larryh

The following chart shows what happens while charging the HVB with a 240 V charger. I used value charging. It decided to charge the battery until the displayed SOC was 30% for 40 minutes, and then continued charging the HVB the next morning for another 1:28 minutes (finishing more than hour before my GO time). The red line shows the fan speed. I assume this is the fan that draws in air from the cabin. It ran from 4:57 pm to 5:08 pm. The dark blue lines indicates if the inlet door for outside air is open or closed. When the count/20 is below 95, it is open. When it is above 110, it is closed. The door remained open the entire time the HVB was charging. Charging stopped and then the door closed at 5:36 pm. I don't think there is a PID to indicate the speed of the fan that draws in outside air. The HVB temperature started out at 99 F and cooled to 97 F while charging. The inlet temperature started out at 95 F and rose to 100 F. The interior cabin temperature started at 90 F and rose to 91 F. The outside temperature was 86 F. Note that value charging didn't continue to pull in outside air to cool the HVB after charging stopped. That would have been useless since the inlet temperature was higher (100 F) than the HVB temperature (97 F). That wouldn't provide very effective cooling.

I think there are two fans for the battery, one that draws outside air and one that draws inside air. There is only one BECM PID to indicate fan speed. I think that refers to the one that draws in air from the passenger cabin. There is also a BECM PID for door count to indicate whether the door for outside air is open or closed.

This is from the FAQs at the MFM web site: Q: Why does my vehicle start charging immediately when I have a Value Charge Profile created for this location? A: The vehicle overrides the Value Charge Profile if the State of Charge of the traction battery is less than 10%. After the vehicle charges up to 10%, it will delay the remainder of the charge until the lower-cost times selected in the Value Charge Profile. The car will be forced to use higher cost windows if you don't allow enough charging time. But it may also use them if the SOC is low.

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.

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.

You can see my data in post 127. There should not be a jump between 13C and 18C. You need to collect more data. Also, make sure the battery has rested at least a couple of hours after charging or driving before recording the measurements. Otherwise, you will get inconsistent results. The ETE starts dropping off rapidly below 10 F. I collect the measurements in the morning before my drive to work.

I have recorded ETE (Energy to Empty) of the HVB each morning for the past two years. The following chart shows ETE (normalized to 100% SOC) vs. temperature. The blue markers are from last year. The red markers are for this year. You can see the the energy capacity of the HVB has decreased about 0.2 kWh from last year. The car is just over 2 years old with 25,000 miles. I don't have any data for the first year I owned the car, but I would have expected the capacity to be around 7.2 kWh that year. The total degradation is then approximately (7.2 - 6.9)/7.2 = 4%.

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.

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.

I use the PIDs listed above. I don't know of any PIDs that provide motor or generator current or power. I simply compute motor/generator output power as 2*pi*torque*rpm/60/1000 in kW. 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). Note the header values for the PIDs in that listing are wrong.

People should be aware of the vulnerabilities of OBD II Scanners. I'm sure a determined hacker can also connect to a Bluetooth scanner, but it will take more effort. Some of the cheaper ones constant broadcast their presence and have easy to guess 4 digit PINs such as 1-2-3-4. It is probably inadvisable to leave the car in a public parking lot with such a scanner still plugged in. ForScan and other applications make it easy for intruders to take control of the car. Some of the more expensive WiFi adapters might let you establish a secure connection.

I would not advise anyone to use a WiFi OBD II scanner. They are not secure. Anyone could use Forscan or another application to obtain the codes to unlock the doors or send the appropriate commands to unlock the doors and start the car, or worse, send commands that will interfere with the cars operation while you are driving. If you use a WiFi adapter, remove it from the car when not in use. A Bluetooth scanner is more secure. Forscan has the ability to change the codes to start the car and reprogram keys.

You could set a Go time when you plan to leave. The car will attempt to make sure the car is fully charged before the Go time regardless of the value charge settings..

The variation should be a percentage of the energy used from the HVB. So the more energy used, the greater the variation. The car will start correcting the ETE if voltages stray too far from what is expected. Otherwise, the car will continue to update ETE based on the total energy drawn and regened back into the battery. If it got the initial ETE at the start of the trip wrong, then ETE and SOC at the end of the trip will be wrong. If the HVB warms up faster than expected or you use much higher levels of power from the HVB than expected, ETE will deviate more from the estimated ETE.

