HV Battery State of Health (SoH) - what to ask before buying
Discussion
XMA Simon said:
Also the failure rate for Li-Ion batteries (in general - not just for cars) is something like 1 in a million. While that sounds good that is one in a million cells and some of these auto batteries have hundreds to thousands of cells. And if they short circuit with significant charge stored they catch fire and it is BBQ time.
So besides the debate around performance all this battery management software is there to minimise the risk of a fire event. So when the software says to switch the battery it becomes a real safety priority to get it done.
Ferrari, Porsche and all the other car companies need to improve communication and transparency particularly in these performance hybrids where rapid, frequent charge / discharge cycles are placing heavy loads on HV batteries.
I suppose now we can see why the 296 Challenge car does without the HV / hybrid gubbins. Imagine a road version of that... it would sell like hotcakes!
It used to be quite simple to evaluate a car. Now you need degrees in chemistry, engineering and IT / software to evaluate them. LOLs.
I'm nowhere near affording a 296 yet so it's not an issue for me but like you say the manufacturers need to sort this out otherwise the depreciation on these £200k plus cars will be horrendous and put buyers off.So besides the debate around performance all this battery management software is there to minimise the risk of a fire event. So when the software says to switch the battery it becomes a real safety priority to get it done.
Ferrari, Porsche and all the other car companies need to improve communication and transparency particularly in these performance hybrids where rapid, frequent charge / discharge cycles are placing heavy loads on HV batteries.
I suppose now we can see why the 296 Challenge car does without the HV / hybrid gubbins. Imagine a road version of that... it would sell like hotcakes!
It used to be quite simple to evaluate a car. Now you need degrees in chemistry, engineering and IT / software to evaluate them. LOLs.
Edited by XMA Simon on Friday 9th January 19:15
I was thinking about the challenge not being a hybrid and then saw your post about it. Could we ever get to a point where instead of paying £30k to replace a failing battery an independent could remove it and you run it as a ICE car or would it be too complicated? It would still have 654hp which is more than enough for most people.
By the way, my comment re the Revuelto is most likely irrelevant based on some reading. Ferrari and Lambo have taken two different approaches. Lambo uses the battery to deliver a fast torque fill punch and it also charges very quickly. It’s more like a capacitor. The 296 is like a traditional PHEV that requires the battery to feed the electric motor to hit peak power and it’s not recharging as quickly. So a degraded battery in a 296 doesn’t provide the same charge buffer required over a lap let’s say. I would have thought with the 296 you will always hit a power limit if you’re on max attack for long enough, it’s just a question of when. It looks like Ferrari has prioritised CO2 rating and EV range in addition to power. And given that Ferrari is offering a battery replacement programme, it seems they also agree that the battery needs to be in tip top shape for the car to operate as intended.
Or something like that lol.
Or something like that lol.
Thank you for all the info, I am actively in the process of viewing a GTS next week, told the sales guy i would like to know the SOH and his reply was 'first time he's been asked this'
It does put me off buying anything Hybrid, i usually whack the car on a trickle charger as soon as i put in garage, now my head is all over the place as to what to do and not to do
It does put me off buying anything Hybrid, i usually whack the car on a trickle charger as soon as i put in garage, now my head is all over the place as to what to do and not to do
MeisterH said:
Thank you for all the info, I am actively in the process of viewing a GTS next week, told the sales guy i would like to know the SOH and his reply was 'first time he's been asked this'
It does put me off buying anything Hybrid, i usually whack the car on a trickle charger as soon as i put in garage, now my head is all over the place as to what to do and not to do
After you buy your car, this is directly from Ferrari Hybrid Charging materials, "When parking for longer than two weeks, please enable Long Parking Mode. The system automatically manages battery levels to maintain the ideal charge and prevent premature battery aging."It does put me off buying anything Hybrid, i usually whack the car on a trickle charger as soon as i put in garage, now my head is all over the place as to what to do and not to do
Frankly, if you are going to store the car for a week, I would use Long Parking Mode. As Ferrari says, "prevent premature battery aging".
I’ve been digging into how the HV battery’s state of health actually shows up in the way the 296 behaves, and thought it might be useful to lay out the mechanics behind it.
