Battery Save Works Until You Stop...

[jaapv]

Hmm... The whole discussion has descended into semantics, I think. Whether the power output is distributed by balancing or by feeding the motors or batteries by preset parameters is too fine a distinction for me...

 

[anko]

Hmm... The whole discussion has descended into semantics, I think. Whether the power output is distributed by balancing or by feeding the motors or batteries by preset parameters is too fine a distinction for me...

But Jaap, it is not pure semantics. It is the difference between a car that becomes sluggish when SOC goes down and one that does not.

And as this is the Technical Dicussion part of the forum, I think it is not so bad to have these discussions here, so that together we can try to fully understand our cars

 

[jaapv]

But the car doesn't become sluggish depending on the SOC as long as you don't Turtle it...
The only thing that varies is the interplay (OK, not balance ) between ICE and EV.

 

[anko]

Oh, you and I have always agreed on this. But some others still may think differently

 

[gwatpe]

Since I have modded my PHEV to power on with a drivers preferred SAVE, CHARGE, or NORMAL mode, I normally leave the mode to power ON in SAVE. The battery depletes only very slowly over a week of driving, when corded recharging is not available. I drove my PHEV for over a month with no cord available, and only had to use CHARGE mode on two occasions, in about 15000km driven. Once when I had been driving slowly in rough rocky terrain and wanted the EV experience, it depleted the battery rather quickly and I had to recharge with ICE.

The PHEV is so easy to drive when it powers ON in SAVE mode. If your drive is not achievable on EV alone, then the option to power ON in SAVE, or CHARGE mode, saves the battery for when the driver can make best use of it, rather than the driver remembering to press the button to keep some battery energy for later.

My mod is not detected by service equipment, so all is good and don't bother to switch back to NORMAL at servicing.

If the drive is mainly local, and EV will do, I just press the button for NORMAL mode. There is always a delay for the ICE to operate, in SAVE mode from power ON, and I can usually remember to press the button before the ICE starts, or at the expense of a fraction of petrol, when I hear the ICE start and then press the button.

I know the frustration drivers whose needs are beyond EV only, operating the PHEV with a depleted battery, when a possible MMC firmware update could be all that is needed to allow a driver to select a preferred operating mode on power ON. Maybe MMC could be lobbied to think about a sticky SAVE as a firmware update.

 

[anko]

The battery depletes only very slowly over a week of driving, when corded recharging is not available. I drove my PHEV for over a month with no cord available, and only had to use CHARGE mode on two occasions, in about 15000km driven. Once when I had been driving slowly in rough rocky terrain and wanted the EV experience, it depleted the battery rather quickly and I had to recharge with ICE.

I am a bit confused. If the above is all true (and I see no reason to doubt that), why would you at all worry about maintaining a high SOC? I mean, why did you feel you had to recharge after that bit of EV off-roading? From your own observations, it seems you don't need the buffer ... Well, maybe twice in 15000km.

 

[maby]

Oh, you and I have always agreed on this. But some others still may think differently

I think it just comes down to a question of different driving conditions, driving styles and priorities. You are certainly one of those PHEV owners that attaches a lot of importance to fuel economy and environmental impact - we have had long and sometimes heated discussions on the interpretation of PHEV and whether or not it is acceptable for it to start the ICE under various conditions. I think jaapv is a bit more pragmatic about it, but he is also a very committed environmentally conscious owner (and lives in a country with very few hills!).

Others, including myself and gwatpe are using it as a general purpose car - it happens to be very tax efficient for me and I value the CV transmission with reduced moving parts. The car is not designed to run on either battery or petrol - it combines the two in order to match driving conditions and meet power demands. By default, it tries to stay in EV mode as much as possible and it is able to cruise pretty well on either power source, but it does fire them both up in response to power demand and that does not have to be very hard acceleration.

Yesterday afternoon I had to go to a local supermarket for some shopping. It was a round trip of about 4 miles on suburban roads with moderate traffic and the speed limit is 30mph all the way and I had a fully charged battery. I drove normally - by my standards - and got back home with the display showing that I had done 96% EV - in other words, it had felt the need to light up the petrol engine for acceleration several times. You or jaapv have already confirmed that the reverse is also true - if running on the petrol engine, it will draw down on the battery to provide the extra boost in response to demands for acceleration.

