Question about Plug-In Hybrid Audi

[Egg_Head]

My nice is looking at a 2021 Audi Q5 w/38k miles and is a plug-in hybrid. She does not have a plug-in charger at her condo nor at work. Very unlikely this vehicle will get much, if any plug time. I know next to nothing about this technology, will not ever or very infrequently plugging in the vehicle affect the life of the battery and overall function of the hybrid system?

 

[skyactiv]

Price a new battery for the fun of it.

 

[fdcg27]

It shouldn't matter if the battery isn't charged from an external source.
The car will still function as a normal hybrid.
The value of the PHEV function is totally negated, however.
The high voltage pack itself should run under ten grand and there are repair options as well, just have to find someone who can do the diagnosis and work.
This does beg the question of why someone would buy a PHEV with no means of taking advantage of the limited EV range offered with external charging?
This appears to be a pretty mild PHEV implementation with less than twenty miles of EV range with a fully charged battery and in HEV mode fuel economy isn't all that good.
It's almost as if VAG was relying on the PHEV function to make EPA fuel economy numbers look more attractive than they really are in typical use.

 

[JD!]

From my viewpoint, it's not ideal. Take my word with a grain of salt - I'm not an engineer, just someone who likes researching whatever junk I'm driving at the moment. I hear from a lot of folks that PHEVs with bad cells/packs come disproportionately from owners who never charge the car.

Some of my theories below - I have minimal evidence to back these up...
- Although the current drawn at minimum state of charge should be relatively low, the voltage sag under load stresses the pack. Constantly operating in this state could lead to accelerated chemical degradation. Furthermore, if the car is stored at minimum state of charge, self-discharge, the BMS, and 12v vehicle electronics draining the 12v battery (which the HV needs to top up) can bring the pack below a safe state of charge.
- Cell imbalance tends to be magnified at low state of charge. Packs generally use resistors to bleed current from higher voltage cells for balancing, and at lower states of charge, it takes a long time to balance. "Top balancing" generally happens with every full charge, who knows when balancing happens otherwise, and how long it takes - it varies from make to make.
- Without charging once in a while to recalibrate the BMS, it may store an inaccurate state of health/actual capacity. As batteries age chemically, capacity decreases and internal resistance increases. If the BMS stored state of health is higher than it should be, it could target a lower min SOC than is necessary to prevent damaging voltage sag under load given the battery's current state.

Just my thoughts. Modern battery management systems probably have a lot of this figured out, but if I were in the same situation, I'd probably set my car to at least run in "battery control" mode (or whatever Audi's equivalent is) with the target charge set at 25-30%.

 

[fdcg27]

From my viewpoint, it's not ideal. Take my word with a grain of salt - I'm not an engineer, just someone who likes researching whatever junk I'm driving at the moment. I hear from a lot of folks that PHEVs with bad cells/packs come disproportionately from owners who never charge the car.

Some of my theories below - I have minimal evidence to back these up...
- Although the current drawn at minimum state of charge should be relatively low, the voltage sag under load stresses the pack. Constantly operating in this state could lead to accelerated chemical degradation. Furthermore, if the car is stored at minimum state of charge, self-discharge, the BMS, and 12v vehicle electronics draining the 12v battery (which the HV needs to top up) can bring the pack below a safe state of charge.
- Cell imbalance tends to be magnified at low state of charge. Packs generally use resistors to bleed current from higher voltage cells for balancing, and at lower states of charge, it takes a long time to balance. "Top balancing" generally happens with every full charge, who knows when balancing happens otherwise, and how long it takes - it varies from make to make.
- Without charging once in a while to recalibrate the BMS, it may store an inaccurate state of health/actual capacity. As batteries age chemically, capacity decreases and internal resistance increases. If the BMS stored state of health is higher than it should be, it could target a lower min SOC than is necessary to prevent damaging voltage sag under load given the battery's current state.

Just my thoughts. Modern battery management systems probably have a lot of this figured out, but if I were in the same situation, I'd probably set my car to at least run in "battery control" mode (or whatever Audi's equivalent is) with the target charge set at 25-30%.

I suspect that it may depend upon the specific operating profile of the car. If the user has even a mild couple mile downhill run on the way home, the kind you'd only really notice on a bicycle, then regen alone would likely bring the pack to 80%. In my case, with about a half mile downhill from the north, regen would probably do this.
Still, were my Accord to be capable of even the rather anemic EV range of this Audi, it would need more than twice the pack capacity that it has, so maybe not.
You've given food for thought.

