Self Charging Hybrid MPG question

Stubod

Cisco001 said:

My 2018 yaris hybrid doing around 56 mpg

..we have a Mazda 1.5 ic only and since owning it we have averaged 55 mpg (Actual tank to tank).....FACT....(I understand you have to add this to any comments to make them valid??)

lmv80

Ok. This thread has provided more detail than I could have imagined. Thank you to everyone who has helped. It’s given lots of food for thought. 

Can people either real world experience of these types of cars provide examples of their typical usage and MPG?  That seems to be most useful advice and guidance. 

estevenin

Just saw this post as passing through towards my own thread. I drive a Toyota Prius, self charging hybrid, and I have seen a few pessimistic comments that don't reflect the reality of what it can give, at least to me.

Disclaimer : I'm a private hire driver, and will usually drive between 10, up to 300 miles a day. I also do personal journeys (motorway only) and small commutes on my days off. I bough a used car (3 years old), so at that time, the biggest depreciation already happened. Here are the numbers that I routinely get :

- For a regular day 150/200 miles in a row, I will do no less than 70 MPG, but as an average, 75 to 80MPG. This figure will vary, depending on how much traffic, how much motorway, if it rains (the car needs more push) but also very important, how well the tyres are inflated. I also drive with extra care for economy, no brutal acceleration, always following the recommended driving patern, except if the situation requires otherwise.

During the first COVID Lockdown, I would very easily reach 87 / 90 / 92 I even did 94 MPG, I think this is even more than what Toyota Advertises. I was myself very surprised that manufacturer numbers are in fact reachable by the consumer, if the road conditions are there.

- For a full motorway journey, (London to Burmingham for example), I would get an average of 60 to 65MGP.
- For a full day in London Traffic, I would get 65 to 70 MPG.
- For a very small commute journey (5 to 10 miles), I would get 50 to 55MPG. Not sure why, but I guess as the car warms up, the mechanism get smoother and less need for power. Hence why I get a better result for longer mileage.

Long story short, for fuel economy (and this is for any car), you need :

- 4 identical tyres, and if possible, with the same wear, with the best possible rating in fuel
- Always have them inflated. I would do it every 1000 miles more or less (Once a week for me, the 50p /1 pound a week cost is easily offset by the fuel economy)
- A sunny day, rain increases tyre adherence and the car needs more push. There can be a difference of 7 to 10 MPG for the same journey.
- Folowing the recommended driving paterns on the screen, not pushing the acceleration more than needed, and anticipating breaks, to brake for as long as possible.
- Easy on the AC or Heating. I would usually put it full the first 10 miles to put the car at the desired temperature, then put a full eco mode and usually the temperature remains.

Hybrids are more fuel efficient by a certain factor (let's say 50% for the sake of the example), so by respecing this on a hybrid, you add 50% more than the efficiency of a petrol car WITH those criterias as well.

Then, driving an hybrid makes total sense if : 

- Every journey that you do is at least 20 miles or more. Less than that, the car don't have time to warm up and you use more fuel, you will be limited to 50/55MPG, which is very low compared to what you can do. I wouldn't get a hybrid if my job is 3 miles a way and I mostly do a morning / evening commute daily.
- If you ride on a steady, 30/40, even 50mph road, to go to work, with little to no traffic or stops. If you only do motorway, again, you'll be limited to 60. If you do traffic, like central london, to 65. This is still ok, but in those cases I would hesitate more with the Diesel option.
If you do a bit of both, steady roads + a bit of traffic or motorway, Hybrid still would do.

