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Discussion Starter #1
Hi All!

New to the forums. I just picked up a T8 XC90 and so far have only driven in hybrid mode. That said I live in a city and noticed that it seems the car is always just using the electric motor, even on the highway sometimes. To the point where a day of driving I get home and it seems I've used almost no gas and only the electric motor.
I am not complaining, awesome to just be electric, but I do intend to take this thing on trips into the mountains and I want to make sure I have electric power when I get there to have the AWD I need.

How can I make sure I have a full battery after 3 hours of driving when I get to the mountains? Should I just put the car into "hold" during that drive?
I guess a followup is if the electric battery is all the way down, do I lose AWD?

Thanks!
Eduardo
 

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Hi All!

New to the forums. I just picked up a T8 XC90 and so far have only driven in hybrid mode. That said I live in a city and noticed that it seems the car is always just using the electric motor, even on the highway sometimes. To the point where a day of driving I get home and it seems I've used almost no gas and only the electric motor.
I am not complaining, awesome to just be electric, but I do intend to take this thing on trips into the mountains and I want to make sure I have electric power when I get there to have the AWD I need.

How can I make sure I have a full battery after 3 hours of driving when I get to the mountains? Should I just put the car into "hold" during that drive?
I guess a followup is if the electric battery is all the way down, do I lose AWD?

Thanks!
Eduardo
You can't completely have a full battery throughout your 3 hour trip even in hold, but hold does save some energy.

For some HVAC, audio, hard acceleration and Start/Stop needs, the vehicle still uses some battery power even when you've selected Hold, but will try to plough it back using ICE. But by the time you arrive at your destination, ICE may not have gotten the chance to fully replace the energy it temporarily "loaned" from Hold mode to fulfill those extra energy needs mentioned above.

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You can't completely have a full battery throughout your 3 hour trip even in hold, but hold does save some energy.

For some HVAC, audio, hard acceleration and Start/Stop needs, the vehicle still uses some battery power even when you've selected Hold, but will try to plough it back using ICE. But by the time you arrive at your destination, ICE may not have gotten the chance to fully replace the energy it temporarily "loaned" from Hold mode to fulfill those extra energy needs mentioned above.

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I am not sure what you mean with this exactly - HOLD would work perfectly. At destination, he will have 100% charge.
Another option would be to remember to just turn on regen when approaching the destination. Put into B mode and the batter in charge and you can recharge it on the last segment.
 

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It is my understanding that the hybrid battery level does not affect having or not having AWD. There is an ISG (integrated starter generator) which will automatically generate power from the combustion engine for the hybrid battery when empty to power the rear e-axle. It is this same ISG that "activates" when the driver presses "Charge" on the Sensus screen to charge the hybrid battery using the combustion engine.

On YouTube checkout Alex on Autos great explanation on the T8 power system:

https://youtu.be/Gj8JAYa-LfI

@5:43 is the start to your answer but watch the whole thing to get a good understanding of how the hybrid system works.

Here are more tech details which discuss the ISG:

https://www.greencarcongress.com/2015/05/20150517-xc90.html .

Please correct me if wrong.

Enjoy!
 

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Discussion Starter #6
Thanks a ton for the answers :) I haven't tried hold yet but figured it would be about that.
I may play around with the personalized modes ... in the hope that anything above 40mph sustained would just use the ICE. I don't think any of the presets really do this unless I use hybrid and floor it into higher rpms to get off the electric motor.

I have been playing around with the systems the last few days but figured I would tap into the knowledge base here for help.

I am very excited about me '21 T8 so hopefully all works out! Will definitely check out those videos above.
 

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I am not sure what you mean with this exactly - HOLD would work perfectly. At destination, he will have 100% charge.
Another option would be to remember to just turn on regen when approaching the destination. Put into B mode and the batter in charge and you can recharge it on the last segment.
Next time, put charge on Hold and be stuck in heavy traffic on a very hot or cold day and see if it maintains that level throughout your journey. That will be test 1

Test 2, put it on Hold, and drive aggressively and see if it will maintain that charge throughout your journey

Test 3: Put it on hold and keep car running while you are parked and inside with music playing and see if it will keep that charge throughout

It's through these scenarios that it "borrows" charge from the saved battery and it later tries to put it back by running ICE. Sometimes it doesn't get a chance by the time you arrive to plough back that charge.

I've had and observed my car for 4 years to know it's behavior by now.





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Discussion Starter #8
That video above was very helpful. It sounds like some complicated engineering but generally speaking the car always has the ability to send extra power to the electric motor if it needs it (using the ICE) regardless of whether or not you have any juice in the battery. The battery is what allows you to run in "pure" mode or in only electric during hybrid operation but doesn't mean you can't use that rear axel even if it is depleted.

IE regardless of whether or not I manage to get that battery to last the 3+ hour drive before we get to the mountains, I shouldn't have to worry about AWD performance even if the battery says that it is empty.....at least that was my take away.
That is actually comforting to know for a person who plans to use AWD often.
 

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Yes, I arrived at the same conclusion as yourself.
I shouldn't have to worry about AWD performance even if the battery says that it is empty.....at least that was my take away.
That is actually comforting to know for a person who plans to use AWD often.
The only "concern" I think is the amount of power or torque available to the rear wheels vs the front wheels at various (particularly low) speeds. Ideally we would look at torque or power curves vs RPM graphs to address this "concern" and I believe this info might be floating out on the intertubes somewhere . . .
 

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I have found in AWD or 4 wheel drive LOW the ICE is charging the battery and I always have at least 1 electric mile showing, therefore, the rear electric motor will never run out of charge...

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