EV Dynamics Physics Experiment

[Automate]

In EV mode you can estimate the electrical power supplied to the motor by computing the power output by the HVB (current x voltage) minus power consumed by the DC to DC converter (used to power accessories).

 

The Air Conditioning compressor also uses power from the HVB so I assume you made sure the AC was off?

 

The AC compressor current can be monitoring in the ACCM (Air Conditioning Control Module) from PID AC_CIC

[larryh]

Both the heater and air conditioning get their power directly from the HVB.  I leave them both off when recording data. 

 

The PID for current consumed by AC is COMP_CURR (Compressor Motor Current).  The power computed using this PID does not match what is shown on the car's display for power being consumed for climate.  The difference is significant. 

[Automate]

The PID for current consumed by AC is COMP_CURR (Compressor Motor Current).  The power computed using this PID does not match what is shown on the car's display for power being consumed for climate.  The difference is significant. 

Is the PID calculated value always high or low?  Does it always seem to be off by the same percentage?

[larryh]

The power calculated from the PID for the AC has very little correlation to what is shown on the display in the car.  It seems to be about the same value no matter what the display in the car shows. 

Edited June 12, 2015 at 01:01 PM by larryh

[Automate]

The power calculated from the PID for the AC has very little correlation to what is shown on the display in the car.  It seems to be about the same value no matter what the display in the car shows. 

Is this with Torque Pro?  Maybe you have the wrong PID or scaling parameters?

 

My 2010 FFH does not have MFT so I only have a relative Accessories Power usage meter with no scale but PID AC_CIC follows what I'm telling the AC to do when monitored with FORScan.  On a hot day when I first turn on the AC the amps go up to around 7.5.  After a while it ramps down to around 1.5 or 2 amps.  When I turn off the AC, amps go to zero.

Edited June 12, 2015 at 09:52 PM by Automate

[Hybridbear]

The power calculated from the PID for the AC has very little correlation to what is shown on the display in the car.  It seems to be about the same value no matter what the display in the car shows. 

Have you been able to get this to work with FORScan? The Focus Electric shows AC amps & AC volts. The amps/volts seem to match pretty well with what the dash shows for kW going to the air conditioning.

[larryh]

Is this with Torque Pro?  Maybe you have the wrong PID or scaling parameters?

 

My 2010 FFH does not have MFT so I only have a relative Accessories Power usage meter with no scale but PID AC_CIC follows what I'm telling the AC to do when monitored with FORScan.  On a hot day when I first turn on the AC the amps go up to around 7.5.  After a while it ramps down to around 1.5 or 2 amps.  When I turn off the AC, amps go to zero.

FORScan reports COMP_CURR.  I haven't checked FORScan recently to see if they fixed it.  The MyView display in the car includes a climate and accessories power meter.  The meter show power usage to 5 kW.

Edited June 12, 2015 at 10:30 PM by larryh

[larryh]

I just tried FORScan with the AC on.  MyView showed 4.2 kW of power for AC.  ACCM_CHVS (Compressor Voltage) was 328 Volts.  COMP_CURR (Compressor Current) was 10.2 amps.  That works out to be 3.3 kW of power.  That doesn't match what MyView is showing. 

 

I then used Torque Pro to monitor the power being consumed from the HVB.  It showed 5.2 kW of power.  MyView showed 4.2 for the AC Compressor and 1.0 kW for accessories.  So MyView is reporting the correct values.  Something is wrong with what FORScan is reporting.

Edited June 12, 2015 at 11:03 PM by larryh

[Automate]

Something is wrong with what FORScan is reporting.

I would report the issue in the FORScan forum.  They have been very responsive to fix bugs and add enhancements I have asked for in the forum.

[Automate]

MyView showed 4.2 kW for the AC Compressor

 

Just thinking about this again, this is an amazing amount of power the AC uses.

 

My whole house AC compressor only uses 4.1kW and it's a 15+ year old low efficiency unit (SEER 10)

 

I realize cars have very little insulation, lots of single pane windows, an engine and lots of electronics generating heat but it's still amazing.  I guess the biggest thing is that cars get very hot when they sit parked in the sun and people expect them to cool down quickly after turning on the AC.

Edited July 25, 2015 at 01:36 PM by Automate

[Hybridbear]

Just thinking about this again, this is an amazing amount of power the AC uses.

