Energi on Fuelly

[murphy]

Does Fuelly have any way to account for power added to the car by charging?

As can be seen from my signature entering miles and gallons doesn't give an accurate picture.

 

Maybe I could take the power consumed during charging and convert it to the equivalent number of gallons.

I have detailed records of power used for charging and what it cost.

 

Any other ideas?

 

[CombsAuthor]

I dunno Murphy...that 145 mpg looks pretty cool to me.

[murphy]

I computed my power input during April and converted to equivalent gallons of gasoline.

I computed the cost of the electricity.

I added it to fuelly as a fillup on the last day of April.

 

A disturbing figure resulted from the calculations.

 

I used 60.51 KWH during April which at $0.16004 cost me $9.68.

60.51 KWH is approximately 1.99 gallons of gasoline using the conversion factor that 1 gallon of gasoline is equivalent to 30.4 KWH.

 

$9.68 / 1.99 = $4.864 per gallon

 

The current price for gasoline in my area is $3.469.

 

It will get better for June through September when the power company will give me a $30 per month credit for allowing them to control my A/C compressor.

[Russael]

Well, with that conversion factor, it may cost you more per gallon, but it's WAY more efficient, so it's money better spent.  I wouldn't worry about that cost per gallon figure at all.

[larryh]

I don't think that is the way you want to calculate your fuel cost savings.  A gasoline engine is only 1/3 as efficient as a electric motor--your calculations fail to take this into account.  Assume that you can get 21 miles on a full battery charge.  I think you can use about 7 kWh before you enter hybrid mode.  So that works out to about 3 miles/KWH.  You used 60.51 kWh or went about 180 miles on electric power.  If you used a normal gas powered car that gets 40 mpg, that would be 4.5 gallons of gas.  I don't know how you are getting $3.469/gallon.  I just checked the stations in my area, it is $4.299/gallon.  So with a gas car, you would have spent $19.35.  You saved $10 with the Energi.

 

Note power companies generally raise the rate during the summer months.  My company charges $0.115445/kWh during the summer and $0.10144 the rest of the year.

Edited May 17, 2013 at 02:13 PM by larryh

[apm]

Here is my recent fuel economy:

 

 

 

I have run 492.1 EV miles using 117KWh which equal 4.2 Miles/KWh. My electric rate is about $0.1169 KWh for a total cost of $13.68 or $0.02779 per EV Mile.

 

For the same period I have 120.1 ICE miles and have used 4.27 gallons which give 28.12 Miles/gallon. The regular gas price is around $3.60 currently, so I have spent $15.37 in gas or $0.12797 per ICE mile.

 

Total cost is 13.68+15.37=29.05 or $0.047452 per mile combined. 

 

I had not gone through the numbers before, but I think the different is remarkable between the EV and ICE per mile cost (about $0.10 per mile difference)

 

If any one believes that my calculations are wrong, please let me know!

 

Regards,
APM

[apm]

By the way, my electric usage for May of 2012 was 3237 KWh and the usage for May 2013 was 3139 KWh or 98 KWh less. The billing month starts the 16 of the month, so the May bill is for the usage from 16 April to 15 May. The FFE came home on Apr 5, so the FFE was using electricity the entire month.

 

Regards,
APM

[larryh]

You also get EV miles from regen and when the ICE charges the battery.   I think you need to do the following to compute what you want:

 

Reset the trip odometer.  Assuming you run in EV mode until the battery is depleted, note the mileage and kWh used when the ICE first turns on.  Those kWh should be used to compute how much electricity you used to charge the battery and to compute the electricity cost.  However, the kWh will probably also include some regen miles resulting in kWh that did not come from the power company.  So I think the only way to do this correctly is to measure the actual kWh from the power company used to charge the battery. In addition, any additional kWh used or EV miles driven while in Hybrid mode were provided by the ICE burning gasoline and not the power company.  So I think the electric cost that you are computing is too low (you are including ICE regen miles in the calculation).

 

For the fuel economy in hybrid mode, you want to take the total miles driven and subtract the initial EV mode mileage until the ICE turned on, and then divide that by the gas consumed.  Consequently, I think the ICE mileage cost that you are computing is too high--you need to include the ICE regen miles.

 

Larry

Edited May 17, 2013 at 10:56 PM by larryh

[apm]

Hi Larry,

 

I think your approach may be correct, but unfortunately it will not work for me. I work from home and I try to stay in EV most of the work week. Sometimes during the weekend the ICE turns on, but not every weekend!

 

I think that Ford should have separated the EV miles from the Hybrid miles in the reporting screens to make the calculations easier. In any case EV + Hybrid is how the EPA number are reported (100MPGe and 41MPG combined). The 41MPG number has to includes electric miles.

 

Regards,
APM

[larryh]

I made a 56.4 mile trip today, mostly freeway/highway driving.  I went 21.6 miles before the ICE turned on.  The ICE consumed 0.83 gallons of gas.  I used 5.9 kWh of plug-in energy.  So the cost for EV mode for me was approximately:

 

5.9 kWh *  $0.10144/kWh / 21.6 miles = $0.0278/mile.

