Temperature effect on range

[Stretch2727]

Below is right from the MB Daimler website. I put the link below as well.

"The thermal management system of the B-Class Electric Drive encompasses on the one hand the air conditioning for the vehicle interior and on the other hand the cooling of the electric drive. This ensures that all components perform to full efficiency even on long uphill slopes or in high outside temperatures. The high-voltage battery is cooled via a low-temperature circuit. At very high temperatures this can be boosted by the coolant circuit of the air-conditioning system. For low temperatures, a battery heater is available."

http://media.daimler.com/dcmedia/0-921-1740090-1-1751040-1-0-0-0-0-0-0-0-0-1-0-0-0-0-0.html

At some point the HV battery cooling will kick in regardless if the AC is on in the interior. This avoids the battery degradation issue the Leaf had with hot weather. (i.e. No thermal management system.) I agree the efficiency loss will not be as much as when the HV battery is cold but there will be some loss of efficiency due to the AC system running to cool the battery.

My prior Ford Focus Electric efficiency would degrade 5-10% when the temperature was 90 deg +. It also used the AC system to cool the battery at high temperatures regardless if I had it on in the car.

 

[ClassESage]

Looks like the efficiency increases to the high 70's F, up to 4.5 mpkWh on my commute. I agree that it will level off and decline, and have made a few projections on the chart. Anyone willing to make a guess?

 

[Stretch2727]

My guess is it will continue to improve to about 90 degrees then level off or decline.

It would be interesting to see your % battery used and miles traveled, so we can calculate a real mpKwh. Is the reading just taken from the dashboard readout which is understood to read low?

4.5 mpKwh is 126 miles of range on a standard charge.

 

[ClassESage]

My guess is it will continue to improve to about 90 degrees then level off or decline.

It would be interesting to see your % battery used and miles traveled, so we can calculate a real mpKwh. Is the reading just taken from the dashboard readout which is understood to read low?

4.5 mpKwh is 126 miles of range on a standard charge.

It's the dashboard readout -- trips are 20 miles using 18-19 miles of GOM (full standard charge registers ~87 miles range on GOM). If efficiency improves to 90 F, I should get near 5 mpkWh.

I will test actual range soon with standard and extended range.

I'm happy about the near 2-fold improvement over winter efficiency.

 

[TonyWilliams]

Here's your range:

Mercedes B-Class ED battery

36.0kWh total – 100% SOC
31.5kWh usable- 90.0% SOC
28.0kWh usable- 80.0% SOC
1.0 kWh unusable- 2.7% SOC


31.5 extended * (4.6 miles per kWh * 1.2 correction factor) = 173 miles

CORRECTION FACTOR: The Mercedes consumption meter is calibrated so that 3.6 miles per kWh will show 3.0 on the dash. The correction factor is 83.7%, or 1.2

Good luck !