Charger Efficiency comparing 110 and 220

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DaveinOlyWA

Well-known member
Joined
Apr 24, 2010
Messages
16,260
Location
Olympia, WA
i thought i saw a thread started on this some where? but cannot find it.

Well i dont have 220 (nor a way to monitor it) so i will need some feedback. so far, after a few cold days (i am sure that makes a slight difference) my mileage performance is not what i expected it to be.

i am averaging 2.5-2.8 miles per kwh. that also includes days where climate control usage was very slight (yesterday it was 48º at 5:40 AM) now, this also includes a day, when i get up charged to 100% (or whatever it is) on 110 volts. range 106 miles. i drove to work, parked it 11 hours including sitting in car at lunch listening to Sat, etc. then drive home, short pitstop on the way. total trip. 20.3 miles, range estimate. 89 miles. so used 17 miles of my estimate on my 20+ mile trip.

plug in, recharge and put another 6.19 Kwh back, so best performance so far, but estimated range tells me i am much higher, so the discrepancy is mostly charger inefficiency??

what is anyone else getting?
 
dont know what i am thinking yet. just posting info wondering what other thoughts we have here on the conversion and efficiency of the system.

yesterdays performance did jump a bit from the previous days, but it was also nearly 10º warmer. too early to tell yet.

but would be nice if someone who had 220 could charge at 110 to compare?

the other thing is that my Carwings is not working so i dont know what the car is reporting. i have range estimates and that kind of stuff, but i am not sending daily reports so i dont know if my Car is reseting its estimates to me. it states 3.6 MPK which would be (i would think) battery to wheels. but it changes very slowly making me think its the average since i got the car. but we shall see. when i get carwings working, i will have a lot more data to work with
 
Your true miles/kWh is odometer difference divided by Kill-A-Watt reading. Anything else you are looking at is either a very rough estimate (bars used) or some computer programmer's guess as to how you will be driving in the future.
 
I did one L1 charge (with a short heavy duty extension cord plus the EVSE cord) with a Killawatt and got a similar wall to wheels result (2.6 miles/kWh). I haven't retried it. With L2 I'm getting the same 3.2 or so miles/kWh as others. The Carwings estimates bear no relationship to wall to wheels reality, and the in-car cumulative figure is also erroneously optimistic, but not quite as much so. The 3.27 you got on a 110 recharge actually sounds pretty good but it does beg the question of why your other cases are not so good. The range estimates are highly sensitive to the most recent driving conditions (terrain, speed) so I'd leave those out of your analysis. The only thing that really matters (to me anyway) as far as judging efficiency is the odometer reading divided by a utility meter, TED, or Killawatt reading.
 
Ok the car currently tells me I am at 3.8 mpk. Now that my "109" mile range is half gone. I now have 55 mile range and have driven 40 miles so I will have to say my range this morning was probably 95.
 
wsbca said:
..The only thing that really matters (to me anyway) as far as judging efficiency is the odometer reading divided by a utility meter, TED, or Killawatt reading.

This is probably an important observation. Gas cars overestimate their mpg all the time - my Rx400h consistently gets 24mpg by pump and odometer, but the in-car display shows 25.3. Why should an electric car be any different - it's still engineered by people who prefer to display optimistic results.

And of course the wall-to-wheels numbers should be about 15% lower than battery-to-wheels.
 
I charged last night for the first time through the KAW EZ using the Nissan provided L1 EVSE. I don't have a TED but now I am seriously considering getting one. Started with an 80% timer charge Friday morning. We did a total of 20.8 miles of very mixed driving over a total of 6 trips. Timer set to charge to 80% Saturday and it charged for a total of about 6 hours and KAW EZ reads a total of 8.28 kWh.

So with 20.8 miles divided by 8.28 kWh I end with about 2.51 miles/kWh.

Carwings shows the following:
Code:
Trips	Total	Consumption	Regeneration	Distance	Energy
1		0.8kWh		1.2kWh		0.4kWh		4.8miles		5.7miles/kWh
2		0.4kWh		0.9kWh		0.5kWh		3.3miles		7.7miles/kWh
3		0.6kWh		0.9kWh		0.3kWh		3.2miles		5.3miles/kWh
4		0.8kWh		1.3kWh		0.5kWh		4.0miles		5.1miles/kWh
5		0.4kWh		0.5kWh		0.1kWh		1.4miles		4.0miles/kWh
6		1.1kWh		1.5kWh		0.4kWh		4.1miles		3.8miles/kWh
From this I get a total of 20.8 miles and 4.1 kWh for a total of 5.07 which matches the front page of Carwings. I have not had a chance to check if these numbers match what is reported in the Leaf but will check when I have access to the car again.
 
if just using what the car is telling me then i am getting the same #'s as you, but if using DMPK, i am getting 70-80% of that.

now granted, the more you regen, the worse this ratio becomes so not sure its valid without determing regen values.

the trees?? has anyone figured out what charge they represent?
 
ok a trip made on 27th and 28th

on 27th drove 53.8 miles around town, recharged 15.2 KWH. minimal climate control. now regen got me 4.3 KWH and .7 used for accessories, so where do i see climate control usage?

on 28th freeway trip 65-70 mph with high climate control usage heater on all the time set at 80º. 57.3 miles, 21.01 KWH with 1.4 KWH regen, 1.5 KWH accessories.

in figuring charging efficiency (i wish i knew how accurate KAW was??)

the car used 11.8 KWH and regen 4.3 KWH minus the .7 KWH that just about equals what was put in from the wall (15.2 KWH) especially if we toss in a bit for climate control.

so again, where do we see energy consumption for climate controls on carwings?
 
