larryh

The BECM is supposed to manage the HVB so that no damage occurs. There have been many times that I have looked at the SOC of the HVB and found it to be below 10% after a trip and the car had rested a while. The HVB still works fine.

That's why I try to avoid Hybrid Mode until the end of a trip and why I immediately charge the HVB at the end of trip after entering Hybrid Mode. The BECM doesn't always correctly estimate the SOC/ETE for the HVB. It can only accurately measures the SOC/ETE of the HVB after it has rested for a couple of hours. If the SOC falls too low, the HVB will be damaged. At the end of a trip last week, I saw the HVB voltage down to 283 V with no load. The BECM estimated the SOC to be 15.2%. To determine the correct SOC, I would have to let the battery rest for a couple of hours and then measure the voltage. But if the rest voltage were really 283 V, the SOC would be -8.5%! I didn't wait two hours to see what the true SOC was. I charged the car right after the trip. The BECM isn't always all that accurate.

When charging, if the HVB temperature is less than 88 F, the HVB seems to warm up. If the HVB temperature is greater than 95 F, it cools down. When it is in the upper 80's/low 90's, the HVB temperature does not vary much while charging. The steady state temperature when charging the HVB using a 240 V charger is around 90 F when the outside temperature is in the 70s. Note that the BECM controls the door that allows the fans to draw in outside air. It also controls the fan that draws in air from inside the passenger compartment. The BECM is off when value charge is waiting to charge. Only SOBDM is active. SOBDM controls the fan that draws in air from the trunk through the HVB and vents it to the car's interior behind the rear seat. Since the BECM is off, little fresh air enters the trunk. The SOBDM fan can only circulate the existing warm air. Hence, value charging doesn't cool the HVB much. It might help to leave the windows open to vent the warm air from the car, but the fan seems to only run at low speed.

I observed the HVB temperature for two 6 hour periods. On Sunday, the car was plugged in and value charge was enabled. The car was waiting to charge. Yesterday, the car was unplugged. The results are summarized in the table below. The temperature ranges are the temperature at the beginning and end of the 6 hour interval. Value Charge HVB Temp Outside Temp Inside Car Temp Trunk Temp Yes 98.6 – 93.2 86.0 – 75.2 95.0 – 86.0 100.4 – 89.6 No 96.8 – 91.4 80.6 – 78.8 93.2 – 86.0 98.6 – 89.6 For both cases, the HVB temperature fell 5.4 F. The temperature ranges were similar for both cases. For the entire time the car was waiting to Charge on Sunday, the HVB fan was recirculating air inside the trunk running at low speed (1750 rpm). The other fan that draws interior air from the car, remained off. The car did not appear to make a serious attempt to cool that HVB when using value charge. The fan is apparently only running to cool the electronics that were active during value charge. Maybe the results would be different if the HVB temperature were significantly higher, i.e. much greater than 100 F?

This is an image of the trunk with the foam insert containing the charger and the tire pump removed. You can see a long black tube that runs the length of the trunk in the middle. There is a shorter black tube immediately to the left. There are fans at the top of each of the tubes. The long tube draws in air from the outside or from the trunk, depending on whether the inlet door is open or closed, and circulates the air through the HVB. The motor controlling the inlet door is at the bottom of the tube. There are holes on the bottom left side of the tube so that it can draw in air from the trunk. If the inlet door is open, those holes are blocked and the car draws in air from the outside through a vent right below the bottom of the tube. If the inlet door is closed, the vent to the outside is closed and the fans draws in air from the trunk through the holes on the bottom left side of the tube. I have only observed the inlet door to be fully open or fully closed and not in an intermediate state in which it draws air from both the trunk and outside. The short tube draws in air from the car's cabin and blows it out through the large opening at the bottom of the tube into the trunk. What I have observed so far while the car is waiting to charge using value charge is that the car draws in air from the trunk via the longer tube and circulates that air through the HVB. The inlet door is closed. The fan in the short tube that draws in interior air from the cabin is off. So it appears to be circulating warm air in the trunk through the HVB. When charging, I observe that the inlet door is open and the car is circulating outside air through the HVB via the long tube. The fan that draws in air from the car's interior may be on or off. When the car was running this morning, it was circulating outside air through the HVB via the long tube. In addition, the fan in the short tube that draws in interior air from the cabin was on, drawing cabin air into the trunk. ForScan seems to show the speed of both of the fans. The BECM provides the fan speed of the fan for the short tube that draws in air from the car's cabin and a count to indicate whether the inlet door is open or closed. The SOBDM provides the fan speed of the fan for the long tube that draws in outside air or air from the trunk.