Baseline Numbers
• The e‑motor contributes roughly 167 hp (123 kW)
• The HV battery is about 7.45 kWh gross, with ~6.5 kWh available once Ferrari’s buffer is accounted for
• If you ran the motor flat‑out from the battery alone, you’d drain it in around three minutes — although the hybrid control system never allows anything close to that in the real world
How the “3‑Minute” Figure Comes About
Take the usable battery capacity and divide it by the motor’s peak draw and you get the theoretical maximum duration. That’s the lab‑math version. Out on the road or track, thermal management and software limits mean you only ever see short, intense bursts — typically 30–60 seconds of full shove before the system starts managing itself.
Track Behaviour
This is where SoH becomes most noticeable because the battery is repeatedly asked for maximum current.
• Around 90% SoH: Hybrid boost is stable through a 20–30 minute session. Torque fill feels identical lap after lap.
• Around 70% SoH: You still get full‑power bursts, but fewer of them. After 5–10 minutes of pushing, the car may start rationing electric assist until regen catches up. The driving experience shifts toward “V6 with hybrid help” rather than the seamless blend you get when the battery is fresher.
• Heat sensitivity: As SoH drops, the pack heats up more quickly, which shortens the window of maximum hybrid contribution.
Fast Road Use
Degradation is much harder to detect on the road because you rarely stress the system continuously.
• 90% SoH: Feels essentially new. Every acceleration has the same hit of torque fill.
• 70% SoH: Peak power is still there, but if you chain several hard pulls together you’ll notice the system backing off sooner. Electric‑only range shrinks, though that’s largely academic in hybrid mode.
Baseline Numbers
• The e‑motor contributes roughly 167 hp (123 kW)
• The HV battery is about 7.45 kWh gross, with ~6.5 kWh available once Ferrari’s buffer is accounted for
• If you ran the motor flat‑out from the battery alone, you’d drain it in around three minutes — although the hybrid control system never allows anything close to that in the real world
How the “3‑Minute” Figure Comes About
Take the usable battery capacity and divide it by the motor’s peak draw and you get the theoretical maximum duration. That’s the lab‑math version. Out on the road or track, thermal management and software limits mean you only ever see short, intense bursts — typically 30–60 seconds of full shove before the system starts managing itself.
Track Behaviour
This is where SoH becomes most noticeable because the battery is repeatedly asked for maximum current.
• Around 90% SoH: Hybrid boost is stable through a 20–30 minute session. Torque fill feels identical lap after lap.
• Around 70% SoH: You still get full‑power bursts, but fewer of them. After 5–10 minutes of pushing, the car may start rationing electric assist until regen catches up. The driving experience shifts toward “V6 with hybrid help” rather than the seamless blend you get when the battery is fresher.
• Heat sensitivity: As SoH drops, the pack heats up more quickly, which shortens the window of maximum hybrid contribution.
Fast Road Use
Degradation is much harder to detect on the road because you rarely stress the system continuously.
• 90% SoH: Feels essentially new. Every acceleration has the same hit of torque fill.
• 70% SoH: Peak power is still there, but if you chain several hard pulls together you’ll notice the system backing off sooner. Electric‑only range shrinks, though that’s largely academic in hybrid mode.
My 296 has been sat at the dealership for nearly 3 months, awaiting rejection.
On top of the problems I’ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times……..without turning a wheel !
On top of the problems I’ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times……..without turning a wheel !
ted 191 said:
My 296 has been sat at the dealership for nearly 3 months, awaiting rejection.
On top of the problems I ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times ..without turning a wheel !
What are they saying about this and why is it taking so long?On top of the problems I ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times ..without turning a wheel !
When I had to reject my 296GTS last year, Although the main dealer was extremely difficult I managed a resolve and monies returned within 7 days. This was within 30 days of Purchase so slightly easier.
Trollbuster said:
What are they saying about this and why is it taking so long?
When I had to reject my 296GTS last year, Although the main dealer was extremely difficult I managed a resolve and monies returned within 7 days. This was within 30 days of Purchase so slightly easier.
