PHEV... 500 mile round trip tomorrow. Any tips on maximising mpg?

[Nick72]

Long drive. But I like driving. Plus, I like driving out of the gates on the 12 lane M6 toll like it is Death Race 2000 (ok I'm exaggerating). 

What's the optimal speed for mpg? Just stick to 70mph. Not in a rush to get there or back.

Put the car into automatic?  Burn through the fully charged Battery straight off or leave it for the country lanes in the last 8 miles in and 8 miles out?

Intrigued and genuinely interested. Feel guilty though because our company car policy only has EV options or ICE vehicle options so I have to click on vehicles above 2 litre which gives a fuel reimbursement rate higher than what it actually costs me. I've raised this being a good corporate citizen and all but for now this is the accepted method. 

Last very long trip averaged I think about 54 miles per gallon.

[philip42h]

I'd guess auto hybrid mode (if that's what it's called) all the way and never exceed about 55 mph. It's speed that kills fuel economy ...

[Red_Corolla]

Drive slowly. End of advice. 😆

Nice being able to claim the higher fuel rate, seems like 2.0 is the most popular size these days but the worse for reimbursement being *just* below that 2000cc threshold. I take the allowance and buy my own car. That way, I can claim tax relief on the difference between 45p/mile and whatever they actually pay me for fuel, so that softens the blow when the rate reduces.

[Nick72]

22 minutes ago, Red_Corolla said:

Drive slowly. End of advice. 😆

Nice being able to claim the higher fuel rate, seems like 2.0 is the most popular size these days but the worse for reimbursement being *just* below that 2000cc threshold. I take the allowance and buy my own car. That way, I can claim tax relief on the difference between 45p/mile and whatever they actually pay me for fuel, so that softens the blow when the rate reduces.

Didn't think of that.

I just went for the 7pc tax vs 40pc. Worked out cheaper than buying or lease. 

[ernieb]

I’ve found that use the EV then let it switch to HEV with a speed range of around 50/60mph. (A balance of speed and economy otherwise the slower the better) I’ve tried to go straight to HEV and it seems to hang onto the EV range and use the ICE. The problem is that weather can make such a difference as you well know as can head winds.

[philip42h]

You're going to doing 90% of the distance in HEV mode, and really want to save the EV 'power' for all the acceleration that you'll need to do leaving the ICE to simply maintain speed. By all means switch to EV mode when you are <range> miles from home ...

Because it is a CVT there isn't any particular speed that is the most efficient - with a standard gearbox (auto or manual) you'd want to be going fast enough to stay in 'top' but that doesn't apply here.

While you are cruising along most of the energy you expend is moving the air out of the way - air resistance is proportional to velocity squared. So, if you go 10% faster you'll expend 21% more energy per 'minute'; 10% slower and you'll be using 19% less energy per 'minute'. But, obviously going 10% increases your journey time by 10% so the saving in fuel is 'only' 9%. Going 10% faster saves time but costs 11% more fuel over the journey.

The question really is, "how slow can you reasonably go?" and still get the journey done before you lose your mind? 🙂

[Bernard Foy]

Just keep below the speed limits, it’s hard driving that eats up juice.

[Nick72]

1 hour ago, philip42h said:

You're going to doing 90% of the distance in HEV mode, and really want to save the EV 'power' for all the acceleration that you'll need to do leaving the ICE to simply maintain speed. By all means switch to EV mode when you are <range> miles from home ...

Because it is a CVT there isn't any particular speed that is the most efficient - with a standard gearbox (auto or manual) you'd want to be going fast enough to stay in 'top' but that doesn't apply here.

While you are cruising along most of the energy you expend is moving the air out of the way - air resistance is proportional to velocity squared. So, if you go 10% faster you'll expend 21% more energy per 'minute'; 10% slower and you'll be using 19% less energy per 'minute'. But, obviously going 10% increases your journey time by 10% so the saving in fuel is 'only' 9%. Going 10% faster saves time but costs 11% more fuel over the journey.

The question really is, "how slow can you reasonably go?" and still get the journey done before you lose your mind? 🙂

65mph lol

[Cyker]

Just drive to enjoy the journey! Sod the fuel economy!

At the rate things are going we won't be able to drive cars if the politicos have anything to do with it (Sadiq Khan can take his £2 daily driving and pay-per-mile charges and stuff them up his proverbial!), so enjoy it while you can!

No point in driving at 50mph the whole way there, bored out of your mind and falling asleep! Enjoy the car! Enjoy the journey!

 

[Terry10]

9 hours ago, Cyker said:

Just drive to enjoy the journey! Sod the fuel economy!

