List your miles and MPGe

[kevin]

SparkevBlogspot:
....

Right now I am trying to get a handle on the miles / kWh number. Whenever someone quotes a mi/kWh number, I have an immediate question. Is the kWh value used to calculate the mi/kWh number a battery to wheel or a wall to wheel number? All of my numbers are based on wall to wheel and include all charging losses which I have measured to be about 22% for the L1 charger at an 8 amp charge rate. If I factor the charging losses out of my calculation, my 3.61 mi/kWh becomes 4.63 mi/kWh. The temperature in my garage is also a factor and right now it gets quite hot even into the late evening.

....

As far as I can tell on all EVs I have driven (Fiat e500, i3, Leaf, Tesla model S) the number displayed on the internal instrumentation (driver display on the Spark) is calculated from the DC consumption so does not include charger or battery losses.

For the first year I owned my Spark I measured and recorded the energy going in (from Chargepoint or using a Killa-Watt when using Level 1) as well as the internal displays. For the first year with ~6000 miles my average consumption from the battery was ~5.7mi/kWh while the energy going in was 4.7 mi/kWh. This implies that the charger and battery are ~83% efficient. I did a few charges at Level 1 and they seem to have about 78% efficiency.

kevin

 

[MrDRMorgan]

Kevin:

Thanks for the good info.

The trip meter in the car does show me much higher numbers. The high 5's are not too difficult to achieve and I actually hit 7.1 by coasting as much as I could. But, put 2 adults in the car, kick on the A/C and push the speed up past 55 and the numbers drop significantly which is to be expected.

 

[kevin]

Kevin:

Thanks for the good info.

The trip meter in the car does show me much higher numbers. The high 5's are not too difficult to achieve and I actually hit 7.1 by coasting as much as I could. But, put 2 adults in the car, kick on the A/C and push the speed up past 55 and the numbers drop significantly which is to be expected.

You have to be careful about doing a complete round trip if there are any hills in your area.

I live in the South SF Bay about 500 ft above the bay - my commute goes down to about t50 feet over 12 miles. I often get 8 or 9 mi/kWh in that direction but only 4.8mi/kWh going back. The overall value over a complete discharge is ~5.7.

In winter the figures are much worse and I have seen ~3.5 on the uphill and ~5 on the downhill in bad weather.

I normally reset the trip meter every time I charge and do 25-60 mile between charges.

kevin

 

[MrDRMorgan]

kevin,

My drive is flat from Manteca to Sacramento. Then there is a slight uphill slope from SAC to Rancho Cordova - the distance is about 15 miles from SAC to my destination. I will be using the DCFC station at SMUD HQ going both ways as it is 63 miles from my home to SMUD HQ. At home I will recharge using the 12-amp charge rate.

I will post my results tomorrow evening. Should be interesting.

 

[SparkevBlogspot]

Nos,

I was wrong about EV vs ICE efficiency. While it is true that EV efficiency with generator factored in is about 30% and ICE (Atkinson / Diesel) 40%, ICE is only peak efficiency. When going slower or faster, it's less, so overall is roughly 30%. Again, some better than others. EV efficiency is only worse when accelerating and hills (high current = more waste). While it could be slightly lower or higher, EV and ICE are comparable for now.

New generation of nat gas generators use combined cycle that use waste heat, increasing the efficiency to around 60%. Then EV efficiency would be 0.6 * 0.9 * 0.9 = 49%. At that point, no gas car can match EV. But as of now, that's rare. As more older nat gas generators go off line, new ones will have such high efficiency, because it will mean more money for greedy electric companies. It won't happen overnight, but it will happen gradually. Will it be 10 years? 20 years? Hard to say, but the point is EV will only get better in time.

I wasn't comfortable with my old assumption, but now I feel better for having more concrete ammo to argue gas bags. Now only if rest of the EV are as quick and fun as SparkEV and Tesla...

 

[nozferatu]

nozferatu:

My mi / kWh for home charging is averaging about 3.61 mi/kWh. My calculated cost per mile is $0.0424 (500 kWh @ $0.095/kWh for solar kWh and 1716 kwH at $0.17 for PG&E tier 1 kWh. This is for 8000 miles).

I do notice my mi/kWh goes up the more miles I drive between charges. I put the Spark EV on the charger almost every night so the "charge losses" may be contributing more significantly to lower mi/kWh numbers when the distance traveled between charges is low; 10-30 miles. I have seen mi/kWh numbers as high as 4.12 for 53 miles traveled and as low as 2.76 for 12 miles traveled. DCFC charge numbers have been about 5.5 mi / kWh. I plan to test this concern more this week.

