Regular vehicle inspections are essential to effective operation and optimal road safety. As electric vehicles (EV) become more common, many manufacturers, drivers, and service providers have added EV chargers to their maintenance checklist. To ensure the proper evaluation and upkeep of EV chargers, the need for reliable calibration standards has emerged. Although electric vehicle supply equipment (EVSE) testing and measuring isn’t yet standardized, compliance with NIST Handbook 44 helps industry professionals ensure measurement accuracy, particularly for customer billing purposes.
What is NIST Handbook 44?
NIST Handbook 44 (HB 44) is a guide issued by the Office of Weights and Measures (OWM)—a department of the National Institute of Standards and Technology (NIST)—that includes specifications, tolerances, and other technical requirements for weighing and measuring devices. Its purpose is to provide guidelines for creating, implementing, and testing weight and measurement devices that:
- Result in accurate, repeatable measurements
- Facilitate transparent transactions between buyers and sellers
- Prevent fraudulent weighing and measuring
Each year, the National Conference of Weights and Measures (NCWM) adopts an updated version of HB 44 that reflects new legislation and industrial advancements. The NCWM adopted the current version in November 2023 for use in 2024.
Why is NIST Handbook 44 important in EV charger calibration and measurement accuracy?
HB 44 is important in EV charger calibration and measurement accuracy because it contributes to industry standardization efforts. In section 3.40 of the handbook, NIST details requirements for accurate measurement and metering. For EVSE that process commercial transactions, or any sale of electricity for vehicle fueling purposes, HB 44 also requires that these elements be displayed to the customer:
- Amount of electricity dispensed
- Unit price
- Total price charged
As of 2024, HB 44 is not federally required. However, many states enforce its guidelines as part of existing legislation or have created new regulations to implement HB 44 standards.
In addition to the handbook, NCWM also oversees the National Type Evaluation Program (NTEP) and awards NTEP certification to EVSE manufacturers and operators that comply with HB 44 requirements. To achieve certification, applicants must meet certain specifications and tolerances by maintaining specific accuracy levels for measuring systems and testing methods.
In states that use HB 44 requirements as a framework to create their own standards for electric vehicle charging compliance, facilities must also become certified through state weight and measurement agencies. For example, the California Department of Food and Agriculture’s Division of Measurement Standards requires California Type Evaluation Program (CTEP) certification for all weighing and measuring devices used in commercial settings.
The primary goal of HB 44’s EVSE requirements—and the state laws they influence—is to establish industry standards for testing and measurement. These standards promote effective ESVE maintenance and instill trust in the fuel marketplace by ensuring customers receive what they pay for.
What are the key EV charger maintenance procedures?
The key EV charger maintenance procedures are those that facilitate safety, support operational efficiency, and align with HB 44 requirements. Here are some of the most important tasks to complete when maintaining EV chargers and charger stations:
✓Cleaning: Clear all dirt and debris from the charger and charging station to remove hazards and allow for easier inspection.
✓Inspection: Look for obvious physical damage or normal wear and tear that could make the charger unsafe or ineffective.
✓Component evaluations: Check all cables, screens, and other hardware for functionality.
✓ Safety assessments: Examine electrical components to ensure safety.
✓ Software updates: Update EVSE software for optimal compatibility, charger performance, data security, and network connectivity.
✓ Testing and calibration: Test EVSE according to HB 44 and other relevant standards and calibrate as necessary for measurement accuracy and transparent billing.
Common EV charger maintenance issues and how to troubleshoot them
Even the most diligent maintenance routines can’t guarantee that problems won’t arise, especially when you consider the rapid advances in EV technology. Some of the most common EV charger issues include:
- Inconsistent charging speeds
- Outdated software or apps
- Loose connectivity
- Damaged cables
- Unreliable availability
Most of these concerns have relatively easy fixes, such as upgrading equipment or replacing parts. Still, it’s best to resolve them as quickly as possible to adhere to electric vehicle charging compliance requirements and keep your customers happy.
Better yet, you can catch them before they cause more significant issues by making sure your methods for calibrating your EVSE are accurate and precise. Consider adding quality EVSE test instruments like these to your maintenance toolkit: