Can we clear up Serial vs Parallel drive?

[kpetrov]

Er what !!!!!!!!!!!!

I was asking if you use up your battery before using petrol at high speed, even if you will need it later? Where does "low cost petrol" come into it? I was referring to the difference between relatively cheap energy from the grid against generating it yourself from petrol - doh! :roll:

"Low cost petrol" came from your statement that "I'm using expensive petrol to recharge the battery while it seems you believe you are using less expensive petrol during SAVE.
To answer your question, of course I'm using the battery on the motorway like you are using yours but do not realize it.

 

[greendwarf]

There's none so blind as those who will not see! This is ACTUALLY what I wrote :-

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn"

Nowhere have I mentioned low cost PETROL but as you seem determined not to engage with the question as to whether it is better to use up cheap grid electricity rather than expensive petrol at high speed, I wish you a profligate New Year. :roll:

 

[Fjpod]

There's none so blind as those who will not see! This is ACTUALLY what I wrote :-

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn"

Nowhere have I mentioned low cost PETROL but as you seem determined not to engage with the question as to whether it is better to use up cheap grid electricity rather than expensive petrol at high speed, I wish you a profligate New Year. :roll:

Unless you live where I do, and your electricity is effectively 25 cents per kilowatt hour.

 

[kpetrov]

There's none so blind as those who will not see! This is ACTUALLY what I wrote :-

So you leave home with a low cost full charge from the grid, get on to a motorway, rapidly deplete the battery for few miles and then use expensive petrol to recharge the battery to use at your destination, rather than press Save? You must have, literally, "money to burn"

Nowhere have I mentioned low cost PETROL but as you seem determined not to engage with the question as to whether it is better to use up cheap grid electricity rather than expensive petrol at high speed, I wish you a profligate New Year. :roll:

You have said already in your example that I'm leaving with full low cost charge. Why you assume I'm avoiding the question as to whether it is better to use up cheap grid electricity rather than expensive petrol. Of course is better to use cheap grid electricity.
Since the battery capacity is an fixed low number and cheap grid electricity is deficient on the motorway we are coming to the actual question of the dispute - topic, a.k.a. Serial or Parallel drive is more efficient to to continue on your journey once your battery is low, keeping in mind you should arrive empty at your charging station.
Yes, you didn't mention low cost PETROL, you imply it by saying using SAVE on the motorway is more efficient than using CHARGE. (in other words you are using less petrol in SAVE than me in CHARGE)
Scientifically is a proven fact that Parallel use of the engine is more efficient than the Serial use of it on speeds that allow direct connection and I gave you links to that.
Other users mentioned that the difference is relatively small, especially if not used correctly and I agree so use SAVE and Happy New Year!

 

[greendwarf]

Ah, I see now - yes, 25c per unit IS relatively expensive - I pay about half that in UK, and. I don't know the difference in petrol prices either. However, I assume electricity is cheaper, otherwise nobody would have an EV.

However, you again misquote me. I never said anything about SAVE being cheaper that CHARGE when burning fuel - you have mistakenly inferred that. At the risk of repeating myself, I was dealing with your assertion that you never use SAVE, which I took to mean you could see no circumstances where it would be useful.

So let's try a different way of explaining this:-

As you state, at high speed the energy stored in petrol is more efficiently (I.e. cheaper) converted by the ICE into motion than at low speed. However, the reverse is true when converting the energy in the battery into motion because wind resistance means you need more energy at high speed to travel the same distance - so more expensive.

The questions, therefore, are not between burning petrol in SAVE against CHARGE but - is it (a) cheaper to charge the battery using the ICE or from the grid? and, if not, (b) can the extra cost be offset by using the surplus battery energy for high speed driving rather than petrol, at the start of a journey? The answer will depend on the prices of electricity and petrol, your speeds, length of journey segments and whether you need (or want) to drive in EV near your destination. I find it difficult to believe that there would NEVER be such a journey that use of SAVE to preserve battery energy would be beneficial to you.

Given the unpredictable nature of motorway driving in Europe (roadworks, accidents, weather etc.) I would rather have the certainty of an EV power reserve in the battery rather than hope I can generate some later by using CHARGE - which at high speed replenishes the battery very slowly.