Chances are the more you drive, the more your average will increase.

 

[MrDRMorgan]

OK. My test is completed and here are the results:

1. Manteca to Sacramento SMUD HQ DCFC Charging station - 59 miles, 13.64 kWh to charge to 100% in 25 minutes. Mi / kWh = 4.33.

2. SMUD HQ to Folsom and back to SMUD HQ - 36 miles round trip, 7.67 kWh to charge to 100% in 20 minutes. Mi / kWh = 4.69

3. SMUD HQ to Manteca home - 59.3 miles. Recharge started at 12-amp L1 rate.

Driving conditions: Outside temp - mid to high 80s; A/C set to 24 deg. C (25 deg. C was a bit warm) and left on for entire trip. Cruise control set to 60 mph and used as much as possible. 1 person in the vehicle - me.

Energy Details screen on dash display showed 29.8 kWh used; 71% driving and accessories; 9% climate; 0% for battery. I guess that leaves 20% still available. The guess-o-meter showed 40 miles left. Note: the guess-o-meter showed 28 miles remaining when I reached the SMUD HQ station on my way up to Folsom.

I am thinking the climate control is cycling both the A/C and heater to try and maintain a constant temperature in the cabin and this gobbled about 9% of the energy consumed during the trip.

Note: SMUD HQ / Greenlots charges by the kWh - not by minute. The cost is $0.20 per kWh. Tax is added to the cost of the kWhs consumed plus a $0.35 transaction fee for the charging session. My total cost for both charging sessions was $5.36 or $0.0564 per mile or $0.2504 per kWh. This is a Greenlots station and they are excellent! SMUD HQ is the best DCFC charging station I have used so far.

Comments?

 

[SparkevBlogspot]

OK. My test is completed and here are the results:

Thanks for the info, and spending extra $ and time to get 100% with DCFC.

Did you happen to record what the car showed as mi/kWh for each leg of the trip? You could figure out charging efficiency.

I found DCFC to be 90% while L1 at 80% (both approximate), so you should get close to 4 mi/kWh with L1. It would be interesting to see if it turns out that way. Of course, that assumes last leg of your jouney had similar conditions as other two.

Another thing I did was to figure out how much money was spent with DCFC vs L1. It turned out DCFC was cheaper compared to tier 1 rate, but probably not cheaper than your solar rate. Since you went all the way to 100%, it would be even worse for DCFC.

 

[MrDRMorgan]

Here is some information on my DCFC charging sessions at SMUD HQ today that might help others decide when to cut off charging for those DCFC charging locations charging by the minute like NRG eVgo.

Charging Session 1 - 13. 64 kWh total: total cost = $3.33

@ 5 minutes - 3.77 kWh - ?
@ 10 minutes - 7.78 kWh - 70%
@ 15 minutes - 11.20 kWh - 88%
@ 20 minutes - 12.84 kWh - 96%
@ 25 minutes - 13.64 kWh - 100%

Charging Session 2 - 7.67 kWh total: total cost = $2.03

@ 5 minutes - 3.97 kWh - 81%
@ 10 minutes - 6.34 kWh - 94%
@ 15 minutes - 7.45 kWh - 99%
@ 16.2 minutes - 7.67 kWh - 100%

So far I have found DCFC charging efficiency to be about 90% and L1 to be about 78%.

 

[SparkevBlogspot]

Charging Session 1 - 13. 64 kWh total: total cost = $3.33
@ 25 minutes - 13.64 kWh - 100%
...
Charging Session 2 - 7.67 kWh total: total cost = $2.03
@ 16.2 minutes - 7.67 kWh - 100%

How is it $3.33 for 25 min? Isn't it $0.10/min with OTG, which should be $2.50? Same with $2.03 with 16.2 min. If you don't have OTG, it would be $5.00 / $3.24?

Something else I noticed is that if you sit in the car and turn it on during DCFC, it tells you how many watts it's charging. Mine showed 45 kW until about 80%, then dropped to about 36 kW at 85% at which point I stopped charging. I was eating in the car, so still it wasn't wasted time, but I think my rule of thumb of "more than one mississippi for 0.01 kWh" is handy; that's 36 kW.

 

[MrDRMorgan]

SparkevBlogspot:

What you say is true for OTG if you are charging at an NRG eVgo DCFC station (I have a membership and pay the monthly membership fee of $14.95 too). The DCFC charging stations at the West Valley Mall in Tracy, CA and the Livermore Premium Outlets in Livermore, CA are both NRG eVgo DCFC stations.

