DaveinOlyWA
Posts: 14470
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 7:50 am

Herm wrote:
DaveinOlyWA wrote: hate to burst your bubble, but many of us have found the 120 volt efficiency to be around 75% so you would have around 19.5 KWH used.
... i am looking at a charging efficiency of probably 88-90% then a set overhead for the charge management (which should be small) and cooling system which is small but still significant.
so the longer the charge time, the greater the hit on the overall charging efficiency. most have seen 85-88% on 240, around 75% on 120.
I'm ok with the efficiency numbers for typical power supplies and chargers, but the 350w fixed overhead sounds a bit too high.. but in any case is all a case of circular logic since NO ONE has measured the wattage going in and out of the battery while being charged.. who will be the first dedicated Lead owner to actually make some measurements?
Phil (the EVSE mod guy) will be making some measurements to better nail down the real efficiency of the 240 volt EVSE and also trying to figure out how much power the cooling system is taking.

remember the 350 watt # is also charger inefficiencies, so if looking at cooling alone, its probably in the 175-200 watt range
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 3500.3 mi, 96.95% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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evnow
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Joined: Thu Apr 22, 2010 11:41 am
Delivery Date: 25 Feb 2011
Leaf Number: 303
Location: Seattle, WA

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 8:31 am

JessEV wrote:After 8.5 hours of charging on L1, I have recovered 7 bars. At 1.33kWh * 8.5 I got 11.3kWh from the wall.
You can't assume 1.33 kWh either - you should measure using a kill-a-watt to get true energy going in at the wall.

Look at this sticky ... this gives the range of each bar. Top bar was 4% and rest 8%. But this is before the firmware upgrade. It would have changed to become more nonlinear now.

http://www.mynissanleaf.com/viewtopic.php?f=31&t=2390
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

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evnow
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Leaf Number: 303
Location: Seattle, WA

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 8:36 am

Herm wrote:I'm ok with the efficiency numbers for typical power supplies and chargers, but the 350w fixed overhead sounds a bit too high.. but in any case is all a case of circular logic since NO ONE has measured the wattage going in and out of the battery while being charged.. who will be the first dedicated Lead owner to actually make some measurements?
I don't think it will be 350w fixed. At least the cooler will depend on temperature, I'd think - unless they don't measure that and the coolant circulates irrespective of the temperature.

My experience is that the change efficiency (or rather the ratio between mpkwh at the wall and at the dash) vary on a daily basis. I don't know whether it is because the charger efficiency varies or because the mpkwh at the dash is not accurate.
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

gascant
Posts: 921
Joined: Tue Nov 23, 2010 4:09 pm
Delivery Date: 13 May 2011
Leaf Number: 2209
Location: San Jose, CA

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 8:41 am

Between Dave's and evnow's posts, I'd say I'm right in the range--wall to wheels about 3.7 mi/kWh. Very non-scientific in that I'm just adding up what my SmartMeter says for the 5 hours I charge (minus the house baseline from midnight-5AM) and dividing that into my mileage for the previous day. Probably good to 5%.

I like the term "Wall to Wheels" as it's very descriptive. I've been calling it "Consumed". Is there a standard term in the EV community?
2011 LEAF SL brilliant silver + QC
DRL's, Seat Heaters, Horn, LEDs and EVSE upgrades
Over 24,300 miles gas-free
http://sfbayleafs.org" onclick="window.open(this.href);return false;

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evnow
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Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 8:45 am

gascant wrote:I like the term "Wall to Wheels" as it's very descriptive. I've been calling it "Consumed". Is there a standard term in the EV community?
Well to Wheels is the standard way to measure CO2 emissions for a gas car. It has now been adopted for EVs. You can see this terminalogy in EPA funded research.
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
Model 3 : 5/10/2018 to ?

gascant
Posts: 921
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Location: San Jose, CA

