GerryAZ
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Re: What's the charging efficiency?

Wed May 29, 2019 8:28 pm

88% or 89% as Sagebrush noted for L2 charging is about right if charging from low SOC to full with 6 kW onboard charger. Efficiency is less at higher SOC because charge rate tapers and cooling pumps/control module power use is constant. Efficiency of L1 charging is much lower, as Nubo noted. If charging from VLBW to full charge, there is significant difference in total energy from the wall at 240 volts using 12-ampere EVSE vs. 30-ampere EVSE with 6 kW onboard charger (higher rate is more efficient).
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL+ purchased 8/10/2019

LeftieBiker
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Re: What's the charging efficiency?

Wed May 29, 2019 9:26 pm

Still, there are advantages to L-1 charging. Aside from not having to install new wiring if you have a good 120 circuit, L-1 charging adds little or even no net heat to the battery, because in many circumstances it seems to radiate the heat away at the same rate L-1 adds it. Not all circumstances, but L-1 is still usually the better choice for lower heat charging.
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PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

powersurge
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Re: What's the charging efficiency?

Thu May 30, 2019 7:53 am

I have heard that you use quite a bit more electricity when using L1 vs L2 charging.

SageBrush
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Re: What's the charging efficiency?

Thu May 30, 2019 8:39 am

LeftieBiker wrote:Still, there are advantages to L-1 charging. Aside from not having to install new wiring if you have a good 120 circuit, L-1 charging adds little or even no net heat to the battery, because in many circumstances it seems to radiate the heat away at the same rate L-1 adds it. Not all circumstances, but L-1 is still usually the better choice for lower heat charging.
6 kW is pretty light. It is ~ equivalent to driving 30 mph
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

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Nubo
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Re: What's the charging efficiency?

Thu May 30, 2019 6:28 pm

SageBrush wrote:
LeftieBiker wrote:Still, there are advantages to L-1 charging. Aside from not having to install new wiring if you have a good 120 circuit, L-1 charging adds little or even no net heat to the battery, because in many circumstances it seems to radiate the heat away at the same rate L-1 adds it. Not all circumstances, but L-1 is still usually the better choice for lower heat charging.
6 kW is pretty light. It is ~ equivalent to driving 30 mph
Put another way, assuming a 24kW pack, it's a 0.25C charge rate. Quite gentle.
I noticed you're still working with polymers.

LeftieBiker
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Re: What's the charging efficiency?

Thu May 30, 2019 8:36 pm

Nubo wrote:
SageBrush wrote:
LeftieBiker wrote:Still, there are advantages to L-1 charging. Aside from not having to install new wiring if you have a good 120 circuit, L-1 charging adds little or even no net heat to the battery, because in many circumstances it seems to radiate the heat away at the same rate L-1 adds it. Not all circumstances, but L-1 is still usually the better choice for lower heat charging.
6 kW is pretty light. It is ~ equivalent to driving 30 mph
Put another way, assuming a 24kW pack, it's a 0.25C charge rate. Quite gentle.
I'm not saying that L-2 charging is harsh, just that it seems to usually result in a net gain of heat for the pack.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
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PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

lorenfb
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Re: What's the charging efficiency?

Thu May 30, 2019 10:45 pm

LeftieBiker wrote:
Nubo wrote:
SageBrush wrote: 6 kW is pretty light. It is ~ equivalent to driving 30 mph
Put another way, assuming a 24kW pack, it's a 0.25C charge rate. Quite gentle.
I'm not saying that L-2 charging is harsh, just that it seems to usually result in a net gain of heat for the pack.
Assuming 6.6 kW for L-2:

I = 6.6 kW / 360 = 18.3 amps (ideally)

P (battery dissipation) = I^2 X R (battery resistance) = 18.3 ^2 X 60 mohms (.06) = 20 watts (fairly cool on the touch)
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F

SageBrush
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Re: What's the charging efficiency?

Fri May 31, 2019 5:53 am

lorenfb wrote: Assuming 6.6 kW for L-2:

I = 6.6 kW / 360 = 18.3 amps (ideally)

P (battery dissipation) = I^2 X R (battery resistance) = 18.3 ^2 X 60 mohms (.06) = 20 watts (fairly cool on the touch)
Yes, and presuming a 4 hour charge, 80 Wh of heat into the pack mass. I've looked it up before but have forgotten -- what is the specific heat capacity of the pack ?
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

lorenfb
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Re: What's the charging efficiency?

Fri May 31, 2019 8:25 am

SageBrush wrote:
lorenfb wrote: Assuming 6.6 kW for L-2:

I = 6.6 kW / 360 = 18.3 amps (ideally)

P (battery dissipation) = I^2 X R (battery resistance) = 18.3 ^2 X 60 mohms (.06) = 20 watts (fairly cool on the touch)
Yes, and presuming a 4 hour charge, 80 Wh of heat into the pack mass. I've looked it up before but have forgotten -- what is the specific heat capacity of the pack ?
Very negligible temp rise, most likely within the accuracy of measurement.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 4.5K miles, 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 20%, temp < 105F

DaveinOlyWA
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Re: What's the charging efficiency?

Fri May 31, 2019 9:53 am

jgc wrote:I've looked around this board, and elsewhere, but can't seem to find an answer to what I hope is a simple question.
My LEAF is 40kWh ... but I don't know how much electricity it takes to charge it up to 40kWh. Is a bit more (say 45kWh) or a lot more (60kWh) or even more? I guess this will be different between different PVSE systems in different countries; ideally I'd want to know it for the UK for typical home charging pods (6kW in my case).

I'm interested to know this so I can more precisely understand what my 'fuel' costs are.
Charging efficiency is based on the speed of the charge. Speaking only on charge to the pack, QC's run 95-96%.

L2 depends on the speed because of overhead used by BMS and cooling system (only cools charger BTW) so the faster the charge, the higher the efficiency simply because less of the power from the wall is used to run the BMS (100% of the time) fans (very rarely) or water circulation pump (variable speed but runs prob 80-90% of the time)

At 6.6 KW, you are looking at prob 91-92%. I am running at 5.8 KW due to limitations of my 50 year old breaker panel and getting roughly 88-89%. The bottom end is level 1 or 120 volts @ 12 amps which runs 75% efficient (yeah one kwh lost for every 3 stored.)

NOTE; All numbers above determined by metered power output from the wall and the miles/kwh reading from the dash. QC figures based on LEAF Spy power meter verses "billed" kwh from public charging provider.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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