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MPG of plug-in hybrids?

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MPG of plug-in hybrids?

Old 18th Dec 2021, 21:36
  #21 (permalink)  
 
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Originally Posted by nickp View Post
It is suggested that the battery should be kept between 20% and 80% of its capacity in order to maximise the life - this will be difficult to do with a hybrid of any variety.
Being too lazy to set up any checking instrumentation, and just going on the bar chart on the panel, the battery in my (old) Auris never gets to the 'full-charge' mark, nor does it get to the point where all the illuminated bars go out - there's always one 'lit'. So it's possible that the control system actually determines the '20% - 80%' criteria.
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Old 18th Dec 2021, 22:32
  #22 (permalink)  
 
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Originally Posted by nickp View Post
It is suggested that the battery should be kept between 20% and 80% of its capacity in order to maximise the life - this will be difficult to do with a hybrid of any variety.
My 2013 Chevy Volt plug-in hybrid is designed with a battery pack of around 16 KwH, but only uses 10.6 or so. So the battery never fully charges or discharges. After 100K miles, there appears no degradation in its ability to hold a charge at the design level. And no user action is required.

People who compare energy consumption/CO2 emissions between BEVs, PHEVs and ICEs often forget that it takes around 6 KwH to refine a gallon of gas. My Volt can go 20 miles on that without producing any additional CO2 at all.
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Old 18th Dec 2021, 23:45
  #23 (permalink)  
 
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Originally Posted by jimtherev View Post
Being too lazy to set up any checking instrumentation, and just going on the bar chart on the panel, the battery in my (old) Auris never gets to the 'full-charge' mark, nor does it get to the point where all the illuminated bars go out - there's always one 'lit'. So it's possible that the control system actually determines the '20% - 80%' criteria.
My hybrid stops charging at 80% and shows range = 0 miles at 20% then switches to petrol at that point. Default modes on starting are HEV or EV. I have mine set to EV as most trips can be done in EV.
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Old 19th Dec 2021, 03:11
  #24 (permalink)  
 
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My Outlander PHEV I charged up in Oz daylight hours using solar panels on my house roof so very cheap to run. If you didnt put your foot down on the accelerator and only did 32 mile trips then no petrol was used at all. But every 3 months it would go to 'stale fuel mode' and make you use up what was left in the petrol tank which was annoying.
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Old 19th Dec 2021, 07:47
  #25 (permalink)  
 
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Originally Posted by ETOPS View Post
I had a Mitsubishi PHEV which for most local trips I ran in electric mode only - there was a switch to inhibit the petrol motor from starting up. With a 30 mile range and charging every night my mpg often showed 180 mpg which I think was the most it could show. More normal mixed mode driving with the car left to decide when to use the petrol gave around 80 mpg.
Long trips on the motorway at 70 mph showed the weakness of the system ....30mpg!!
I was quite surprised to find that electric vehicle range decreases with speed which is the opposite of a fossil fuel car. So for range electric cars have to drive on A roads to extend range (unless they only want to do 20 miles of course).
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Old 19th Dec 2021, 07:54
  #26 (permalink)  
 
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I just took my Mk 4.5 Mondeo 2.0 straight Diesel (not Hybrid, not ad-blu) on a small Christmas holiday trip this week.
I drove from Farnborough to Birmingham and stayed in a Premier Inn. No charging points in the car park.
I then drove to York, popped to Thirsk (a few charging points), Hemswell (charging points being fitted) and again stayed in a York Premier Inn. No charging points.
Finally returning home via Lincoln. There were a couple of charging points but not many. Maybe three a floor.
This trip was performed over four days.
Round trip was 650 miles which I managed on £85 of fuel. Mondeo 4.5 Diesel does about £10 per hundred miles on average.

The point of all this is that the trip would have been extremely challenging using electric due to the distance, time scale and availability of charging points, not to mention enducing range anxiety.

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Old 19th Dec 2021, 07:56
  #27 (permalink)  
 
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Anyone care to comment on how a 40 ton truck would manage on batteries?
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Old 19th Dec 2021, 08:14
  #28 (permalink)  
 
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Originally Posted by munnst View Post
I just took my Mk 4.5 Mondeo 2.0 straight Diesel (not Hybrid, not ad-blu) on a small Christmas holiday trip this week.
I drove from Farnborough to Birmingham and stayed in a Premier Inn. No charging points in the car park.
I then drove to York, popped to Thirsk (a few charging points), Hemswell (charging points being fitted) and again stayed in a York Premier Inn. No charging points.
Finally returning home via Lincoln. There were a couple of charging points but not many. Maybe three a floor.
This trip was performed over four days.
Round trip was 650 miles which I managed on £85 of fuel. Mondeo 4.5 Diesel does about £10 per hundred miles on average.

