Fuel consumption in relation to Drive battery levels.

[Trex]

Thank you, greendwarf! I feel so much less lonely now

Hi Anko,

Hey I have always been dumping that battery SOC straight away on the highway. But then again I might have been charging it back up again too much. :lol:

I now wish I had done a data point just under 50% SOC. :roll:

Regards Trex.

 

[Trex]

...... as not often we have opportunity to have an effective test track.

Gday gwatpe,

Yes I have my own little test track but only at 105kph to probably keep my licence or annoy other drivers. :lol:

Regards Trex.

 

[anko]

Thank you, greendwarf! I feel so much less lonely now

Hi Anko,

Hey I have always been dumping that battery SOC straight away on the highway. But then again I might have been charging it back up again too much. :lol:

I now wish I had done a data point just under 50% SOC. :roll:

Regards Trex.

Yes, you are right. I do apologize for not acknowledging that

Cheers, Anko

 

[anko]

One thing that came to mind is this: due to differences in ambient temperature, AUS / NZ results may differ from EUR results.

Why? I suspect most people from down under will be running their A/C's, because otherwise, they would not survive the test to report on it. Well, A/C adds an extra power demand per unit of time that is independent of SOC. Right? At low SOC, when the engine is already running at 75% load (as in very efficient), hence the engine will not run more efficiently when the power demand from the A/C is added to the equation. But at high SOC, when the engine is generally running at less than 75% load, the load of the engine (and with the load, the efficiency) can be increased when power demand from the airco is added.

Botom line: I would expect the differences in efficiency / fuel consumption between low and high SOC be smaller with A/C on and bigger with A/C off.

 

[maby]

One thing that came to mind is this: due to differences in ambient temperature, AUS / NZ results may differ from EUR results.

...

Botom line: I would expect the differences in efficiency / fuel consumption between low and high SOC be smaller with A/C on and bigger with A/C off.

Not only Aus/NZ! My AC has not been turned off since we took delivery of the car - either cooling or heating it. It is drawing a kilowatt much of the time.

 

[anko]

Theirs perhaps a little bit more ... he said jealously :mrgreen:

 

[Trex]

One thing that came to mind is this: due to differences in ambient temperature, AUS / NZ results may differ from EUR results.

Why? I suspect most people from down under will be running their A/C's, because otherwise, they would not survive the test to report on it. Well, A/C adds an extra power demand per unit of time that is independent of SOC. Right? At low SOC, when the engine is already running at 75% load (as in very efficient), hence the engine will not run more efficiently when the power demand from the A/C is added to the equation. But at high SOC, when the engine is generally running at less than 75% load, the load of the engine (and with the load, the efficiency) can be increased when power demand from the airco is added.

Botom line: I would expect the differences in efficiency / fuel consumption between low and high SOC be smaller with A/C on and bigger with A/C off.

I should have put a note that these tests were run without the AC and it was 31 deg C when I ran them.

But I did say at the bottom of the first page:

I even did one run with the AC on because it is bloody hot here but it DID make a difference so I had to rerun that test.

The things I do. :lol:

Regards Trex.

I have put the did in capitals now to emphasise it.

Regards Trex.

 

[Trex]

Hi folks

Have done some more data points.

I retested 9 bars showing to make sure a different day of testing did not make a difference.

I then did a 8 bar and a 7 bar.

I will put them in the first post to keep them together.

I will add another Note about the AC. :lol:

Regards Trex.

 

[anko]

I should have put a note that these tests were run without the AC and it was 31 deg C when I ran them.

but I did say at the bottom of the first page:

I even did one run with the AC on because it is bloody hot here but it DID make a difference so I had to rerun that test.

The things I do. :lol:

Regards Trex.

I have put the did in capitals now to emphasise it.

And yet you survived :shock: Sorry for not acknowledging all the things you do for us

 

[Trex]

I should have put a note that these tests were run without the AC and it was 31 deg C when I ran them.

but I did say at the bottom of the first page:

I even did one run with the AC on because it is bloody hot here but it DID make a difference so I had to rerun that test.

The things I do. :lol:

Regards Trex.

I have put the did in capitals now to emphasise it.

And yet you survived :shock: Sorry for not acknowledging all the things you do for us

No problem.

I think I must be getting old. I used to say it was "bloody hot" when it gets to 40 deg C which it does in summer.

Now only 31 deg C. :lol:

 

[Neverfuel]

Hi Trex

I have had my engine start up over the last two days to warm the car - and I have the electric heater AND the normal settings are at minimum. So I have really cold feet - 31 degrees, I am jealous

 

[Trex]

Hi Trex

I have had my engine start up over the last two days to warm the car - and I have the electric heater AND the normal settings are at minimum. So I have really cold feet - 31 degrees, I am jealous

Hi Neverfuel,

I have never had the petrol motor start for cold but the heat here can get very exhausting over summer. But I am probably just getting old.