Some have said that :
- The money saved is lost on interests or depreciation. It depends how many miles you do. If you do little, then yes, like with any car in england really. I would not recommend buying a new car at all. There is absolutely no perks whatsoever, the results are the same with a 3 year old car that has been fully serviced, so far in 2 years, absolutely flawless, never had any breakdown or even to change any piece (not even a brake). I would buy a 3/4 year old car, with 40 to 60k mileage. For a prius, this is 10 to 12k. For another model, this can be less. So we are not that far from a normal petrol in that situation. For my personal case, even the battery hasn't lost performance, I'm sure on the paper that it did. ( I might have done 83MPG instead of 80 if the car was brand new)
- Plugin is better : Not true. Plugin Hybrids are EXACTLY the same as hybrids, if you do not charge them (at least for the prius, can't speak for the others as I only tried the plugin prius as well, but it is my understanding that it is similar). You can choose to charge them, in that case, having a bigger electric battery, the range will be higher. But if you don't or can't charge them (as I understand it is your case), then it will results to be exactly the same MPG. You will never run on "petrol only" if you forget to charge, it will act as a self-charging hybrid. The battery on a self charging very rarely gets fully charged except going downhill, so with the bigger battery on the plugin, this will be the same and only a small portion of the battery capacity will be used. So, with no charge, you get exactly the same results - it's basically the same car -, but you pay more to get it. No point.
- Congestion charge is free. Not true, you pay. Only plugin is free, and this will stop in october.
- Urban stop/start type driving then the hybrid will give significant efficiency benefits. It depends. If urbans is central london, 20MPG, then any braking situation does not give enough grip to properly charge the battery, and more time is spent on accelerating or beeing idle. Best to be in a steady 30/40/50mpg road, drive it for let's say 3mn, then have a clean / slow brake for a roundabout, then start again. Best possible sceneario. 
- Motorway or dual-carriage way they provide no benefit at all. Yes and no. 70 MPH pushes the engine too far, in such a way that the car uses mainly petrol all the way. That beeing said, if you find yourself in a 50mph roadworks zone, or if the road goes slighly down, then the speed of the car will then allow you to release the accelerator and the car will run on full electric. At that speed, miles are going quickly, and 2/3 miles in full electric is a lot. It is not true that the car is limited to 3 miles on EV, as if you barely press the accelerator, the battery is used less, mostly the already existing car traction is used. If the road goes slighly down, you might even be able not to accelerate, and you will do a 70mph whilst slowly charging. There are always times where you need to lift the break up : the battery charges. Or you need to break to avoid a car : It charges. You will then use that when the road goes slightly down or in a roadwork portion, and this is when the economy happens.

It's my understanding that the prius is one of the most if not the most fuel efficient self-charging hybrid, hence why I chose it for the job, but I can't really speak for a car where the advertised MPG is lower as I never tried it. The advertised MPG will be, in reality, 15 to 20 MPG less if you drive it well. But, with perfect road conditions and an enough long journey, you can really get quite close to it. This would give you a good idea for your own situation.

That is my own experience, and I think it is not an average one, as most drivers I know are always at least 10 MPG below what I do. Mostly because of poor tyre quality / combination or poor driving patterns. But a hybrid with poor driving patterns, is also pointless as you minimize its potentiel to basically almost beeing a petrol car.

It's personaly my best car investment, and wouldn't get anything else than this. Mostly because it adapts perfectly to my driving patterns. I don't have a driveway, so the time lost in charging a plugin or EV, would offset the benefits of the fuel efficiency, as time on the road is money for me. And the cost of a used petrol car vs a used hybrid, is not that different. But again, if you recognized your patterns here then it could be an option, if you don't, you might miss out on the potential and the extra money spent on purshase, might not worth it.

Hope that helps

AdrianC

estevenin said:

- For a very small commute journey (5 to 10 miles), I would get 50 to 55MPG. Not sure why, but I guess as the car warms up, the mechanism get smoother and less need for power.

Petrol engines run richer - they inject more fuel - when cold in order to warm up. Remember manual chokes?

Hybrids are more fuel efficient by a certain factor (let's say 50% for the sake of the example), so by respecing this on a hybrid, you add 50% more than the efficiency of a petrol car WITH those criterias as well.

Where on earth have you got this figure from?

A non-plugin only gets energy from one place, the petrol pump.

Some of the kinetic energy wasted to heat by brakes in a non-hybrid, or frictional losses in the engine on the over-run, is converted to electricity, but not much - especially if you drive in a way that very rarely uses the brakes. 

- Plugin is better : Not true. Plugin Hybrids are EXACTLY the same as hybrids, if you do not charge them

Not true. Plugins have larger motors, and considerably larger and heavier batteries.

You will never run on "petrol only" if you forget to charge, it will act as a self-charging hybrid.

Exactly. Petrol only. You're not getting that energy from anywhere else, are you?

The battery on a self charging very rarely gets fully charged except going downhill

Which shows how little the regenerative braking contributes.

So, with no charge, you get exactly the same results - it's basically the same car

But heavier. You're right, though, a plugin that never gets plugged in is pointless.