The following figure shows the efficiency map for a typical permanent-magnet synchronous motor similar to the one used in the Energi. The solid lines are the efficiency contour lines. The maximum efficiency contour line is the closed path at the lower left. The dashed line shows the path taken during maximum acceleration. That path is not particularly efficient--it is, in fact, probably the least efficient path. The straight section of the path is the constant torque section below 15 mph--the motor is outputting maximum torque, but less than maximum power. The curved section is the constant power section above 15 mph--the motor is outputting maximum power, but less than maximum torque. Below 30 mph, you want to supply maybe 1/4 maximum torque to operate the motor at maximum efficiency (i.e. the path taken goes through the maximum efficiency region within the closed loop contour). Once you get above about 30 mph, you want less torque/power. That means slow acceleration is most efficient. It appears at lower speed, i.e. less than 15 mph, operating the motor at any torque other than about 1/4 maximum torque, the motor is less efficient. In other words, at about 1/4 maximum torque, the motor operates most efficiently. At higher speeds, i.e. above about 30 mph, the behavior is different. At constant speed the car is more efficient with increasing power/torque. With increasing speed, the car is more efficient with decreasing power/torque (efficiency decreases with increasing speed). That would explain why the motor is more efficient climbing hills. It requires more torque/power at the same rpm when climbing a hill versus traveling on a level road. During acceleration, you want to keep the power/torque low.

Things are not perfect. There may be stray current or noise that is affecting the current sensor measurements. From the plot in post 66, it appears the generator is wasting almost 2 kW of power when rpm exceeds 6000. I'm not familiar enough with motors/generators to state all the sources of wasted energy, so I just lump them all under the term "friction". I don't know exactly what the generator/motor torque measurements are. When it is named torque measured from AC source, that would imply there are other sources for measuring torque. The car may well have actual torque sensors, but no communication path exists to report them to the SOBDMC. Or alternatively, Ford has decided there is no reason to report the actual torque sensor measurements to the outside world. Without a manual explaining exactly what the GTQ_OUT or MTQ_OUT measurements are, we can only speculate what they are. From my experience with the torque measurements reported by the car, they don't seem to be consistent with what I would expect.

The generator circuit is most likely open in EV mode, so no power is consumed by the generator to generate electricity. I can only guess how it works since I don't have enough insight into what is going on inside the car. When the car is in neutral, the motor is disconnected from the HVB so no power is consumed from or sent to the HVB. I see similar results for the motor when the car is in neutral.

This is a plot of generator power vs. rpm in EV mode. I'm not exactly sure how to interpret this plot. My best guess is that this is the amount of power that is being provided to the generator to keep it spinning at the given rpm. If that power were not provided, the generator would slow down to due to internal friction. Internal friction from the generator is consuming almost 2 kW of power when rpm exceeds 8000. I assume that the electric motor has to provide this much power to maintain speed to overcome friction inside the generator, plus it has to provide additional power to overcome other friction sources.

The following chart illustrates why you can't use the HVB voltage to determine SOC while driving. Instead, you have to use ETE as described in the previous posts to estimate SOC while driving. This is data collected during a 60 mile commute home. At 72% SOC, you can see the HVB voltage varied from 315 to 336 volts while driving. That is quite a range. At 336 volts, the SOC varied from 72% to 94%. At 315 volts, SOC varied from 48% to 76%. The more power consumed or regened to the HVB, the greater the voltage is from equilibrium. Using voltage alone, one cannot accurately estimate the SOC of the HVB. ETE must be used instead. When the power output of the HVB is minimal, then voltage will be close to the equilibrium voltage, but there will still be error in the SOC if that value is used to compute SOC (the error will however be small, i.e. maybe 5%).

See post 21: http://www.fordfusionenergiforum.com/topic/3179-ev-dynamics-physics-experiment/?p=20696 That contains the torque, rpm, and power data for the motor. The plot above is for the generator. The generator performs no useful function when in EV mode. It just spins--no power is being supplied to the generator and the generator is not producing any power. The only reason there would be any torque is from friction. This would tend to slow the generator down.