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 8:51 am

evnow wrote:
gascant wrote:I like the term "Wall to Wheels" as it's very descriptive. I've been calling it "Consumed". Is there a standard term in the EV community?
Well to Wheels is the standard way to measure CO2 emissions for a gas car. It has now been adopted for EVs. You can see this terminalogy in EPA funded research.
Thanks evnow. "Wall to Wheels" it is, then.
The nice thing about the SmartMeter (which I forgot to add, above) is that it gives you the actual cost of the electricity consumed. So, in the first half of my billing cycle, I've found that it's costing me $1.90/day to commute 61 miles RT. At $9.50/week it beats the Prius's $24 pretty handily.
2011 LEAF SL brilliant silver + QC
DRL's, Seat Heaters, Horn, LEDs and EVSE upgrades
Over 24,300 miles gas-free
http://sfbayleafs.org" onclick="window.open(this.href);return false;

Herm
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Location: Timbuktu, Mali

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 9:01 am

DaveinOlyWA wrote:
Phil (the EVSE mod guy) will be making some measurements to better nail down the real efficiency of the 240 volt EVSE and also trying to figure out how much power the cooling system is taking.

remember the 350 watt # is also charger inefficiencies, so if looking at cooling alone, its probably in the 175-200 watt range
I would consider the overhead any extra power that does not go into the battery, that would include charger losses, charger cooling losses, EVSE loses and EVSE cooling losses.. plus whatever other load is running on the car at the time (not including AC) necessary to run the charger, probably carwings communications, BMS plus assorted computers and sensors. Yeah, perhaps it does add up.

Herm
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Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 9:17 am

evnow wrote: Well to Wheels is the standard way to measure CO2 emissions for a gas car. It has now been adopted for EVs. You can see this terminalogy in EPA funded research.
Some people could care less about CO2.. in any case power at my outlets is CHEAP, only $0.11 a KWh, all I care about is range or "battery-to-wheels" efficiency.. if we had an on-board genset like the Volt then we would worry about MPG including the efficiency of the genset in the chain.. but I really could care less about the local utilities power plant/transmission line efficiency, even EVSE charger cords losses are almost meaningless. Again, power at the outlet is cheap and plentiful.. plus its American made .. in most places.

GroundLoop
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Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 11:12 am

I care about two things:

1) Cost per mile, which becomes Miles per kWh as a normalized measure. (I prefer Watts per Mile)

2) Useable Range, and predicted range while driving, because it impacts planning and useability

To that, end I'm keeping detailed track of the total energy consumed by the LEAF. This is represented completely and accurately by the SDG&E utility meter. It's what I pay. I don't care if the EVSE is lossy, the charger is inefficient, or the energy goes to waste-heat during charging -- I have to pay for it, and I don't have any control over it. To some extent, I don't even care if the meter is inaccurate. It is what it is.

So, if I begin my day at 100%, drive my commute and errands, and charge up at midnight, that's a really good and irrefutable measure of cost. Not a lot of wiggle room or estimated factors.

Right now I'm running about 2.5 mi/kW. I know this is lower than most, but it's because I drive the Leaf like any other car, without special considerations for power savings.


For Range, I'm having a harder time. I believe our long-term solution to this is a real Geek Screen with the numbers we crave: Instantaneous Watt consumption, true battery SOC, and some detailed representation of recent performance. This information is so massaged and 'interpreted' by the time it's presented on the Dash or Carwings, that it's nearly useless. The battery bars are the only thing with some basis in constants, and they're both non-linear and subject to change.

I will continue to seek the data via CANbus.

DaveinOlyWA
Posts: 14470
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Leaf Miles / KWh is Wrong Or Usable bat. cap. is not 24

Sun May 29, 2011 11:13 am

gascant wrote:
I like the term "Wall to Wheels" as it's very descriptive. I've been calling it "Consumed". Is there a standard term in the EV community?
i have mine...

AMPK= AC miles per kwh which would be..."wall" power

DMPK= DC miles or "battery" power. but my acronym thread was not very popular so your YMMV on understanding while using these terms

so my efficiency is determined by DMPK/AMPK. the AMPK is measured and considered accurate and like yours i am right at 3.7 AMPK as well. the DMPK is determined by resetting the Leaf's meter which is accurate based on something i am assuming. not sure of my understanding of that, but it has been pretty much dead on consistent
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 3500.3 mi, 96.95% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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