I’m having to go through Ferrari finance (owned by Ferrari) and they won’t reject it, so now using the financial ombudsman.When I had to reject my 296GTS last year, Although the main dealer was extremely difficult I managed a resolve and monies returned within 7 days. This was within 30 days of Purchase so slightly easier.
ted 191 said:
My 296 has been sat at the dealership for nearly 3 months, awaiting rejection.
On top of the problems I ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times ..without turning a wheel !
I think so many hybrid cars are poorly cared for at Ferrari Dealerships in the UK. I visited one Ferrari Dealer who had approximately six 296s for sale outside in the cold rain, only one was plugged in. Even the salesman said to me, "gee, maybe we should plug these in?" Yes, mate, maybe you should. On top of the problems I ve had, whilst in the care of a main dealer, the car has been regularly charged via the 400 volt battery, the 12 volt battery has now depleted to 10.9 volts and it has gone into limp mode three times ..without turning a wheel !
I'm really sorry you guys had to get the cars rejected.
This is not really applicable to high performance hybrids like Ferrari and Lambo, but still offers some stats for normal PHEVs:
https://www.topspeed.com/how-phev-batteries-from-d...
https://www.topspeed.com/how-phev-batteries-from-d...
Out of interest, what is the actual outcome everyone is worried about? Ofcourse all cars need due diligence and have common failure points, what is the big concern of a battery SoH vs any other high ticket failure gearbox/turbos etc.
I'm not trying to troll just working out what the problem really is, it'll hit 0% in a few years and not even start the engine? It will no longer have enough to juice to boost road driving / track driving? Or just it wont have much electric only range?
SF90s are coming up to 5/6 years now are we seeing replacements under the Ferrari hybrid warranty happening / are needed by many cars? BEVs obviously hold up very well in reality, PHEVs do seem worse but even the worst examples seem to basically flatline around 70% - do we not expect Ferrari to match that? Or is that already bad enough?
They seem like such a bargain regardless to me!
I'm not trying to troll just working out what the problem really is, it'll hit 0% in a few years and not even start the engine? It will no longer have enough to juice to boost road driving / track driving? Or just it wont have much electric only range?
SF90s are coming up to 5/6 years now are we seeing replacements under the Ferrari hybrid warranty happening / are needed by many cars? BEVs obviously hold up very well in reality, PHEVs do seem worse but even the worst examples seem to basically flatline around 70% - do we not expect Ferrari to match that? Or is that already bad enough?
They seem like such a bargain regardless to me!
Chrisatronic said:
Out of interest, what is the actual outcome everyone is worried about? Ofcourse all cars need due diligence and have common failure points, what is the big concern of a battery SoH vs any other high ticket failure gearbox/turbos etc.
I'm not trying to troll just working out what the problem really is, it'll hit 0% in a few years and not even start the engine? It will no longer have enough to juice to boost road driving / track driving? Or just it wont have much electric only range?
SF90s are coming up to 5/6 years now are we seeing replacements under the Ferrari hybrid warranty happening / are needed by many cars? BEVs obviously hold up very well in reality, PHEVs do seem worse but even the worst examples seem to basically flatline around 70% - do we not expect Ferrari to match that? Or is that already bad enough?
They seem like such a bargain regardless to me!
Thanks for your comment. In an earlier post I go through the likely driving implications of a degrading HV battery (HVB).I'm not trying to troll just working out what the problem really is, it'll hit 0% in a few years and not even start the engine? It will no longer have enough to juice to boost road driving / track driving? Or just it wont have much electric only range?
SF90s are coming up to 5/6 years now are we seeing replacements under the Ferrari hybrid warranty happening / are needed by many cars? BEVs obviously hold up very well in reality, PHEVs do seem worse but even the worst examples seem to basically flatline around 70% - do we not expect Ferrari to match that? Or is that already bad enough?
They seem like such a bargain regardless to me!
If a car is under Ferrari hybrid warranty / the hybrid extension programmes, then in general there’s not much to worry about in day-to-day terms — it’s mainly an ownership/risk question once you’re out of cover. There are already cars being advertised (at Ferrari dealers) with HVB SoH readings in the 60s, so the key question is really: what happens if it keeps degrading?
