Why EV Chargers Reduce Power in Hertford

One day the car charges quickly, the next it seems noticeably slower, even though nothing appears to have changed. There is no warning light, no error message and no obvious fault, just reduced charging speed.

At JJB Electrical, this is one of the most common concerns we hear from homeowners in Hertford. In most cases, the charger is not broken at all. Instead, it is doing exactly what it was designed to do.

EV chargers are designed to protect your home first

Modern EV chargers are built with multiple layers of safety protection. If the charger detects something that could put your home, wiring or vehicle at risk, it will automatically reduce power rather than shut down completely.

This behaviour often catches homeowners off guard. From the outside, it feels like the charger is underperforming, when in reality it is responding to conditions within the electrical system.

Electrical supply limitations in Hertford homes

Many properties in Hertford were built long before electric vehicles were common. While the wiring may be safe, it was not designed to support sustained high loads for several hours at a time.

If an EV charger detects voltage drop, unstable supply or shared circuit stress, it may reduce output to avoid overheating cables or causing nuisance tripping. This is especially common in homes with older consumer units or where multiple high-demand appliances are used simultaneously.

Load balancing quietly limits charging speed

Some EV chargers use built-in load monitoring. This means the charger constantly checks how much power the rest of the home is using. When demand increases, such as when ovens, showers or heat pumps are running, the charger automatically reduces its draw.

This happens silently in the background. Homeowners often assume the charger is faulty when it is actually preventing the main supply from being overloaded.

Earthing issues can trigger power reduction

Correct earthing is critical for EV charging safety. If the charger detects inconsistent or high resistance earthing, it may lower charging power to reduce risk.

In Hertford homes, we often find older earthing arrangements that technically work but do not meet modern expectations for continuous high loads. The charger reacts by limiting output rather than stopping entirely.

Temperature plays a bigger role than people realise

EV chargers monitor internal temperature as well as cable temperature. If heat builds up due to cable routing, insulation or restricted airflow, the charger will reduce power to protect itself and the wiring.

This is common in garages or external installations where cables run through loft spaces or walls with poor ventilation.

Why software settings can affect charging speed

Many smart chargers allow users to set schedules, limits or off-peak charging modes. Sometimes these settings are forgotten after installation.

We regularly attend Hertford properties where the charger is capped at a lower output because of an old setup profile. The homeowner assumes the charger is slow, but the limitation is actually intentional within the software.

When reduced power is a warning sign

While power reduction is often a normal safety response, it can also indicate an underlying electrical issue. Loose connections, undersized cables or aging consumer units may not cause immediate faults but will trigger protective behaviour in EV chargers.
Ignoring reduced charging speeds can allow small issues to worsen over time.

How a professional EV charger inspection helps

At JJB Electrical, our EV charger inspections go beyond checking the unit itself. We assess supply capacity, earthing, consumer unit protection and cable routes to identify why charging power is being reduced.

In many cases, simple upgrades such as improved circuit protection or corrected cable sizing restore full charging performance safely.

Why Hertford homeowners trust JJB Electrical

We install and maintain EV chargers across Hertford and understand how local housing stock affects charging performance. Our electricians are NAPIT registered and experienced in integrating EV charging safely into both older and modern homes.

We focus on long-term reliability rather than quick fixes.

Book an EV charger check in Hertford

If your EV charger in Hertford is charging slower than expected, do not ignore it. Reduced power is often your system asking for attention.

Call 01992276121 to book an EV charger inspection or to discuss upgrading your electrical supply. JJB Electrical provides trusted EV charging solutions throughout Hertford.