Sorry if this is a dumb question... T4 recharge power loss when battery depleted

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typolee
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Joined: Mon Sep 06, 2021 10:30 am

Post by typolee »

Sorry if this seems a dumb question. Had to drive my dad to hospital (long journey away) in his T4 recharge. Everything seemed fine until the battery was totally depleted. I came to some steep hills and there was an apparent loss of power. I.e. in felt like a littler 1.5 litre pulling a heavy car up a hill!! Is this what happens? When the battery is depleted you lose the power of the battery therefore acceleration is terrible? I'm concerned as I have one on order coming down from an XC90 and I'm not really concerned its not the car for me. Might have a build slot if anyone wants one?

bba
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Post by bba »

Not a T4 but mine is nothing like that at all, might you have been running it in “pure” mode? For a journey like that it should be in “Hybrid”, the default.
Hope your dad is ok.
Used to have an XC40 T5 Recharge Inscription Pro MY21 with Polestar and useless Pilot Assist
typolee
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Post by typolee »

Thanks for your lovely reply. No definitely in hybrid mode. Did the whole run in hybrid. Battery had gone pretty quick tbh which it to just the petrol engine for most of the route. Returned 50mpg for the 140 miles. However like I say performance was shocking. I'm wondering whether its because its the T4 not the T5 which appears to have far more grunt as a petrol engine.
T4_recharge_guy
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Joined: Wed Jun 23, 2021 8:06 am

Post by T4_recharge_guy »

Firstly I hope your dad is ok. As you may guess from my username I have a T4 recharge and have never experienced a loss of power or the car struggling as you describe. Perhaps there is a fault of some sort on his car.
typolee
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Joined: Mon Sep 06, 2021 10:30 am

Post by typolee »

T4_recharge_guy wrote: Mon Sep 06, 2021 1:37 pm Firstly I hope your dad is ok. As you may guess from my username I have a T4 recharge and have never experienced a loss of power or the car struggling as you describe. Perhaps there is a fault of some sort on his car.
So you've not noticed once the battery is depleted no power loss and the 130bhp 3 cylinder engine is sufficient?
T4_recharge_guy
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Post by T4_recharge_guy »

When the battery is completely depleted the only difference I notice (and this is in stop start traffic) is that I can hear the engine idling / running.
The only time I’ve ever had a loss of power is when fast accelerating in battery mode and the speed hits 60mph which is when the car takes a second or so to change gear and has been discussed on here previously.

Other than that never had a loss of power so to speak
typolee
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Post by typolee »

T4_recharge_guy wrote: Mon Sep 06, 2021 2:10 pm When the battery is completely depleted the only difference I notice (and this is in stop start traffic) is that I can hear the engine idling / running.
The only time I’ve ever had a loss of power is when fast accelerating in battery mode and the speed hits 60mph which is when the car takes a second or so to change gear and has been discussed on here previously.

Other than that never had a loss of power so to speak
Thanks for your advice. Its much appreciated. I just cant see how once the battery is depleted its still producing the 201bhp and giving full acceleration? I just presumed this was what the issue was yesterday when the battery had gone I was left with the tiny petrol pulling the car up the steep hills.
Deleted User 3359

Post by Deleted User 3359 »

The Power is nothing to do with the remaining charge in the battery, until you exhaust the battery. So a bit of simple physics. Your 201bhp is approx 150 kW. The limit is on how quickly you use up that current, not that the current reduces (this is a significant feature of lithium based batteries)... I don't know what the kWH of the batteries are, but lets say they are 30kWH therefore the battery is capable of producing (very simplistic example and is only theoretical), so you could only run at flat out for 30/150 Hours = 12 minutes! on a fully charged battery... If you run at half power you'll get 24 minutes... etc....

There will be control systems involved to stop you running the battery down below the level at which it can be recharged etc..

If dealing with conventional lead acid batteries, the guide is that they shouldn't be discharged below 50% capacity (i.e. a 100 AmpHour battery) can only give you 50 amps before you damage the battery, but that could be a big heavy load of say 50 amps for an hour, or it could be 5 amps for 10 hours or 0.5 amp for 100 hours...
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Greggspies
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Post by Greggspies »

A feature of the XC40 hybrid is that even though the battery is sufficiently depleted for the gauge to show zero miles left and for the engine to take over it never gets truly exhausted. There is still sufficient energy kept in reserve to drive the electric motor when strong acceleration is needed. Regen then recovers that energy in the normal way of things.
MY22 T5 Recharge Inscription Pro in Denim Blue with Blond Interior
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Moss
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Location: Belgium & France

Post by Moss »

typolee wrote: Mon Sep 06, 2021 10:36 am Sorry if this seems a dumb question. Had to drive my dad to hospital (long journey away) in his T4 recharge. Everything seemed fine until the battery was totally depleted. I came to some steep hills and there was an apparent loss of power. I.e. it felt like a little 1.5 litre pulling a heavy car up a hill!! Is this what happens? When the battery is depleted you lose the power of the battery therefore acceleration is terrible? I'm concerned as I have one on order coming down from an XC90 and I'm not really concerned its not the car for me. Might have a build slot if anyone wants one?
My wife’s Volvo XC40 doesn’t feel like my usual 462 HP Audi Q7’s either, but I think that’s to be quite naturally expected.
If you are used to the XC90, it's good to remember that it’s the largest Volvo SUV while the XC40 is the smallest, so there is a difference indeed.
More in general, if you want it to feel like a big powerful car, my sincere advice to you is to buy a big powerful car.
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