The DCFC charging station at SMUD HQ is a Greenlots station and a posted sign states $0.22 per kWh plus a $0.35 transaction fee. No membership fee is required. The numbers I provided were taken directly from my online statement this afternoon. Unfortunately, I have found only one other Greenlots DCFC station and that is in Citrus Heights, CA and it is the one I will use when I visit my daughter in Roseville, CA.

 

[MrDRMorgan]

SparkevBlogspot:

You asked what the car displayed for each leg. Here are my numbers. Note: the trip meter was reset at each charging.

Leg 1 from my home to SMUD HQ: 58.84 miles @ 4.8 mi / kWh
Leg 2 From SMUD HQ to Rancho Cordova and back to SMUD HQ: 34.8 miles @ 5.3 mi / kWh
Leg 3 from SMUD HQ to my home: 59.3 miles @ 5.4 mi / kWh

When I look at these numbers it makes me wonder if, about 75% through leg 1, dropping the cabin temp from 25 deg. C to 24 deg. C had an impact on the mi / kWh numbers. That was the only change I made during the trip. I also wonder if using the cruise control gobbles a little power too.

 

[MitchD]

my mileage, 1,315 my MPGe 129 Loving every mile of it!!

 

[MrDRMorgan]

The Infotainment display has an interesting section under electric info section called energy details. At the bottom of the screen is a running total of the quantity of kWh used since the last full AC charge. This value is not reset if DCFC is used to recharge the battery. This makes it easy to determine the charging efficiency of both DCFC and AC charging stations.

I repeated my run to Folsom, CA yesterday and this time my wife came along. We made two DCFC charging stops at the SMUD HQ station and one 120Volt AC 12-amp charging session upon returning home. Here are the results averaged for the two trips on 6/23 and 6/24.

Home to SMUD HQ - 4.51 mi / kWh (charger to wheel) DCFC
SMUD HQ to Folsom and back to SMUD HQ - 4.45 mi / kWh (charger to wheel) DCFC
SMUD HQ to Home - 3.78 mi /kWh. (charger to wheel) L1 @ 12 amps.

At each stop on the second trip, I recorded the car's Energy Used values.

My calculations, combining data for both days, show The SMUD HQ DCFC station charging efficiency is 88% and my home L1 charger at a 12-amp charging rate is 75% (very hot garage)

If I divide the 2-day charger to wheel numbers above by the efficiency values I calculated, I get:

Home to SMUD HQ - 5.13 mi / kWh (battery to wheel) DCFC
SMUD HQ to Folsom and back to SMUD HQ - 5.06 mi / kWh (battery to wheel) DCFC
SMUD HQ to Home - 5.04 mi /kWh. (battery to wheel) L1 @ 12 amps.

If I take the total mileage of the 6/24 trip and divide it by the total kWh the car said it used, I calculate 5.21 mi / kwh (battery to wheel) for the trip. If I take the mileage of the 6/24 trip and divide it by the total charger kWh required for the trip (wall to wheel), I get 4.14 mi / kWh. Average charging efficiency for the 6/24 trip (DCFC and home combined) was 79.4%.

Note: The A/C was on the entire time and set to 23 deg. C. Energy Details showed 9% used for climate.

 

[SparkevBlogspot]

Home to SMUD HQ - 4.51 mi / kWh (charger to wheel) DCFC
SMUD HQ to Folsom and back to SMUD HQ - 4.45 mi / kWh (charger to wheel) DCFC
SMUD HQ to Home - 3.78 mi /kWh. (charger to wheel) L1 @ 12 amps.

Going by my out of pocket cost MPGe table and $3.60/gal + $0.095/kWh (your solar rate, using 1/2 of $0.19/kWh from table) and assuming all this was only solar instead of DCFC, you'd get

4.51 mi / kWh = 4.51 / 4 * 75.8 * 2 = 171 MPGe
4.45 mi / kWh = 4.45 / 4 * 75.8 * 2 = 169 MPGe
3.78 mi /kWh = 3.78 / 4 * 75.8 * 2 = 143 MPGe

Pretty damn good, MrDRMorgan! Of course, this doesn't factor in your eVgo OTG membership fee, which would reduce them by about 25% (depends on how much you drive). However, if you didn't have solar and had to pay $0.17/kWh, that'd be

4.51 mi / kWh = 4.51 / 4 * 84.7 = 95 MPGe
4.45 mi / kWh = 4.45 / 4 * 84.7 = 94 MPGe
3.78 mi /kWh = 3.78 / 4 * 84.7 = 80 MPGe

Again, not counting eVgo membership fee. Still pretty damn good, sir!

