Charge mode is still the king in my Phev.

[Trex]

Hi folks,

The wife let me borrow the Phev last night so I could run a couple of tests. I bought the bloody thing and I have to ask whether I can borrow it off her or the kids. :lol: They love it. And they thought I was mad when I told them I was buying it. :roll:

But anyway back to the tests. I picked the flattest area around here ( and it is very flat across the river valley here) on the dual lane freeway that runs past our small city. It is made up of approx. 12kms of 100kph zone and 10km of 110kph zone.I picked that stretch for its easy turn around at each end as well as its flatness.

Now the tests I wanted to run were:

1. How long does it take to charge the drive battery from empty to 1/2 on the charge meter on a very flat area that is not normally typical of my drives.
2. Compare my fuel consumption to forum member "maby" in the discussion at the bottom of the page. See:

http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1890&start=10

So the test consisted of driving in one direction then the other followed by a quick turnaround at each end. Traffic was light, mainly semi trailers at that time of the night which I overtook as here in NSW they are speed limited to 100kph. I sat on 105kph . I used cruise control the whole time except at each end when I was turning around.

Test 1. It took 24 min to charge the battery to 1/2 on the Phev's gauge from empty in this test. I pressed the charge button and the fuel computer reset button when the petrol motor started after I emptied the small bit of charge my wife left in the Phev. Fuel computer showed approx. 10.4L/100k the whole time in this test.

This I normally see at approx. 30 min. (to get 1/2 charge) but as I said it was very flat so watching the hybrid display the graphic lines going into the battery (charging) never stopped. On a normal drive climbing hills you would see the charging stop or the direction of the lines on the hybrid display reverse and come out of the battery.

Test 2. With a empty battery and pressing reset on the fuel computer I saw 10.4L/100k on the display which after doing its hybrid thing of charge, ev, charge, ev etc settled down to a range of 7.2 to 7.4L/100k depending on the ev, charge cycle you read it at. This is plain old normal mode.

So in comparison to maby's test he got approx. 44mpg (6.4l/100k) and I got approx. 7.3l/100k but he was travelling between 50 and 60mph (approx. 80-100kph) and I was travelling at 105kph the whole time except when turning around.

Now you probably want to know why I said "Charge mode is still the king in my Phev" for the topic title.

Now notice I said "with a empty battery" in test 2. After test 1. I had 1/2 a charge in the drive battery and showing 10.4L/100k on the fuel computer of the Phev. Well I pressed the charge button again and emptied the drive battery and drove in EV mode at the same speed of 105kph and I noted the fuel consumption figure when the petrol motor started again. And guess what it was.

6.3L/100k.

If we want to make a comparison of my figures.

7.3L/100k divided by 10.4L/100k x 100 gives the percentage the petrol motor ran = 70.2% subtract from 100 gives 29.8% EV from test 2. which is plain old normal mode.
6.3L/100K divided by 10.4L/100k x 100 gives the percentage the petrol motor ran = 60.6% subtract from 100 gives 39.4% EV from the charge I built up in Test1. using the charge button.

So I will keep smashing that charge button like I do as well as making sure I avoid series mode. It helps reduce the fuel consumption on my Phev as I have stated many times before.

It is up to you if you want to test this strategy on your own Phev. It is your fuel, your Phev and your money.

Regards Trex

 

[anko]

Hi Trex,

Nice testing going on there. Upfront, I would expect some improvement from changing many small alterations into one big alteration (as long as you keep your SOC < 50%), as the generator does not need to start the engine, every minute and a half or so. But not that much!

I believe, two more tests are in order:

- Do your 2nd test again, but now in Save mode with >> 50% SOC. Compare the results to the 7.2 - 7.4 you got now. Best to do 5, 70 and 80% :mrgreen:
- Start off with 80% SOC. Reset the computer. Let it drop to 50% and then use Charge to get it back up to 80%. Compare there consolidate results with the 6.3 you got now.

When is your next time slot for the car? :lol: ;-)

Cheers, Anko

 

[maby]

...

