EVMetricsOBD

Use Cases

EV owners who want insight without a dealer visit. Professionals who need reports their customers can act on. Two different tools inside one app.

Overview Showcase Vehicles Vehicle Data API Use Cases Adapters ECUs

iPhone & iPad — For EV owners and enthusiasts

Bluetooth OBD dongle. No tools. No appointment. Works in a car park.

iOS / iPad · Case 01

Pre-purchase battery health check

Buying a used Jaguar I-Pace. Seller claims "perfect battery." You have 20 minutes.
The used EV market has a battery transparency problem. State of charge is visible on the dash, but state of health — the true measure of how much capacity the battery has lost — is not. Dealers rarely volunteer it and most buyers have no way to check.

With a £25 Bluetooth OBD dongle and EVMetricsOBD, you can read the BMS directly before signing anything.
  • 1 Plug a Bluetooth ELM327 dongle into the OBD port under the dashboard. Turn ignition on (not engine start).
  • 2 Open EVMetricsOBD on iPhone. Select Jaguar I-Pace template. Tap Connect — pairs automatically.
  • 3 Go to Health → State of Health. The app queries the BECM (7E4) directly and returns SoH as a percentage of original factory capacity.
  • 4 Check Battery → Cell Voltages. All 18 module banks should read within ±15 mV of each other at rest. Large spreads indicate cell imbalance.
  • 5 Run a DTC scan. Any stored fault codes — especially P0A80 (Battery Degradation) — appear with AI-generated severity ratings and recommended actions.
  • 6 Tap Generate Report. Share the HTML report with the seller or keep it for your records.
A 92% SoH reading and balanced cells in under 10 minutes. You negotiate £1,500 off a car showing P0A80 that the seller "didn't know about" — or you walk away from one showing 78% with imbalanced modules.
Hardware needed: any ELM327 Bluetooth LE dongle (OBDLink MX+, Vgate iCar Pro, Carista). Budget ~£20–£45.
iOS / iPad · Case 02

Charge curve logging during a session

I-Pace owner. Noticing DC fast charging feels slower than it used to. Is the taper starting earlier?
EV charging curves taper as the battery fills — that's normal. What's not normal is a taper that starts significantly earlier than it should, or a curve that looks different from what the manufacturer published. The Charging Graph tool plots active power (kW) against SoC (%) in real time, building a permanent record of every session.
  • 1 Connect OBD dongle at the DC charger. Select Charging Graph category on the Dashboard tab.
  • 2 The app polls HV voltage, HV current and SoC from the BECM every few seconds.
  • 3 Watch the curve build. Note the SoC at which power starts to taper — typically above 80% on a healthy pack.
  • 4 Compare across sessions over time. A taper that creeps earlier across weeks may indicate emerging thermal management issues.
Confirmed charging taper was starting at 72% SoC rather than the expected 80%+. Booked a service appointment with evidence — the dealer found a marginal coolant pump performance DTC.
iOS / iPad · Case 03

Warning light — what does it actually mean?

Amber warning light appeared on a Saturday afternoon. Dealer earliest appointment: two weeks.
Dealership diagnostic appointments are expensive and slow. For many fault codes, the most important question is whether the car is safe to drive right now — not what the full repair involves. AI Fault Analysis gives you a structured answer within seconds.
  • 1 Open app. Go to Health → AI Fault Analysis. Tap Scan.
  • 2 App reads DTCs from all mapped ECUs. Each code is sent to Gemini AI simultaneously.
  • 3 Within seconds, each fault card shows: severity (Critical / High / Moderate / Low), system affected, likely causes, symptoms, recommended actions and a plain-English safe-to-drive note.
  • 4 Share the report with your mechanic or independent specialist before the appointment — saving diagnostic time and money.
P0AA6 (Hybrid Battery Voltage System Isolation Fault) — severity HIGH. Safe-to-drive note: "Avoid motorway driving; get to an authorised service centre within 48 hours." Booked a mobile JLR specialist for Monday morning rather than waiting two weeks.
iOS / iPad · Case 04

Small EV fleet health checks with an iPad

Fleet of 8 I-Pace company cars. Monthly battery health reporting needed for lease resale planning.
Fleet managers need reliable, repeatable health data across multiple vehicles. The iPad's large screen makes it ideal for side-by-side comparison while walking a car park, and the Diagnostic Report export gives a consistent monthly record per vehicle.
  • 1 Each vehicle gets a 5-minute scan: SoH, SoC, cell voltages, DTC check. The app remembers the last Bluetooth device per vehicle profile.
  • 2 Generate and export a Diagnostic Report per vehicle as an HTML file.
  • 3 Compare SoH trends month-on-month. Identify vehicles declining faster than expected before they become a lease penalty problem.
Identified two vehicles with SoH declining faster than the fleet average at 18 months. Flagged for warranty review — both were replaced under JLR's battery warranty before lease return.
Professional & Workshop

Mac & Wired USB — For workshops, independents & fleet technicians

Wired ELM327 USB adapter. Sustained sessions. Multi-ECU sweeps. Real-world complex diagnostics.