 

The cost per mile for hybrid mode was then:

 

$4.299 /gallon * 0.83 gallon / (56.4-21.6) miles = $0.1025/mile.

 

So gas is more than 3.5 times more expensive than electricity (for this trip).

 

If you keep track of the regen miles and the total gas used, you might be able to estimate the costs more accurately. 

Edited May 18, 2013 at 12:06 AM by larryh

[larryh]

The kWh displayed at the bottom right is the plug-in energy consumed by the car, i.e. energy from the power company.  So the total electric cost to operate the car is correct, i.e. $13.68.  And of course, the gas consumed is 4.27 gallons for a cost of $15.37.  Now you need to separate plug-in energy miles from gas miles.  If you knew the regen miles, you could estimate the plug-in energy miles and the gas miles.  You would have to record the regen miles before resetting the trip odometer and at the end of the trip(s) looking at the lifetime summary display when you turn the car off and compute the difference.  Let's assume that you had 70 regen miles.

 

Then of the 492.1 EV miles, 422.1 of the miles were from plug-in energy.  And of course, for 612.2 - 492.1 = 120.1 miles the ICE was on.

 

Assuming the percentage of regen miles was the same for the plug-in energy miles and the ICE miles.  Then we can associate

 

70*422.1 / (422.1 + 120.1) = 54.5 of the regen miles with the plug-in energy and

 

70*120.1 / (422.1 + 120.1) = 15.5 of the regen miles with the ICE.

 

So the total plug-in energy mileage is 422.1 + 54.5 = 477.6

and the total ICE mileage is 120.1 + 15.5 = 135.6.

 

So the plug-in energy cost is $13.68 / 477.6 = $0.0286 / mile.

The ICE cost is $15.37 / 135.6 = $0.1133 / mile.

 

In your case, gas is almost four times more expensive than electricity.

 

However, you don't seem to be getting very high mileage in hybrid mode:  135.6 / 4.27 = 32 mpg.  I would expect more.  The worst case hybrid mileage that I observed was about 37 mpg when it was cold and I had the heater on.

Edited May 17, 2013 at 10:57 PM by larryh

[larryh]

I'm not sure that the above calculations are valid.  In hybrid mode, it appears that regen miles and EV miles can differ.  Regen miles may only include estimated additional EV miles gained from energy recaptured through regenerative braking.  I'm not sure that it includes the EV miles associated with the ICE charging the battery or when slowing down without using the brakes.  The display doesn't seem to provide enough information to separate EV miles into plug-in energy vs ICE.  I think you have to keep track of EV miles yourself while the car is using plug-in energy (Energi Plug-In Power Mode) vs. when the ICE is running (Hybrid Mode).

 

So the actual Hybrid Mode mileage is probably greater than 32 mpg.

Edited May 18, 2013 at 03:45 PM by larryh

[murphy]

It doesn't really matter.

The cost to operate the car is the cost of gasoline plus the cost of charging electricity.

 

Fill the gas tank and charge the battery.

That is the starting point, record the odometer.

Keep track of all battery charges from that point on, which requires the installation of a KWH meter to have accurate data.

 

The next time the gas tank is filled also fully charge the battery and record the odometer.

The cost of the tank of gasoline plus the cost of all of the charges is what it cost to go the difference in the odometer readings.

 

MPGe can be computed by dividing the total KWH value for the period by 34 KWH (it's on the window sticker) to get equivalent gallons of gasoline.

Divide the number of miles driven by the sum of the actual gallons plus the equivalent gallons to get MPGe.

 

If you want slightly better accuracy the constant is actually 34.02 KWH in a gallon of gasoline.

 

Regen miles are included automatically since they are part of the total miles the car moved during the period.

[larryh]

To answer your original question, this is from the FAQs for Fuelly:

 

What vehicles won't work at Fuelly?

Fuelly is built to track vehicles from motorcycles and scooters up to a standard SUV. All of our assumptions are based on the idea that the vehicle will use liquid fuel in a single tank. Anything outside of that range won't work at the site.

That means Fuelly can't track electric vehicles like the Plug-in Prius or Chevy Volt. (If you have a Volt, try voltstats.net instead.) Fuelly also can't track commercial trucks, Bi-fuel vehicles, RVs, motorhomes, or lawn equipment.

 

 

Hopefully, Ford will update MyFord Mobile soon, as advertised, so that we can track energy consumption better.

 

I assume it will work just fine to track MPGe using Fuelly.  You will also have to compute the cost per gallon of "MPGe" fuel--you can't just enter the cost per gallon for gas if you use MPGe.  That cost will vary quite a bit depending upon how much plug-in power you use versus gas.

 

So for the period ending 4/30, did you run solely on plug-in power for 112.6 MPGe?  And for the period ending 5/15, did you run exclusively in hybrid mode for 46.4 MPG?   Then what you entered is correct.  Even though your electric cost is $4.866 / MPGe gallon, you are getting 112 MPGe in plug-in energy mode vs. only 46.4 MPGe for hybrid mode.  Your cost per mile in plug-in energy mode is $4.866 / 112 = $0.04344.  You cost per mile for hybrid mode is $3.469 / 46.4 = $.074762931.  So hybrid mode costs you about twice the amount as plug-in energy.