That is my own experience, and I think it is not an average one, as most drivers I know are always at least 10 MPG below what I do. Mostly because of poor tyre quality / combination or poor driving patterns. But a hybrid with poor driving patterns, is also pointless as you minimize its potentiel to basically almost beeing a petrol car.

The vast majority of what you describe is simple fuel-efficient driving. It doesn't matter what the fuel source is. Drive badly, use more of it.

Don't over-inflate tyres, though. It may reduce rolling resistance on dry roads, but it also reduces grip and increases wear.

BOWFER

As much as PHEVs are the bane of pure EV owners' lives (hogging chargers at pathetically low charge rates for their 20 miles), there's no doubting they're better than hybrids in that an owner can feasibly run around for weeks without ever using the ICE engine.

born_again

BOWFER said:

As much as PHEVs are the bane of pure EV owners' lives (hogging chargers at pathetically low charge rates for their 20 miles), there's no doubting they're better than hybrids in that an owner can feasibly run around for weeks without ever using the ICE engine.

Why  PHEV owner would ever use a charge point unless it is free is a mystery. As at best it works out the same cost as petrol, at worst more expensive.

BOWFER

born_again said:

BOWFER said:

As much as PHEVs are the bane of pure EV owners' lives (hogging chargers at pathetically low charge rates for their 20 miles), there's no doubting they're better than hybrids in that an owner can feasibly run around for weeks without ever using the ICE engine.

Why  PHEV owner would ever use a charge point unless it is free is a mystery. As at best it works out the same cost as petrol, at worst more expensive.

Where I live, the (cynical) evidence is many PHEV owners just like the easy and bigger parking spaces.

scrappy_returns

estevenin said:

Just saw this post as passing through towards my own thread. I drive a Toyota Prius, self charging hybrid, and I have seen a few pessimistic comments that don't reflect the reality of what it can give, at least to me.

Disclaimer : I'm a private hire driver, and will usually drive between 10, up to 300 miles a day. I also do personal journeys (motorway only) and small commutes on my days off. I bough a used car (3 years old), so at that time, the biggest depreciation already happened. Here are the numbers that I routinely get :

- For a regular day 150/200 miles in a row, I will do no less than 70 MPG, but as an average, 75 to 80MPG. This figure will vary, depending on how much traffic, how much motorway, if it rains (the car needs more push) but also very important, how well the tyres are inflated. I also drive with extra care for economy, no brutal acceleration, always following the recommended driving patern, except if the situation requires otherwise.

During the first COVID Lockdown, I would very easily reach 87 / 90 / 92 I even did 94 MPG, I think this is even more than what Toyota Advertises. I was myself very surprised that manufacturer numbers are in fact reachable by the consumer, if the road conditions are there.

- For a full motorway journey, (London to Burmingham for example), I would get an average of 60 to 65MGP.
- For a full day in London Traffic, I would get 65 to 70 MPG.
- For a very small commute journey (5 to 10 miles), I would get 50 to 55MPG. Not sure why, but I guess as the car warms up, the mechanism get smoother and less need for power. Hence why I get a better result for longer mileage.

Long story short, for fuel economy (and this is for any car), you need :

- 4 identical tyres, and if possible, with the same wear, with the best possible rating in fuel
- Always have them inflated. I would do it every 1000 miles more or less (Once a week for me, the 50p /1 pound a week cost is easily offset by the fuel economy)
- A sunny day, rain increases tyre adherence and the car needs more push. There can be a difference of 7 to 10 MPG for the same journey.
- Folowing the recommended driving paterns on the screen, not pushing the acceleration more than needed, and anticipating breaks, to brake for as long as possible.
- Easy on the AC or Heating. I would usually put it full the first 10 miles to put the car at the desired temperature, then put a full eco mode and usually the temperature remains.

Hybrids are more fuel efficient by a certain factor (let's say 50% for the sake of the example), so by respecing this on a hybrid, you add 50% more than the efficiency of a petrol car WITH those criterias as well.

Then, driving an hybrid makes total sense if : 

- Every journey that you do is at least 20 miles or more. Less than that, the car don't have time to warm up and you use more fuel, you will be limited to 50/55MPG, which is very low compared to what you can do. I wouldn't get a hybrid if my job is 3 miles a way and I mostly do a morning / evening commute daily.
- If you ride on a steady, 30/40, even 50mph road, to go to work, with little to no traffic or stops. If you only do motorway, again, you'll be limited to 60. If you do traffic, like central london, to 65. This is still ok, but in those cases I would hesitate more with the Diesel option.
If you do a bit of both, steady roads + a bit of traffic or motorway, Hybrid still would do.