Now you probably want to know why I said "Charge mode is still the king in my Phev" for the topic title.

Now notice I said "with a empty battery" in test 2. After test 1. I had 1/2 a charge in the drive battery and showing 10.4L/100k on the fuel computer of the Phev. Well I pressed the charge button again and emptied the drive battery and drove in EV mode at the same speeds of 105kph and I noted the fuel consumption figure when the petrol motor started again. And guess what it was.

6.3L/100k.

If we want to make a comparison of my figures.

7.3L/100k divided by 10.4L/100k x 100 gives the percentage the petrol motor ran = 70.2% subtract from 100 gives 29.8% EV from test 2. which is plain old normal mode.
6.3L/100K divided by 10.4L/100k x 100 gives the percentage the petrol motor ran = 60.6% subtract from 100 gives 39.4% EV from the charge I built up in Test1. using the charge button.

So I will keep smashing that charge button like I do as well as making sure I avoid series mode. It helps reduce the fuel consumption on my Phev as I have stated many times before.

It is up to you if you want to test this strategy on you own Phev. It is your fuel, your Phev and your money.

Regards Trex

All interesting figures and I can well believe them - what you are doing is effectively to manually implement the "Long Distance" mode that I was asking for some time ago. By actively managing the Charge button, you are effectively getting the wide hysteresis loop that the Toyota hybrid drive train implements as standard. Personally, I can't be bothered with such active power flow control, but I would love the car to have a "Long Range" button which sets the power management to something similar to what you are implementing.

That said, I would also like confirmation from a LiIon battery specialist what the likely impact on battery life expectancy will be. I have heard it said (from gwatpe, I think) that LiIon batteries effectively have a maximum number of charge/discharge cycles rather than a simple temporal life expectancy - if that is the case, then it is possible that this active management using repeated Charge cycles is going to shorten the lifetime of an expensive component. What is the best strategy for a long battery life? Keep it fully charged? Keep it flat? Cycle it?

 

[DazzyB]

I thought I'd contribute to this thread as I am a new owner and have started to try out different strategies on my daily commute. Notwithstanding any major traffic hold-ups, the drive is pretty consistent in terms of speed, timings, load conditions, etc.

This morning I set off with full charge and a predicted EV range of 32 miles (51.5km). My route consists of:
9.5 miles suburban
28 miles motorway
5.5 miles suburban
13 miles motorway
2 miles suburban
Total 58 miles (93km)

The long motorway section is over the Pennine range so climb followed by decent. On the motorway sections I used cruise control to maintain a steady 60mph apart from a few overtaking bursts.
I didn't use the charge or save buttons at all but did make use of some braking regen on steeper downhill sections.

It was a cold, wet, dark morning so heater, wipers and headlights were on almost continuously.

So, the PHEV ran in EV mode for 22 miles (35km) before running out of charge and starting the ICE. This is low compared to the starting range (32miles) but over half of this was on the motorway at 60mph with a significant section of that being quite a steep climb.

By the time I came off the 2nd section of motorway, EV range was showing 1 mile and I didn't notice the ICE come on for the last 2 mile suburban section.
Journey time was 86 minutes, average speed 40.5mph (65kph)

The displayed MPG at the end of the journey was 61mpg (4.63l/100km).

So what should I do next and what should I try to record? I plan to do the same journey next week firstly using the charge mode on the motorway sections so that I can do more suburban in EV mode and then on another trip I will try using the save mode from the beginning of the motorway and using EV on the suburban sections. I'm open to suggestions though.

It's worth noting that I'm very happy with the displayed 61mpg but I appreciate I will need to accurately measure how much petrol (and grid power) I'm actually using to be able to calculate the real costs of each strategy.

Thoughts...?

 

[anko]

My approach would be:

On the first motorway stretch, engage Save mode when you have about 5 or 6 miles of EV range left. When exiting the motorway at the end of the first stretch, disengage Save mode.
Two miles before the en of the second motorway stretch, engage Charge mode. Disengage when exiting the motorway for the second time.

