MPG for those interested

[sportse]

Today 150 miles, mostly 90 km/h (56 mph) roads, also some 70 km/h (43.5 mph) roads and very little urban:
3,6 l/100 km = 78.5 mpg.

I set my ACC to 60 mph actual (62 indicated) and kept it there for 50 miles.

Fuel economy was 60mpg.

If you go any faster it drops, slow down it increases.

[John Ratsey]

A week ago I returned from a 1600 mile round trip from southern England to north Scotland. Overall mpg based on fuel used was 74.3. I had expected the rural Scottish roads with max 50 mph to favour very good mpg but this didn't prove to be the case for, I think, the following reasons: (i) Uphill sections which pushed the engine out of its zone of optimum efficiency; (ii) long downhills which exceeded the battery's ability to store regenerated energy; (iii) single track roads with sharp braking and limited potential for regeneration and (iv) wind drag in open areas (I feel that the Crosstar is vulnerable to crosswinds (roofbars?). The best mpg was on motorway sections where I joined the queue of lorries (but at least 50m behind whatever I was following). At one stage the fibometer was claiming 84.5mpg over 170 miles. After allowing 6% optimism that's 79mpg.

[John Ratsey]

When brake pedal applied regen gives more power, when accelerator pedal released regen power depends on the speed of the car, when I drive with speed 40km/h in D mode and leave accelerator pedal I get ~ 5kw regen, when on same speed I choice B mode I get ~ 8kw regen if I remember correctly, maximum regen that I seen with brake pedal pressed is 29-30kw both in D mode and B mode.

This is useful information as it highlights the need for gentle braking to maximise regeneration. Heavy braking must temporarily generate at least 100kW of energy, much of which doesn't go into the battery.

[sportse]

A week ago I returned from a 1600 mile round trip from southern England to north Scotland. Overall mpg based on fuel used was 74.3.

That's as good as generally the car will do on roads up to 50mph - I can regularly repeat that on similar roads myself.

My 100+ mpg trip and the same trip the next day at 96mpg were a result of:

1) A fully warmed up engine, and setting off a few minutes after stopping

2) Warm outside temperatures

3) A fully chilled interior, so the a/c just had to maintain it rather than cool it down.

[guest9814]

When brake pedal applied regen gives more power, when accelerator pedal released regen power depends on the speed of the car, when I drive with speed 40km/h in D mode and leave accelerator pedal I get ~ 5kw regen, when on same speed I choice B mode I get ~ 8kw regen if I remember correctly, maximum regen that I seen with brake pedal pressed is 29-30kw both in D mode and B mode.

This is useful information as it highlights the need for gentle braking to maximise regeneration. Heavy braking must temporarily generate at least 100kW of energy, much of which doesn't go into the battery.

Don’t forget to coast when this possible (if you watch power flow it’s when blue lines from battery becomes green to battery  when you gently press and release accelerator pedal, at that moment motor taking minimal power from battery or 0 or has little regen), this gives more mpg than regen alone, don’t brake hard , that giving huge regen power but if that brisk hard braking most of energy will go to heat in inverter and battery, the longer you braking gently the more energy will be stored, but again braking only if we need to stop car and we not have distance / time to reduce speed by coasting, there another trick try not stop car, even if you speed very low and you approach traffic light that may change to green any second try not stop car completely (to move standing car motor work harder and taking more current  from battery).

[John Ratsey]

That's as good as generally the car will do on roads up to 50mph - I can regularly repeat that on similar roads myself.

My 100+ mpg trip and the same trip the next day at 96mpg were a result of:

1) A fully warmed up engine, and setting off a few minutes after stopping

2) Warm outside temperatures

3) A fully chilled interior, so the a/c just had to maintain it rather than cool it down.

I reckon you were helped by either a tailwind or a height difference between the two ends. If they were part of round trips then what were the mpgs on the other halves?

Don’t forget to coast when this possible (if you watch power flow it’s when blue lines from battery becomes green to battery  when you gently press and release accelerator pedal, at that moment motor taking minimal power from battery or 0 or has little regen), this gives more mpg than regen alone, don’t brake hard , that giving huge regen power but if that brisk hard braking most of energy will go to heat in inverter and battery, the longer you braking gently the more energy will be stored, but again braking only if we need to stop car and we not have distance / time to reduce speed by coasting, there another trick try not stop car, even if you speed very low and you approach traffic light that may change to green any second try not stop car completely (to move standing car motor work harder and taking more current from battery).

