Why nearly half of UK EV drivers have stood in the rain swearing at a broken charger

Roughly 46% of UK EV drivers report having stood in front of a broken public charger in the last twelve months. The Public Charge Point Regulations 2023 require 99% uptime on any rapid charger ≥50kW, enforced by the Office for Product Safety and Standards, with a maximum penalty of £10,000 per charge point per occurrence for non-compliance. ZapMap's field data, measured the way drivers actually experience it, puts many public networks at an effective uptime between 80% and 92%. That's the gap. That's the lawsuit. That's the bad TripAdvisor review. The villain in this post is the "99% uptime" headline — the kind that sits proudly on a vendor brochure with no SLA clause behind it, no service credits attached and no measurement methodology disclosed.

If you're a facilities manager, a hotel GM, a fleet operator or a landlord with chargers on your forecourt, the rest of this is the conversation your charger vendor doesn't want to have.

The regulation almost nobody enforces (yet)

The Public Charge Point Regulations 2023 came into force in November 2023 and set, for the first time, statutory uptime requirements for public charging. The headline numbers:

• 99% mean uptime per calendar year on rapid units ≥50kW, measured per chargepoint.
• Contactless payment required on units 8kW and above for new installs.
• Open data on price and location, published to a single open standard.
• 24/7 helpline for users in trouble at a unit.

Enforcement is real but slow. The Office for Product Safety and Standards has begun spot-audits of major networks; civil penalties are up to £10,000 per chargepoint per breach. Multiply that across a 40-unit forecourt and the maths gets your attention. More importantly: liability for failure now lives with the operator, in writing, in regulation. That changes the conversation with your installer materially. They were already meant to deliver uptime. Now they're meant to deliver it under threat of an OPSS fine.

MTBF vs SLA-credited uptime — the two numbers that look the same and aren't

Here's the trick. When a manufacturer says 99.5% uptime, they almost always mean MTBF-derived availability — a calculation based on Mean Time Between Failures of the hardware in lab conditions. It's a real number. It's also useless to you.

What you need is SLA-credited uptime. That's the number measured at your site, in your weather, on your back-office connection, including the failure modes the manufacturer didn't think to test for — and, crucially, the number you get service credits refunded against when it's missed.

The difference, in practice, on a typical commercial site:

• MTBF availability (manufacturer headline): 99.5%
• Real-world site uptime (what users see): 91–94%
• SLA-credited uptime (what you get money back on): whatever your contract says. Often nothing. Often zero pounds.

If your maintenance contract doesn't define how uptime is measured, what the carve-outs are, and what the service credit per percentage point of breach is, then the uptime number is marketing.

The four reasons chargers actually fail

After 200+ commercial sites we can tell you the failure modes are almost always the same four. In rough order of frequency:

1. Comms failure. The SIM card lost signal, the back-office is having a wobble, the OCPP connection dropped, the unit thinks it's offline even though the hardware is fine. Roughly 40% of "broken charger" reports. Fixable remotely in minutes if anyone notices. Often goes undetected for days if monitoring is poor.

2. Payment-terminal jams. The card reader on a public charger is a moving part exposed to British weather. Card-acquiring outage, payment-terminal failure, NFC antenna issue. Maybe 20% of failures.

3. Tripped RCD or supply issue. Earth fault, lightning event, transient on the supply, single-phase imbalance. The unit shuts itself down because it's meant to. 15–20%.

4. Genuine hardware failure. Contactor failure, cooling-fan failure on DC rapids, cable damage from forklifts or shopping trolleys, vandalism. The rest, 20–25%. The only failure mode where physical replacement is required.

The first three are detectable and resolvable remotely with the right monitoring stack. The fourth requires a parts SLA and an engineer with a van. If your contract doesn't promise either, you don't have a maintenance contract — you have a phone number.

Why open protocols actually matter

OCPP — Open Charge Point Protocol — is the open standard that lets chargers talk to back-office systems regardless of manufacturer. Version 1.6 is the workhorse, 2.0.1 is the current standard for new installs.

If your chargers are OCPP-compliant, you can switch back-office providers without ripping the hardware out. You can hire your own monitoring team. You can integrate with your fleet management software, your building management system, your finance platform. You own the data.

