I bought a brand-new Nissan Leaf, serviced it through Nissan's authorised network, and less than four years later Nissan confirmed a serious internal battery fault. I am still without a fully funded repair.

A documented account of a high-voltage battery failure, the early symptoms I did not recognise, Nissan's own diagnosis, and how Nissan Fermoy and Nissan Ireland handled it.

2022
Bought New
6
Nissan Services
Internal
HV Battery Fault
Unresolved
October 2026
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The story in 30 seconds

  1. 1February 2022: I bought the car new from Nissan Fermoy.
  2. 2I had it serviced regularly at the same dealership — six times in total.
  3. 3Before 100,000 km, I noticed brief, repeated power hesitations on a hill. I did not recognise them as battery symptoms at the time.
  4. 4In late 2025 a serious battery failure developed: sudden charge collapse under load and loss of power.
  5. 5Nissan Tech Line confirmed an internal fault in the HV battery.
  6. 6Warranty cover was declined because the car had passed 100,000 km.
  7. 7Months of correspondence, including through my solicitor, have not produced an agreed, fully funded repair.

How to read this page:

Evidencedocuments I hold Owner recollectionwhat we remember experiencing Opinionmy own view

Key Document: Nissan Fermoy invoice, 18 February 2026

"Charge dropping while driving checked and confirmed. Carry out main battery test on road under load and under normal driving. Recorded all data under txt format and forward to Nissan Tech Line. Nissan Tech Line advised internal fault in HV battery."

Evidence: invoice Nissan's own finding, recorded on Nissan Fermoy's invoice.

Current status — October 2026

After many months of direct correspondence, and subsequently formal correspondence through my solicitor, the matter remains unresolved. A final letter issued in September requested a response by 5 October. As of 14 October, my solicitor had confirmed that no response had been received. Separately, a complaint concerning the hire-purchase finance arrangements has been submitted to the Financial Services and Pensions Ombudsman and remains subject to its process.

Manufacturer warranty claim Declined, March 2026
Solicitor's final letter (deadline 5 October) No response at 14 Oct
FSPO complaint (finance) Initial assessment
Agreed, fully funded repair None agreed
01

Bought New. Serviced by Nissan.

In February 2022, I bought a brand-new Nissan Leaf 40 kWh SV Premium from Nissan Fermoy in Cork, financed under a hire-purchase agreement with AIB Finance & Leasing. I chose Nissan because it pioneered mass-market electric cars, because the Leaf had a strong reputation, and because I believed buying and servicing through the official dealer network meant proper EV expertise and aftercare. It was a significant investment for my family.

I brought the car back to the same dealership for servicing throughout its life. I did not ignore warning lights. I relied on Nissan's authorised network to look after it.

Less than four years after I bought it, Nissan's own technical team confirmed a serious internal fault in its high-voltage battery — the single most important and expensive component in an electric car.

Evidence: purchase records

Vehicle: 2022 Nissan Leaf SV Premium (40 kWh)

Purchased: 15 February 2022, new from Nissan Fermoy

Finance: Hire purchase, AIB Finance & Leasing

02

Early Signs I Didn't Recognise

Owner recollection Before the car reached 100,000 km, I repeatedly experienced a brief hesitation in power at the same point on a hill near my home. It was momentary, the car carried on, and I did not think of it as a battery problem.

Only after the severe failure in late 2025 did I connect the two. Looking back, I believe those hesitations were an early sign of the same fault.

Important clarification

This is my own retrospective recollection. It is not a Nissan diagnosis, and no test was carried out before 100,000 km that recorded it. I have sought the car's stored diagnostic records to establish whether anything was logged before that point.

Opinion An ordinary owner has no way of knowing that a momentary hesitation on a hill could be the high-voltage battery giving early warning. That is exactly why owners rely on the manufacturer's network.

03

When It Became Dangerous

In late November 2025 — about a week after a routine service at 106,894 km — the fault became severe. On hills and under load, the displayed state of charge collapsed and the car went into reduced-power "turtle" mode:

State of charge dropped from approximately 80% into turtle mode going uphill, with a severe loss of power.

State of charge dropped from 50% to 18% over roughly 1 km on a hill.

State of charge dropped from 82% to 5% going uphill, then recovered to 78% coming back down. The charge had not actually disappeared; the car appeared to be limiting power as the battery voltage sagged under load.

