Electric company cars

[Squaredy]

1 hour ago, difflock said:

Followed this thread with interest.

Not likely to be buying a BEV since we bought the Toyota only 6 month ago.

But interested(and if the bloody Skoda had not shit hersel prematurely I might have considered a BEV, a couple of years hence)

Anyway, how is MPGe calculated?

Tried doing some research having seen silly high like 100 to 150 MPG figures being quoted.

How is this possible?

Since most of the electric generated is still  subject to the first law of thermodynamics in respect of its generation with its inherent inefficiencies plus the transmission losses?

Thoughts?

With electric cars, fuel economy is measured in miles per kilowatt-hour.  My Kia gives around 4 miles per Kwh.

[openspaceman]

14 minutes ago, Squaredy said:

With electric cars, fuel economy is measured in miles per kilowatt-hour.  My Kia gives around 4 miles per Kwh.

Does it in practice?

 

My daughter is 50 miles away and says she is far too busy to check how much charge it takes and note the mileage.

 

She also got annoyed that I selected a higher regeneration setting when I used it as she was quite happy to use the brakes to slow down. Politics and economics degree don't relate much to real world common sense.

[difflock]

22 minutes ago, Squaredy said:

With electric cars, fuel economy is measured in miles per kilowatt-hour.  My Kia gives around 4 miles per Kwh.

So

 Therefore, a liter of gasoline has 8.76 kW/hr of energy in it, which is a much more manageable number.27 Sept 2021

 

And since we are getting 45mpg for every 40kW/hr(4.54 *8.76kW/hrs) of petrol

=bloody hell= nearer to 1 mile per kW/hr

how can this be correct?

 

Edited February 26, 2022 by difflock

[Squaredy]

3 minutes ago, openspaceman said:

Does it in practice?

Yes.  More in summer less in winter. 

 

We use ours on max regeneration always.  It means you effectively do the majority of the braking by just easing off the accelerator,  You only really use the brake pedal in emergency or if you fail to anticipate conditions ahead,

[difflock]

😬😬😬

[openspaceman]

2 minutes ago, Squaredy said:

Yes.  More in summer less in winter. 

 

We use ours on max regeneration always.  It means you effectively do the majority of the braking by just easing off the accelerator,  You only really use the brake pedal in emergency or if you fail to anticipate conditions ahead,

So do you measure electricity you put in by your home meter or just use the indicator in the vehicle?

[Squaredy]

2 minutes ago, openspaceman said:

So do you measure electricity you put in by your home meter or just use the indicator in the vehicle?

I did in the early days.  Fairly simple really - plug it in and it is 7kw.  So in one hour it eats 7 units of electricity.  Even after 10 hours it has only used 70 units - about £10 when we bought it.  About £15 now.

[Dan Maynard]

47 minutes ago, difflock said:

So

 Therefore, a liter of gasoline has 8.76 kW/hr of energy in it, which is a much more manageable number.27 Sept 2021

 

And since we are getting 45mpg for every 40kW/hr(4.54 *8.76kW/hrs) of petrol

=bloody hell= nearer to 1 mile per kW/hr

how can this be correct?

 

I think the engine is only 30% efficient at converting energy from fuel to motion whereas the electric motors are more 90-95% at converting electrical energy to motion.

 

The disparity is from the hidden gap when the power station converts fuel to electricity which is only 30-40% efficient. 

[doobin]

9 hours ago, Dan Maynard said:

I think the engine is only 30% efficient at converting energy from fuel to motion whereas the electric motors are more 90-95% at converting electrical energy to motion.

 

The disparity is from the hidden gap when the power station converts fuel to electricity which is only 30-40% efficient. 

Plus charging losses.

[openspaceman]

10 hours ago, Squaredy said:

I did in the early days.  Fairly simple really - plug it in and it is 7kw.  So in one hour it eats 7 units of electricity.  Even after 10 hours it has only used 70 units - about £10 when we bought it.  About £15 now.

Ok that's good so charging losses don't skew the mileage.

 

I doubt I will ever have an EV as I have 4 cars sitting here, one classic, one 4wd and mine and my wife's small runabouts.

 

What I would be interested in getting a handle on is the effect of charge efficiency as the battery ages, I'm, guessing internal losses will build up over time so would expect less of the initial electricity put in to be available. I think my home battery is warranted to give 80% of its initial capacity for 8 years but that doesn't tell me what percentage of what I put in I will get out.