Some have said that :
- The money saved is lost on interests or depreciation. It depends how many miles you do. If you do little, then yes, like with any car in england really. I would not recommend buying a new car at all. There is absolutely no perks whatsoever, the results are the same with a 3 year old car that has been fully serviced, so far in 2 years, absolutely flawless, never had any breakdown or even to change any piece (not even a brake). I would buy a 3/4 year old car, with 40 to 60k mileage. For a prius, this is 10 to 12k. For another model, this can be less. So we are not that far from a normal petrol in that situation. For my personal case, even the battery hasn't lost performance, I'm sure on the paper that it did. ( I might have done 83MPG instead of 80 if the car was brand new)
- Plugin is better : Not true. Plugin Hybrids are EXACTLY the same as hybrids, if you do not charge them (at least for the prius, can't speak for the others as I only tried the plugin prius as well, but it is my understanding that it is similar). You can choose to charge them, in that case, having a bigger electric battery, the range will be higher. But if you don't or can't charge them (as I understand it is your case), then it will results to be exactly the same MPG. You will never run on "petrol only" if you forget to charge, it will act as a self-charging hybrid. The battery on a self charging very rarely gets fully charged except going downhill, so with the bigger battery on the plugin, this will be the same and only a small portion of the battery capacity will be used. So, with no charge, you get exactly the same results - it's basically the same car -, but you pay more to get it. No point.
- Congestion charge is free. Not true, you pay. Only plugin is free, and this will stop in october.
- Urban stop/start type driving then the hybrid will give significant efficiency benefits. It depends. If urbans is central london, 20MPG, then any braking situation does not give enough grip to properly charge the battery, and more time is spent on accelerating or beeing idle. Best to be in a steady 30/40/50mpg road, drive it for let's say 3mn, then have a clean / slow brake for a roundabout, then start again. Best possible sceneario. 
- Motorway or dual-carriage way they provide no benefit at all. Yes and no. 70 MPH pushes the engine too far, in such a way that the car uses mainly petrol all the way. That beeing said, if you find yourself in a 50mph roadworks zone, or if the road goes slighly down, then the speed of the car will then allow you to release the accelerator and the car will run on full electric. At that speed, miles are going quickly, and 2/3 miles in full electric is a lot. It is not true that the car is limited to 3 miles on EV, as if you barely press the accelerator, the battery is used less, mostly the already existing car traction is used. If the road goes slighly down, you might even be able not to accelerate, and you will do a 70mph whilst slowly charging. There are always times where you need to lift the break up : the battery charges. Or you need to break to avoid a car : It charges. You will then use that when the road goes slightly down or in a roadwork portion, and this is when the economy happens.

It's my understanding that the prius is one of the most if not the most fuel efficient self-charging hybrid, hence why I chose it for the job, but I can't really speak for a car where the advertised MPG is lower as I never tried it. The advertised MPG will be, in reality, 15 to 20 MPG less if you drive it well. But, with perfect road conditions and an enough long journey, you can really get quite close to it. This would give you a good idea for your own situation.

That is my own experience, and I think it is not an average one, as most drivers I know are always at least 10 MPG below what I do. Mostly because of poor tyre quality / combination or poor driving patterns. But a hybrid with poor driving patterns, is also pointless as you minimize its potentiel to basically almost beeing a petrol car.

It's personaly my best car investment, and wouldn't get anything else than this. Mostly because it adapts perfectly to my driving patterns. I don't have a driveway, so the time lost in charging a plugin or EV, would offset the benefits of the fuel efficiency, as time on the road is money for me. And the cost of a used petrol car vs a used hybrid, is not that different. But again, if you recognized your patterns here then it could be an option, if you don't, you might miss out on the potential and the extra money spent on purshase, might not worth it.