 

[jaapv]

No, you're still young- the temperature has obviously never dropped under 10 C. for you.

 

[Trex]

No, you're still young- the temperature has obviously never dropped under 10 C. for you.

Hey jaapv,

Been awhile. I been away and you have been away. :lol:

Not very often under 10 C. . Seat heaters are all we need here.

Regards Trex.

 

[Trex]

Ok I will bump this topic as I have seen that people have been mistakenly in my opinion say that battery levels make no measurable difference in fuel consumption.

As can be seen by this long test it certainly makes a difference in mine.

And it shows that max regen can not be achieved till down under at least 14 bars on the display.

Regards Trex.

 

[gwatpe]

I have only seen the regen at max on the dial on the MMCS [60kW] with an empty battery.

 

[maby]

Ok I will bump this topic as I have seen that people have been mistakenly in my opinion say that battery levels make no measurable difference in fuel consumption.

As can be seen by this long test it certainly makes a difference in mine.

And it shows that max regen can not be achieved till down under at least 14 bars on the display.

Regards Trex.

I guess the answer is that your tests were done under close to ideal conditions and still showed a difference of less than 10% between the two extremes of battery charge. In practice, almost all the difference occurs close to 100% charged. I've run quite a few tests under real-world (i.e. South East England) conditions and have never been able to detect any consistent difference in fuel economy at different states of charge - but even the 10% would get lost in the noise really.

 

[anko]

I guess the answer is that your tests were done under close to ideal conditions and still showed a difference of less than 10% between the two extremes of battery charge. In practice, almost all the difference occurs close to 100% charged. I've run quite a few tests under real-world (i.e. South East England) conditions and have never been able to detect any consistent difference in fuel economy at different states of charge - but even the 10% would get lost in the noise really.

Trex put in a lot of effort to produce results in a controlled test / controlled environment. Exactly what we always wanted / needed. And now these results are dismissed, because the conditions were too good? Hmmm, I don't understand that. The fact that you cannot detect a difference in an uncontrolled 'test' or the fact that the differences appear to get lost in the noise does not mean the do not exist.

BTW: I also saw a step up in consumption when SOC gets close to 50%. Exactly what I have predicted from the beginning, as approx. at 50% the first reduction of charge current takes place.

 

[maby]

I guess the answer is that your tests were done under close to ideal conditions and still showed a difference of less than 10% between the two extremes of battery charge. In practice, almost all the difference occurs close to 100% charged. I've run quite a few tests under real-world (i.e. South East England) conditions and have never been able to detect any consistent difference in fuel economy at different states of charge - but even the 10% would get lost in the noise really.

Trex put in a lot of effort to produce results in a controlled test / controlled environment. Exactly what we always wanted / needed. And now these results are dismissed, because the conditions were too good? Hmmm, I don't understand that. The fact that you cannot detect a difference in an uncontrolled 'test' or the fact that the differences appear to get lost in the noise does not mean the do not exist.

BTW: I also saw a step up in consumption when SOC gets close to 50%. Exactly what I have predicted from the beginning, as approx. at 50% the first reduction of charge current takes place.

Read my comment in context, will you?

I was responding to Trex saying "as I have seen that people have been mistakenly in my opinion say that battery levels make no measurable difference in fuel consumption." and pointing out that the reason why some people say that the battery level makes no measurable difference in fuel economy is because for those of us operating in the real world, the difference is not measurable. My fuel consumption swings between about 30mpg and close to 50mpg depending on environment and driving conditions - Trex's observed figure which is about 7% at best and significantly less once the SOC gets below about 80% is simply lost in the noise.

 

[anko]

Read my comment in context, will you?

I was responding to Trex saying "as I have seen that people have been mistakenly in my opinion say that battery levels make no measurable difference in fuel consumption." and pointing out that the reason why some people say that the battery level makes no measurable difference in fuel economy is because for those of us operating in the real world, the difference is not measurable. My fuel consumption swings between about 30mpg and close to 50mpg depending on environment and driving conditions - Trex's observed figure which is about 7% at best and significantly less once the SOC gets below about 80% is simply lost in the noise.

Sorry, Maby. You are right. All this time I thought you and I still disagreed on whether or not there was an efficiency penalty associated with high SOC. And it must have been because of that, that I misinterpreted your response. Sorry again. Non native speaker, you know But it is good to hear we are ll on the same page now