A few points to separate out:
It won’t “hit 0% and not start the engine.” The ICE can still run even if EV mode and e-boost are limited. The usual symptoms of a tired pack are less EV range, and potentially more conservative e-boost / reduced repeatability under sustained high load (track, repeated hard pulls), rather than the car becoming undriveable.
SoH isn’t a single “fail point.” In most cases you’ll see gradual changes (range/boost/time in e-modes), unless you get an actual fault (cell imbalance, isolation fault, etc.) which would trigger warnings and restrictions.
Out of warranty is where it bites. If you’re out of cover and you need to replace a 296 HVB, you’re looking at roughly £35k (order of magnitude) which obviously changes the “bargain” maths completely.
So for anyone shopping these, the practical questions are:
is the hybrid warranty active and continuous, and
what does Ferrari actually do in practice at different SoH levels / symptoms.
If anyone has real-world SF90/296 examples (mileage/usage/SoH and what Ferrari did), that’d be really useful data for this thread.
The one issue that could occur whilst your car is under warranty is down time. If you start to get regular HVB error codes, etc and Ferrari determines that you need a new HVB under the warranty, no doubt that the car is going to be out of action for a while.
OK so it's more of a 'computer says no' concern.
If some certain (unknowable) combination of degradation / cell balancing / heat / other occurs to the point where the car ecu basically says no, you're in limp mode until the battery is repaired/replaced.
I guess everyone is in wait and see territory, hence the current depreciation / market timidness. Hopefully by the time this actually starts hitting cars (if not yet, when? 8, 10, 15 years?) a good indie solution will exist.
Interesting! Seems like right now the 'sweet spot' might actually be a newer car with some manufacturer warranty left, get to year 5 then get out. Or if you think the battery risk is overblown a later car could prove a real bargain, maybe keep an eye on SF90s as a guide.
If some certain (unknowable) combination of degradation / cell balancing / heat / other occurs to the point where the car ecu basically says no, you're in limp mode until the battery is repaired/replaced.
I guess everyone is in wait and see territory, hence the current depreciation / market timidness. Hopefully by the time this actually starts hitting cars (if not yet, when? 8, 10, 15 years?) a good indie solution will exist.
Interesting! Seems like right now the 'sweet spot' might actually be a newer car with some manufacturer warranty left, get to year 5 then get out. Or if you think the battery risk is overblown a later car could prove a real bargain, maybe keep an eye on SF90s as a guide.
Chrisatronic said:
OK so it's more of a 'computer says no' concern.
If some certain (unknowable) combination of degradation / cell balancing / heat / other occurs to the point where the car ecu basically says no, you're in limp mode until the battery is repaired/replaced.
I guess everyone is in wait and see territory, hence the current depreciation / market timidness. Hopefully by the time this actually starts hitting cars (if not yet, when? 8, 10, 15 years?) a good indie solution will exist.
Interesting! Seems like right now the 'sweet spot' might actually be a newer car with some manufacturer warranty left, get to year 5 then get out. Or if you think the battery risk is overblown a later car could prove a real bargain, maybe keep an eye on SF90s as a guide.
Agreed. To me, the SoH is not something to be scared of, it's just another thing to check like the car's mileage. Some people like buying a 2k mile car instead of a 12k mile car. The 12k mile car is likely much closer to needing new brake pads, new tyres, etc. It's not like the 12k mile car is a bad car, it's just likely closer to needing some work. If some certain (unknowable) combination of degradation / cell balancing / heat / other occurs to the point where the car ecu basically says no, you're in limp mode until the battery is repaired/replaced.
I guess everyone is in wait and see territory, hence the current depreciation / market timidness. Hopefully by the time this actually starts hitting cars (if not yet, when? 8, 10, 15 years?) a good indie solution will exist.
Interesting! Seems like right now the 'sweet spot' might actually be a newer car with some manufacturer warranty left, get to year 5 then get out. Or if you think the battery risk is overblown a later car could prove a real bargain, maybe keep an eye on SF90s as a guide.
A 70% SoH HVB car is probably closer to the point of getting errors and needing a new battery than a 95%. But that doesn't mean the 70% is "bad".
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