I use charge mode for better fuel consumption.

Hi all.
First post but been reading discussions for over a year to learn all I can about this great car and thanks everyone who has contributed.

Having been a owner of a Phev, what we call a Outlander Phev Aspire here in Australia (top of the range model) for nearly a year(early April 2014), I thought I would let people know my thoughts on the charge mode from my findings in my car (cannot speak for everyone's Phev).

Probably 90% of our driving is Ev mode but on those long distance trips outside the Hv battery range I use the charge mode for better fuel consumption, which no one here on this forum has seemed to bring up, so it may only be my car that does this.

From experimenting I have found that even at 115 kph indicated (110 kph gps ) on the freeway with the car in parallel mode I get 8lts/100ks in save mode against 7.5lts/100ks in charge mode. I know this is not a lot of difference but this is at its worst ie charge mode, ev mode, charge mode, ev mode etc, at higher speed . By making sure that I have Hv battery range left for the slower parts of the trip ,through towns etc, I can get this down to about 6.5lts/100ks which I think is excellent for a car this size.

Our previous car, a Toyota Prius, would get approx 5lts/100ks on the same trip but was not near as quiet and comfortable and could not do the all of our local driving in ev mode at a substantial cost saving if charged at off peak or using solar panels.

About the only downside I see in using the charge mode on my car would be it could be considered a rapid charge and if done too often may cause the Hv battery to age quicker than normal but in our case we do not travel longer distances frequently. As an aside, my car is definitely sluggish with the Hv battery empty around the city or town (in serial mode ) so I will save at least a some battery charge for driving when away from home.

Has anyone else tried this technique and found something similar? Or is it just my Phev ?
Regards Trex.

Has been discusses an awful lot on this forum

Trex said:

From experimenting I have found that even at 115 kph indicated (110 kph gps ) on the freeway with the car in parallel mode I get 8lts/100ks in save mode against 7.5lts/100ks in charge mode. I know this is not a lot of difference but this is at its worst ie charge mode, ev mode, charge mode, ev mode etc, at higher speed .

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Are you sure, as this is a very unlikely result.

First of all, in Save mode, you maintain a particular SOC, where in Charge mode you enhance your SOC. How can you have a lower fuel consumption and enhance your SOC at the same time?

When I am doing 100 kph gps in charge mode, my car uses 11l/100km. In Save mode it alternates between 11l/100km and 0l/100km, averaging out at about 7 - 8 l/100km.

Mitsu Australia claims that frequent use of the Charge button makes the car 20 (?)% less efficient. I have sent them an email end of december asking them to clarify their statement. I have not received a response from them.

I would agree that using Charge mode on the faster stretches to build up SOC for the slower stretches should be more efficient than driving in pure EV mode all the time. Even though it contradicts the statement of Mitsu Aus. This is why I sent them the email.

Trex said:

About the only downside I see in using the charge mode on my car would be it could be considered a rapid charge and if done too often may cause the Hv battery to age quicker than normal but in our case we do not travel longer distances frequently.

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Charging during Save mode goes as fast as during Charge mode. The difference is that is intermittent instead of constant.
Charging during regen breaking goes much, much faster.

From the other side of the World, still Cold and alof of snow.
I do not really undersand what you are gaining, please explain
Do you drive exactly the same route often, and have measured this differences between different modes in your car? then i can see your point and found this interesting test results.
Because by doing all the transactions of energy, petrol-engine-generator-battery-EV will not gain anything as we have losses between every transaction.
You might be able to use the energy more efiicient, but not save any.
The increase of fuel consumption does not indicate that it is fast charging, if you run 100km/h with consumin 7,5 liters/hour, and it increases to 8 liters/hour, the consumption for the charging is only 0,5 liters/hour, not much.