 

My whole house AC compressor only uses 4.1kW and it's a 15+ year old low efficiency unit (SEER 10)

 

I realize cars have very little insulation, lots of single pane windows, an engine and lots of electronics generating heat but it's still amazing.  I guess the biggest thing is that cars get very hot when they sit parked in the sun and people expect them to cool down quickly after turning on the AC.

You are correct that people demand a lot from car AC. Ford recently sent out a press release about this: https://media.ford.com/content/fordmedia/fna/us/en/news/2015/07/22/tips-for-staying-cool-with-your-ford-vehicle-this-summer.html

[larryh]

I don't use AC for my commute to and from work.  It takes too much power.  The last time I tried it, I set the climate temperature to 78 F.  AC averaged 2.5 kW for the 15 minute commute--that's about 0.7 kW energy.  The commute normally takes 1.6 kW of energy.  That's a 50% increase in energy consumption.

 

For longer trips, I wait for the cabin to cool down before turning on AC.  After some time, the energy consumed by AC eventually falls below 1 kW. 

[rbort]

The fusion AC is a much more of electric hog than the CMAX AC. Mine starts out at 2.5 kw but soon drops to 600 W.

 

-=>Raja.

[Hybridbear]

The fusion AC is a much more of electric hog than the CMAX AC. Mine starts out at 2.5 kw but soon drops to 600 W.

Have you done a scientific experiment to prove this? Both cars use the same system. Please don't make wild statements that have no factual basis.

[stevedebi]

Have you done a scientific experiment to prove this? Both cars use the same system. Please don't make wild statements that have no factual basis.

I would expect the opposite, because I think the interior volume is larger on the C-Max due to the high roof.

[rbort]

 

 

Have you done a scientific experiment to prove this? Both cars use the same system. Please don't make wild statements that have no factual basis.

 

From what Larry and others have said in the past, the AC draw on the Fusion is higher than the AC draw on the Cmax that I see with the climate meter.  No science here, just looking at the car meter on mine and comparing what is being said on other's cars.

 

Most recently above Larry says "AC averaged 2.5 kW for the 15 minute commute"  To average 2.5kwh draw means it started out much higher than 2.5 kwh draw.  Mine generally starts at 2.5kwh, maybe I'm just in a cooler climate though lately I've been driving when its in the 90's out.

 

Here is a video coming back today from Delware to MA, this part is in NJ, temps in the low 90's and you can see the AC drawing 600w.

 

http://youtu.be/yPA-g2IOB2c

 

Picture below shows trip log showing car netting around 48mpg without much hvb battery usage and later 54 when I used most of it towards the end of the trip.  Also the trip meter upon arrival to Delaware and once again upon arrival home tonight.

 

-=>Raja.

Edited July 27, 2015 at 05:45 AM by rbort

[Automate]

@rbort The AC uses a variable speed compressor and only uses full power when there is a big difference between the actual temperature and the desired temperature.

 

Have you looked at it after your car has been soaking in the hot sun and is 100+ and you turn the AC on max or the temperature setpoint down to minimum?

[Hybridbear]

From what Larry and others have said in the past, the AC draw on the Fusion is higher than the AC draw on the Cmax that I see with the climate meter.  No science here, just looking at the car meter on mine and comparing what is being said on other's cars.

 

Most recently above Larry says "AC averaged 2.5 kW for the 15 minute commute"  To average 2.5kwh draw means it started out much higher than 2.5 kwh draw.  Mine generally starts at 2.5kwh, maybe I'm just in a cooler climate though lately I've been driving when its in the 90's out.

If the answer is "No, I have no scientific evidence to back up my statement" then please don't make the statement. It adds no value. MN has been very humid lately, highs in the upper 80s to low 90s with dew points in the 70s. The AC must work very hard to remove all the humidity from the air. Perhaps you have not experienced such humidity in MA and for that reason you do not see the same kind of power consumption.

[rbort]

 

 

MN has been very humid lately, highs in the upper 80s to low 90s with dew points in the 70s.

 

That is no different that here, my central air has been running in the house for the past 3 weeks.   No 100's here but a "heat wave" as they call it when the high temp is above 90F for 3 days.

 

I guess the best way to find out is to turn on the AC on the fusion and the Cmax at the same time in the same place and see what the draw is.  I have a friend that has a Fusion in Fredericksburg, VA.  I'll be down there 1st weekend in October.  Remind me to try this experiment for you and we can see after both cars are sitting in the same sun and temp what the climate draw is and how quickly the draw drops down.

