Miles per kwh so far... my calcs vs. the LEAFs calcs

[evnow]

I'm keeping track of 3 efficiencies.

1. Wall to wheels as shown by Blink
2. Efficiency shown by Leaf
3. Efficiency and kwh shown by Carwings

1 & 2 - are close to each other, after discounting the charging inefficiency from 1.

2 & 3 should match. There is no reason why they shouldn't. But they don't match. Carwings is more optmistic by 10% to 35%. After gathering a week of stats, I'll call Leaf CSR and lodge a bug.

 

[DaveinOlyWA]

Carwings also ignores the power used by accesories as well. The wall obviously cannot.
either way your method cannot be used as e en a basic guideline. Track your charging over a week at least a month would be better. I do 120 charging and a stage similar numbers and my charging from the wall is around 3.2 AMPK

 

[edatoakrun]

Where I live electricity is $0.27 /kWh at the moment. So the 2.8 miles/kWh translates to 0.095 $/mile. I traded in my 2002 VW Golf TDI for the LEAF. It got 42 miles/gal. Currently Diesel is $3.88/gal here so that comes out to 0.092 $/mile. So, my fuel costs are slightly more per mile by going with the electric car. So much for the electric car yielding fuel savings!

Question:

These results are based on using the level 1 trickle charger. Is there any reason to believe my results will be any better using the level 2 charger (I don't have an easy way to measure the current consumed by my level 2 charger)?

Did you expect fuel cost savings, paying 27 cents per kWh?

The great benefit to grid efficiency and lower fuel costs of EV's only occur if owners charge off- peak, and utilities charge rates that pay them to do it. I assume the 27 cent figure is not a time-of-use rate?

If so, ask your utility why you don't get one. Or, if you want revenge, only charge at peak-demand periods. This will cause your utility to take a loss, even charging you the 27 cent rate.

Here in North California, Diesel is now over $4, and gas is nearly there. And (PG&E) off-peak power is 6 cents a kWh, so the cost comparison is quite a bit different.

I would appreciate it if someone could do an accurate L1/L2 charge efficiency comparison. If it's a significant discrepancy, I might want to start shopping for a L2 EVSE.

 

[garygid]

I believe CARWINGS does include the power for accessories, and Heat/Cool (used while driving). Power used for pre-heat/cool is when the LEAF is "Off", so is probably not included.

 

[DeaneG]

... And (PG&E) off-peak power is 6 cents a kWh, so the cost comparison is quite a bit different...

If you are going to quote low off-peak rates, you also have to mention the very high on-peak rates which your daytime household electricity usage will be billed at under that plan. Driving may then seem cheap, but your home's air conditioner will be very expensive. You need to consider that as a cost of charging too.

 

[akohekohe]

Did you expect fuel cost savings, paying 27 cents per kWh?

The great benefit to grid efficiency and lower fuel costs of EV's only occur if owners charge off- peak, and utilities charge rates that pay them to do it. I assume the 27 cent figure is not a time-of-use rate?

If so, ask your utility why you don't get one. Or, if you want revenge, only charge at peak-demand periods. This will cause your utility to take a loss, even charging you the 27 cent rate.

Here in North California, Diesel is now over $4, and gas is nearly there. And (PG&E) off-peak power is 6 cents a kWh, so the cost comparison is quite a bit different.

I would appreciate it if someone could do an accurate L1/L2 charge efficiency comparison. If it's a significant discrepancy, I might want to start shopping for a L2 EVSE.

I actually will get the first 1,000 or so kWh free since I have a reverse metering agreement and last year, before I got the leaf, I produced 1,030 kWh more than I used (which the utility got to keep). So I should be able to drive around 3,000 miles for free so it is still a good deal for me but not for most people here. The utility does have a program for electric vehicles (I can't use it because of the reverse metering arrangement) that cuts about $0.06 / kWh off the rate but that still leaves you at $0.21 AND there are significant installation costs, $2,000 or so, which will make the payback take about 100,000 miles.

 

[evnow]

Hawaii is one of the few states where solar makes sense at current PV costs.

 

[garygid]

PV is rather compelling in CA also, since our e-rates are mostly in the 13 to 33 cents range, and not likely to go down.

 

[DeaneG]

PV is rather compelling in CA also, since our e-rates are mostly in the 13 to 33 cents range, and not likely to go down.

... especially after you add the EV usage, many people will be solidly into the highest rate tier in the summer.

 

[edatoakrun]

... And (PG&E) off-peak power is 6 cents a kWh, so the cost comparison is quite a bit different...

If you are going to quote low off-peak rates, you also have to mention the very high on-peak rates which your daytime household electricity usage will be billed at under that plan. Driving may then seem cheap, but your home's air conditioner will be very expensive. You need to consider that as a cost of charging too.

