High voltage battery health

So I just got my car back from annual service. Dealer report on the inspection has a line item called HV battery health. My 3 year old car with 3k miles shows 85% health.
Anyone knows what that even means? How would they know the health of the battery? By somehow testing how much charge it holds? Does 85% seem reasonable? I've never look into tesla battery much, but supposedly it degrades very slowly over time and mileage as max range shrinks? My EV range still shows 15 miles on full charge.

 

CHT GBT:
How to Interpret It for Warranty / Resale

Ferrari’s hybrid warranty terms (for SF90 and 296) cover the HV pack for 8 years / 50 000 mi, with a trigger threshold usually around 70 % SOH.
So:

• 85 % = healthy, but trending low for a 3-year-old car.
• Monitor annually; if it drops significantly (e.g., below 75 %), keep those reports — they document progressive loss for warranty evaluation.
• 
  When a service includes “HV Battery Health,” it usually means the technician ran an SDLink battery check.
  
  ➡️ Request this report:
  “Could you please email me the SDLink diagnostic report showing the HV battery SOH data and cell-voltage summary?”
  
  That printout is usually a single page titled:
  
  High Voltage Battery Diagnostic Summary or E-Diff/Battery Control Unit – Test Results.
  2️⃣ Locate These Lines on the Report
  You’ll typically see something like this:
  Pack nominal capacity: 7.45 kWh
  Usable capacity: 6.32 kWh
  State of Health (SOH): 85 %
  State of Charge (SOC): 98 %
  Number of charge cycles: 184
  Min/Max cell voltage: 4.09 V / 4.11 V
  Delta: 0.02 V
  
  Here’s what each means:
  • SOH (State of Health) = capacity now ÷ capacity when new → “battery health” number.
  • SOC (State of Charge) = how full the pack is right now.
  • Cycle count = total full-equivalent charge/discharge cycles (important for warranty).
  • Voltage delta = spread between cells; >0.05 V can indicate imbalance.
  
  So when the dealer listed “HV Battery Health 85 %,” it’s this SOH figure.
  
  Confirm It’s the Traction Pack, Not the 12-V Li-ion Battery
  
  Ferrari 296s have two separate batteries:
  • A small 12-V lithium-ion battery (for accessories and startup)
  • The HV battery pack (for hybrid propulsion)
  
  Sometimes the word “battery health” can refer to either.
  
  Look for wording like “High Voltage,” “Hybrid System,” or “RHTBMS.”
  
  If it mentions only “12 V Li-ion,” then 85 % would mean the auxiliary battery (less relevant).
• 
  Key takeaways
  1. 85 % = estimated usable capacity, not charge level.
  2. Measured by the BMS, not a physical drain-to-empty test.
  3. Slightly lower than ideal for 3 years / 3 k mi, but within plausible range for Ferrari’s high-output hybrid design.
  4. If it drops below ≈ 70 % during the 8-year HV-battery warranty, Ferrari would replace or repair the pack.
  5. To maximize longevity: keep it plugged in when parked, avoid repeated full-power electric launches on low SOC, and maintain coolant service intervals.

 

Here’s the safe, owner-accessible way to view hybrid system and HV battery diagnostic data on your Ferrari 296 GTB/GTS without using dealer software or voiding warranty.

This works on both U.S. and EU cars built since 2022.

You can open a hidden “cluster test” or technician menu on the driver display that shows data like:

• Hybrid system status (SOC, voltage, temperatures)
• HV battery pack voltage and current
• Estimated SOH (sometimes listed as “Battery Condition” or “Batt Health %”)
• Charge cycle counter

You can’t change anything — it’s read-only.

Step-by-Step: Accessing the Diagnostic Menu

⚠️ Safety first: Do this only when the car is stationary, in Park, ignition on (engine off). Don’t press the brake or accelerator.

1️⃣ Enter ignition-on mode

• Sit in the driver’s seat.
• Press the Engine Start/Stop button without pressing the brake pedal.
• Wait for the full digital cluster to illuminate.

2️⃣ Open the service / cluster menu

• On the left haptic pad (or rotary dial, depending on year), press and hold both the “Back” and “OK” buttons together for about 5–7 seconds.
• The screen will flash and display “Service Menu” or “Cluster Diagnostics.”

3️⃣ Navigate to “Hybrid Data” or “Battery Information”

• Use the scroll wheel or arrows to move to the Hybrid System submenu.
• You’ll typically see data lines such as:
• 
  HV Batt Voltage: 355 V
  HV Batt Current: 0 A
  HV Batt SOC: 98 %
  HV Batt Health: 85 %
  HV Batt Cycles: 187
  Cell Delta: 0.02 V
  
  Some clusters show “SOH 85 %,” others “Batt Health 85 %” — they’re equivalent.
  
  4️⃣ Exit
  • Press Back until you return to the normal tachometer / hybrid gauge view.
  • To completely leave service mode, turn the car off for > 30 seconds.
  
  Notes
  • If you don’t see “Hybrid Data”, your software version may hide it for owners. Some U.S. dealers disable this view; if so, ask them to include a printout at each service.
  • The numbers refresh every few seconds — you can watch pack voltage drop slightly as the system warms.
  • You can’t harm anything: it’s diagnostic-only.
  • Take a phone photo of the screen — it’s useful for tracking battery health over time.
  