A petrol engine gets app. 4 horsepower/liter of fuel/hour, so when your car consumes 8 liters/hour, you use app. 32 horespower, similar to 23kW, therefore you get 10/23=0,43 hour EV mode = 43km in 100km/h.
If you increase the use of electrical, 23kw for running the car and 10kw for fast charging, the use of fuel should be: 33kw=45hp, 45/4 = 11,25 liters/hour.
So IF your car would fast charge the battery when driving, you should see consumption figures on your dash arround 11 liters/100km when you cruse in 100km/h down the freeway

Sorry for all theroetical stuff and all figures and estimate, but i can not help it, i just loves it!

Theoretical calculation. If you want to get electricity from petrol Engine + generator, you can say you get 2 kWh/1 liter of fuel.
So for charging you battery 10kWh you will burn app 5 liters of fuel, and then you get 35-40km of EV mode?(in Sweden this time of the year we only get about 33km)
So if your car run on less than 10liter/100km, theoretical it is much better to not charge the battery with th petrol Engine in your car.
This is the theoretical behind it, but do you notice different?

Please comment and correct me if i am wrong, i do this calculatons for my customers alot when it comes to boats and fuel consumptions, especially when people try to sell a gas boats and prommise fuel consumptions in crusing speeds so low that they could should nominated to the Nobel price for invention a gas Engine with 90% efficiency!

Hi Anko,

First off I find the trip computer on my car very accurate compared to manual calculations so I trust it.

If I do a reset on it I find that my consumption initially at the same speed is 10lts/100ks ie at 110kph gps is exactly the same for save or charge mode. But over time yes save mode will drop down to 8lts/100ks. But also for charge mode it goes from 10lts/100ks when charging to 0lts/100ks when in ev mode and I am finding it averaging over time to 7.5lts/100ks.

Like I said it might be my car.

Like I also said having Hv battery charged for doing the slower sections in Ev mode is also helping my car's fuel consumption.

As for Mitsubishi Australia I have seen those comments, as well as it supposed to takes 3lts to charge from 0 to 80% if at a standstill (80% being when charging stops), but have not tested it but I will one day.

Regards Trex

I would tend to agree with anko (for once) - on a long trip, the difference between Charge mode and Save mode should be so small as to be undetectable. it is certainly true that if you engage Charge with a flat battery, you will burn extra petrol bringing the level up, but once the battery gets up to about 80%, Charge and Save should be pretty much identical. Save mode does allow the battery to drift down and I have wondered about engaging Charge immediately I leave the house with a full battery if I'm going to be away from power for a long time - I shall give it a try next weekend.

MartinH said:

If you increase the use of electrical, 23kw for running the car and 10kw for fast charging, the use of fuel should be: 33kw=45hp, 45/4 = 11,25 liters/hour.
So IF your car would fast charge the battery when driving, you should see consumption figures on your dash arround 11 liters/100km when you cruse in 100km/h down the freeway

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anko said:

When I am doing 100 kph gps in charge mode, my car uses 11l/100km.

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Where theory meets real world

Trex said:

If I do a reset on it I find that my consumption initially at the same speed is 10lts/100ks ie at 110kph gps is exactly the same for save or charge mode. But over time yes save mode will drop down to 8lts/100ks.

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So, that is exactly more or less the same as what I am seeing. Although I see 11lts/100km @ 100 kmh.

Trex said:

But also for charge mode it goes from 10lts/100ks to 0lts/100ks and I am finding it averaging over time to 7.5lts/100ks.

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And this doesn't make sense, unless ..... at some point your battery reaches 80% SOC and, without you noticing, the car drops out of Charge mode and continues as an EV allowing the average consumption to drop below what you see in Save mode.

anko said:

Trex said:

If I do a reset on it I find that my consumption initially at the same speed is 10lts/100ks ie at 110kph gps is exactly the same for save or charge mode. But over time yes save mode will drop down to 8lts/100ks.

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So, that is exactly more or less the same as what I am seeing. Although I see 11lts/100km @ 100 kmh.

