T8 - should you ever use the charge mode?

kozmokr · Jan 6, 2018

Talking fuel efficiency only, when, if ever should one use the charge mode?
Common sense mandates that charging an electric battery using ICE is as wasteful as it can get.
However, I wouldn’t think they put that option there if it wouldn’t be useful at least in some scenarios.
Am I missing something here? Perhaps charging on a steady freeway cruise and then using that with pure mode in the city is actually efficient?

FusionRedXC60 · Jan 6, 2018

Charge mode allows battery to be recharged to higher than the current level. The charging is from brake regeneration and excessive ICE output I think. It is not aggressively using ICE even in charging mode.You can tell from the RPM before and after changed to charge mode.

Hold mode only keeps the current battery level, not higher. Excessive battery energy will be used whenever possible.

If neither charge or hold is chosen, battery will be used whenever possible and only maintained at a low level, maybe 33%.

It is about when you prefer to use the recycled battery energy, immediately, or in future.

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Nickshu · Jan 6, 2018

I use the charge mode frequently. 2-3 days per week I have a commute between two cities. I use Pure to get out of city 1 which depletes the fully charged battery down to about 3 miles left, then I use Power + Charge mode on for the highway portion to recharge the battery which gets back up to about 11 miles by the time I arrive at city 2, then I use Pure mode again in city 2 until I get to my destination. On the trip home I do the same in reverse. Works great.

I have done this drive in all hybrid, and in all power mode which results in about 23MPG. Using the method above I get about 31-35 MPG on this trip. The ICE only runs on the highway portion of the trip, the rest is all electric on the ERAD.

amb3rgris · Jan 6, 2018

I have used Nichshu’s method of “highway charge, city electric” as well.
I believe the gas engine is most efficient at consistent highway speeds, while the electric motor is best at low speed stop and go.

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Gary-16-Xc90 · Jan 6, 2018

^ ^^+2

Same with me except I use Pure mode + Charge even while cruising down the open freeway. I then disengage Charge once traffic or speed limits go below 50 mph. Both Hybrid and Pure will run the battery down to an indicated charge of zero - recharging via kinetic energy and braking when possible which keeps the charge between 1/16 and 1/8.

I have estimated that I take a 1/2 gal. hit to recharge from 0 to 33% over ~20 miles at steady +65mph. Now, though we can charge up to 95%, but that can take up 60 miles to achieve with a hit of ~ 1.5 gal. Whether it makes financial sense would be a good discussion over a beverage of your choice. :beer: But driving in the “city” on all electric is very efficient.

Here are some more ramblings....

I have been using Power Mode more on the freeway and notice that it keeps the indicated to at least 1/4 Charge.

I find that the T8 runs most efficiently when the charge is 50% or more. No data, just antidotal and an observation via the performance diagram.

My current lifetime MPG average is now 32.5 even with -10 or lower temps. During Spring, Summer and Fall, I average 36 mpg -all based on one charge a day and judicious use of Charge of open freeways.

Look for other threads as the subject of Charge has been passionately discussed. There is no right or wrong -just bad, better, and best practices.

derickma · Jan 6, 2018

Nickshu said:
I use the charge mode frequently. 2-3 days per week I have a commute between two cities. I use Pure to get out of city 1 which depletes the fully charged battery down to about 3 miles left, then I use Power + Charge mode on for the highway portion to recharge the battery which gets back up to about 11 miles by the time I arrive at city 2, then I use Pure mode again in city 2 until I get to my destination. On the trip home I do the same in reverse. Works great.

I have done this drive in all hybrid, and in all power mode which results in about 23MPG. Using the method above I get about 31-35 MPG on this trip. The ICE only runs on the highway portion of the trip, the rest is all electric on the ERAD.

I use the exact same method except on the highway I use pure mode with charge enabled.If the snow is bad I'll use AWD,

tillsbury · Jan 7, 2018

I'm going to guess that it would depend on how fast you're travelling at "highway" speeds. Over here, the limit is 100k and much of my "highway" is more like 90-95k (the main trunk road in NZ is almost entirely single lane). Fuel economy is very good on the ICE when travelling at 90-95k, around 6-7l/100k. Putting charge on increases this to 12-14, so there's a very serious hit to economy. I'm not sure whether this would make the charging worthwhile.

If you were doing more like 80-90mph on your highways, then I could believe that the additional fuel used in charging might not be quite so proportionately high. At those speeds your overall fuel economy is going to be significantly worse anyway.

Nickshu · Jan 7, 2018

Gary-16-Xc90 said:
^ ^^+2

Same with me except I use Pure mode + Charge even while cruising down the open freeway. I then disengage Charge once traffic or speed limits go below 50 mph. Both Hybrid and Pure will run the battery down to an indicated charge of zero - recharging via kinetic energy and braking when possible which keeps the charge between 1/16 and 1/8.