 

[kpetrov]

Ah, I see now - yes, 25c per unit IS relatively expensive - I pay about half that in UK, and. I don't know the difference in petrol prices either. However, I assume electricity is cheaper, otherwise nobody would have an EV.

However, you again misquote me. I never said anything about SAVE being cheaper that CHARGE when burning fuel - you have mistakenly inferred that. At the risk of repeating myself, I was dealing with your assertion that you never use SAVE, which I took to mean you could see no circumstances where it would be useful.

So let's try a different way of explaining this:-

As you state, at high speed the energy stored in petrol is more efficiently (I.e. cheaper) converted by the ICE into motion than at low speed. However, the reverse is true when converting the energy in the battery into motion because wind resistance means you need more energy at high speed to travel the same distance - so more expensive.

The questions, therefore, are not between burning petrol in SAVE against CHARGE but - is it (a) cheaper to charge the battery using the ICE or from the grid? and, if not, (b) can the extra cost be offset by using the surplus battery energy for high speed driving rather than petrol, at the start of a journey? The answer will depend on the prices of electricity and petrol, your speeds, length of journey segments and whether you need (or want) to drive in EV near your destination. I find it difficult to believe that there would NEVER be such a journey that use of SAVE to preserve battery energy would be beneficial to you.

Given the unpredictable nature of motorway driving in Europe (roadworks, accidents, weather etc.) I would rather have the certainty of an EV power reserve in the battery rather than hope I can generate some later by using CHARGE - which at high speed replenishes the battery very slowly.

Ohh my... I am not comparing fuel prices in different countries. Of course all comparisons I am drawing should be done with equal variables.
On most places on the planet to fill from the grid will be cheaper of course. No doubt or argument whatsoever.

Regarding the air resistance with el. propulsion: lower the speed better the efficiency no doubt about it but we can't compare Serial vs Parallel based on that. Both modes should be compared at same speed otherwise we are comparing apples vs. oranges.
Under 65km/h the parallel mode is unavailable so SAVE is just an intermittent CHARGE.

Taking on your real-life example given the unpredictable nature of motorways and since you are specifically referring to my use of SAVE.
Yep if not checking the traffic I could use SAVE, but usually will drive the battery down to 40% and CHARGE back to 60% in parallel mode, rinse and repeat. Once the traffic is slower than 65km/h will switch to EV.
If the traffic is light and predictable will discharge the battery down to almost 0 and CHARGE it back to an amount needed for the city driving ahead or to reach the next charging point.
I may actually use SAVE in very long journeys if I know that SAVE will put the battery under less stress.

 

[greendwarf]

So all you are doing is manually emulating SAVE mode by switching in and out of CHARGE - now I understand :idea:

 

[kpetrov]

You can say that, but with CHARGE you force the vehicle into more efficient parallel mode sooner and constantly, while in SAVE it constantly seesaw without much control. Starting and stopping the engine constantly I find unnecessary and more damaging as well.
With CHARGE I have and better control over the exact amount of charge that battery need to be for the rest of the trip. It goes only up and the mode can be disabled once the battery reach an wanted level.

 

[user 5728]

You can say that, but with CHARGE you force the vehicle into more efficient parallel mode sooner and constantly, while in SAVE it constantly seesaw without much control. Starting and stopping the engine constantly I find unnecessary and more damaging as well.
With CHARGE I have and better control over the exact amount of charge that battery need to be for the rest of the trip. It goes only up and the mode can be disabled once the battery reach an wanted level.

This is exactly what I prefer to do in many cases.

 

[Lukehawkins]

You can say that, but with CHARGE you force the vehicle into more efficient parallel mode sooner and constantly, while in SAVE it constantly seesaw without much control. Starting and stopping the engine constantly I find unnecessary and more damaging as well.
With CHARGE I have and better control over the exact amount of charge that battery need to be for the rest of the trip. It goes only up and the mode can be disabled once the battery reach an wanted level.

Kpetrov, can you give us an example of how you would do this. For example, if you had a trip to do that was 10km of local low speed driving, followed by 70kms of highway driving (with a few hills in there), followed by 15kms of local low speed driving and traffic. How would you use charge mode in that scenario? Do you cycle it on and off through the highway portion? Or just leave it on once battery is depleted, say, to 50% or something like that?