Trex said:

But also for charge mode it goes from 10lts/100ks to 0lts/100ks and I am finding it averaging over time to 7.5lts/100ks.

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And this doesn't make sense, unless ..... at some point your battery reaches 80% SOC and, without you noticing, the car drops out of Charge mode and continues as an EV allowing the average consumption to drop below what you see in Save mode.

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Does it actually "drop out of Charge mode", or does Charge become equivalent to Save? I would have hoped that it would be the latter in order to avoid having to subsequently keep an eye on the battery level and hit "Charge" again.

maby said:

Does it actually "drop out of Charge mode", or does Charge become equivalent to Save? I would have hoped that it would be the latter in order to avoid having to subsequently keep an eye on the battery level and hit "Charge" again.

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I assumed it would switch to it's default mode. With your driving style and strategy, I assumed you had already encountered this situation?

anko said:

maby said:

Does it actually "drop out of Charge mode", or does Charge become equivalent to Save? I would have hoped that it would be the latter in order to avoid having to subsequently keep an eye on the battery level and hit "Charge" again.

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I assumed it would switch to it's default mode. With your driving style and strategy, I assumed you had already encountered this situation?

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No, I've never used Charge mode other than as a quick experiment when we first took delivery of the car - I currently put it in Save mode at the start of a long journey but the firmware does allow the charge level to drift down in Save, hence my interest in the behaviour in Charge mode.

Given that the design purpose of Charge mode is to bring the battery level up in anticipation of either needing the extra power for prolonged hill climbing, or to support a period of EV-only driving in a low emissions zone (ignoring questions about EV-only mode), it would seem to make sense for it to stay in Charge mode once selected until deselected - I cannot easily predict how long it is going to take to recharge my battery, so I could find myself selecting Charge mode an hour before I reach that mountain, the car only actually takes half an hour to get up to 80%, drops back to normal mode and I don't notice - arriving at my mountain (or zero emissions zone) with a flat battery!

I think Mitsu suggests to activate Charge like half an hour or so before getting to the mountains. Not hours.

When towing, I have it active all the time. Which is fine as I never hit 80% (which is not fine )

anko said:

I think Mitsu suggests to activate Charge like half an hour or so before getting to the mountains. Not hours.

When towing, I have it active all the time. Which is fine as I never hit 80% (which is not fine )

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I'll test it later today. I will only be doing a short journey, but the car will be fully charged so, if you are correct, it should refuse to allow me to engage Charge mode.

In theory, the petrol engine is most efficient when at constant revs & speed on the motorway, driving the front wheels, so applying charge then shouldn't consume too much extra petrol, but provide extra battery power to enable EV only running during the start stop parts of the journey.

My PHEV is being delivered on Monday, so can try putting theory into practice then!

In theory, if you charge 10kWh to the batteries, this Power must come from some kind of source, in this case the petrol Engine, and to produce 10kWh it will consume app. 5 liter of fuel, regardless of you idling or crusing down motorway.

MartinH said:

In theory, if you charge 10kWh to the batteries, this Power must come from some kind of source, in this case the petrol Engine, and to produce 10kWh it will consume app. 5 liter of fuel, regardless of you idling or crusing down motorway.

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True, but you need to view it in the context of a petrol driven car in a normal pattern of usage. If you really are cruising at a steady speed, at or above the engine's most efficient speed, on the flat for a prolonged period of time, then charging the battery is going to use additional petrol that would not otherwise be burned and the economics of it are questionable. A car in normal use is going to be varying speed, going up and down hills, running at a speed that is less than optimum for fuel economy, then there is scope for putting some energy that would otherwise be wasted into the battery.

Hi again,

Sorry been out, a quick post before I sleep. I will try tomorrow to answer more questions.

Anko, you are mistaken on what I am doing when on the freeway. I am running in Ev mode till it runs out of charge then putting the car in charge mode till the hv battery gets to a level that is less than 80%, where it would stop charging anyway, (I actually only go to 50%, takes about 1/2 an hour) then back to ev mode till it runs out of charge then back to charge mode etc. etc.