The point of all this is that the trip would have been extremely challenging using electric due to the distance, time scale and availability of charging points, not to mention enducing range anxiety.
That is what makes PHEVs an attractive solution for many people. Many of the advantages of an EV, especially for short journeys, which are the majority, plus no range anxiety for long journeys coupled with good mpg.
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Old 19th Dec 2021, 08:18
  #29 (permalink)  
 
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Originally Posted by munnst View Post
I was quite surprised to find that electric vehicle range decreases with speed which is the opposite of a fossil fuel car. So for range electric cars have to drive on A roads to extend range (unless they only want to do 20 miles of course).
. I donít. You will also find an ICE fuel economy decreases as speed increases once it passes its peak economy which usually occurs between 50 to 60.
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Old 19th Dec 2021, 10:19
  #30 (permalink)  
 
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Originally Posted by tdracer View Post
. I know that some plug-in hybrids will periodically run the petroleum engine to keep it lubricated and make sure the fuel doesn't go bad with age.
This is something to take into account. I had a motorbike which ran on unleaded and left it in the garage for about a year. When I started it, it wouldn't run and when I drained the carb, it was full of green sludge, so the same would apply to hybrid cars if you didn't run them on petrol for long periods.
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Old 19th Dec 2021, 11:06
  #31 (permalink)  
 
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Originally Posted by chevvron View Post
This is something to take into account. I had a motorbike which ran on unleaded and left it in the garage for about a year. When I started it, it wouldn't run and when I drained the carb, it was full of green sludge, so the same would apply to hybrid cars if you didn't run them on petrol for long periods.
We are told that the latest 10% ethanol fuel deteriorates with time because ethanol is hygroscopic. Surely the only source of water is the air in the fuel tank and the only new air entering the tank is what replaces the fuel? So where does the water come from - if you filled the tank to the brim there would seem to be no way the amount of water in the fuel could increase no matter how long you left it? My petrol mower starts perfectly well after four months over the winter and I never drain the tank.
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Old 19th Dec 2021, 11:17
  #32 (permalink)  
 
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Most hybrids that I know of have a small but adequate range with running on battery alone because they deliberately use a smaller and cheaper battery. Hybrids that are packed to the brim with the latest battery technology are way too expensive to be caring about saving the planet or your hard earned. The small battery is a winning formula in these types of vehicles, which also reduces operating costs when they need replacing.
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Old 19th Dec 2021, 11:17
  #33 (permalink)  
 
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Originally Posted by chevvron View Post
This is something to take into account. I had a motorbike which ran on unleaded and left it in the garage for about a year. When I started it, it wouldn't run and when I drained the carb, it was full of green sludge, so the same would apply to hybrid cars if you didn't run them on petrol for long periods.
In my experience it does not happen. 1, Driving will cause the contents of the tank to be agitated. 2, Even in full EV the engine will start to occasionally support the battery if it is required. 3, Cab heating is done by running the engine,
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Old 19th Dec 2021, 12:14
  #34 (permalink)  
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Originally Posted by Ninthace View Post
Actually a PHEV that does 140 mpg would do 1400 miles on a tankful provided it did it in the course of a normal driving pattern rather than all at once.
Ah, so are the manufacturers saying that IF a PHEV running in combined battery and ICE mode had its battery charged back up to full from a wall socket every time it ran out, e.g every 25 miles or whatever, then the overall MPG achievable - maybe after a month of driving and perhaps 40 battery recharges - would be these ridiculous figures they quote?!

If so, that is a con. The MPG figures should be how far can the car drive on ONE full tank of fuel and ONE full charge* of its battery. Otherwise they are completely meaningless, and cannot be compared to anything.

* from a wall socket. Charging the battery while driving from the engine or regenerative braking, would be allowed, since the power to do that would come from the fuel in the tank.
.

Last edited by Uplinker; 19th Dec 2021 at 12:24.
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Old 19th Dec 2021, 12:52
  #35 (permalink)  
 
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Originally Posted by Uplinker View Post
Ah, so are the manufacturers saying that IF a PHEV running in combined battery and ICE mode had its battery charged back up to full from a wall socket every time it ran out, e.g every 25 miles or whatever, then the overall MPG achievable - maybe after a month of driving and perhaps 40 battery recharges - would be these ridiculous figures they quote?!

If so, that is a con. The MPG figures should be how far can the car drive on ONE full tank of fuel and ONE full charge* of its battery. Otherwise they are completely meaningless, and cannot be compared to anything.