At the rate things are going we won't be able to drive cars if the politicos have anything to do with it (Sadiq Khan can take his £2 daily driving and pay-per-mile charges and stuff them up his proverbial!), so enjoy it while you can!

No point in driving at 50mph the whole way there, bored out of your mind and falling asleep! Enjoy the car! Enjoy the journey!

 

Got to agree 100% with the above I am sorry to say.

Bored and falling asleep are a real concern

Terry

[AndrueC]

As with all vehicles, minimise your use of brakes.

https://ecomodder.com/blog/hypermiling-101-driving-without-brakes/

As for speed I rarely go above 60mph even on motorways. I just sit in lane one and watch the rest of the world rush by. You have to pay more attention around junctions but otherwise I find it results in a pleasant relaxed drive. I don't get bored or fall asleep because I'm constantly watching what other drivers are doing (and commenting on it, often sarcastically 🙂 ). On the other hand I only drive on motorways for leisure so I'm never in any particular hurry. I'm happy to arrive 'when I arrive'.

[Nick72]

Right. Two thirds the way there. Stopped at services for breakfast.

M6 averaging 40 to 45mph through the long 50mph average speed check so used up the Battery on that. Pretty sure I just managed 55 miles on the Battery but will check the analytics data later. Battery range seems optimised for 40 to 45mph from my previous analysis and charts posted here so that was useful.

Rest of the journey averaging about 53mpg under ICE (not e mpg). Averaging 60 to 70mph.

Lane tracing assist does not work well in the dark despite the motorway being well lit. And when light seems to have a strong near side bias (to the point where I can occassionally hear the cats eyes being driven over). Adaptive cruise seems pretty solid.

 

Thanks for all the responses thus far.

[Roy124]

Yesterday I did a there and back. One way I used ACC 70 on the dual carriageway and 50/55 on the A road. Dual carriageway was half the journey. The numbers are instructive.

Out was a score of 84/100 

EV31% Distance 19% 58mpg 70min 44 mph 

In was 92/100

EV45% 27% 61.4mpg 78min 39 mpg 

I did not use ACC for the first half but the ACC set at 70 for the dual carriageway. 

So I did indeed improve my consumption at a cost of 8 minutes.  Was it worth it? 

No.  Every little rise and dip I was playing the pedal.  The car would shut down the ICE and a moment later decide it need more power.  It was quite tiring just trying to beat the system. If I had been driving fast then I would expect to play the pedals but for a more relaxed drive, ACC or CC and a bit of thumb work was far more relaxing and saved 10% on the journey time. 

 

[Roy124]

Nick, pretty much bears out my experience. 

Only thing I might add, watch the speed when you have ACC set but the traffic is fluid with trucks steady around 60.  It will allow your speed to bleed off and before you know it cars start to stream passed. 

[ernieb]

Typically I set the ACC to 65mph which is 60mph (GPS accuracy) on motorways. As the sections of the M1 I use regularly have a number of restricted sections this seems to work out well enough it terms of economy and making progress. I’ve compared the times, aways difficult due to traffic, temperature etc., and on a 100 miles motorway section there does not seem to be a lot more to be grained when compared to travelling at the speed limit in the non controlled sections. I just get frustrated with the constant overtaking and manoeuvring.

I’ve found that there seems little to be gained reserving the user EV range after all the car still has 30% of the traction Battery left for full bore acceleration. I’ve also noticed that the MyT all recordings of the car’s use of EV when I’ve used my 70% is much higher than I’d noticed or expected. Looking at the map and noting the sections of EV use it’s much higher, which I’ve taken to be the cars momentarily using EV or recovering energy without the display being updated.

I’ve lost concluded that the cars ACC works just as well as me trying to be ultra clever, it just sorts it all out really well.

Overall after playing with how I drive the car and how well I could get my EV score etc., I just enjoy the car, still a joy to drive and gives me results I could never have achieved in my previous Subaru XV.

Nick, it will be interesting to see how you feel about your trip and what results you achieve.

[Nick72]

4 minutes ago, ernieb said:

Typically I set the ACC to 65mph which is 60mph (GPS accuracy) on motorways. As the sections of the M1 I use regularly have a number of restricted sections this seems to work out well enough it terms of economy and making progress. I’ve compared the times, aways difficult due to traffic, temperature etc., and on a 100 miles motorway section there does not seem to be a lot more to be grained when compared to travelling at the speed limit in the non controlled sections. I just get frustrated with the constant overtaking and manoeuvring.