I am sorry I wasn't more clear in the first post.

Regards Trex.

Trex said:

Hi again,

Sorry been out, a quick post before I sleep. I will try tomorrow to answer more questions.

Anko, you are mistaken on what I am doing when on the freeway. I am running in Ev mode till it runs out of charge then putting the car in charge mode till the hv battery gets to a level that is less than 80%, where it would stop charging anyway, (I actually only go to 50%, takes about 1/2 an hour) then back to ev mode till it runs out of charge then back to charge mode etc. etc.

I am sorry I wasn't more clear in the first post.

Regards Trex.

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I am surprised if that is more efficient than normal operation - you seem to be introducing an extra step in the power flow that must carry its own inefficiencies.

MartinH said:

In theory, if you charge 10kWh to the batteries, this Power must come from some kind of source, in this case the petrol Engine, and to produce 10kWh it will consume app. 5 liter of fuel, regardless of you idling or crusing down motorway.

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The PHEV normally does not do a lot of idling.

In order to charge while idle (or better: when parked), you first need to start the engine. The first fuel used is spent to overcome the internal resistance of the engine. But when you start charing while cruising, you don't need to overcome the internal resistance of the engine, as the engine was already running.

maby said:

Trex said:

Hi again,

Sorry been out, a quick post before I sleep. I will try tomorrow to answer more questions.

Anko, you are mistaken on what I am doing when on the freeway. I am running in Ev mode till it runs out of charge then putting the car in charge mode till the hv battery gets to a level that is less than 80%, where it would stop charging anyway, (I actually only go to 50%, takes about 1/2 an hour) then back to ev mode till it runs out of charge then back to charge mode etc. etc.

I am sorry I wasn't more clear in the first post.

Regards Trex.

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I am surprised if that is more efficient than normal operation - you seem to be introducing an extra step in the power flow that must carry its own inefficiencies.

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No extra steps are introduced with this strategy. In normal driving mode, you will see this pattern (1 = engine on, 0 = engine off):

11110111101111011110111101111011110

In the scenario Trex describes, you will see this pattern:

11111111111111111111111111110000000

Different pattern, same amount of 1's and 0's.

On the other hand, the longer you run in charge mode, the higher the SOC will get. The higher the SOC, the less the charge current. Less charge current will result in a less efficient system. (This is why I said earlier that Maby's strategy of using Save to maintain a high SOC may not be very efficient). But as long as you stay under 50%, the charge current is not reduced and you should be fine.

Rex's strategy does prevent frequent engine starts and stops. Perhaps this could result in improved efficiency. But then, why the claim from Mitsubishi?

anko said:

...

No extra steps are introduced with this strategy. In normal driving mode, you will see this pattern (1 = engine on, 0 = engine off):

11110111101111011110111101111011110

In the scenario Trex describes, you will see this pattern:

11111111111111111111111111110000000

Different pattern, same amount of 1's and 0's.

On the other hand, the longer you run in charge mode, the higher the SOC will get. The higher the SOC, the less the charge current. Less charge current will result in a less efficient system. (This is why I said earlier that Maby's strategy of using Save to maintain a high SOC may not be very efficient). But as long as you stay under 50%, the charge current is not reduced and you should be fine.

Rex's strategy does prevent frequent engine starts and stops. Perhaps this could result in improved efficiency. But then, why the claim from Mitsubishi?

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but is it not the case that, in normal driving mode at speeds below parallel hybrid mode, the power to drive the motors is coming directly off the generator - possibly with some excess output from the generator being dumped into the battery? Under Rex's strategy, much of the power from the generator is being pumped into the battery and subsequently drawn back out of the battery to drive the motors. I know Lithium batteries are pretty efficient, but this still has to be less efficient than driving the motors directly from the generator, surely?