All my electricity comes from wind farms. My total electric bill each month for my house is between $40 and $50. The cost for charging the car is $15/month. It don't use enough electricity to make solar panels worthwhile. I will be moving in about three years. I'll leave electricity generation to the power companies. I never pay $0.38/kWh since I don't ever charge the car during peak hours. It is about $0.06/kWh during off peak hours when I charge.

I don't want the car to use any electricity during peak hours. When Value Charging is enabled, the car consumes about 60 watts of power while waiting to charge. That is unacceptable during peak hours. Electricity costs $0.38 / kWh during peak hours. If it consumed 60 watts of power during peak hours, the cost for that electricity would exceed my savings and there would be no point to signing up for cheaper electric rates with the power company for EV charging. You can see one of my many complaints against Value Charging here: http://www.fordfusionenergiforum.com/topic/821-leave-it-plugged-in/?p=4422. I have also complained to Ford directly about how it works. If I plugged in the car when I get home from work, Value Charging would be consuming 60 watts of electricity for 5 hours during peak hours. That is unacceptable. I don't want to have to get up in the middle of the night to plug in the car after peak hours, so I use the timer. I don't really use Value Charging. The charger is disabled when I arrive home from work until well after peak hours. Value Charging is only a backup if the electricity goes out and the timer is set incorrectly. The only time I override the timer is on Sunday afternoon and let Value Charging do its thing. There are no peak electric rates during the weekend. It does what I want on Sunday afternoon. The HVB is depleted when I arrive home and I let it charge the HVB immediately up to whatever it wants (10-40%). It then finishes charging on Monday morning. Value charge has always been charging the HVB immediately after plugging in (for various reasons known only to Ford) from day 1. Not every time, but many times. What I have been posting regarding value charging immediately charging the car after plugging in are not isolated incidences. It has consistently done that since I have owned the car. That's simply the way value charging works and why I use a timer instead.

I cannot conclude anything from these results. I would need to know how Ford intended for it to work. It seems suspect that I was unable to get it to charge from 12:00 am to 3:00 pm when I moved the Go time to an earlier time so it would be unable to finish charging unless it started prior to 3:00 am. Ford states that the car may charge the HVB when the SOC is low and it does do so, so it may simply be charging the HVB because the SOC is low. I cannot rule that out. Or it may be software errors. I would have to experiment with GO times when the SOC is not low to see if it makes any difference in how Value Charging works. In any case, I use a timer connected to the charger to prevent the car from charging during the real peak hours on weekdays from 4:00 pm to 9:00 pm.

According to the charge log, the first time the car charged from 5:52 pm to 6:01 pm for 9 minutes to 10% displayed SOC. The second time it charged from 7:18 pm to 7:24 pm for 6 minutes to 8% SOC. So it didn't charge very long either time.

I changed the GO time to 7:05 am. I unplugged the charger and plugged it back in. It started charging again. It says it will finish at 5:35 am. It predicts it will take 2.5 hours to charge the car. So from 3:00 am to 5:35 am sounds about correct. It charged the car to 7.5% displayed SOC. The displayed SOC, which was previously 10%, was now down to 1% when charging started (I did have the car running for a little while to draw down the HVB SOC). But note the start time didn't make sense. It was not the current time, but a time about an hour ago.