I have estimated that I take a 1/2 gal. hit to recharge from 0 to 33% over ~20 miles at steady +65mph. Now, though we can charge up to 95%, but that can take up 60 miles to achieve with a hit of ~ 1.5 gal. Whether it makes financial sense would be a good discussion over a beverage of your choice. [emoji481] But driving in the "city" on all electric is very efficient.

Here are some more ramblings....

I have been using Power Mode more on the freeway and notice that it keeps the indicated to at least 1/4 Charge.

I find that the T8 runs most efficiently when the charge is 50% or more. No data, just antidotal and an observation via the performance diagram.

My current lifetime MPG average is now 32.5 even with -10 or lower temps. During Spring, Summer and Fall, I average 36 mpg -all based on one charge a day and judicious use of Charge of open freeways.

Look for other threads as the subject of Charge has been passionately discussed. There is no right or wrong -just bad, better, and best practices.

Maybe Pure + Charge is a bit better on the highway....but Power mode is so much more fun. I mean it is a 400HP vehicle after all....

In the words of my sales guy "Who buys a 400HP T8 just to drive it around in hybrid mode all the time, whats the fun in that? I mean if you want to do that I can just sell you a Toyota a Highlander Hybrid instead, they are alot cheaper" (Dealer is also a Toyota dealer). LOL.

derickma · Jan 7, 2018

tillsbury said:
I'm going to guess that it would depend on how fast you're travelling at "highway" speeds. Over here, the limit is 100k and much of my "highway" is more like 90-95k (the main trunk road in NZ is almost entirely single lane). Fuel economy is very good on the ICE when travelling at 90-95k, around 6-7l/100k. Putting charge on increases this to 12-14, so there's a very serious hit to economy. I'm not sure whether this would make the charging worthwhile.

If you were doing more like 80-90mph on your highways, then I could believe that the additional fuel used in charging might not be quite so proportionately high. At those speeds your overall fuel economy is going to be significantly worse anyway.

You take a hit on the highway fuel economy to get a better mileage in the city. I know I need about 15 km charge to get from the highway to home. On the highway I charge it to about 15 then put it in save mode. When I get off the highway I put it in pure mode and I can make it home on electric only in stop and go traffic.

I have the car set up to give me the average of every trip and the KM/L average drops significantly once you start driving in the city, I probably dive about an hour on the highway at about 120km/hour. On each trip I get about 5-6 L/100 km and that's in sub zero temps. Before the update when I could only charge up to about 10km I was averaging about 12-10L/100KM and that was in the summer.

I also use the charge mode in drive thru's and in traffic when crawling along or when going above 80, Especially in winter as the ICE helps keep the car warm also.

derickma · Jan 7, 2018

Nickshu said:
Maybe Pure + Charge is a bit better on the highway....but Power mode is so much more fun. I mean it is a 400HP vehicle after all....

In the words of my sales guy "Who buys a 400HP T8 just to drive it around in hybrid mode all the time, whats the fun in that? I mean if you want to do that I can just sell you a Toyota a Highlander Hybrid instead, they are alot cheaper" (Dealer is also a Toyota dealer). LOL.

I save the power mode for when teenagers pull up in their parents car and want to race.. you know special occasions

sumane · Jan 7, 2018

When people say 35mpg, is that from the instrument cluster? I've realized all mpg values in the car show only gasoline usage, and ignore electric motor (i.e. if you are driving almost always in electric only, it can go into 1000mpg+). So looking and comparing mpg numbers from there across trips is not useful unless you always start with full and end with empty battery, or other always identical values (or you purely care about amount of gas you used, vs efficiency)

Is there a way to see aggregate estimate (like MPGe) anywhere, to be actually able to tell how efficiently are you driving? Or is this something we need to be computing ourselves.

taofen_wang · Jan 7, 2018

Nickshu said:
Maybe Pure + Charge is a bit better on the highway....but Power mode is so much more fun. I mean it is a 400HP vehicle after all....

In the words of my sales guy "Who buys a 400HP T8 just to drive it around in hybrid mode all the time, whats the fun in that? I mean if you want to do that I can just sell you a Toyota a Highlander Hybrid instead, they are alot cheaper" (Dealer is also a Toyota dealer). LOL.

I use power mode when it snows and the roads are not cleared out. The power mode plus winter tires gives me confidence to drive at 65km/h on freeway.