I'm not alone here - several have commented on the desirability of maintaining a decent level of charge to improve the performance of the car - gwatpe has gone to the lengths of building a modification for his car. I would prefer a Prius type mode which keeps the SOC around 50% - this will allow the regen brakes to operate and is probably kinder to the batteries than holding them up at close to 100% all the time or letting them run right down for hours on end. I just don't see any downside to it - if you are travelling significantly beyond your EV range, you are going to be driving primarily on petrol. If I'm doing 200 miles or more, then the improvement in fuel efficiency that I'll achieve by carefully planning when to use up my 25 miles of EV is so tiny that it's just not worth the effort or the performance impact of trying to climb a steep hill towards the end of my journey with a completely flat battery.

 

[jaapv]

I think your solution is fine for very specific users. The average use will be: leave home, drive through (sub) urban traffic on EV, reach the Motorway, activate save, end of motorway, deactivate save, drive on EV again, etc.
it appears to me that Mitsubishi thought this through quite correctly but did not anticipate our governments making this car tax-friendly for people who would be better off from a technical point of view driving a Diesel.

 

[anko]

I think it just comes down to a question of different driving conditions, driving styles and priorities.

I do appreciate these differences and I do understand my country is flat and yours isn't. Also, I can easily imagine that I am more concerned with fuel economy than some others. And less with performance than some others. But this is not what this is about. At least not to me.

I'm not alone here - several have commented on the desirability of maintaining a decent level of charge to improve the performance of the car

For the time being, I simply do not believe that allowing the SOC to drop impacts the performance of the car, at least not as long as you do not let it drop below 20%.

To me, the discussion is not about different needs or circumstances or priorities, but about the question: is performance impacted by low SOC, yes or no? We are in the Technical Discussions section, after al

My personal experiences with towing, even in France and Austria, tell me that performance is not impacted by low SOC, as long as I manage to stay out of the Turtle zone. And various Mitsubishi documentation seems to back this up, where they state that at 20% SOC output of the battery is reduced. And as long as I think I could be right with this, I am stuck with this gut feeling that it is not a very good idea to advocate a driving style or tools that aim at maintaining high SOC, as (I believe) these may have an impact on fuel economy, how little it may be.

All of the above, again unless you need this driving style or these tools to keep yourself out of the Turtle zone. Let me put it this way: if gwatpe could create a device that fires up Charge mode whenever a heavy trailer is detected, I would be more than interested

 

[maby]

I think your solution is fine for very specific users. The average use will be: leave home, drive through (sub) urban traffic on EV, reach the Motorway, activate save, end of motorway, deactivate save, drive on EV again, etc.
it appears to me that Mitsubishi thought this through quite correctly but did not anticipate our governments making this car tax-friendly for people who would be better off from a technical point of view driving a Diesel.

I think Mitsubishi's omission is more fundamental than that. The PHEV is a large, quite expensive 4WD estate car with a reasonable level of off-road ability - few people are going to buy a vehicle of those characteristics and use it exclusively for short range urban trips. I may be at the far end of the spectrum with my three or four days per week of urban short hops combined with three or four day weekends when I do 200 miles or more with no possibility of charging, but the majority of owners - yourself included - are going to use their PHEVs for summer and/or winter holidays that will involve driving a couple of thousand miles over a period of two or three weeks with little or no opportunity to charge. This forum is littered with threads discussing the best strategy for such usage - with and without a heavy caravan hanging off the back. We end up proposing a variety of patterns of usage of the Charge and Save buttons, but these are blunt tools to solve the problem. Mitsubishi presumably have mathematical models of the car that they used to design the software - it would have been easy for them to work out what is the best strategy, taking into account all the factors including fuel economy, performance and battery life expectancy and to give us the choice between several modes of operation - including the Pure EV that Anko and our Polish friend are so keen on.

 

[jaapv]

They could never have worked out a detailed strategy for the simple reason they cannot know what roads and conditions will be encountered on a specific journey. The result is that silicon cannot replace the driver's brain here. The only thing they could do is optimize for the minimum number of button presses for average use. Which they did.

 

[jaapv]

+1

I think it just comes down to a question of different driving conditions, driving styles and priorities.

I do appreciate these differences and I do understand my country is flat and yours isn't. Also, I can easily imagine that I am more concerned with fuel economy than some others. And less with performance than some others. But this is not what this is about. At least not to me.

I'm not alone here - several have commented on the desirability of maintaining a decent level of charge to improve the performance of the car

For the time being, I simply do not believe that allowing the SOC to drop impacts the performance of the car, at least not as long as you do not let it drop below 20%.