Value charging is simply unpredictable. I experimented with the GO times for Monday morning. I set the GO time for 5:30 am. It begins charging immediately when I plug in this afternoon. It shows the charge time from 5:11 pm to 4:55 am in the morning. 5:11 pm is the current time. I assume that it plans to finish at 4:55 am in the morning. It says it will take 2.5 hours to charge. So I decide to make the GO Time later. I unplug the car, change the GO time to 11:30 am, and then plug the charger back in. It now states it will charge from 3:00 am to 5:30 am and is waiting until then to charge. Since it will finish by 5:30 am, I decide to change the GO time to 6:30 am. It begins to charge immediately. I change the GO time to be sooner to 6:10 am. It then shows that will charge from 3:00 am to 5:30 am and is waiting until then to charge. I change it again to a later time and it starts charging immediately. I let it charge. It charges to a display SOC of 10%. Value charge is simply unpredictable if it will charge immediately or not. In addition, it does not recognize the charge window from 12:00 am to 3:00 am as the next least cost window, and refuses to schedule charging during that time when I use the 240 V charger. It did schedule charging during that time when I used the 120 V charger. It doesn't matter in any case. I have a timer connected to the charger to control when the car actually charges. I simply use Value Charging as a backup in case the power goes out and the timer isn't working properly. I prefer having the car charge immediately when I plug in when the SOC is low. If the SOC should fall too low, it could damage the HVB.

The lowest cost window has always been from 3am to 4pm. The value charge profile is set the way I intend it to be set. The highest cost window is from 4pm to 12 am (during peak hours to avoid exorbitant electric rates). I have no reason to change the value charge profile. I want the lowest cost window from 3 am to 4 pm so I can charge the car when I get home from work from 3 pm to 4 pm, if I want the car charged for later in the afternoon.

The value charge window is already set from 3am to 4 pm. And as I have mentioned, I don't know the exact criteria for when the car will start charging immediately or not. It does not always do it when the SOC is low. Its works the way that it works.

The 120V vs 240V charging is for the default value charge profile. It is not used for my home value charge profile. In any case, the default is 240V charging.

The car does not always charge immediately when the SOC is low and value charging is enabled. Only Ford knows the exact criteria for overriding the value charge profile. The settings are correct. There is nothing to change. Ford said they override the value charge profile when SOC is low and I observe the car doing so. So I do not suspect there is anything wrong.

The least cost value charge window was from 3 am to 10 am for this charge location using the 120 V charger. The GO time was at 5:30 am. The car charged immediately to a displayed SOC of 15%. There is no way to conclusively determine the exact reason why the car charged immediately for 57 minutes when the car was plugged into the 120 V charger. The 120 V charger takes too long to charge the car. There is not enough time in the lower cost value charge windows prior to 5:30 am, so it has to charge in the highest cost charge window. But it probably did not have to charge for 57 minutes. It probably charged for 57 minutes because of low SOC.

The car knows it is plugged into a 240 V charger. It shows the correct estimated time to charge the car using the 240 V charger. The least cost value charge window for the location using the 240 V charger is from 3:00 am to 4:00 pm. The Value Charge profile provides 5.5 hours of lower cost charge windows from 12:00 am to 5:30 am prior to the GO time at 5:30 am. It only takes 2 hours to charge the HVB using the 240 V charger. There is no reason (other than low SOC) for the car to start charging immediately in the highest cost charge window. It only does this when the SOC is low. The car charges the HVB immediately because of low SOC and overrides the value charge schedule.

I do have another frequent destination that I use the 120 V charger at and have a Value Charge profile similar to what I have at home. The only difference is the highest cost profile is longer from 10 am to 12 midnight. Last night I plugged the car in at 4:21 pm. It charged immediately in the highest cost value charge window for 57 minutes to 15% displayed SOC. Then it charged in the second highest value charge window starting at midnight until 2:21 am. It then completed charging from 3:00 am to 4:58 am in the lowest cost charge window. The Go time was 5:30 am. So It needed to charge in the second highest value charge window from 12 midnight to 3:00 am. However, with the 120 V charger, it probably needed to charge immediately to ensure the car was fully charged by 5:30 am, but not for 57 minutes. It appears it was attempting to charge the car to 15% displayed SOC again. So this is not the best example.