 

[littlescrote]

Just to follow up on this thread as another thread has discovered difference sin the way kpetrov's car behaves in Save and Charge modes compared to others.

His does not go into parallel mode in Save, but does in Charge, whereas others, me included, do go into parallel mode in Save just as readily as Charge. So efficiency of adding charge to the battery is the same in both cases for the majority of us.

There could be considered one advantage of depleting the battery to a low SoC and then using Charge to build up again rather than going into Save mode at a higher charge level and that would be reduced number of engine start cycles. But the PHEV manages the engine temperature anyway for that to not be considered an issue, ie it won't go into parallel mode until the engine has warmed up.

Kpetrov, can you give us an example of how you would do this. For example, if you had a trip to do that was 10km of local low speed driving, followed by 70kms of highway driving (with a few hills in there), followed by 15kms of local low speed driving and traffic. How would you use charge mode in that scenario? Do you cycle it on and off through the highway portion? Or just leave it on once battery is depleted, say, to 50% or something like that?

Without presuming to answer for them, I'm assuming that it would be done by running down the battery during the first 10km and part of the highway until maybe 10% left. Then go into Charge mode until 80% (not more as the battery's ability to absorb high charge rates is reduced) and then repeat as necessary leaving only enough charge to complete the final 15km section.

The rest of us, with vehicles that go into parallel mode in Save, would just hit Save at the end of the first local stint (or shortly into the highway bit) to have enough for the final 15km stint. That's exactly what the Save mode was designed for.

 

[kpetrov]

You can say that, but with CHARGE you force the vehicle into more efficient parallel mode sooner and constantly, while in SAVE it constantly seesaw without much control. Starting and stopping the engine constantly I find unnecessary and more damaging as well.
With CHARGE I have and better control over the exact amount of charge that battery need to be for the rest of the trip. It goes only up and the mode can be disabled once the battery reach an wanted level.

Kpetrov, can you give us an example of how you would do this. For example, if you had a trip to do that was 10km of local low speed driving, followed by 70kms of highway driving (with a few hills in there), followed by 15kms of local low speed driving and traffic. How would you use charge mode in that scenario? Do you cycle it on and off through the highway portion? Or just leave it on once battery is depleted, say, to 50% or something like that?

littlescrote said it right regarding how my vehicle behave and what aprox. I would do on trip like that.
Will run in EV all the way to 20%-30% battery just to have some buffer for unexpected traffic or even 50% if big mountain ahead and will hit Charge. Will turn it off once I have enough battery charge to arrive empty.
Up mountain always Charge, down coasting as much as possible or EV-Normal

Usually I am turning off Charge around 60% and cycle 20% to 60% on long trips, will Charge it to 80% if entering a big city only.
My goal is to use the engine only in parallel mode.

 

[DaveL59]

OK so I gave the charge button a tri last long-ish round trip of approx 180 miles.

Typically I'd put the car in save mode once on the motorway and let it run in normal once back off onto regular town roads 75-80 miles later. I'd get to my sisters with perhaps 5 miles left on the GOM. Once home I'd have used a little over 1/3 tank of petrol.

Same trip, similar traffic and delays tho it is colder now, but using charge instead of save and the car used just over half a tank of petrol :-( I did drop charge mode when stationary in incident related queues and engage it again once moving again so wasn't wasting fuel when not rolling. End of trip showed 7 miles GOM range when I parked at home since I'm not so far off the motorway this end of the trip. Sure, turn charge off earlier on the motorway and run it flat if you can be bothered but it'd not have made so much difference on the extra fuel used I reckon.

It's a 2.4L 2019 4HS with a towbar, A/C (or climate) always on, full charge and tank when setting off so to me, other than it keeping the engine running "more considerately" it seems the less efficient way to use the car.

 

[littlescrote]

If you had anything other than smooth constant speed above about 60mph then Charge is bound to be less efficient than Save as it will continue to run the engine in sub optimal conditions (decelerating, slower speed etc), whereas Save will cut it off.

