Tuning the Battery Aging Model

[msandeep]

Curious - why does the Miles Per KWH change from summer to winter? I thought this metric was independent of the battery state. Is it due to heating/cooling?

[hjaime]

Air conditioning eats up battery

[leafedbehind]

Update on my 3 year old leaf:
Date - 9/23/2014
11 capacity bars (lost first bar in April 2014 @20,700 miles)

Delivered - Sept 11, 2011
Manufactured - July 2011

Location - Mountain View, CA
Miles/kwh - 3.9
Odometer - 23,187
Capacity - 54.6054 AHr
LeafDD "H" - 67.86

Almost always charge to 80%. Car often garaged at home -- detached garage can get warm. Battery aging model pretty close to my experience with this car, if I plug in 7 days/week in the sun (that's really an overestimation of how long it is in the sun).

[cwerdna]

Curious - why does the Miles Per KWH change from summer to winter? I thought this metric was independent of the battery state. Is it due to heating/cooling?

Air conditioning eats up battery

As does the heater. This was esp. true of the power hungry resistive heater in the '11 and '12 Leafs. I'm not clear if the '13 Leaf S' resistive heater is more efficient but the hybrid heater in the '13+ SV and SL helps for many folks.

Also, during winter, there's more likely to be rain, slush or snow, which increases rolling friction, thus reducing efficiency further.

[tivollix]

The main reason is that air density increase when as temperature decrease.

Curious - why does the Miles Per KWH change from summer to winter? I thought this metric was independent of the battery state. Is it due to heating/cooling?

Air conditioning eats up battery

As does the heater. This was esp. true of the power hungry resistive heater in the '11 and '12 Leafs. I'm not clear if the '13 Leaf S' resistive heater is more efficient but the hybrid heater in the '13+ SV and SL helps for many folks.

Also, during winter, there's more likely to be rain, slush or snow, which increases rolling friction, thus reducing efficiency further.

[RegGuheert]

The main reason is that air density increase when as temperature decrease.

At lower speeds, air density has very little effect on energy consumption.

OTOH, when it is 10F outside, the heater might consume as much electricity as the drivetrain. This is particularly true at lower speeds, and is not influenced by the presence of a heatpump at such low temperatures.

[tivollix]

Ok, I just referred to the law of physics and common sens. Also when it is 10F I am not using the cabin heater when not connected to the wall power.
Sure a 6KW heater is using 6KW when it is 10F outside, that why we have heated seats that use 50W instead...
Also many people forget that ICE car consumption can go from 50MPG in summer to 40MPG in winter, at least up North.

The main reason is that air density increase when as temperature decrease.

At lower speeds, air density has very little effect on energy consumption.

OTOH, when it is 10F outside, the heater might consume as much electricity as the drivetrain. This is particularly true at lower speeds, and is not influenced by the presence of a heatpump at such low temperatures.

[TimLee]

...
Sure a 6KW heater is using 6KW when it is 10F outside, that why we have heated seats that use 50W instead...

Not all LEAFs have heated seats.

And many people don't like the car cabin at 10F, even if they have heated seats.

The most significant factor on winter efficiency is heat.
Second most is snow / rain.
Air density is a much less significant factor.

[tivollix]

Your are pretty sure of your affirmation but we agree on the factors. Case closed.

Not everybody is using the car the same way and it is fine.

In my case I am not using much the heater when driving to preserve range.
But what do I know, Quebec is not that cold

...
Sure a 6KW heater is using 6KW when it is 10F outside, that why we have heated seats that use 50W instead...

Not all LEAFs have heated seats.

And many people don't like the car cabin at 10F, even if they have heated seats.

The most significant factor on winter efficiency is heat.
Second most is snow / rain.
Air density is a much less significant factor.

[thimel]

Just lost my second capacity bar. So time for an update

Manufactured - 05/11
Delivered - 6/11/11
P3227 updte - 9/14/13
Location - Sunnyvale, CA (near San Jose)
Miles/kwh - 4.2
Odometer - 32209
Capacity - 51.57
Date - 10/10/14
Parked in sun - 5 days/week in Palo Alto