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Gary-16-Xc90 · Jan 7, 2018

sumane said:
When people say 35mpg, is that from the instrument cluster? I've realized all mpg values in the car show only gasoline usage, and ignore electric motor (i.e. if you are driving almost always in electric only, it can go into 1000mpg+). So looking and comparing mpg numbers from there across trips is not useful unless you always start with full and end with empty battery, or other always identical values (or you purely care about amount of gas you used, vs efficiency)

Is there a way to see aggregate estimate (like MPGe) anywhere, to be actually able to tell how efficiently are you driving? Or is this something we need to be computing ourselves.

You can always use the VOC log, export the data and perform your own computations.

Personally, all of my MPG figures are quoted from Fuelly.com. which does not currently support a means to compute MPGe as best that I know. (They just recently released an App update that allows users to specify the trim and engine for released models so maybe an independent MPGe computation is or will be available.)

Bayman48 · Jan 7, 2018

Is there less power when in hybrid vs. power mode...i mean when i punch the pedal, doesn't it use all 400 hp and torque that point? It doesn't retard the power output does it?

FusionRedXC60 · Jan 8, 2018

Bayman48 said:
Is there less power when in hybrid vs. power mode...i mean when i punch the pedal, doesn't it use all 400 hp and torque that point? It doesn't retard the power output does it?

In hybrid mode it only uses rear e-motor when tire slipping is detected. So I think you won't get 400HP in hybrid mode.

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Seti · Jan 8, 2018

Gary-16-Xc90 said:
...
I have estimated that I take a 1/2 gal. hit to recharge from 0 to 33% over ~20 miles at steady +65mph. Now, though we can charge up to 95%, but that can take up 60 miles to achieve with a hit of ~ 1.5 gal. Whether it makes financial sense would be a good discussion over a beverage of your choice. :beer: But driving in the "city" on all electric is very efficient...

Given the T8's 50L tank, sacrificing a gallon and a half over long distance driving is somewhat a bad idea.

The car seems to be efficient in charging up to 33% without much fuss, and it uses les fuel to get to that level. But beyond 33% battery level, ICE struggles a lot to charge up the battery.

I know this because, I tried charging the battery using ICE while driving on the freeway in one of my recent long distance trips and I realised that the car is quick to charge to 30-50% but takes much longer to go beyond the 50% battery charge mark! I drove for a couple hours charging the hybrid battery through ICE after it reached the 40% level, and it struggled much longer to rise just above the 50% mark. I then gave up because I felt charging to 90% will take much longer time and a comple waste of fuel.

IO was happy to keep the 50% and manage to harvest more using regenerative braking etc. Only through braking friction was I able to move the level from 50% to 90% much quicker. This is how I did it. After charging up to 50% using ICE, I pressed Hold. Then each time I got something from friction, I'd immediately cancel and reapply Hold. I kept doing this until I got to tthe 90% mark. I found that this was much quicker and efficient than using ICE.

Now, if only there was a home button for Save I could press and depress quickly without having to page through screens, minimising Maps etc to get to the Save/ Hold button. Another anticipated mods from Volvo's future Sensus update I'm hoping to see in my 2016 T8 lifetime

Gary-16-Xc90 · Jan 8, 2018

^ Good points, Seti. I have done it a couple of times where I fully expected heavy traffic and slow speeds. I agree not a great idea on transcontinental trips.

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VolvoUhu · Jan 12, 2018

I was tempted to start a new thread - but figured as an extension of the OP question, has anyone figured out the threshold between regenerative braking and old school disc brakes engage? In the T8’s regen braking gauge there’s a section near the bottom that’s orange/red, is that when the calipers start engaging or do they actually start further up the gauge?

arch1981 · Jan 12, 2018

Just want to say....great thread!!! Too bad the dealer didn’t tell me this, I just came across the button as I was setting up my Spotify in the car.

I’m looking forward to trying out the suggestions in here.....I was driving and using the battery up within 20 -25km and not using the car to charge as I didn’t know.....I now will on my highway drives....thanks for the thread!!!!

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VolvoUhu · Jan 12, 2018

arch1981 said:
Just want to say....great thread!!! Too bad the dealer didn't tell me this, I just came across the button as I was setting up my Spotify in the car.

I'm looking forward to trying out the suggestions in here.....I was driving and using the battery up within 20 -25km and not using the car to charge as I didn't know.....I now will on my highway drives....thanks for the thread!!!!

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Would have been great during our OSD but then again at the time ours was limited to 33% recoup vs. the latest 95% post update it got at US delivery in October.

T8 - should you ever use the charge mode?

kozmokr

FusionRedXC60

Nickshu

amb3rgris

Gary-16-Xc90

derickma

tillsbury

Nickshu

derickma

derickma

sumane

taofen_wang

Gary-16-Xc90

Bayman48

FusionRedXC60

Seti

Gary-16-Xc90

VolvoUhu

arch1981

VolvoUhu

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