 

-=>Raja.

[larryh]

I ran the AC again for my commute home under nearly identical conditions to the previous commute.  Climate temperature was set to 78 F.  In both cases, the outdoor temperature was 85 F, the HVB temperature rose from 96 F to 102 F, and the interior temperature of the car ranged from 100 F initially down to 82 F at the end of the commute. 

 

There were two major differences between the commutes:

  1.  For today's commute, the average power consumed by AC was about 0.8 kW.  It peaked briefly at 3 kW and then leveled out at about 0.8 kW.  For the previous commute, the average power consumed by AC was about 2.5 kW.  I observed a sawtooth pattern between 2 kW and 3 kW.

  2.  The inlet temperature of the air used to cool the HVB remained steady around 97 F today.  For the previous commute, it started out at 97 F and fell gradually to 86 F.  So the air used to cool the HVB was about 11 F degrees cooler even though the temperature inside the car was the same.  But that was a futile effort, since the HVB temperature rose the same amount to 102 F on both days.

Edited July 27, 2015 at 09:23 PM by larryh

[rbort]

^^^ Doesn't that go back to the old saying...use the AC to cool yourself when necessary, not the battery.  Remember Gary?  "I use the AC all the time to keep the battery cool"?  or "I cool the battery while charging with the AC for better cell  'thermal' balance"

 

-=>Raja.

Edited July 27, 2015 at 10:46 PM by rbort

[stevedebi]

^^^ Doesn't that go back to the old saying...use the AC to cool yourself when necessary, not the battery.  Remember Gary?  "I use the AC all the time to keep the battery cool"?  or "I cool the battery while charging with the AC for better cell  'thermal' balance"

 

-=>Raja.

What ever happened to GaryG anyway? He is in another league for hypermiling, and I wonder what his numbers are right now.

 

EDIT: I mean, the man achieved mid 50s MPG on a 2009 Escape Hybrid, while the second best I know of was around 40. And that was lifetime MPG.

Edited July 28, 2015 at 04:26 PM by stevedebi

[rbort]

He got banned from the forum for insulting people all the time. Rolling the car in neutral to get a high miles per gallon might be a form of hypermiling but it's not exactly what the OEM manufacturer expected.

 

EDIT:  "I mean, the man achieved mid 50s MPG on a 2009 Escape Hybrid, while the second best I know of was around 40"

 

He probably rolled in N half way across the country!

 

-=>Raja.

Edited July 29, 2015 at 05:46 AM by rbort

[Taz]

I can confirm what Raja is seeing with his C-max. I was in Vegas with mine. It was 115F or hotter. I set the temps inside to 78F and used recirc mode. I saw a peak of 3kW for not very long and then after a few minutes settled down to about a 1/2 bar in the climate display. The ONLY time I saw greater peak consumption is when on the way out of Vegas hit a freak heavy rainstorm.

 

I switched it to defrost and saw a draw of over 4kW. Somehow it seemed to have both the heater and AC on while disable the recirc mode. I adjusted the temp so it wouldn't try to heat the air as well as cool it (so it seemed) and energy consumption dropped quite a bit.

 

The key with the AC is to use recirc mode. Even when the outside temps according to the C-max were indicating 120F on the hot roads, once the temps had stabilized inside with recirc on, I typically saw very close to a 1/2 bar in the climate display. Based on my EV mode usage, it was very minimally impacted as I tried to pre-cool the car while plugged in when I could. So it seems what the display was telling me was pretty accurate.

[stevedebi]

He got banned from the forum for insulting people all the time. Rolling the car in neutral to get a high miles per gallon might be a form of hypermiling but it's not exactly what the OEM manufacturer expected.

 

EDIT:  "I mean, the man achieved mid 50s MPG on a 2009 Escape Hybrid, while the second best I know of was around 40"

 

He probably rolled in N half way across the country!

 

-=>Raja.

Raja,

He was very opinionated, and has been since I've known him on the FEH forum. I'm actually wondering how his Energi is doing with all the stuff he does to the battery, but I don't think the neutral use will have any effect on the transmission.

 

And yes, he used a lot of neutral to achieve his mileage. He posted some videos over on the Greenhybrid FEH forum if you are interested, but I don't have a direct link. My 2008 FEH had a lifetime of 30 or so with AWD, and I was pleased with that.