🔋 EV Battery Check — £79
Aviloo Certified
No Call-Out Fee
Mobile · Pontypridd & RCT
07896 657792
12V + HV Battery Checks
No Call-Out Fee
07896 657792
Plug-in Hybrid · Pontypridd & RCT

PHEV
Battery
Health Check.

Your PHEV has two batteries — and both need attention. PAD checks your 12V auxiliary battery, runs a full OBD diagnostic across every system, and on supported models performs an Aviloo certified high-voltage battery SOH test — the same certificate used by dealers and insurers across Europe.

Understanding Your PHEV

Your PHEV Has Two Batteries.

Most PHEV owners know about one of them. PAD checks both — and on supported models, certifies the one that matters most to resale value.

🔋 12V Auxiliary Battery

Every PHEV — like every car — has a standard 12V battery that powers the vehicle's electronics: lights, infotainment, ECU, door locks, and starter systems. This battery is entirely separate from the high-voltage pack and degrades just like any standard car battery.

  • PAD tests voltage, cold cranking amps (CCA), and state of charge
  • Many PHEV owners experience 12V failures because the car rarely fully engages the starter motor
  • A flat 12V can prevent the entire car from functioning — even if the HV battery is full
  • Test takes around 5 minutes using professional battery testing equipment
✓ Covered on ALL PHEVs — included in diagnostic visit

⚡ High-Voltage Traction Battery

This is the large lithium-ion battery pack that stores energy for electric driving. Its State of Health (SOH) determines your real-world electric range and is the most important factor in PHEV resale value. Unlike the 12V, degradation is invisible — there's no warning light.

  • SOH measures current capacity as a percentage of original factory capacity
  • A PHEV with 75% SOH delivers only 75% of its advertised electric range
  • On supported models, PAD measures SOH using Aviloo certified equipment
  • Every covered PHEV test includes an official Aviloo certificate — independent proof of battery condition
  • Not all PHEVs are currently supported — check the coverage tool below
✓ Aviloo certified certificate included on supported models
What PAD Checks on Your PHEV

Three Checks. One Visit.

Every PAD PHEV appointment covers the full picture — we don't just plug in and leave.

01
🔋

12V Battery Test

Professional battery load test measuring voltage, cold cranking amps (CCA), and state of charge. We identify weak or failing 12V batteries before they leave you stranded — a common PHEV problem.

✓ Included on all PHEV visits
02
🔌

Full OBD Diagnostic

Professional multi-system scan covering engine, hybrid system, ABS, airbag, EPS, gearbox, charging system, and all body control modules. Not just the engine light — every system, every fault code.

✓ Included on all PHEV visits · From £25
03

HV Battery SOH Test

On supported PHEV models, PAD measures the high-voltage traction battery's State of Health using Aviloo certified equipment. Official Aviloo certificate issued — the independent proof used by dealers and insurers.

✓ Aviloo certificate included · £79 · Supported models only
Important: PAD's Aviloo certified HV battery SOH test is available on supported PHEV models only. All PHEVs receive the 12V battery test and full OBD diagnostic scan regardless of Aviloo coverage. Use the vehicle checker below to confirm whether your specific PHEV model supports the full HV battery SOH test.
HV Battery Coverage

Check Your PHEV HV Battery Coverage.

The Aviloo certified HV battery SOH test is available on the models below. Click any brand to see supported PHEV variants, or use the reg/search checker.

All PHEVs get the 12V battery test and full OBD scan. The Aviloo certified HV battery SOH test is available on supported models only — these are marked in green below. If your PHEV isn't listed, contact us — coverage is expanding regularly.
Check HV Battery Coverage by Reg or Make & Model

Enter your UK reg — we check whether your PHEV's high-voltage battery is covered for an Aviloo certified SOH test. All PHEVs receive the 12V test and full diagnostic regardless.

DVLA lookup — no data stored

Why It Matters

PHEV Battery Problems You Can't See.

Silent Range Loss

PHEV HV battery degradation doesn't trigger a warning light. A car advertised with 30 miles electric range may only deliver 20. Without an SOH test, neither buyer nor seller knows.

🔋

12V Failures Are Common

PHEVs often use the electric motor rather than the starter motor, so the 12V battery rarely gets properly charged. This leads to surprisingly early 12V failures that can stop the car completely.

💰

Resale Value Hit

A PHEV without battery certification sells for less as buyers factor in unknown degradation risk. An Aviloo certificate supports your asking price — or gives a buyer grounds to negotiate fairly.

📋

Warranty Check

Most manufacturer battery warranties require the SOH to stay above a certain threshold (typically 70%). A test before warranty expiry gives you documented evidence if a claim is needed.

Common Questions

PHEV Battery FAQ.

A plug-in hybrid has two distinct batteries. The 12V auxiliary battery is a standard lead-acid or AGM battery that powers the vehicle's electronics — lights, ECU, locks, and in some models the starter motor. The high-voltage (HV) traction battery is the large lithium-ion pack that stores energy for electric driving. Both can degrade and both can cause problems — PAD checks both.
In a standard petrol car, the alternator charges the 12V battery every time the engine runs. In a PHEV, the car often operates in electric mode without the engine running — which means the 12V battery can go long periods without being properly charged. This leads to premature 12V battery failure, which can prevent the entire car from starting or operating, even when the high-voltage battery is fully charged.
On supported PHEV models, yes. PAD uses Aviloo certified equipment to measure the State of Health (SOH) of the high-voltage plug-in battery. This tells you what percentage of the original battery capacity remains, and an official Aviloo certificate is issued as permanent proof. Not all PHEV models are currently supported — use the checker above to confirm your vehicle, or contact us before booking.
All PHEVs receive the 12V battery test and a full OBD diagnostic scan regardless of Aviloo coverage. The Aviloo HV battery SOH test is an additional service on supported models only. If your PHEV isn't currently covered, we can still give you a complete picture of the vehicle's electrical and mechanical health from the diagnostic scan.
No. Both the 12V load test and the Aviloo HV battery SOH test are non-invasive. The HV test reads data from the battery management system without discharging, modifying, or stressing the battery in any way. There is no risk to the battery or vehicle warranty.
A full OBD diagnostic including the 12V battery test is from £25–£45 depending on the service level. Where your PHEV supports the Aviloo HV battery SOH test, the full service including the Aviloo certificate is £79 flat rate. No call-out fee within 10 miles of Pontypridd.
Book Your PHEV Battery Check

12V Test. Full Diagnostic.
Aviloo HV SOH Where Covered.

Mobile across Pontypridd and RCT · No call-out fee · We come to you

Book Now WhatsApp to Book 07896 657792