I’ve found that there seems little to be gained reserving the user EV range after all the car still has 30% of the traction battery left for full bore acceleration. I’ve also noticed that the MyT all recordings of the car’s use of EV when I’ve used my 70% is much higher than I’d noticed or expected. Looking at the map and noting the sections of EV use it’s much higher, which I’ve taken to be the cars momentarily using EV or recovering energy without the display being updated.

I’ve lost concluded that the cars ACC works just as well as me trying to be ultra clever, it just sorts it all out really well.

Overall after playing with how I drive the car and how well I could get my EV score etc., I just enjoy the car, still a joy to drive and gives me results I could never have achieved in my previous Subaru XV.

Nick, it will be interesting to see how you feel about your trip and what results you achieve.

Thanks Ernie. I was just about to comment on what seems to be a 4mph difference between speedo and actual via GPS. Speedo saying 4mph at 70mph.

Will trawl through the data later tonight when back.

Lots of lorries and imbiciles today.

[nlee]

12 minutes ago, Nick72 said:

Thanks Ernie. I was just about to comment on what seems to be a 4mph difference between speedo and actual via GPS. Speedo saying 4mph at 70mph.

Will trawl through the data later tonight when back.

Lots of lorries and imbiciles today.

Fairly standard that the Speedo over-reads around 5-10% or so versus GPS speed. It's been similar on all cars I've had. Legally, the Speedo cannot over read actual speed so they are generally set slightly higher than actual to compensate for all the variables than can affect the speedo like tyre inflation, wear etc.

[philip42h]

3 minutes ago, nlee said:

Legally, the Speedo cannot over read actual speed

... where you meant under read / understate actual speed of course ... 😉 The car cannot be going faster than the speedo says it is ...

Previous RAVs have over stated the actual speed by around 10%; with this one is pretty much exactly 5% - so 3.5 mph at 70. Indicated 70 is a real 66.5 and an indicated 75 is a real 71 (and a bit). Obviously temperature, tyre pressures and tyre wear will have an impact on that too ...

[nlee]

12 minutes ago, philip42h said:

where you meant under read / understate actual speed of course ... 😉 The car cannot be going faster than the speedo says it is ...

I think that's what I meant. My head always plays tricks on me with this but yes, the second part of your sentence is absolutely what I meant!

Also, I realise that tyre wear wasn't necessarily the best example as it has the opposite effect.

[philip42h]

1 hour ago, ernieb said:

I’ve found that there seems little to be gained reserving the user EV range after all the car still has 30% of the traction battery left for full bore acceleration

Maybe, but once you go into "full bore acceleration" mode up a long hill, say, you'll start to eat into that 30% reserve - reducing it to maybe 20%. At this point the car will remember that it is a self-charging hybrid and continue to run the ICE as a generator to get you back up to your 30% reserve. And that's absolutely fine from a performance perspective, but not so great for an economy perspective.

If you still had, say, 80% of the traction Battery left the car could use the same 10% - so now down to 70% - and still be comfortably above the 'reserve' threshold.

If it were me, I'd reserve the traction Battery, and pure EV range, until I knew something that the car didn't - that we were within remaining EV range of our destination. But there again, I don't have a PHEV ... 😉

[nlee]

I generally find the Battery consumption increases (i.e. less miles/kWh) on the motorway at 70mph. Within 3 miles I'm on the A55/M56 so I tend to drive EV to the dual carriageway, switch to HEV mode then go back to EV when I get to country lanes and urban areas. I'm sure I read that recommendation in the manual or some blurb on the internet. It also makes sense from an emissions perspective to use EV in built up areas. I always make sure there is no EV range left before I get to a charger, or it doesn't make sense having a PHEV, so will sometimes use it on the motorway.

[ernieb]

Philip. I think what your saying makes sense but my experience when doing longer trips has mainly been of relatively flat roads with inclines rather than step hills and even so I’d not be gunning the car that often. I know that Nick has reduced the traction Battery to nearly flat but as he said at the time he was pushing hard all the way.  I guess like most of the comments it’s down to driving style, route topography and temperature all of which can and does make massive differences to the economy and performance.

[Roy124]

We have the odd Roman road around us, what goes up must come down 😁

[ernieb]

20 minutes ago, Roy124 said:

……… what goes up must come down 😁

That’s what I think every time I go out with the walking group.

[Big_D]

11 hours ago, AndrueC said:

As for speed I rarely go above 60mph even on motorways. I just sit in lane one and watch the rest of the world rush by.

I'm the same. I've reached that stage in my life where I'll get there when I do. I've been told that driving with me is like driving Miss Daisy 😀