 

If you have mixed hybrid modes and plug-in energy modes, you are going to have compute the MPGe price per gallon.

Edited May 19, 2013 at 02:12 AM by larryh

[larryh]

I have updated my fuel-up at Fuelly to reflect MPGe rather than MPG.  I don't have a meter to measure how many kWh I use to charge the car.  In addition, I charge at multiple locations.  So I am going to have to rely on what the car tells me it used for plug-in energy.  The mileage changed from 80.5 MPG to 59.2 MPGe.

 

For 908.6 miles I have driven the car, the total electric and gas cost was $60.29.  So if I go 12,000 miles per year, the estimated annual cost is about $796/year.

 

I used 11.291 gallons of gas which cost $46.28.  I used 138.1 kWh of plug-in electric power, or 138.1/34.02 = 4.059 equivalent gallons, which cost $14.01.  So the total equivalent gallons consumed was 11.291 + 4.059 =15.35 equivalent gallons.  The price per equivalent gallon was then ($46.28 + $14.01)/15.35 = $3.928 / equivalent gallon.

Edited May 19, 2013 at 10:13 AM by larryh

[murphy]

My mileage dropped from 145 MPG to 77.3 MPGe when I added the electricity cost to the Fuelly entries.  This is very close to the MPGe value that the car was reporting at the end of April.  I decided it would be too much trouble to add the electricity values to Fuelly at the time they occur so I am going to add them on the last day of each month.

 

If you are using the 120 volt charger a Kill-A-Watt meter will give an accurate measurement of the KWH used to charge the car.  They are available for about $20.

 

A hard wired meter for 240 volts cost me around $105.  It has a resolution of 0.01 KWH.

 

This is the one I installed.

 

http://www.ekmmetering.com/ekm-metering-products/electric-meters-kwh-meters/basic-kwh-meter-100a-120-240-volt-3-wire-60hz-ekm-25ids.html?gclid=CK3Qitri07UCFZOe4AodXAcAlA

Edited May 19, 2013 at 10:54 AM by murphy

[larryh]

Whenever you make an entry into Fuelly, you will have to include both gas gallons and electric equivalent gallons used during the period of time for the entry.  Otherwise, the reported MPGe for that entry is going to be incorrect since you didn't give it the correct energy consumed for the distance driven.  Are you planning to also fill up your gas tank at the end of each month so you know much gas you used in addition to how many equivalent electric gallons you used, or are you planning to use what the car reports it used for gas?  I think it would be much simpler to make an entry each time you filled up with gas, including both gas and equivalent electric gallons (as I did above).  But then you will have to account for any plug-in energy or gas used during the trip from the gas station until you get home if you are using a meter for electric usage.  You will have to rely on the car for this.

 

Note that my car reported it used 12.92 gallons of gas.  I only put in 11.29 gallons.  This is based on the lifetime summary display showing 70.5 MPG vs. my calculated 80.5 MPG.  I believe I reset the lifetime summary before I left the dealer when I purchased the car.

Edited May 19, 2013 at 12:37 PM by larryh

[murphy]

I have fuelly configured to use odometer readings instead of miles driven.  It is not practical to fill my tank at the end of the month since I've had the car for 34 days and only used 2.6 gallons and that was because of a trip out of town.  Most months I won't use any gasoline.  I don't care about the instantaneous accuracy of the fuelly report.  Entering the electric equivalent gallons and cost at the end of the month will yield my average MPGe.

 

I like your signature note about tracking MPGe.

 

The three fuel-ups on Fuelly currently are my guess as to what the dealer put it in at 6.8 miles on the odometer, my one and only gasoline fill just to get a reading, and one electric conversion fill.

[larryh]

I want to be able to use Fuelly to track trends and seasonal variations, so I am interested in correct MPGe readings for each entry.

 

I have the option of purchasing a submeter from the electric company for $70 for the charging station.  The advantage would be a rate of $0.0585 per kWh during off-peak hours.  But if I use it during peak hours, the rate is a very expensive at $0.3785 per kWh, which would wipe out any savings from off-peak hours.  I would be able to monitor energy usage with the submeter.  Unfortunately, the car decides to charge whenever it wants regardless of how I set the value-charge settings.  It likes to charge up immediately to about 20% if it is empty and disregard my value charge settings.  I would probably have to install some sort of timer to prevent it from charging during peak hours.  Also, it seems to be constantly running various pumps and fans while plugged-in, but not charging.  Also, peak hours are at the time you would like to charge the most:  4 p.m. to 9 pm.  I am not going to remember to go out and plug in the car at 9 pm every night.

 

I'm not sure that the electric company would like it if I used another circuit to charge the car during peak hours--that would defeat the purpose of the discounted rates for off-peak hours.

 

I would have to pay for installation of the submeter.  I wonder how expensive that would be.  I'm not sure that the discounted prices for electricity will offset the cost of doing this any time soon.

Edited May 19, 2013 at 05:46 PM by larryh