the compressor. It sure sounds like a well built motor and compressor combination.

Jimmy