I updated the chart below to show the three piece-wise sections of torque vs. rpm with three colored lines. The generator torque as a function of rpm is as follows, where y is the generator torque in N-m (positive) and x is the generator rpm (negative): y = -1.3x/2000, -2000 <= x; y = 2.5e-8x^2 – 0.0001x + 1, -2000 <= x <= -6000; y = x/6000 + 3.5, -6000 <= x It seems strange that torque would be such a perfect piece-wise linear/parabolic function with round and non-arbitrary constants. In addition, the colored lines in the plot have "corners". I don't think a plot of actual torque would have corners. What would suddenly be changing to create the corners at -2000 and -6000 rpm? It looks to me like someone took the actual torque vs. rpm curve of the generator and created a piece-wise approximation, and the car is simply reporting this approximation. The sensors that measure current to the motor are not perfect. So if the car is computing torque based on the current/voltage input to the motor, the result is not necessarily going to be match the commanded value.

As another example, when I arrived home today, the HVB voltage was 290.45 V and SOC was 14.96% (which is estimated based on an ETE of 1.06 kWh). If you look at the plot above, 14.96% SOC is about 5% above the solid black line at 290.45 V. The car cannot measure the true equilibrium voltage of the HVB until the HVB has rested a while. The measured 290.45 V is not the equilibrium voltage and hence one cannot simply look up the SOC based on the chart above. We are forced to estimate the SOC based on ETE as described in the previous post. One hour later, after the HVB has rested, we can now measure the voltage of the HVB and use the chart above. One hour later, the voltage is measured to be 291.42 Volts. Based on the chart above, that corresponds to a SOC of 9.85%, which is what the car reports. Based on the actual SOC of 9.85%, the car then revises the current ETE estimate from 1.06 kWh to 0.7 kWh. The energy in the HVB is rather low. It should not be left in such a low state for very long.

As an example how the HVB state changes between the time I arrive at work and the time I leave, consider a commute in the winter time. When I arrived at work, the voltage was 311.13 V and SOC was 62.02%. When I left work about 9 hours later, the voltage had risen to 311.8 V and the SOC had fallen to 55.18%. The BECM cannot accurately measure the HVB voltage while driving since the voltage fluctuates greatly with power. So instead, it has the monitor the amount of energy drawn from the HVB. It keeps an estimate of the amount of energy remaining in the HVB at all times (known as Energy to Empty or ETE). That morning ETE was 6.44 kWh when I started to work and 4.14 kWh when I arrived. That means the car consumed 6.44 - 4.14 = 2.30 kWh of energy from the HVB as measured by the car. The SOC at the start of the trip was 96.54%. At 100% SOC, ETE would be 6.44 kWh/0.9654 = 6.67 kWh. SOC is simply the fraction of the original 6.67 kWh of energy remaining the HVB. When I arrive to work, ETE is 4.14 kWh and thus the car estimates the HVB SOC to be 4.14/6.67 = 62.02%, which was the value reported by the car. The car now sits for 9 hours and gives the HVB time to rest. When I begin my commute home, the car can read the true equilibrium HVB voltage, which is 311.8 Volts. From the curve in the chart above, it then determines that SOC is 55.18%. It couldn't use this chart when I arrived at work because it could not measure the equilibrium voltage of the HVB. It takes time for chemical reactions to reach equilibrium. Thus I see the SOC jump from 62.02% when I arrived at work to 55.18% when I left work. The car simply did not compute the correct ETE at the start of the trip. That is impossible to do. You cannot know the amount of energy that the HVB will provide until after the fact. The amount of energy that the HVB provides depends on how much power you draw from the HVB. If you draw more power, you get less energy out of the battery. Sometimes the HVB voltage rises, sometimes if falls, and sometimes it remains the same from the time I arrive to work to the time I leave. In any case, only after the battery has rested a while can the above chart be used to determine SOC. Otherwise, it has to estimate SOC based on estimated ETE, which may be inaccurate.

The following chart plots HVB SOC vs. voltage. The SOC seems to depend only on HVB voltage and nothing else. HVB temperature and degradation of the HVB do not seem to influence SOC. The measurements were made prior to and after completing trips when little power is drawn from the HVB. While driving, the voltage will fluctuate greatly with the power drawn from the HVB. To make this plot correctly, I would need to wait for the chemical reactions in the HVB to achieve equilibrium. Until equilibrium is achieved, the voltage of the HVB will change. That means I should let the HVB rest for a few hours before making measurements. That is obviously not the case when I take measurements at the end of a trip. As a consequence, the markers do not all fall on a straight line. In particular, between 310 and 320 volts, their appear to be two lines of markers. The top line is the measurements made when I arrive at work and the lower line is the measurements I make when I leave work. Between the time I arrive and leave, the voltage may change until chemical reactions reach equilibrium.

Tesla provides a charger with the car that plugs into a 40 amp outlet. You don't need a Level 2 charger.