Well, I've posted this info so many times, I thought everybody would be sick of it, but since you ask, the complete tariffs,including E1 and E9 rates are here:

http://www.pge.com/tariffs/ERS.SHTML#ERS

If I buy an EV and change from E1 to E9A, I expect my average kWh cost to decrease from about 12.2 to 9 cents per kWh, under 6 cents for the EV, and 11-12 cents for the rest of my home. I will have additional cost savings, by heating my home and water with my geothermal heat pump (rather than propane) at the (now reduced to 6.2 cents a kWh) winter off-peak rate.

Single meter time-of-use gives you the greatest benefits if you make the same energy efficiency efforts in your home, as you do with your vehicle.

And you are correct, in that air conditioning load is the single biggest driver of not only of individual bills, but total grid electricity peak costs, in most of the US.

 

[EVDRIVER]

PGE rates go upward of $.47 per kwh

 

[LEAFer]

Move to SMUD territory

For normal whole-house rates they now only have two tiers (used to be three) based on usage. In round numbers, anything (each month) after 600kWh (or some rates 1000) is 18c, below that level 10c/kWh for Winter (Nov 1-Apr 30). In Summer: Tier II is 19c, Tier I 11c.

(It's more complicated and a few other factors ... but won't affect many. If you want details: http://www.smud.org/en/residential/rates/Documents/1-R.pdf )

TOU is available: Winter: 10/11c for Off/On-peak. Summer: 10/16/24c Off/On/Super-peak.

For EVs you need a 2nd meter. Then you can put the house on either regular or TOU, but EV on TOU: Winter: 7.5c/11c (Off/On-peak); Summer: 8.4c/24c. So all you need to do is avoid the 6 hour Summer On-Peak 24c rate between 2pm-8pm.

 

[Spies]

PGE rates go upward of $.47 per kwh

The PG&E electric vehicle E9A Summer peak rate at 201% baseline usage (tier 4 of 5) and higher maxes out at $0.56915 currently. Hopefully I will never be charged that rate but as I drive my Leaf more I am going to be close. I am already in tier 3 territory now. Once I cross over into tier 4 territory its time to seriously consider installing solar.

I should add that my baseline per day is 12.1 kWh Summer and 12.6 kWh Winter and my last billing month with the Leaf I averaged 21.3 kWh per day.

E9A is when the whole house as well as the EVSE is on one meter and thus the same rate.

 

[edatoakrun]

PGE rates go upward of $.47 per kwh

The PG&E electric vehicle E9A Summer peak rate at 201% baseline usage (tier 4 of 5) and higher maxes out at $0.56915 currently. Hopefully I will never be charged that rate but as I drive my Leaf more I am going to be close. I am already in tier 3 territory now. Once I cross over into tier 4 territory its time to seriously consider installing solar.

I should add that my baseline per day is 12.1 kWh Summer and 12.6 kWh Winter and my last billing month with the Leaf I averaged 21.3 kWh per day.

E9A is when the whole house as well as the EVSE is on one meter and thus the same rate.

Assuming you have an appropriate location, wouldn't solar give you a very good payback?

 

[evnow]

Back on topic, pls.

 

[sproqitman]

Finally getting data from both CARWINGS and the Blink. Yesterday's drive:

CARWINGS 6.3 kWh
Blink 9.4 kWh

I'm assuming CARWINGS is reporting consumption by the car, and Blink is reporting consumption by the charger. So does 68% efficiency from wall-to-wheels sound about right? I'm new at this EV stuff, so I just want to know if this is within expected parameters. With gas at $3.75/gallon and electricity at $0.12/kWh, I'm still getting the equivalent of 90 MPG.

 

[derkraut]

Finally getting data from both CARWINGS and the Blink. Yesterday's drive:

CARWINGS 6.3 kWh
Blink 9.4 kWh

I'm assuming CARWINGS is reporting consumption by the car, and Blink is reporting consumption by the charger. So does 68% efficiency from wall-to-wheels sound about right? I'm new at this EV stuff, so I just want to know if this is within expected parameters. With gas at $3.75/gallon and electricity at $0.12/kWh, I'm still getting the equivalent of 90 MPG.

Seems to me your consumption rate is in the ballpark, based upon what other drivers have posted so far.

 

[mwalsh]

How many miles was this? And under what circumstances?

 

[DaveinOlyWA]

a single trip cannot be used. track 20 of them then report back.

a thumbnail tells me i might be getting in the 75% range.

 

[garygid]

It is believed that the kWh value reported by CW is incorrect (too low), especially when the Regen kWh is high.

I believe that the Regen kWh is incorrectly handled when the "total kWh" is calculated.