Hope that helps

Buy yourself a true inflate and save enough money to buy it outright several times over.
In my experience (70plate chr) hybrids on long motorway journeys achieve MPG figures comparable to diesels. Around town it was miles better, stop start traffic was great for it, albeit hellish to drive in. The best road for it was one on my cummote home which has traffic calming measures meaning average speed is circa 10-12mph meaning you could drive the entire road length in EV mode. Over the hundreds and hundreds of miles miles I drove I never saw the battery full. I couldn't work out what the charging conditions were. Some times it would charge at tickover, others not. Sometimes  it would charge on the over run, others not. Sometimes it would charge with the engine under load, others not. I also couldn't predict when the electric motor would help and when it wouldn't.
For me the best fit appears to be diesel still.

estevenin

AdrianC said:

Hybrids are more fuel efficient by a certain factor (let's say 50% for the sake of the example), so by respecing this on a hybrid, you add 50% more than the efficiency of a petrol car WITH those criterias as well.

Where on earth have you got this figure from?

A non-plugin only gets energy from one place, the petrol pump.

Some of the kinetic energy wasted to heat by brakes in a non-hybrid, or frictional losses in the engine on the over-run, is converted to electricity, but not much - especially if you drive in a way that very rarely uses the brakes. 

"For the sake of the example".

Those are not figures, rather an easy way to explain a mathematical formula. If a petrol gives you an output of x, then the fuel economy driving increases it to x+y. If a hybrid gives you an output of x*1.5, then the fuel economy is not : x*1.5 + y, rather, it will be x*1.5 + y*1.5.

So, if we compare :

Petrol with fuel economy (minus) Petrol with heavy driving  = y

Hybrid with fuel economy (minus) Hybrid with heavy driving  = y*1.5

The fuel economy factor is applied both time.

This is why I gave so much detail on the fuel economy, to help the poster recognize if that goes within its own driving patterns (Or if he would be willing to consider it). As without so, you loose that extra factor and driving an hybrid becomes a questionable investment. 

The factor is purely artificial.

AdrianC said:

- Plugin is better : Not true. Plugin Hybrids are EXACTLY the same as hybrids, if you do not charge them

Not true. Plugins have larger motors, and considerably larger and heavier batteries.

Not better, in terms of fuel economy, as requested by the poster. Not arguing the hardware.

If you never usd the plugin function, it will charge it's battery the same way as a self charging battery will. The small battery on the self-charging model, very rarely gets full. (Let's say, 90 out of 100, arbitrary numbers for the sake of the example). Then, the big battery, if working in a self-charging mode, would get the same output, meaning 90, but out of 500 this time (bigger capacity), so those 410 left of capacity are left unused. In both cases, the output is 90, because braking can only give you so much charging. So without using the plugin function, it is not worth the extra cash to get the Plugin version.

AdrianC said:

You will never run on "petrol only" if you forget to charge, it will act as a self-charging hybrid.

Exactly. Petrol only. You're not getting that energy from anywhere else, are you?

The regenerative braking will provide that energy. So you will not find yourself in a situation, where you have to make a full journey in "Petrol only" mode, as, like a self-charging hybrid and explained above, it will work the same way. You will just not use its full capacity.

Both CAN run on petrol only when the battery has used all the electricity and you haven't had any deceleration, it usually happens when in traffic (or 20mpg roads, where braking will have little effect because too short), so driving in traffic only, once again would reduce the perks of driving a hybrid, whichever model.

scrappy_returns said:

In my experience (70plate chr) hybrids on long motorway journeys achieve MPG figures comparable to diesels. 't.
For me the best fit appears to be diesel still.

I would tend to agree if the journeys are motorway only, not for any other kind of journey. Also we have to consider the cost of Diesel, which is likely to continue to become a turn-off for people.

benbay001

I own a 2010 Auris Hybrid.

My previous car was an iQ 1.3l, which was just over half as heavy as the Auris, yet got circa 43mpg.

The Auris gets 52mpg no matter how or where i drive it.

I almost definitely drive it harder than 90% of other Toyota Hybrid drivers and am well aware that i could get better MPG if i tried, but for me, its nice having a smooth, reliable automatic that happens to get great MPG.

As has been mentioned before, the efficiency comes from recooping what would otherwise be wasted heat energy when braking.

Using the "Dr Prius" app on my phone, connected by bluetooth, when i maximise the regenerative braking it registers 90A charge current, which at 200V is 18KW maximum recooped energy losses. Hardly to be sniffed at.

Other efficiencies also come from the engine switching off as soon as you lift off the accelerator (pumping losses arent insignificant), and not needing to run the engine when doing stuff like going between traffic lights. Also, unlike simple stop start, the AC compressor is powered by a separate electric motor so the engine doesn't need to turn on when stationary.