* from a wall socket. Charging the battery while driving from the engine or regenerative braking, would be allowed, since the power to do that would come from the fuel in the tank.
.
Why? That is just as unrealistic a model of use. Real world use figures would be better, I have done 14171 miles on 494 litres of fuel. You do the maths.

Edit to add: If you read the mpg claims, most manufacturers do admit their mpg tests are done under fairly strict conditions but I have equalled their claim by doing 1340 miles on 26 litres last year.

Last edited by Ninthace; 19th Dec 2021 at 14:54.
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Old 19th Dec 2021, 14:21
  #36 (permalink)  
 
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Originally Posted by munnst View Post
I was quite surprised to find that electric vehicle range decreases with speed which is the opposite of a fossil fuel car. So for range electric cars have to drive on A roads to extend range (unless they only want to do 20 miles of course).
Ignoring the use of heating, air con etc the range of an electric car depends solely on the form drag curve - the faster you go, the more drag, the less range. Form drag is proportional to the square of the speed.
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Old 19th Dec 2021, 18:24
  #37 (permalink)  
 
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Six years in to plug in hybrid ownership, an A3 Etron, we get over 1000 miles from each 37 litre tank. The trip computer is currently showing 180+mpg.

It only has a twenty mile range on battery only however thatís most of our motoring, and when we need to go further thereís the petrol engine. We get free electricity 00:00-06:00 so we charge it on a timer and it costs us pennies to run.

As with most things in life, if you take advantage of its capabilities itís really efficient, if however you get one as a tax dodge, never charge it and drive using the petrol engine itíll be worse than a normal petrol car.

If you stick it in sport mode the 150hp petrol engine and 100hp motor come online together and it goes like stink. Fantastic for A road overtaking. I force the engine to come on every couple of weeks to stop it deteriorating if we havenít been on any longer journeys.

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Old 20th Dec 2021, 10:09
  #38 (permalink)  
 
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Originally Posted by nickp View Post
We are told that the latest 10% ethanol fuel deteriorates with time because ethanol is hygroscopic. Surely the only source of water is the air in the fuel tank and the only new air entering the tank is what replaces the fuel? So where does the water come from - if you filled the tank to the brim there would seem to be no way the amount of water in the fuel could increase no matter how long you left it? My petrol mower starts perfectly well after four months over the winter and I never drain the tank.
A fuel tank is not a sealed vessel. When you put fuel in, or take fuel from the tank, air needs to be able to move out of or into the tank and this offers a path for moisture to end up in the fuel.
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Old 20th Dec 2021, 10:40
  #39 (permalink)  
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Hi Ninthace;

I thought I had explained why; It is effectively cheating. And it's not MPG - miles per gallon either, it is miles per gallon and battery output. The figure they quote includes any number - unspecified - of battery charges during the time it takes to consume one full tank of fuel - which could be 1 month. If a PHEV driver only ever went 20 miles between charges, their "MPG" would be infinite. That is what is meaningless - it gives no metric of the performance and efficiency of their offering.

I mean, you could turn it round and say that a PHEV will go 1,000 miles between battery charges, implying a very good battery - (but only if you kept filling up the petrol tank !!).

To be able to compare PHEV models' performance, the same test needs to be applied to all models. You cannot do this with PHEV cars unless you specify how many battery charges are included - some might say 10 recharges, others might say 20, or 40; who knows?

I would specify one tankful of fuel and one full battery charge, then drive the car until it stops and work out the combined miles per gallon of the ICE assisted by the electric motor. That would give a reliable figure that could be compared with other PHEV cars.

For Mini, or anyone else to claim an MPG figure - to one decimal place, I ask you! - for a PHEV, without specifying the conditions of the test is simply meaningless and false.

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Old 20th Dec 2021, 12:05
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I made the same point back in post #4. MPG claims for PHEVs are meaningless, a bit like claiming flight duration for gliders, but then so are claims for ICE which are also conducted under unrealistic conditions. The best and fairest test would be an average of real world use figures for a cross section of users

When I bought my PHEV the deciding factors were battery range (the longer the better), build quality, warranty length and the quality of dealer support, Mpg claims never entered into my thinking - I used common sense, it was a low drag car with a 1.6 litre engine running on the Atkinson cycle with battery support. I expected it to be frugal but I also knew the majority of my driving would be electric. That said, PHEV was a compromise, I wanted the lowest life time costs based on up to 6 years ownership but I could not afford pure EV. I was also concerned about range and recharging, PHEVs get round that.
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