 

[gwatpe]

Test 1. It took 24 min to charge the battery to 1/2 on the Phev's gauge from empty in this test. I pressed the charge button and the fuel computer reset button when the petrol motor started after I emptied the small bit of charge my wife left in the Phev. Fuel computer showed approx. 10.4L/100k the whole time in this test.

I have been running some tests with the Torque PRO app and logging the data on my 800km first leg of another trip. I have tested the CHARGE mode from empty, and my PHEV returned about 12L/100km, compared to your 10.4L/100km. I noticed the same constant fuel consumption at a speed of 100kph GPS. This is a fair bit of difference in the numbers, and I am sure the battery took longer to get to half full than half an hour. Will be running this test again to check the times.

I will reset the PHEV computer like you are doing as a second check, to see if the OBD reports the same data.

 

[Trex]

Hi Trex,

Nice testing going on there. Upfront, I would expect some improvement from changing many small alterations into one big alteration (as long as you keep your SOC < 50%), as the generator does not need to start the engine, every minute and a half or so. But not that much!

I believe, two more tests are in order:

- Do your 2nd test again, but now in Save mode with >> 50% SOC. Compare the results to the 7.2 - 7.4 you got now. Best to do 5, 70 and 80% :mrgreen:
- Start off with 80% SOC. Reset the computer. Let it drop to 50% and then use Charge to get it back up to 80%. Compare there consolidate results with the 6.3 you got now.

When is your next time slot for the car? :lol: ;-)

Cheers, Anko

Hi Anko,

Just did maby's 1st test this morning ie he tested full charge and pressed save and then emptied the battery and then tested normal mode.

I have already tested the empty battery (normal mode) in my first post so I checked the full battery and pressed save test as it was fully charged this morning.

I slipped out while my wife was still asleep so she did not know I took the phev. :lol:

Anyway test done in the same place at same speed etc.

Result:

There was hardly any difference in the fuel consumption but the Phev behaved completely different. I have not pressed the save button ever before when the SOC is that high so it was new to me.

Pressing reset on the Phev's fuel computer when up to speed of 105kph the first time gave a 8.5L/100k then settled down to 7.5/100k and I expected to see that hybrid thing of charge, ev, charge, ev ect. and it was showing charge on the hybrid display but the petrol motor never stopped except when slowing down (and getting regen) to turn around at each end of the runs.

Anyway I will stick with my charge button strategy as I like the Petrol motor shutting down and going into Ev mode (on the highway) and it gives me better fuel consumption the way I do it.

Summing up. The fuel consumption was practically the same like maby saw in his tests.

Regards Trex.

 

[Trex]

All interesting figures and I can well believe them - what you are doing is effectively to manually implement the "Long Distance" mode that I was asking for some time ago. By actively managing the Charge button, you are effectively getting the wide hysteresis loop that the Toyota hybrid drive train implements as standard. Personally, I can't be bothered with such active power flow control, but I would love the car to have a "Long Range" button which sets the power management to something similar to what you are implementing.

That said, I would also like confirmation from a LiIon battery specialist what the likely impact on battery life expectancy will be. I have heard it said (from gwatpe, I think) that LiIon batteries effectively have a maximum number of charge/discharge cycles rather than a simple temporal life expectancy - if that is the case, then it is possible that this active management using repeated Charge cycles is going to shorten the lifetime of an expensive component. What is the best strategy for a long battery life? Keep it fully charged? Keep it flat? Cycle it?

Hi maby,

You are making a good point about the drive battery life expectancy which is why I do this test every six months. See:

http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1877

So far so good but it is early days.

As for the "Long Range" button I often think the same thing but it would have to be turned off before we got home so no charge was left in our Phevs and it is ready for the grid charge I think.

Regards Trex.

 

[anko]

I slipped out while my wife was still asleep so she did not know I took the phev. :lol:

Indeed :lol:

There was hardly any difference in the fuel consumption but the Phev behaved completely different. I have not pressed the save button ever before when the SOC is that high so it was new to me.