 

[Trav]

My nice is looking at a 2021 Audi Q5 w/38k miles and is a plug-in hybrid. She does not have a plug-in charger at her condo nor at work. Very unlikely this vehicle will get much, if any plug time. I know next to nothing about this technology, will not ever or very infrequently plugging in the vehicle affect the life of the battery and overall function of the hybrid system?

Check out the parts availability and price for that part in Europe. At this point in time I would stay well clear of that car.

https://audi.oempartsonline.com/v-2...lus--2-0l-l4-electric-gas/electrical--battery

 

[Passport1]

Doesn't make sense if no charging is expected. Perhaps she is planning to purchase a house with a garage and didn't tell you?

 

[Egg_Head]

Doesn't make sense if no charging is expected. Perhaps she is planning to purchase a house with a garage and didn't tell you?

No, she's not buying a home anytime soon. She's just locked onto this car and quite frankly is very stubborn. I am her uncle who is "the car guy" and she asked my opinion. I understand she is not obligated to take my advice as I have already given her variations of all the points previously made here and she counters with "research" from ChatGPT. Kids these days, I'll tell ya ...

 

[The_Jeff]

I suspect that it may depend upon the specific operating profile of the car. If the user has even a mild couple mile downhill run on the way home, the kind you'd only really notice on a bicycle, then regen alone would likely bring the pack to 80%. In my case, with about a half mile downhill from the north, regen would probably do this.

You would need to Regen down Mt Washington to get a meaningful fill of the pack.

I have a Prius Prime and per the car I might get "4%" charge after a long downhill.

I, like OP's wife, don't use the plug-in feature all that much, mostly because it's cheaper right now for me to run gas. My electricity is 21 cents per marginal kWh and I've calculated my break-even point to be $3/gal summer, $3.75 in winter, which gas is currently winning. It is nice having two potential fuel sources over the car's life cycle, in case "the man" jacks the price of one of them up.

I DO use the plug-in when I'm at my off-grid second property, to steal some surplus electricity for the ride home. I also throw it on a charger for a few minutes to avoid a cold start if I just want to move the car to a different parking spot, for example. I have lithium, which I assume OP does as well, and my owners manual basically says to charge it right before I use it for best battery maintenance. The car, in gas hybrid mode, also occasionally drains then refills the "hybrid partition" as some sort of internal rebalancing/ maintenance. I assume Audi has similar moves.

Finally, my car is capable of charging the all-electric "partition" via button sequence off the gas motor. I've never used it but it has theoretical advantages-- like if you're on a road trip and going to hit a cheap gas station, stash some power in the battery bank so you'll have more range on the next fill-up. If OP did this once in a while they could sleep soundly about "stretching" the battery without the inconvenience of finding an outlet to plug the car into.

 

[fdcg27]

You would need to Regen down Mt Washington to get a meaningful fill of the pack.

I have a Prius Prime and per the car I might get "4%" charge after a long downhill.

I, like OP's wife, don't use the plug-in feature all that much, mostly because it's cheaper right now for me to run gas. My electricity is 21 cents per marginal kWh and I've calculated my break-even point to be $3/gal summer, $3.75 in winter, which gas is currently winning.

I DO use the plug-in when I'm at my off-grid second property, to steal some surplus electricity for the ride home. I also throw it on a charger for a few minutes to avoid a cold start if I just want to move the car to a different parking spot, for example. I have lithium, which I assume OP does as well, and my owners manual basically says to charge it right before I use it for best battery maintenance. The car, in gas hybrid mode, also occasionally drains then refills the "hybrid partition" as some sort of internal rebalancing/ maintenance. I assume Audi has similar moves.

Finally, my car is capable of charging the all-electric "partition" via button sequence off the gas motor. I've never used it but it has theoretical advantages-- like if you're on a road trip and going to hit a cheap gas station, stash some power in the battery bank so you'll have more range on the next fill-up. If OP did this once in a while they could sleep soundly about "stretching" the battery without the inconvenience of finding an outlet to plug the car into.

So you can't even move your PHEV without throwing some charge in it?
I can drive the HAH the first couple of miles from home the next morning in EV mode with regen from the final half mile or so home on regen.

 

[The_Jeff]

So you can't even move your PHEV without throwing some charge in it?
I can drive the HAH the first couple of miles from home the next morning in EV mode with regen from the final half mile or so home on regen.

I could if I feather the pedal and turn the HVAC off but it's cringey getting that accidental cold start in for no reason.