 

[kpetrov]

OK so I gave the charge button a tri last long-ish round trip of approx 180 miles.

Typically I'd put the car in save mode once on the motorway and let it run in normal once back off onto regular town roads 75-80 miles later. I'd get to my sisters with perhaps 5 miles left on the GOM. Once home I'd have used a little over 1/3 tank of petrol.

Same trip, similar traffic and delays tho it is colder now, but using charge instead of save and the car used just over half a tank of petrol :-( I did drop charge mode when stationary in incident related queues and engage it again once moving again so wasn't wasting fuel when not rolling. End of trip showed 7 miles GOM range when I parked at home since I'm not so far off the motorway this end of the trip. Sure, turn charge off earlier on the motorway and run it flat if you can be bothered but it'd not have made so much difference on the extra fuel used I reckon.

It's a 2.4L 2019 4HS with a towbar, A/C (or climate) always on, full charge and tank when setting off so to me, other than it keeping the engine running "more considerately" it seems the less efficient way to use the car.

Colder now, you didn't use the charge accumulated and once you can't keep constant 45mph you should disengage charge not only when stationary. One should disengage charge going downhill as well. All that makes a difference.

 

[DaveL59]

Thanks for the replies, I guess it all comes down to how much you want to micro-manage your PHEV and personally I don't.

As for turning charge off on down-slopes etc, Save does that automatically and with B4 selected slows smoothly enough when I back off the throttle. Around home I'm atop a 40% slope so tend to use B5 locally if not charged to gain some better speed control.

The few miles remaining when I got home from that trip I didn't really mind since I had some local errands next day. Was able to run in EV mode for those, tho on the uphill return the car did feel sluggish compared to just running it in normal where the engine can fire up for extra boost. Given these are side roads tho, speed wasn't an issue so it did OK.

The bulk of that long trip was at 50-70+ as are most motorway journeys. Sure there was variation with traffic but in save the engine would be picking up most of the time unless slowing or on down-slopes. So I'll be sticking with save in future I think, I'd rather a relaxed drive than be faffing with frequent multi-presses on the save/charge button since I don't have seperate buttons for each mode.

 

[littlescrote]

I agree Dave

 

[kpetrov]

Thanks for the replies, I guess it all comes down to how much you want to micro-manage your PHEV and personally I don't.
...
So I'll be sticking with save in future I think, I'd rather a relaxed drive than be faffing with frequent multi-presses on the save/charge button since I don't have seperate buttons for each mode.

Nobody is arguing about that, Save is more automatic and fool-proof for relaxed drive.
Charge is very useful going from a big city to a big city though.

 

[DaveL59]

Thanks for the replies, I guess it all comes down to how much you want to micro-manage your PHEV and personally I don't.
...
So I'll be sticking with save in future I think, I'd rather a relaxed drive than be faffing with frequent multi-presses on the save/charge button since I don't have seperate buttons for each mode.

No body is arguing about that, Save is more automatic and fool-proof for relaxed drive.
Charge is very useful going from a big city to a big city though.

I guess it depends on how much it bothers you to run on petrol in town. Personally it doesn't and besides tis a lot less fuel than my old v6 Alfa used at its 22mpg. Overall per trip if I'm using 2-3 gallons less petrol on save vs charge, carbon footprint is lower so I think that's enough concession

 

[kpetrov]

Thanks for the replies, I guess it all comes down to how much you want to micro-manage your PHEV and personally I don't.
...
So I'll be sticking with save in future I think, I'd rather a relaxed drive than be faffing with frequent multi-presses on the save/charge button since I don't have seperate buttons for each mode.

No body is arguing about that, Save is more automatic and fool-proof for relaxed drive.
Charge is very useful going from a big city to a big city though.

I guess it depends on how much it bothers you to run on petrol in town. Personally it doesn't and besides tis a lot less fuel than my old v6 Alfa used at its 22mpg. Overall per trip if I'm using 2-3 gallons less petrol on save vs charge, carbon footprint is lower so I think that's enough concession

I would do it for efficiency mostly and less exhaust gasses in the city not carbon specifically.
I don't consider the carbon as pollutant, even the opposite, the only beneficial emission from human activity and promoting the carbon cycle in nature.