Pressing reset on the Phev's fuel computer when up to speed of 105kph the first time gave a 8.5L/100k then settled down to 7.5/100k and I expected to see that hybrid thing of charge, ev, charge, ev ect. and it was showing charge on the hybrid display but the petrol motor never stopped except when slowing down (and getting regen) to turn around at each end of the runs.

Have you thought about the amount of revs your engine did in your first test compared to the second? With 30% EV driving you saw, the engine must have made 30% less revolutions, as the speed was the same. To me this means 30% less internal resistance to conquer. How can this not lead to a reduced consumption? Even when it requires the use of the generator as a starter engine every now and then? And, if there was no efficiency advantage from letting the car go do its normal cycle, why would Mitsubishi go through the effort of implementing one? Why not let the car work the same at 30% SOC as it does at 80 or more? Just as a normal petrol car. If not to reduce wear and tear on the engine?

Summing up. The fuel consumption was practically the same like maby saw in his tests.

In your own test you saw 7.2 - 7.4 depending on where you were in the cycle. Giving the fact that you pressed the reset with an empty battery, it would be fair to note 7.2 as the outcome of your test. Compared to the 7.5 in the next test, the difference is 0.3 liter per 100 km. Or close to a full barrel in the 60.000 km I have done so far. Whether that is significant is something everybody should decide for himself ;-)

 

[anko]

As for the "Long Range" button I often think the same thing but it would have to be turned off before we got home so no charge was left in our Phevs and it is ready for the grid charge I think. .

Every normal petrol or diesel car has this "Long Range" option. It is on by default and cannot be switched off :mrgreen: . To me it seems like what you guys are looking for or are trying to build is a petrol car that changes into an EV for the last 30 miles, rather than a plug-in hybrid car. And think truly believe that a hybrid car is much, much more clever than a combination of a normal car and an EV car.

For example, let's not forget, a normal car does not have regen breaking. A PHEV with high SOC has strongly reduced to even non existing regen braking.

Trex, I think what you are looking for is not so much a "Long Range" button, but a longer hysteresis cycle. The problem is indeed that it is very difficult to reach the next charge point with a not too high SOC. A shorter cycle, like the one we have now, helps with this. Or you have to interveen yourself.

 

[maby]

...

Hi maby,

You are making a good point about the drive battery life expectancy which is why I do this test every six months. See:

http://www.myoutlanderphev.com/forum/viewtopic.php?f=10&t=1877

So far so good but it is early days.

As for the "Long Range" button I often think the same thing but it would have to be turned off before we got home so no charge was left in our Phevs and it is ready for the grid charge I think.

....

I guess that depends to some extent on your pattern of usage. For me, it really is two separate cars - one that is doing maybe ten miles per day - to all intents pure EV - and one that is used to cover some hundreds of miles over a period of days with no opportunity to charge - almost pure petrol. If I forget to turn off the "Long Range" mode and arrive home with 50% SOC, it's not going to make that much of a difference to my overall running costs or environmental impact.

 

[maby]

...

Trex, I think what you are looking for is not so much a "Long Range" button, but a longer hysteresis cycle. The problem is indeed that it is very difficult to reach the next charge point with a not too high SOC. A shorter cycle, like the one we have now, helps with this. Or you have to interveen yourself.

But you would not be forced to use the hypothetical "Long Range" button and it would typically apply to circumstances where it really didn't matter what you SOC is when you arrive at your destination. I'm away from any opportunity to recharge for four days this weekend - the car would be in its "Long Range" mode for at least the first three of them. In practice if I made a mistake and drove home in "Long Range" mode, arriving home with 50% SOC, the impact on my overall fuel consumption would still be pretty low. Monday to Thursday next week, it would be in "Normal" all the time and running close to 100% EV before being put back into "Long Range" mode on Thursday afternoon.

