EV Charger Uptime: What Operators Should Demand From a Hardware Supplier

Short answer: uptime is the share of time a charger can actually charge. It decides revenue and whether drivers come back — in J.D. Power’s 2026 US study, 12 % of public charging visits still ended without a charge. Use 97 % per connector per year (the US NEVI requirement) as a minimum benchmark. Uptime is designed in — modular power, accessible parts, detailed diagnostics, remote fixes — and then managed through monitoring, spare parts and service contracts. Write the supplier’s part of it into the contract.

What 97 % actually allows

Uptime per connector	Downtime per year	Downtime per month
99 %	≈ 3.7 days	≈ 7 hours
97 %	≈ 11 days	≈ 22 hours
95 %	≈ 18 days	≈ 1.5 days
90 %	≈ 36.5 days	≈ 3 days

A single DC fault that waits two weeks for a part from abroad uses more than a year’s allowance at 97 %. That is why spare parts close to the site matter as much as hardware quality.

Why chargers go down

Cause	Typical fix	Prevent with
Lost communication (4G, back end)	Remote reset, SIM or router check	Ethernet + 4G fallback; local authorisation list
Damaged cable or connector	Replace cable or connector	Cable management, holsters, inspections
Payment terminal fault	Replace or reset terminal	Certified terminals, remote monitoring
Power module failure (DC)	Swap the module	Modular design, spare modules on site
Contactor, fan or filter problems (DC)	Replace part, clean filters	Preventive maintenance
Firmware or software bugs	Update firmware	Tested OCPP integration, OTA updates
Grid or site supply issues	Utility or electrician	Surge protection, good earthing
Vehicle compatibility problems	Firmware update	Interoperability testing

Uptime is designed in

Ask the supplier how the charger is built for availability:

Design feature	Why it matters
Modular DC power	One failed module reduces power instead of stopping the charger — see power modules
Front access to parts	Faster repairs, fewer specialist tools
Detailed error codes over OCPP	Remote diagnosis before sending a technician
Remote reset and configuration	Many faults fixed without a visit
Over-the-air firmware updates	Bugs fixed across the fleet at once
Robust cables and connectors	The most-handled parts; replaceable on site
Two communication paths	Ethernet plus 4G keeps the charger online
Environmental protection	IP and IK ratings, corrosion class, temperature range for the site — see IP and IK ratings

Then it is managed

1. Monitor every connector in the CPMS with alarms — see CPMS software.
2. Keep a spare-parts kit at or near each region: cables, connectors, a power module, contactor, fans, filters, control board, payment terminal — see the spare-parts list.
3. Train local technicians on the supplier’s diagnostics.
4. Preventive maintenance: inspect cables, clean filters, check torque on terminals, test RCDs.
5. Track the numbers: uptime per connector, session success rate, mean time to repair — see network KPIs.

What to write into the supply contract

Clause	What to ask for
Spare parts	List and prices of spare parts; availability for at least the product’s expected life
First-order spares	A recommended kit delivered with the first shipment
Technical support	Response time for remote support, languages, time zones
Warranty process	How faults are reported, evidence needed, replacement part shipping times
Firmware	Support and update period; security patches
Training	For your technicians, on site or online
Documentation	Service manual, error-code list, wiring diagrams

How VULTAE supports uptime

Our DC chargers are built from power modules, report detailed fault codes over OCPP 1.6J / 2.0.1, support remote reset and over-the-air firmware updates, and connect by Ethernet, Wi-Fi or 4G. We recommend a first-year spare-parts kit with every order and support remote diagnosis with your technicians. See our warranty and service terms.