Mac / Professional · Case 01

Degraded Pack, Dead Module Sensors & Warm A/C

2020 Jaguar I-Pace EV (185k km). Range feels down and A/C stopped getting cold. No warning lights or obvious DTCs.
One component telling three connected stories. A degraded HV pack, whose thermal sensing is compromised, on a car whose A/C shares the battery's refrigerant loop. No code told you any of it; correlating the live OBD channels told you all three.
  • 1 Capacity vs Cell Balance: Capacity Health settled flat at 70% across all scans, while Cell Voltage Spread remained tight (0.01–0.03V). This is uniform aging, not a single weak cell — exactly the profile for the I-Pace HV battery recall.
  • 2 Compromised Thermal Sensing: Several per-module temp sensors read impossible values (one stuck at -15°C, another flapping wildly to -216°C) while the pack's average sat at a sane 16°C. These are blind spots in the thermal safety net.
  • 3 Cold Loop, Warm Cabin: Refrigerant line sat steady at -9°C but the evaporator stayed at 20°C and vents blew warm. The cold is being made but not transferred — pointing to a thermal-management/chiller-valve fault on the shared HVAC/battery loop.
The three stories together gave the owner a concrete, data-backed reason to push for a warranty/recall assessment for the HV battery pack and thermal management system, instead of a simple "monitor it" outcome.
Read full case study →
Hardware needed: wired ELM327 USB adapter with FTDI or CH340 chipset. Ensures sustained connection for multi-day diagnostic snapshots.
Mac / Professional · Case 02

Hot No-Start After 30 Mins — Oil Hot, Coolant Cold

2019 Jaguar XF (Petrol V6). Drives normally for ~30 minutes, starts knocking audibly, then won't restart once hot. Only a "coolant level low" warning.
The temperature gauge hid the overheat. The coolant sensor read low (60°C) even as the oil cooked to 100°C. That divergence is the classic signature of coolant not circulating. Correlating the channels exposed the fault where standard gauges and DTC scans found nothing.
  • 1 Monitor Thermal Divergence: Lined up side-by-side, engine oil rocketed to 100°C (full operating temp) while engine coolant maxed out at 60°C (~30°C below normal). Heat in the block wasn't reaching the coolant sensor.
  • 2 Correlate with Warnings: The "coolant level low" warning (without an overheat light) pointed straight at low coolant causing an airlock, leaving the sensor in a vapour pocket reading cold.
  • 3 Assess Engine Stress: The audible knock after 30 mins of slow driving under load confirmed the hidden overheat was causing detonation, actively stressing the engine.
  • 4 Diagnostic Escalation: Stop driving it hot. Run integrity gates (compression, leak-down, combustion-leak) to check for thermal damage before throwing parts like a thermostat or water pump at the circulation issue.
Repair is ongoing, so the final outcome remains TBD.
Read full case study →
Mac / Professional · Case 03

Crank-No-Start with Dead Headlights & Signals

2020 Jaguar XF (Diesel). Engine cranks but never catches, whilst headlights and indicators are totally dead. Tempting to blame one common electrical cause.
A dramatic symptom (dead lights) can look related to a no-start when it's actually a second, independent fault. The EVMetricsOBD scan separated a mechanical timing failure from a completely independent BCM output issue.
  • 1 Rule Out Total Power Loss: The BCM is alive. Lock/unlock still flashes brake lights and the hazard switch produces a rapid audible cue (hyperflash warning) even though external indicators are dead.
  • 2 Identify Brown-out Sentinels: Initial scan showed 11.4V and impossible readings (232°C charge-air, -50°C tyre temps) — a classic flat-battery brown-out. Swapping the battery left the faults present, moving the diagnostic downstream.
  • 3 Isolate the Electrical Fault: The selective failure (dead indicators/headlights but working brake lights) points at a shared exterior-lighting feed, fuse, or BCM output driver, not a dead battery or main earth.
  • 4 Diagnose the Mechanical No-Start: The fast, free cranking with no compression and a static camshaft confirmed a snapped/jumped timing chain. This is completely separate from the lighting fault.
Repair is ongoing, so the final outcome remains TBD.
Read full case study →

iPhone & iPad

Download on the App Store. Any Bluetooth ELM327 dongle. Start reading your battery's health today.

Download on App Store

Mac

Available on the Mac App Store. Use with any wired FTDI or CH340 USB ELM327 adapter.

View Mac app →