What you describe is my normal technique but it doesn't work on some of the Scottish roads (even A roads) which are single track with passing places and it's a matter of using passing places. Sometimes I had to brake suddenly when I was about to pass a passing place and saw an oncoming vehicle while at other times I felt I couldn't decelerate at my normal speed because an oncoming vehicle was waiting for me.

I wonder if pure EVs have a much better burst regeneration capability.

[guest9814]

Pure EV another story they have big battery at last 24kwh, so brisk braking that pushing 30kw of power nothing for them they charging at 50kw DC and I think  that slowest DC charging today, but there maybe another brick on road, when battery hot it’s  BMS reduces power that can be pushed in battery or power taken by traction motor, so if you push brake pedal  hard enough you will use braking pads.
Today I did trip 14 km from shop to home with staring position slightly higher then end point and warmed engine, no one on roads, coasted as much as I can , I get 117 MPG this time, no A/C used as I fell comfortable when outside 27-28 degrees C, only fan blowing, most of time 30mph.

[sportse]

maintain it rather than cool it down.

I reckon you were helped by either a tailwind or a height difference between the two ends. If they were part of round trips then what were the mpgs on the other

It’s a flat urban trip, straight roads and mostly 40mph limits with some 30 and some 50 too.

I’ve just done the same trip today, this time with 2 passengers and got 86mpg. It’s 28 degrees, air con working hard.

Return trips can’t be compared, as I parked up and ran the engine before the return trip without powering down.

Mpg for the return was 44 one day and 47 the next - including 60-90 minutes of stationary engine running with the air con set for 21.

[Kremmen]

I've decided to remove my Spritmonitor link.

The M4 is due to partially open up by July 16th from 50mph to 60mph so my MPG is going to drop. Plus I'm deliberately not going above 60mph in the unrestricted zone just to keep my stats here higher.

Plus, if next weekend does get to 36C+ then I will open both garage doors and run the Jazz AC for a short while to cool down and that will kill the MPG.

[Jazzik]

I've decided to remove my Spritmonitor link.
................../................
so my MPG is going to drop.

May I say that I find that a very strange reason to remove the link...?

[Kremmen]

I see it as a MPG competition and I've decided to retire rather than drive to boost my figures. I'm getting well above my old Civic average 45mpg.

I'll still enter my details into SM but just not display them here.

[peteo48]

Just on air con and its effect on mpg. Interesting trip yesterday to Dunham Massey Park with 3 and a half up. Car is parked in full sun. Opened doors to help get a bit of heat out then set off. The fibometer was showing 62 mpg.

It's a 16 mile round trip. Traffic quite light. Max speed 50 mph but mostly on country lanes where doing around 35 ish. Ordinarily I would expect the mpg to creep up but, at the end of this trip, the fibometer had dropped to 59.6.

Outside it was about 28 degrees. I managed to park in the shade but the Air Con was blasting out for the whole trip back (8 miles). Recirculation on the same time as well.

Wish now I'd set one of the trips. Another variable was an extra adult and child but I now have no doubt at all that, when on full blast, the Climate Control will cut mpg by a good 10%.

This must be where the 10% figure comes from. Over time the effect on mpg of Aircon/Climate Control will even itself out and probably not have that much effect overall but I can now give the 10% more credence than I did. Air Con can drink fuel.

[Jazzik]

I see it as a MPG competition...

I didn't realize at all that this forum and the information it discloses could be considered a "competition".
I thought it was more about exchanging information...

[peteo48]

It can be. I must admit I get "sore loser" syndrome when I see these guys with mpg over 60 mpg

[sportse]

In normal cars the air con runs from the engine by a belt, so runs anyway when the engine is on. There will be a hit to mpg as there will be more load on the engine.

With Jazz, it's a fully electric system so requires power to work.

In hot weather, I wonder what the difference in economy is between an ordinary car a/c and a Jazz a/c - maybe not a huge difference if both systems are under high load?

The Jazz system is probably more efficient in lighter load situations, plus works from the HV battery when the engine is off too.