 

[BMWTurboDzl]

My nice is looking at a 2021 Audi Q5 w/38k miles and is a plug-in hybrid. She does not have a plug-in charger at her condo nor at work. Very unlikely this vehicle will get much, if any plug time. I know next to nothing about this technology, will not ever or very infrequently plugging in the vehicle affect the life of the battery and overall function of the hybrid system?

She'll take a huge hit on depreciation when she goes to sell it in 5-7 yrs. Munson's are going to low-ball her because "the battery is old".

 

[fdcg27]

I could if I feather the pedal and turn the HVAC off but it's cringey getting that accidental cold start in for no reason.

Same. I turn off the HVAC when parking. Otherwise, when ambient is below the set temp it forces engine start.

 

[goblin]

Oh come on now. She can charge every time she gets to WholeFoods or to most libraries, or any other supermarket where they sell locally-made scented candles, hand-made soap and have the pictures of the farmers they buy their milk from.

And with the ballpark 30 miles charged every hour at those types of charges, she'll be all topped-off in the time that my spends at Wholefoods to get from the fruits and veggie section to the meats.

 

[GrumpyCat]

Price a new battery for the fun of it.

Price a new engine and transmission for your ICE.

 

[GrumpyCat]

It shouldn't matter if the battery isn't charged from an external source.
The car will still function as a normal hybrid.
The value of the PHEV function is totally negated, however.

No, it is not. A PHEV has a higher capacity battery than a plain hybrid so in the event one has excess regenerative power there is a place to put it.

The high voltage pack itself should run under ten grand and there are repair options as well, just have to find someone who can do the diagnosis and work.

Lots of 3rd parties making replacement battery assemblies.

This does beg the question of why someone would buy a PHEV with no means of taking advantage of the limited EV range offered with external charging?

Because if you need it and don't have it you can't get it. Am pretty sure your argument fails exactly the same for 400 HP ICE vehicles, "why buy if you are not using all 400 HP?"

 

[GrumpyCat]

She'll take a huge hit on depreciation when she goes to sell it in 5-7 yrs. Munson's are going to low-ball her because "the battery is old".

Car dealer will low-ball you for not having nitrogen in your tires. For not using $15/qt "synthetic" every 3,000 miles. For not having receipts proving one only used ethanol-free gasoline.

 

[Brons2]

From my viewpoint, it's not ideal. Take my word with a grain of salt - I'm not an engineer, just someone who likes researching whatever junk I'm driving at the moment. I hear from a lot of folks that PHEVs with bad cells/packs come disproportionately from owners who never charge the car.

Some of my theories below - I have minimal evidence to back these up...
- Although the current drawn at minimum state of charge should be relatively low, the voltage sag under load stresses the pack. Constantly operating in this state could lead to accelerated chemical degradation. Furthermore, if the car is stored at minimum state of charge, self-discharge, the BMS, and 12v vehicle electronics draining the 12v battery (which the HV needs to top up) can bring the pack below a safe state of charge.
- Cell imbalance tends to be magnified at low state of charge. Packs generally use resistors to bleed current from higher voltage cells for balancing, and at lower states of charge, it takes a long time to balance. "Top balancing" generally happens with every full charge, who knows when balancing happens otherwise, and how long it takes - it varies from make to make.
- Without charging once in a while to recalibrate the BMS, it may store an inaccurate state of health/actual capacity. As batteries age chemically, capacity decreases and internal resistance increases. If the BMS stored state of health is higher than it should be, it could target a lower min SOC than is necessary to prevent damaging voltage sag under load given the battery's current state.

Just my thoughts. Modern battery management systems probably have a lot of this figured out, but if I were in the same situation, I'd probably set my car to at least run in "battery control" mode (or whatever Audi's equivalent is) with the target charge set at 25-30%.

I really don't think this has anything to do with this thread. Toyotas have had hybrid battery packs go hundreds of thousands of miles and the Toyota hybrid setup is generally considered reliable. Are you saying Audi is significantly worse? You openly state that you "have minimal evidence to back these up"

 

[Trav]

Price a new engine and transmission for your ICE.

I can repair or rebuild almost any automotive engine and many transmissions and diff but I cannot rebuild a battery pack which cost over 22K for that Audi part only. A brand new 2.0 gas engine for that car is less than half that, I can buy a brand new short block for under 3K for that car.

https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/battery/80a915100k/

 

[goblin]

I can repair or rebuild almost any automotive engine and many transmissions and diff but I cannot rebuild a battery pack...

Let's not despair. It's an Audi. There is still an engine on it, which will likely need replacement before the battery goes belly up.