High voltage battery health

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.