The Incident That Frightened My Family

Owner recollection My wife was driving and pulled out onto a main road at a normal pace. The car did not accelerate as she expected, with traffic approaching from behind. She found it a genuinely frightening experience.

That is why this was never just an inconvenience for us. A car that may not respond when you need to accelerate out of a junction is a safety concern for whoever is driving it — and from that point we could not trust it.

04

Nissan's Own Diagnosis

I brought the car to Nissan Fermoy. On the first visit (8 December 2025) a static test was carried out and nothing conclusive was found — at rest, the battery appeared broadly healthy.

On the second visit (17 December 2025) the car was road-tested under load using Nissan's CONSULT diagnostic equipment, and the data was sent to Nissan Tech Line.

My interpretation of the dataapproximate cell-voltage readings under load

Most cells: approximately 3,300–3,350 mV
One cell/module: approximately 2,950 mV
A gap of roughly 300 mV, which I understand to be far beyond normal variation

Those figures and what they mean are my own reading of the data. Nissan's finding is separate, and it is on paper: the Nissan Fermoy invoice dated 18 February 2026 records that charge dropping while driving was "checked and confirmed", that the battery was tested on the road under load, and that "Nissan Tech Line advised internal fault in HV battery."

Evidence: invoice Full wording quoted at the top of this page.

05

The Warranty Position

Nissan's Leaf warranty has two separate parts that are easy to confuse. Nissan Fermoy confirmed this distinction in its correspondence with me.

Electric Vehicle System warranty

5 years / 100,000 km, whichever comes first

Covers relevant defects in the EV system. This is the warranty my dispute is about — an internal battery defect.

Battery Capacity warranty

8 years / 160,000 km

Covers qualifying loss of capacity below a specified threshold. My problem is not ordinary capacity degradation, so this warranty is not the issue.

Evidence: correspondence Nissan relied on the vehicle's recorded mileage of 108,484 km when it was presented on 8 December 2025 — past the 100,000 km limit. In March 2026, Nissan Fermoy formally declined manufacturer warranty cover on that basis.

My position Symptoms of the fault were manifesting before the car reached 100,000 km, even though I did not understand their significance at the time. Whether that should bring the fault within the warranty is disputed, and I am not claiming it has been established.

The warranty is not the only question

A manufacturer's warranty is separate from a consumer's statutory rights. Because the car was supplied under a hire-purchase agreement in February 2022, statutory rights may exist under that agreement independently of Nissan's warranty. Those rights have not been determined.

06

Six Nissan Services: What the Records Show

The car was serviced six times at Nissan Fermoy, spanning over 90,000 km. The invoices record routine items — brakes, tyres, filters — and in some cases general fault-code checks, such as "plugged in for faults and updates all OK".

6 October 2022 — 16,217 km

Routine service.

11 April 2023 — 32,493 km

Routine service.

26 October 2023 — 48,828 km

Routine service, plus recall R23A6 (VCM).

28 May 2024 — 67,128 km

Routine service.

28 January 2025 — 85,304 km

Routine service — the last service before the car passed 100,000 km, during the period when I now believe early symptoms were present.

17 November 2025 — 106,894 km

Routine service. Severe symptoms began approximately one week later.

Evidence: service invoices The six routine-service invoices supplied to me contain no record of cell-level traction-battery testing under load. Some general fault-code checks were recorded. Whether more extensive battery testing was reasonably required, or would have identified the developing fault, remains an open question.

To be precise, these are three separate points: what the invoices record; what was actually done; and what a dealer should reasonably have done. I can only document the first.

What I do know is that, in December 2025, a static check did not identify the fault, and Nissan only confirmed it when the car was tested on the road under load.

07

What Has Happened Since

Various proposals and potential repair arrangements have been discussed during months of correspondence. However, no arrangement has been agreed that would provide a properly repaired vehicle at no cost to me. I remain extremely disappointed by that outcome.

Evidence: invoice Nissan Fermoy also invoiced me €283.75 for the under-load diagnostic examination that confirmed the internal HV battery fault.