But if you're on tier 3 at $0.33/kWh, above would be cut by half, making it even less than Prius. People who assume EPA MPGe number while their home rate is higher than tier 2 is spending (wasting) more money. That's why I keep harping on this MPGe issue to tell everyone to be careful not to spread EPA MPGe number without knowing their true cost MPGe.

Note: The A/C was on the entire time and set to 23 deg. C. Energy Details showed 9% used for climate.

Lots of gas bags complain how EV range would be drastically reduced when they don't even have EV. I keep telling them that it's about 10%, because freeway uses about 12 kW and small home AC uses between 1 kW to 1.5 kW. Your data proves this, and I suspect other people's measurements will also bear this out.

 

[MrDRMorgan]

SparkevBlogspot:

I factor my annual NRG eVgo membership fees into my lease cost analysis as an annual fixed cost like insurance, license fee, etc. My spreadsheet model shows, at the end of the lease and driving only 6500 miles annually, I will save $1127 over what I would spend on gasoline alone if I just drove the truck and did not have the Spark EV. My wife and I both use the Spark EV as much as is possible without exceeding 10,000 per year. Our daughter is currently using the Honda and is responsible for all gasoline costs. So, essentially, we currently have little or no gasoline costs.

My goal was to pay for the Spark EV lease and other fixed costs just by the gasoline savings I expected to realize. It seems to be working. I filled my truck up on June 10 and today, June 24, the truck has traveled only 50 miles. The Spark EV is pushing 1200 miles as of today mainly because I have been doing a lot of range testing and making sure I knew where DCFC stations were and how to use them. That task has been successfully completed. I figure July will be my first month of "normal" use.

I really like my Spark EV!!

 

[SparkevBlogspot]

driving only 6500 miles annually,

I hope you can stick to that. I thought I'd drive 7500 miles a year, tops. Now the projection is over 15K miles! It's just way too fun and quick compared to my gas car and no range problem with DCFC. I have to force myself to grudgingly at least start the gas car from time to time to keep the stuff running. Unfortunately, I still need the gas car for those rare times I need to tow. I wish SparkEV can tow 1000 lbs...

I really like my Spark EV!!

It's a gateway drug! ;-)

 

[MrDRMorgan]

SparkevBlogspot:

The 6500 miles value is the annual mileage value I estimated I would drive the truck. My wife normally drives the Honda but we let our daughter drive the Honda to work so both my wife and I will be driving "Sparkie". The miles we save for some of my wife's Honda mileage and my truck mileage must remain under 10,000 miles per year for the 3-year lease. We expect to get real close to that number so I expect we will still run up some Honda and truck mileage too. I just do not know how much as we are trying to cover all mileage with the Spark EV.

It has been very hot here the past 3 days and the A/C impact to the total kWh used in the car is significant - 10-11%. I assume the heater in winter will do the same thing.

Here is a question I have - Does anyone know what charging station will be required to charge the Chevy Bolt and how long it will take?

 

[SparkevBlogspot]

It has been very hot here the past 3 days and the A/C impact to the total kWh used in the car is significant - 10-11%. I assume the heater in winter will do the same thing.

10% is significant, but not unexpected. It's less than 10 miles. It's not like you're losing 50% range like some gas bags would have people believe.

Here is a question I have - Does anyone know what charging station will be required to charge the Chevy Bolt and how long it will take?

I read some press release that says 80% in 45 minutes. Assuming similar 4-5 mi/kWh as SparkEV, 200 mile range would be about 50 kWh battery. DCFC at 50 kW (or 45 kW at eVgo with SparkEV) at 45 minutes would give 75% charge, pretty close. However, number of miles you can drive per unit of charge time would be similar to SparkEV, maybe bit less due to heavier battery. eg. 20 minute DCFC may give you 70 miles which would be 33% instead of 80% on SparkEV.

Frankly, I like 1 hour for 80% (or 90%) better if that's what Bolt ends up being. That's 1C charge rate which is better for the battery not to mention I don't have to leave in middle of lunch to disconnect DCFC and move the car.

 

[MrDRMorgan]

Assuming it would take approximately 1.5 hours of DCFC charging to fully recharge the battery in the Bolt, how long would it take to recharge at home using an L2 charger - 15+ hours?

I do not know what will happen to home charging but we are going to need a lot more DCFC charging stations with more than one dual charger cable at each location - like Tesla's charging locations with multiple stations.