Drove a leaf today

I've never seen more than 2.95 kwh (Chargepoint L2) from 240v.
I've never seen more than 3.02 kwh (KAW or Watts Up Pro) when charging at home with 120v.
Also, when I compare the KAW and WUP to the house smart meter I see an accuracy error of about 30-50 watts (out of ~1350w). I've never measured the total kwh difference because that would mean shutting off all the power in my home for a couple of hours.


Mike

 

EPA actually used 3.2kWh for PiP and 33.7kWh per gallon equivalent.

 

My latest numbers...
234 kwh /(33.7 kwh/gal) ~= 6.94 gal
thus:
EV: 1232/6.94 = 177 MPGe
HV: 252/4 = 63 mpg
combined: (1232+252) / (10.94) = 135 MPGe

Note that I think the granularity of the HV gallons sometimes provides a misleading number. I drove to SF and back and it clicked from 2 gal to 3 gal at 150m. So at 149 miles I was at 74.5 mpg, then at 150 miles I was at 50 mpg...so I could be at 4.9 gal right now...last fillup was ~90 days ago.



Mike

 

This is partly why I feel like the right thing to do is to always use the lifetime EV ratio screen and just take the difference between successive fillups.

 

I would suggest using the kWh from the dashboard, up converting first, and use the gallons from actual fuelups at the pump, along with odometer readings.

 

double post

 

Mike, you need to add charging losses to the 234 kWh to be consistent with EPA definition of MPGe.

154.28 MPGe EV is excellent.

 

Lifetime stats are great. I think they give a great overview useful to anyone interested in the car.
I currently am finding it very useful to have monthly stats to find out how much cold and ther variables affect it. Daily information also gives some interesting comparisons, however the data tracking can be a bit much

 

That is the great thing about voltstats.. daily tracking without the fuss. Then one can dig in when there is free time.
Does your tesla have any automated tracking of data?

 

openvehicles.com is a project for a generic OnStar like system created for the Tesla roadster. The Ampera version is rolling out at the moment. I don't know if anyone is working on the PiP version.


unfortunatly Voltstats doesn't let me input fuel costs, electric or gasoline, and it also assumes all EV miles are 93 MPGe since it does not gather kWh consumption from the vehicle or from OnStar.

 

Yes, I know...but I do not think the generic "add 15%" is accurate. 80-90% of my charging is from a L2 (240v) Chargepoint...and I know it is more efficent than when I charge at home with 120v. How much? I don't know...maybe 3% - 5% more. So how do I account for that? If we (generically) want to compare numbers that others can easily compare against then I think it is best to just use the raw numbers provided by the car.
If we want to be "honest" then we must account for some charging losses. If we want to be accurate, then we must measure and keep lots of records (or measure a few times and estimate from there).

None of my rough calculations point to 15% as the charging losses. The best (worst) I can estimate is about .25 kwh per 2.7 kwh used or ~9%...or said another way 2.95 kwh consumed from the wall and .25 lost...~8%.

When I get some time I'm going to try and more accurately measure. This would involve several days of EV only driving, measuring each charge from the same charger, observing kwh consumed change on display, enough days where the 1 kwh granularity error is small. Then comparing total kwh charged with kwh consumed.

One thing I have not heard anyone discuss are discharge losses.

Mike

 

If you have from the wall measurements, or arrive at a conversion factor for your vehicle, then I would say use them. I think we will see some seasonal variance in charging losses due to temperature. IMO, we should use the EPA method, from the wall, and what most of us pay for.

I am also making a leap and assuming we are all wanting to compare fuel economy and not just fuel efficiency.

I use 1.15 as a generic conversion factor, which is something like a 13% loss.

what do you mean by "discharge loss" ? accessory loads like HVAC, headlights, etc ?

 

When you charge the battery you have some losses in the form of heat...so, for example, you draw 3 kwh from the wall but the battery only receives 2.7 kwh. When you drive you also lose some energy to heat. Some of these losses are in the motors and are included as part of the energy needed to drive. But the battery also gets warm (thus losses) and I suspect that the measurement in the car is downstream from these losses, but upstream from the motor losses, etc. Now, maybe "charging losses" accounts for both charge and discharge losses.

Mike

 

I think so.

Maybe it's better to think of it as it is taking 3kWh to replace the 2.7kWh delivered from the battery.

 

Discharge loss is included in your EV miles, as part of vehicle efficiency.

 

Have we confirmed the kWh reported by ChargePoint includes charging loss? I checked their site and didn't find that answer.

 

Chargepoint will usually report 12kWh for my 10.4 kWh at the battery. sometimes a little less. the variability is most likely just the HV mode buffer state at the time I plug in. it also includes some energy to operate the battery thermal management.

 

Humm, wonder why that question wasn't answered?
I don't have a PIP, but I have a gen 3 that I run on power mode all the time.... The volt felt slower.... I attributed it to the longer hood that may give the illusion of a slower ride.

At any rate, I was expecting something special, I was let down.

I did notice a little more power in the volt if I forced it to "hold" mode so the engine was forced to assist.

Alan.. Sent with Tapatalk 2

 

The question was about the Leaf vs the PiP.

I don't have a PiP to compare against but I know my Volt leaves my Gen II Prius in the dust off the line. In general, 0-60 may not capture the effect, maybe 0-30 does.

My 2012 does not have "hold" mode, so it was just EV from the battery.

 

They send the power down the wire...how could they know how much goes in the battery and how much is lost as heat? Besides, they use this info for billing purposes...do you think that they would exclude losses?

Mike