February 2022 Car bought new from Nissan Fermoy under a hire-purchase agreement with AIB Finance & Leasing.
Nov–Dec 2025 Serious battery symptoms develop. Nissan carries out diagnostic testing.
February 2026 Nissan's invoice records Tech Line's conclusion of an "internal fault in HV battery".
March 2026 Nissan Fermoy formally declines manufacturer warranty cover on mileage grounds.
May 2026 The CCPC responds to my enquiry about consumer rights and hire-purchase responsibilities.
June 2026 onwards My solicitor corresponds with the relevant Nissan parties.
September 2026 I submit a separate complaint involving AIB to the Financial Services and Pensions Ombudsman.
26 Sept 2026 My solicitor confirms a revised final formal letter has been issued to Nissan Fermoy, with Nissan Ireland copied.
30 Sept 2026 The FSPO confirms my complaint is under initial assessment.
5 Oct 2026 Deadline given in the final letter for Nissan's response.
14 Oct 2026 My solicitor confirms he has received no response.

No legal proceedings have been issued and no court or ombudsman has made any finding. This section will be updated as the matter progresses.

08

Why This Experience Has Damaged My Confidence in Nissan

Opinion

I bought this car from Nissan's own dealer because I trusted the brand and its network. I went back to that dealer for every service. When the battery failed, Nissan's own technical team confirmed the fault. Yet nearly a year after the failure began, I still do not have a properly repaired car at no cost to me.

I understand that warranties have limits. But from where I stand, a serious internal defect in the core component of a car that was less than four years old, maintained within the manufacturer's own network, has been treated as a question of a few thousand kilometres on the odometer. That is not the after-sales support I expected when I chose Nissan.

If I were buying an electric car again, I would want to know — before signing anything — exactly what battery checks are included in servicing, and exactly what the manufacturer will and will not stand over if the battery fails.

Advice for Other EV Owners

  • Report unexplained power loss or charge fluctuations immediately, even brief ones, and get the dealer's findings in writing.
  • Ask your dealer what battery checks are included in a routine service.
  • If symptoms happen under load — on hills or accelerating — ask for the car to be investigated under load. In my case a static check found nothing.
  • Read your actual warranty terms, and understand the difference between defect cover and capacity-degradation cover, including their time and mileage limits.
  • Check for open recalls on your car through official Nissan channels using your VIN.
  • Don't keep driving a car with unpredictable, severe power loss until it has been professionally assessed.
  • Know that a warranty isn't your only protection. In Ireland, statutory consumer rights may exist independently of a manufacturer's warranty, and if you bought on hire purchase, the finance company may also have responsibilities.

Leaf owners can optionally use an app such as LeafSpy with an OBD2 adapter to monitor cell voltages themselves. It is a useful extra, not a substitute for professional diagnosis.

Useful consumer links:

Why I'm Publishing This

I purchased a new electric vehicle from an authorised Nissan dealership and returned to that dealership throughout its life for servicing. Before the vehicle was four years old, Nissan's own technical team had confirmed a serious internal battery fault.

I understand that warranties have conditions. But I remain deeply disappointed by the support I received, the lack of an agreed fully funded solution, and the experience of spending months trying to resolve a serious problem with a relatively young vehicle.

I am publishing this account because I believe prospective EV buyers deserve to understand what can happen when a major battery component fails, and how important the precise terms of after-sales support can become.

Background — not part of my case

Wider Context

For readers who want more context, these sources are included with their limitations clearly stated. None of them establishes what is wrong with my particular car.

U.S. recalls

The U.S. National Highway Traffic Safety Administration has published Nissan recalls for certain U.S. 2019–2022 Leaf vehicles, relating to a battery fire risk associated with rapid charging. The filings describe lithium deposits in battery cells and possible state-of-charge fluctuation.

These recalls apply to specific U.S. vehicles. They do not establish that my Irish car has the same defect, or that it is covered by them.

Other owners' accounts

Other Leaf owners, including some in Ireland, have described battery faults, escalation from local dealers to specialist centres, high repair quotes and warranty disagreements on the MyNissanLeaf forum.

These are unverified owner experiences. I have not verified them, and they are not evidence of a systematic defect or of wrongdoing by anyone.

Disclaimer & Right of Reply

This website documents the personal experience and honest opinions of a private individual and consumer. Factual statements are based on documents in my possession, including invoices, correspondence and diagnostic data. Recollections and opinions are labelled as such.

Nothing on this site is a finding of legal fault or liability, and no court, regulator or ombudsman has made any determination in this matter. Those questions remain disputed.

If Nissan Fermoy, Nissan Ireland, AIB Finance & Leasing, or any other named party believes a factual statement on this page is inaccurate, they can contact me. I will promptly correct any verified factual error, and any substantive response may be published alongside this account.

This website is a consumer information resource published in good faith. It is not a commercial enterprise.

Last updated: 19 October 2026