I have already mentioned the MFM Web site FAQs that state two reasons why the car overrides the Value Charge Profile and charges the HVB immediately after plugging the car into the charger: low SOC and low HVB temperature. You have already seen two examples starting with this post http://www.fordfusionenergiforum.com/topic/1683-obd-ii-data-for-hvb/?p=21630 where there are 5.5 hours of lower cost value charge windows to complete two hours of charging, yet the car charges immediately when I plug it in during the highest cost charge window.

Displayed SOC is what MFM reports. Absolute SOC is the actual SOC of the HVB. Using the 120 v charger during weekdays is problematic. The car won't finish charging in time for me to go to work if I use Value Charging (and don't charge during peak hours). In addition, the electric rate for 120 V charger is twice the rate for the 240 V charger--only the 240 V charger is on the separately metered circuit for the special EV rates. Using the 120 V charger would only increase the length of time it charges immediately after plugging in. The highest cost charge Value Charge window is during peak hours from 4:00 pm until 12:00 am. The next highest charge window is from 12:00 am to 3:00 am. The least cost charge window is from 3:00 am to 4:00 pm. I have the same schedule for both weekdays and weekends. There is absolutely no reason it should need to charge immediately when I plug it in at 5:00 pm to be ready for work by 5:30 am. If it is attempting to minimize charging costs, it can use the lowest cost charging window from 3:00 am to 5:30 am. If it needs more time, it can use the second least cost charging window from 12:00 am to 3:00 am. There is absolutely no need to charge during the highest cost charge window from 4:00 pm to 12:00 pm. It only takes two hours to charge. Value Charging must be using some other criteria, i.e. low SOC of the HVB, to initiate immediate charging. It would be very difficult to reverse engineer all the criteria Ford uses for Value Charging.

All the PID measurements are quantized--they are have to fit into 8 or 16-bit binary numbers. For the HVB, the resolution is 1 C degree. So the temperature is going to jump in steps of 9/5 of a Fahrenheit degree. I have no idea what algorithm Ford uses for Value Charging. It is different every time. I haven't tried to find a correlation between how much the car will charge the HVB immediately after plugging in when using Value Charging. It the HVB is not depleted, it will wait until the lowest cost charge windows to charge. The past three weeks it charged from (absolute SOC): 15.49% to 43.72% when HVB temp was 99 F, 16.10% to 42.34% when HVB temp was 102 F, 16.21% to 32.16% when HVB temp was 95 F.

This is the same data for a week earlier using value charging. This time it charged until the displayed SOC was 15% for 22 minutes. It then continued for another 1:40 minutes the next morning, completing 50 minutes before the GO time. This time it ran the fan that draws interior air from the cabin the entire time while charging from 5:43 pm to 6:05 pm. The HVB temperature started out at 95 F and cooled to 93 F while charging. The inlet temperature started at 90 F and cooled to 89 F. the interior cabin temperate was steady at 86 F. The outside temperature was 72 F. Again, the inlet door closed after charging had finished. So it appears the car decided not to continue cooling the battery after charging stop, even though the outside air was much cooler than the HVB.

If the SOC of the HVB is low, it may override the value charge settings and charge immediately. This has nothing to do with window sizes and charging rates. It overrides value charging with both Level 1 and Level 2 charges. When it does as you say, you simply don't have value charging set up properly. I always charge the car in the early morning hours. So I don't know how much the HVB cools down over night (if I did not charge the HVB).

What's the point of doing that? If you don't allow enough time for the car to charge in the lowest cost charge window, it is going to have to charge using higher cost charge windows. It is going to look for the next highest cost charge window and start charging at the beginning of that window (or immediately if you plug the car in in the middle of that charge window). It will then stop when there is sufficient time to complete charging in the lowest cost charge windows. Finally, it will resume charging at the start of the lowest cost charge windows and complete charging.

During my 60 mile commute last week, the fan that draws in interior air remained off until the HVB reached 102 F. Then it remained on for the remainder of the trip. The HVB stayed at 102 F. The interior temperature was 92 F. The outside temperature was 79 F. The HVB inlet door temperature was 95 F.