 

[anko]

In practice if I made a mistake and drove home in "Long Range" mode, arriving home with 50% SOC, the impact on my overall fuel consumption would still be pretty low. Monday to Thursday next week, it would be in "Normal" all the time and running close to 100% EV before being put back into "Long Range" mode on Thursday afternoon.

To me that doesn't make sense. Forgetting to use up the remaining EV range at the end of a four day trip is not less 'damaging' than accidentally driving on petrol instead of electricity on your next EV day. The impact of miles driven on petrol instead of on electricity does not depend on the length of the trip to which these miles belong.

 

[maby]

In practice if I made a mistake and drove home in "Long Range" mode, arriving home with 50% SOC, the impact on my overall fuel consumption would still be pretty low. Monday to Thursday next week, it would be in "Normal" all the time and running close to 100% EV before being put back into "Long Range" mode on Thursday afternoon.

To me that doesn't make sense. Forgetting to use up the remaining EV range at the end of a four day trip is not less 'damaging' than accidentally driving on petrol instead of electricity on your next EV day. The impact of miles driven on petrol instead of on electricity does not depend on the length of the trip to which these miles belong.

In percentage terms, it does. If I've driven several hundreds of miles over several days, I will inevitably have burned a lot of petrol - if I forget to switch to Normal mode on my return journey, I may arrive home with a few miles of EV range left - the impact will be extremely small compared with the rest of the journey - and I will pull less power off the grid when I next recharge, further reducing the overall impact. Don't turn it into a religion - you are making your contribution towards the environment every time you drive 20 miles on pure EV - when you drive 200 or 300 miles on petrol, arriving home with 10 miles of EV range left is not a capital crime!

 

[anko]

Maybe in terms of percentage of your last trip. But not in terms of percentage of your total miles driven. So who cares, that it was part of along trip? The environment doesn't. But even then, it is not %-ge that pollute. It is the burning of fossil fuels. Believe me, I have no desire to turn it into a religion at all, but as this is the Technical Discussions section, we should not bend the facts

 

[maby]

Don't want to turn it into a religion at all. But we should not bend the facts

I really don't think that I am - most people think in percentage terms, not absolutes. If I've burned 40 litres of fuel over the weekend, I'm afraid an extra half a litre more or less really is not an issue. If I can get through the rest of the week burning none at all as opposed to the 4 or 5 that the Landcruiser would burn, then I feel that I have done plenty to save the world!

 

[maby]

...

, but as this is the Technical Discussions section, we should not bend the facts

I don't think I did bend any facts - I said "the impact on my overall fuel consumption would still be pretty low." - and that is true - it might result in me doing 41mpg overall instead of 42mpg - that is a pretty small impact in my book!

 

[anko]

My "bending the facts" was clearly about your suggestion that the impact of burning fuel on a longer trip was less than that of burning fuel on a shorter trip. Please, don't start pulling my statements out of their context

 

[DazzyB]

My approach would be:

On the first motorway stretch, engage Save mode when you have about 5 or 6 miles of EV range left. When exiting the motorway at the end of the first stretch, disengage Save mode.
Two miles before the en of the second motorway stretch, engage Charge mode. Disengage when exiting the motorway for the second time.

I set off this morning with this approach in mind. Exactly the same journey as before.

The predicted EV range with full charge was 24 miles. As before, heating, lights and wipers were used for the whole journey.

After 13 miles, with a range of 7 miles left on the battery I pressed the Save button.
By the time I came off the motorway for the middle suburban section the range had crept back up to 8 and I switched off Save.
I got through the suburban section and a short way onto the next motorway stretch and still had 2 miles of battery left so I pressed Save again.
I disengaged Save again when I left the motorway and ran the last section on EV, reaching my destination with no battery range left.

Overall mpg for this trip: 73.7mpg
To recap from my earlier post, same journey, very similar conditions, same cruise control speed on motorway but no use of the Save button: 61mpg

I would say that's a significant improvement.

 

[anko]

Wow. If that result is reproducible, it would be great! Thanks for the feedback.