Author Topic: MPG for those interested  (Read 63406 times)

Lord Voltermore

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Re: MPG for those interested
« Reply #555 on: December 13, 2022, 11:06:26 AM »
Just done a long trip heading  west across europe ,mostly motorway.  . At plus 9C I  was struggling to achieve 5.5 liters per 100 km  (51 mpg) . Didnt often go into EV mode     But later, when the temperature had dropped to minus 3C   I managed 4.9 litres   57 mpg ,and a bit more often in EV .More like what I was expecting for the speeds in winter.

Cold battery is less efficient ,and cold air is more dense aerodynamically.   So why was it better at  minus 3 than it was  at plus 9 ?  No real difference in speed or terrain. 

I noticed  that when MPG was poor the windfarm windmills were  going at a good speed and I could tell from their orientation that, for hundreds of miles, I was predominantly battling against a headwind.   This was not noticeable as buffeting when driving, or strong enough to sway  leafless trees. 

Yet later when mpg improved  to 57 mpg  the windmills were largely dormant , so little wind, and what there was appeared to be a tail wind for me.  I think had I been travelling in the opposite direction my mpg would have improved overall and typically averages out over time. 

I cant claim it was all due to wind direction as the poor mpg section did include some heavy rain which may have also increased tyre rolling resistance. 
« Last Edit: December 13, 2022, 11:11:56 AM by Lord Voltermore »
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John Ratsey

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Re: MPG for those interested
« Reply #556 on: December 13, 2022, 11:54:49 AM »
A headwind makes a big difference to the mpg as the drag loss increases in proportion to the square of the effective speed (vehicle speed + headwind speed) so a 10mph headwind at 60mph results in the drag loss for 70mph - an increase of 36% while a 20mph headwind at 60mph increases the drag loss by 78%.
2022 HR-V Elegance, previously 2020 Jazz Crosstar


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Re: MPG for those interested
« Reply #557 on: December 15, 2022, 11:58:43 AM »
Just recorded my lowest ever mpg today - didn't really need to fill up but this will see me through into the new year. 47.9 mpg after 4 successive readings above 60 mpg.

Apparently we are in the coldest snap since February 2021 so not too bad. I don't stint myself in the cold weather either - heated seats and steering wheel on along with rear screen and mirror clearing. I also haven't done any significant trips so a lot of my driving has been when the car is below operating temperature. EV mode rarely kicks in these days. I have had a full house of battery bars for over a month.

A bit of perspective - this lowest reading so far is significantly above the average for my MK3 so I'm not complaining.

Lincolnshire Rambler

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Re: MPG for those interested
« Reply #558 on: December 23, 2022, 06:00:17 PM »
Just over 19,000 miles and a global average of 65.4 according to the fibometer! Thatís a real mix of rural urban A roads motorways city centres and mountain passes! Lots of frozen cold starts but most journeys in excess of 30 mins of driving!


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Re: MPG for those interested
« Reply #559 on: December 23, 2022, 07:18:43 PM »
If your Jazz shows the same deviation as ours, that equates to 62.5 MPG in real life.
If nothing goes right, go left!


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Re: MPG for those interested
« Reply #560 on: January 12, 2023, 03:29:53 PM »
My latest graphs attached plus new graph for cost at £/mile qnd Accumulative.
Did this in view of RAC published numbers giveing petrol car cost of £0.17/mile with an economy of 40mpg. (Diesel £0.20/mile.
The electric car equivelent using rapid chargers is - £0.20/mile.

My cost is accumulatively - £0.133/mile.

Happy with Crosstar economy. - Added info - the fill consumption this time was down to 44.87mpg - the winter effect, less than last Jan figure, first annual figure from new was 54.83mpg
« Last Edit: January 13, 2023, 07:48:11 AM by aphybrid »


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Re: MPG for those interested
« Reply #561 on: January 25, 2023, 08:03:14 AM »
This one is our first number.
Full Istanbul heavy traffic.  1450km 4.3lt/100km

This one is also full heavy traffic in Istanbul. But weather little warm that time + I was using too   140km 3.8lt/100km


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