Don't Buy a Used EV Without a High Voltage Battery Fault Check
High voltage battery faults are the most serious — and most expensive — issue an EV can have. Get an independent HV system inspection before you buy, carried out safely by trained technicians.
Fast booking • Report same day • Mobile service across the UK
Why this matters: EV high voltage systems can operate at over 400V. Faults in insulation, wiring or the battery pack itself pose real safety risks and can be extremely costly to repair. This check should only ever be carried out by trained, qualified technicians — never attempt to inspect an HV battery yourself.
Why Get an HV Battery Check Before You Buy?
A high voltage fault isn't something you can see or hear on a test drive. It requires specialist equipment and training to detect safely and accurately.
Insulation Resistance Testing
We test insulation resistance between the HV system and the vehicle chassis, a key safety measure that identifies leakage faults before they become dangerous.
Cell & Pack Integrity
We assess individual cell voltages and pack balance for signs of internal faults, damage, or degradation that could lead to failure or a costly replacement.
HV Wiring & Connectors
High voltage cabling, connectors and interlocks are inspected for damage, corrosion, or incorrect prior repair work — common after accident damage or poor previous repairs.
Avoid a Five-Figure Mistake
A failed HV battery pack can cost thousands to repair or replace. This check gives you the evidence to negotiate, or walk away entirely.
How It Works
A safe, professional process from booking through to your final report.
Contact Us
Call or WhatsApp us with the car details and seller location.
We Book The Check
We arrange a convenient time with you or the seller, using the correct safety procedure.
Full HV Inspection
Our technician safely tests insulation resistance, cell balance, HV wiring and runs a full fault code scan.
Get Your Report
Receive an easy-to-read report same day, so you can decide with confidence.
What's Included In The Check
A thorough, safety-led inspection of the entire high voltage system.
Checks for leakage between the HV system and vehicle chassis.
Identifies weak, damaged or imbalanced cells within the pack.
Checks cabling, connectors and safety interlocks for damage or corrosion.
Reads live and stored HV, BMS and battery fault codes.
Actual battery capacity vs. original factory capacity.
Looks for signs of previous HV work, incorrect repairs or accident damage.
Confirms thermal management is functioning correctly to protect the HV battery.
Plain-English summary with a clear pass/concern rating and our honest recommendation.
Why Trust Our Inspection
High voltage work demands the right training and equipment. Here's what sets our check apart.
HV Trained Technicians
Our technicians hold recognised high voltage EV qualifications for safe, competent inspection work.
Professional Diagnostic Equipment
We use manufacturer-level diagnostic tools to accurately read HV battery and BMS data.
Independent & Unbiased
We work for you, the buyer — not the seller or the dealer. Our report reflects exactly what we find.
Fast Turnaround
Reports are delivered the same day, so you can make a decision before the car is sold to someone else.
Simple, Transparent Pricing
No hidden fees. Know the price upfront before you book.
Pre-Purchase High Voltage Battery Fault Check
- Full insulation resistance test
- Cell voltage & balance assessment
- HV wiring & connector inspection
- Full live & stored fault code scan
- Same-day written report
- Mobile — we come to the vehicle
- Carried out by HV trained technicians
Covers all major EV brands including Tesla, Nissan, BMW, Hyundai, Kia, VW, Audi, Mercedes and more.
Frequently Asked Questions
Is it safe to inspect a high voltage battery before purchase?
Yes, when carried out by a trained technician using the correct safety procedures and equipment. This is exactly why this check should never be attempted without the right qualifications.
What does an insulation resistance test actually check?
It measures whether the high voltage system is properly isolated from the vehicle's chassis, which is a key indicator of pack and wiring integrity, and a critical safety measure.
How is this different from a standard battery health check?
A standard check focuses on capacity and degradation. This inspection goes further, specifically testing the safety and integrity of the high voltage system itself, including insulation, wiring and cell-level faults.
Which EV brands and models can you check?
We check all major electric vehicle brands including Tesla, Nissan Leaf, BMW i3/iX, Renault Zoe, Hyundai Kona/Ioniq, Kia e-Niro/EV6, VW ID range, Audi e-tron, Mercedes EQ range, and more.
How long does the check take?
A full HV battery inspection typically takes between 1 and 1.5 hours depending on the vehicle and diagnostic access required.
Can you check the car at the seller's address?
Yes, we operate as a mobile service and can attend the seller's home, a dealership, or a neutral meeting point across the UK.
Know The High Voltage System Is Safe Before You Buy
An HV battery check costs a small fraction of what a serious high voltage fault could cost you — in repair bills or in safety. Get in touch today and buy with confidence.