  Reading What You See
  
  • SOH ≥ 85 %: Typical for 3 years on a small performance-hybrid pack.
  • SOH < 75 %: Start documenting; Ferrari warranty usually triggers around 70 %.
  • Cell delta > 0.05 V: Indicates imbalance; mention it at service.
  • Cycle count: Each “cycle” ≈ full discharge/charge equivalent; 150–250 is common after 3 years.
  • 
    

 

Really helpful post - thank you. FWIW when I asked last December (car 18 month old) Ferrari said they measured it at 85% on my GTS. My friend’s slightly younger GTB was at 89%. Will check again when I next get the car out.

 

That's interesting. Could you share your mileage and typical driving pattern? (How much ED mode do you use and if you're typically on performance or qualify) I'm going to try use some of these data points and do some back of envelope calculations to see how best to preserve the battery while not sacrifice fun.

 

Ok so full disclaimer, I have no prior background in EV or battery technology. Here's my take from a few quick google searches for curiosity. All number I try to be on the pessimistic/conservative side.
1. EV Lithium batteries are rated generally at 2000 full charge cycles for their lifetime. Quick calculation for sanity check: Typical Tesla real world range 200 miles * 2000 = 400,000 miles. Ok, impressive! We can live with that.
2. Ferrari 296, 15 mile EV range * 2000 cycles = 30,000 miles if drive exclusively on EDrive.
3. It's beneficial for extending life by not draining it too far and not over charging (I think OEM charger would manage the over charging part)
4. Rapid charging/discharging at fast charger hurts battery life. One chart I found showed degradation over time is twice as fast.
5. Degradation is not strictly linear, it tends to drop more in the first few years and then levels out more. This is good news for me seeing 85% SOH after 3 years. Hopefully the drop slows down from here. My first reaction was the 85% seemed low because the car only had 3k miles on it and should at most have under 100 charge cycles (or 5% of total life) on the battery.

According to the MyDrive Analysis (the spinning car after shutdown), my driving pattern averages roughly 33% on electric power. So 30k miles on EV life hopefully means the car will be totally fine until 100k miles. Great, I can live with that. Even if it's 50k miles, that's acceptable also, that's 10-15 years of enjoyment for a typical supercar owner.

Here's my conjecture if all the above findings are true. It's better to not overly use the car in Edrive only, every 15 miles eats up a drive cycle and you risk over draining the battery. I currently use it going in and out of the neighborhood and maybe in heavy traffic sitting at stop lights. Also, per point number 4 above, I know we had the debate over whether to use the car in qualify or performance by default. My theory is it's better to use performance as Ferrari recommends unless you need the extra boost. Qualify must be draining and charging the battery at a more aggressive rate repeatedly. In my experience, on typical streets, performance is already so fast that there aren't really that many opportunities to go full throttle, few quick blasts when the road is empty for giggles is my typical usage pattern. If you're not going constant full throttle in performance mode, why call for more power to go qualify.

Having said that, it's just a car. Not gonna sweat over the battery, use it as it pleases you. If it breaks, buy a new one. Some folks here think the car is going to depreciate to zero anyway...

 

I couldn’t get into the menu with those instructions

 

“1. EV Lithium batteries are rated generally at 2000 full charge cycles for their lifetime. Quick calculation for sanity check: Typical Tesla real world range 200 miles * 2000 = 400,000 miles. Ok, impressive! We can live with that.
2. Ferrari 296, 15 mile EV range * 2000 cycles = 30,000 miles if drive exclusively on EDrive.”

I’’m not sure a 15 EV range on the 296 battery is equivalent to a full cycle like a normal electric battery. And I don’t know.

 

I think it makes sense. Tesla battery is roughly 15x the size of a 296. Tesla full cycle range is in the same ballpark as 15 x 15=225 miles.

 

I tried it and could not get it to work on a ‘25 RHD GTS

 

In the NSX, the battery manufacture stated that it has 50k charge cycles, 10+ year life span. The battery cells in 296 are supplied by SK on, likely similar to EHW5 battery cells in NSX. As 3 time NC1 NSX owner (17, 19, 22), it is now nearly 10 years old, I have yet heard anyone had to replace high voltage battery yet.

There are some information on life span and charge cycles in this video, it also mentioned the deeper the depth of discharge, the fewer charge cycle battery can last:

 

That's a very good data point

 

Typical use isn’t running down the battery to zero. And likely it won’t let you anyway.

Normal use is running in performance mode which manages the battery half full. Then uses the capacity to fill in for peak needs. Under such uses the battery will last quite a long time. How long have Prius been on the road with low battery failure? Over 25 years?

No reason to believe the battery pack will need replacement over and above expected failure rates.

 

Same here. Not sure what is meant by left touch pad and back controls.

on the ‘23 are you talking about the scroll wheel to control the volume, on the left side and back of the steering wheel?

 

I believe those instructions were generated by hallucinating AI. For topics where there are not a lot of info on the web to copy paste from, AI doesn't work very well.