If your chargers are on a proprietary protocol, you can do exactly what your back-office provider lets you do, at the price they decide, until they go bust or hike the price. The handful of UK installers still selling proprietary kit will tell you it's "more reliable" or "tighter integration". It is not. It is a customer-lock-in strategy with a hardware wrapper.

Demand OCPP 1.6 minimum. Ask for OCPP 2.0.1 on anything specced for 2026 or later. Get it in writing.

What unreliability actually costs — a hotel example

Site: Mid-market 60-room hotel near the M5. Two 50kW rapid chargers in the car park, marketed on the booking page and listed on ZapMap.

The reality at 87% effective uptime:

• 60 rooms × 70% average occupancy × 30% guest EV adoption (rising fast in 2026) = roughly 38 EV-driver bookings per week.
• ZapMap field data suggests 1 in 8 prospective EV bookings are declined or cancelled when the property's chargers show as offline at the time of search.
• That's ~5 lost bookings per week. At an average £170 room rate plus £35 ancillary (breakfast, bar, parking) = ~£205 per booking, ~£1,025 per week, ~£53,300 per year.
• Adjust for the fact that some lost bookings would have been lost anyway: realistic net revenue loss ~£11,400 per year on those two rapids alone.

That's before reputational cost. That's before the one-star TripAdvisor review titled "Chargers were broken AGAIN" that sits at the top of the property's reviews for nine months.

The cost of a maintenance contract that actually delivers 99% SLA-credited uptime, with remote monitoring, 4-hour response and parts-on-site? Roughly £500–£800 per charger per year on rapids. On the example above, £1,000–£1,600/year of maintenance saves £11,400 of lost revenue. The maths is not subtle.

The contract clauses to demand

When you're signing a charger contract — install, maintenance or both — these are the lines that separate a real SLA from a marketing brochure.

1. Uptime definition. "Uptime" must be defined in measurable terms. Per-charger, per-month, per-socket. Specify whether scheduled maintenance, force majeure, DNO outage, and customer-caused outage count against the percentage. (Some should. Some shouldn't. Be specific.)
2. Measurement methodology. Who measures? With what tooling? Reported how often? A vendor who measures their own uptime and emails you a PDF once a quarter is not a vendor. Demand machine-readable monthly reports.
3. Service credits. Real money, real percentages. "1% of monthly service fee per 1% breach of SLA, capped at 100% of monthly fee." Or stronger.
4. Response and resolution times. Distinguish the two. Response is the engineer acknowledging the ticket. Resolution is the charger working again. Demand both.
5. Parts SLA. What spare parts are held where, and what's the time-to-site for replacement? On rapids, anything over 48 hours is unacceptable.
6. OCPP compliance, certified. Not "OCPP-compatible". OCPP certified to version 1.6 or 2.0.1. Demand the certificate.
7. Step-in rights. If the vendor folds, can you migrate to another back-office without ripping hardware out? This question alone separates serious vendors from temporary ones.

What to ask before you sign

1. "Show me your last 12 months of per-site uptime data — anonymised is fine."
2. "What's your SLA-credited uptime number, and what credit do I get when it's missed?"
3. "Are your chargers OCPP-certified or OCPP-compatible? Which version?"
4. "If you go out of business, what happens to the back-office connection?"
5. "What's your 4-hour response coverage by postcode? Show me the map."

The short version

The regulation says 99% on rapids. The marketing brochures will say it too. The number that matters is SLA-credited uptime, defined in your contract, measured by an agreed methodology, refunded in real service credits when missed. OCPP open protocol, certified. Defined response and resolution times, with parts SLAs. Anything less and you're funding the next vendor pivot, not buying a reliable charger network.

Want us to do the maths on your site?

Book a site survey at /site-survey and we'll come back with an uptime audit of any existing chargers, a real SLA contract template, and a route to fixing the comms-and-monitoring stack first — because that's the failure mode that takes 40% of your network offline. Including the SLA credit schedule. Especially the SLA credit schedule.

Site Survey

Read this article in the app at energy-partners.co.uk/insights/ev-charger-reliability-uk. Energy Partners installs and manages commercial EV charging, solar and battery storage for UK venues — talk to us.