To me, the discussion is not about different needs or circumstances or priorities, but about the question: is performance impacted by low SOC, yes or no? We are in the Technical Discussions section, after al

My personal experiences with towing, even in France and Austria, tell me that performance is not impacted by low SOC, as long as I manage to stay out of the Turtle zone. And various Mitsubishi documentation seems to back this up, where they state that at 20% SOC output of the battery is reduced. And as long as I think I could be right with this, I am stuck with this gut feeling that it is not a very good idea to advocate a driving style or tools that aim at maintaining high SOC, as (I believe) these may have an impact on fuel economy, how little it may be.

All of the above, again unless you need this driving style or these tools to keep yourself out of the Turtle zone. Let me put it this way: if gwatpe could create a device that fires up Charge mode whenever a heavy trailer is detected, I would be more than interested

 

[maby]

They could never have worked out a detailed strategy for the simple reason they cannot know what roads and conditions will be encountered on a specific journey. The result is that silicon cannot replace the driver's brain here. The only thing they could do is optimize for the minimum number of button presses for average use. Which they did.

I don't think that's true - I could tell the car what I'm planning on doing and it could configure itself to match - modern 4WDs like the Jeep offer similar. "Until further notice, I'm going to be driving at motorway speeds on relatively flat roads, moderately loaded with no opportunity to charge", "Until further notice, I'm going to be driving with a heavy trailer on the back and no opportunity to charge", "Until further notice, gwatpe is going to be driving off-road across the Outback in temperatures approaching 50 degrees". I know that this is dependent on the driver selecting the correct option, but that is no worse than the current situation where we are trying to guess optimum strategy and implement it by pressing combinations of the Charge, Save, ECO and 4WD Lock buttons. Mitsubishi have gone to the trouble of fitting those buttons, so they do not consider it to be a simple "turn on and drive" car, but the many discussions that come up here show that the choice of settings is not as intuitive as might be desired.

 

[jaapv]

Sorry - I think pushing a button at the right time is far better than an elaborate programming of the car each time you start off plus reprogramming each time the conditions change - there must be tens of thousands of variables involved.

 

[anko]

I think Maby does mean pushing a button (or returning a knob). And the button already exists and its usage is very simple:

"If the drive ahead of you is such that you risk ending up in the Turtle Zone, select Charge. Otherwise, do noting."

I think very few drivers risk ending up in Turtle Mode on the majority of their drives. Not even gwatpe, per the post he made earlier today. But if you did, than indeed, a Diesel might have been a better choice.

 

[jaapv]

Plus:
If you need some electricity at the end of the drive and are driving at motorway speeds, select Save.
If you are in the mountains keep the car on Charge.

 

[Grigou]

Let me put it this way: if gwatpe could create a device that fires up Charge mode whenever a heavy trailer is detected, I would be more than interested

For me, if Gwatpe could create a mod (optional of course) that fires up Charge mode when the car is in parallel mode, and stops it in all other circumstances, I would be very interested

Because :

- the ICE is more efficient between 65 and 120 kph, in parallel mode
- it's better to charge with an efficient ICE
- on long travels, I need to charge the battery very often, and sometimes at high SOC (to be able to drive in EV at less of 50 kph in towns and villages : I don't like hearing the ICE in town when I drive at very slow speed, and I know that the serie mode at low speeds is all but efficient ...)
- on many roads, the car switches very often from serie to parallel to serie etc ... (roundabouts, other cars ...) so I have to push too often the Charge button.

 

[Neverfuel]

I didn't think that the ICE could run the generator when in parallel mode. Otherwise there would be more than 147 kW available at maximum power (87 from ICE for the front wheels, 60 from drive battery for the rears). In the technical manual it looks like the ICE is disconnected from the generator when coupled through the CVT? :?

 

[maby]

I didn't think that the ICE could run the generator when in parallel mode. Otherwise there would be more than 147 kW available at maximum power (87 from ICE for the front wheels, 60 from drive battery for the rears). In the technical manual it looks like the ICE is disconnected from the generator when coupled through the CVT? :?

The ICE is never disconnected from the generator, but the load placed on the generator to charge the battery will be reduced as your speed increases because there is less power available to spare after that required to move the car has been satisfied. Running in parallel mode at around 50 in Charge or Save mode, the battery will charge up - possibly quite slowly.

 

[Neverfuel]

Hi Maby

Surely that means that pressing charge when in parallel mode will not "cost" any fuel as the engine will be directly coupled to the wheels via the CVT and the back EMF from the front motor is being compensated by the drive battery. So there must be an optimum speed/drag/SOC where the charge button works at its optimum charge level?