DeaneG said:
And of course the wall-to-wheels numbers should be about 15% lower than battery-to-wheels.
I expect the car wings and Leaf to show about 15% better numbers than wall to wheel readings. Anything more - there is some problem with the way Nissan calculates the numbers.
 
KWH%20distribution-trip.jpg

KWH%20distribution.jpg


screenshots i am referring to.

miles 53.8 and 57.3 with kwh from wall of 15.2 and 21.01.

now if using straight carwing #s. on the 27th 53.8 miles traveled at 6.4 DMPK makes real "DKWH" at 53.8/6.4=8.40 DKWH

on the 28th 57.3/4.2=13.64
 
I believe that the CARWINGS "total" kWh numbers are calculated incorrectly, ROUGHLY having the (Full) "Regen" subtracted from "Consumed" where the "Recovered" Regen has (most likely) already been subtracted.
 
garygid said:
I believe that the CARWINGS "total" kWh numbers are calculated incorrectly, ROUGHLY having the (Full) "Regen" subtracted from "Consumed" where the "Recovered" Regen has (most likely) already been subtracted.
So, you are saying 27.2 is already the net - not 21.5 ? That gives 3.97 mpkwh - a more believable figure. Still high compared to what OP says (less athn 3 mpkwh, w-to-w).
 
Without all the numbers, it is difficult to tell. But, I suspect that the following MIGHT fit the data better:

1. A/C and Heating might be incorrectly combined into the other-energy ("H") category.

2. The motor uses "T" Total energy from the battery:
a. "C" recovered from the "W" used to charge from the wall, and
b. "E" recovered from the Regen ("R") energy used to re-charge the battery while driving.

T=C+E
C+H is less than W, perhaps 85% to 90% of W (this includes losses in: EVSE, wires, charger, battery energy-in, and the larger battery energy-out loss)

E is less than R, assume E = 0.8 R (80% of R gets recovered)

3. The Net energy consumed by the "motor" is "C".

4. The motor energy-usage sensor in the LEAF might be reporting Z= C+E - R (outbound power minus inbound power) as the "consumed" figure to CARWINGS, which is incorrectly interpreted there as "Total consumption", and they use Z-R as their net motor-energy consumption value.
Note that Z-R=C+E-R-R

To figure net consumption however, we want just "C", but they are "almost" using C-R, way too low if there is any significant % of regen.

Assuming I am guessing correctly, instead of subtracting R they should ADD R and subtract E. Or, assuming E= 80% of R, just ADD something like 20% of R.

Doing that, adding about 0.2 x R to the CARWINGS "consumption" value, AND adding properly-reported "Other" energy usage value gets one closer to a value that matches "C+H", and is a reasonable percentage of W.

-------
Summary: take CARWINGS "consumption" and ADD (0.2 x R) and add a reasonable "other" figure, and see if that gives you a better-matching miles/kWh figure, and more-reasonable Wall-Charging losses.
 
Too bad no one has put kw meter on the car like there should have been all along. This would show total in to the pack and total out as well as go back up for regen giving an accurate net. One could take the start and finish numbers and compare them to the wall usage easily.
 
i still have to say that climate controls are not being shown here. with only 2 days to work with, i cant really say other than the 27th at 6.4 kwh was minimal climate control, the 28th was on more than 70% of the trip and i am to believe it went from .7 to 1.5??

also, why would Carwings lump accessories and climate controls together when the actual car does not?

sorry dont believe that and i am certain that this missing data will account for the discrepancies in the #'s.

one other piece of data to toss in. the Car's performance record i also reset daily. its the only thing in all this that makes sense

on the 27th it was 4.8, the 28th 3.6 that would give DKWH of 11.21 and 15.92 or 74% and 76% from the wall.

so we go back to Carwings figures where battery plus regen are 16.1 and 14.7 minus accesories or 15.4 and 13.2 KWH the car actually uses but Carwings seems to subtract regen from the figures it uses to get the DMPK figure??

have to agree with Gary, not right. the only thing that really matters is what needs to be replaced in the battery. which would be the 15.2 and the 21.01 AKWH. now assuming that is accurate we either have missing data or pretty poor charging efficiency.

we need more data to crunch.
 
ok, still not sure what is going on, but did a few test runs today and the climate controls are being combined. i did a run today with defrost both front and rear blasting away. did you know it runs as high as 4½ KWH? like wow! and it did register. so not sure what happened on the 28th since i would think that it would be higher than the 1.5 kwh recorded but then again, i was not the driver and probably am not getting accurate info, so there we go.

my efficiency is not as high as i expected it to be and wondering if charging at 220 volt is more efficient?
 
DaveinOlyWA said:
my efficiency is not as high as i expected it to be and wondering if charging at 220 volt is more efficient?
It's quite possible as the on-board charger will have to increase voltage a lot higher than it would if it were on 220.

I know that even regular computer power supplies are very often at least a couple percent more efficient when running on 220 vs 120 and they are only converting AC to low voltage DC.

Really would be nice for someone to run some accurate tests...
 
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