EV Charger Repair

Portable Charger — 3.3 kW

Plugs into a standard household socket; the control box sits in the cable itself.

Best for: overnight top-ups, a second car, travel, or as a backup charger.

Charging time: adds about 3.3 kWh per hour (~15–20 km of range per hour). A 40 kWh battery from empty takes roughly 12–13 hours; a typical overnight top-up of 20 kWh takes about 6 hours.

Repair note: the in-cable control box is the usual failure point — heat damage, water ingress and broken plug pins are all repairable or replaceable faults.

AC Wallbox — 7.4 kW / 11 kW / 22 kW

A fixed wall-mounted charger on a dedicated circuit — the standard home setup.

• 7.4 kW (single-phase): ~7.4 kWh per hour (~35–45 km of range per hour). A 40 kWh battery charges empty-to-full in about 5.5–6 hours — comfortably overnight.
• 11 kW (three-phase): ~11 kWh per hour. The same 40 kWh battery takes about 3.5–4 hours.
• 22 kW (three-phase): ~22 kWh per hour — full charge in about 2 hours, for cars whose onboard charger supports it. Many models cap AC charging at 7.4 or 11 kW, so the car, not the wallbox, sets the real speed.

Best for: daily home charging, workplaces, hotels and fleet depots.

Repair note: contactors, control boards, RFID/app modules and cooling fans are the common service items — all diagnosed and repaired at component level where practical.

DC Fast Charger — 30–120 kW

Converts AC to DC inside the station and feeds the battery directly, bypassing the car's onboard charger — this is what makes true fast charging possible.

Charging time: a 60 kWh battery from 20% to 80% (36 kWh) takes roughly 45–60 minutes at 30–50 kW, and about 20–30 minutes at 100–120 kW. Charging slows above ~80% by design, to protect the battery.

Best for: commercial sites, fuel-station-style stops, fleets and public charging points.

Repair note: power modules, cooling systems, contactors and communication boards are serviceable items; we diagnose module-level faults and replace failed modules to bring a station back online.

The Cable & Charging Gun

Chargers come in two designs: tethered (the cable is fixed to the charger) or socket-outlet (you bring your own cable).

The gun and cable take the most physical wear of any part of the charger: bent pins, cracked handles, worn latches and damaged insulation are the faults we see most.

A damaged gun or cable is a safety item, not a cosmetic one — it is repaired or replaced, never taped over.

The Plug Must Match the Car

The connector is fixed by the car's inlet — a charger can only serve a car if the plug matches. We stock, repair and replace guns and cables for all five connector families below.

Lead-Acid E-Bike Chargers

What it is: the standard fan-cooled charger brick supplied with most electric bikes and scooters that run sealed lead-acid batteries. It charges in stages — bulk, absorption, then a low float that holds the pack full.

Battery classes: 48V, 60V and 72V packs built from 12V blocks, in the common 12Ah, 20Ah and 32Ah battery sizes. The class on the label is the pack's nominal voltage: a charger sold as "48V" actually raises the pack to roughly 58–59V at the top of the charge (about 14.4V per 12V block) before dropping back to float.

Current & time: typically 2–3A, so a full charge from empty takes about 6–8 hours — overnight charging is the normal pattern for these packs.

Repair note: fan failure and dried-out capacitors are the usual faults on this class. Both are repairable — and a charger whose fan has stopped will run hot and cut out mid-charge, so it should not be ignored.

Lithium (Li-ion) E-Bike Chargers

What it is: a CC/CV charger for lithium-ion packs — constant current first, then constant voltage, then a hard stop. A lithium charger never floats; when the pack is full, charging ends.

Full-charge voltages (4.2V per cell, exact): 54.6V for a 48V pack (13 cells in series, 13S) · 67.2V for a 60V pack (16S) · 84V for a 72V pack (20S). The number on the charger must match the pack exactly.

Never mix chemistries: a lead-acid charger must never be used on a lithium pack. Its float stage holds voltage on the pack indefinitely and its peak voltage does not match the lithium pack's cut-off — the results range from a BMS that keeps tripping to genuinely damaged cells.

Repair note: before anything else we meter the charger's actual output against its label. A charger delivering even 1–2V over specification is a battery killer, and output-voltage drift is one of the faults we test for on every lithium charger.

LiFePO4 Chargers

What it is: chargers profiled for lithium iron phosphate packs, which charge to 3.65V per cell — a different endpoint from Li-ion, so a Li-ion charger is not a substitute.

Full-charge voltages (3.65V per cell): 58.4V for a 48V pack (16S) · 73V for a 60V pack (20S) · 87.6V for a 72V pack (24S).

Custom packs exist: not every pack follows the standard series counts — a 23S LiFePO4 pack, for example, charges to about 84V full. So "72V" on a battery does not always mean the same charger. Always match the charger to the pack's stated full-charge voltage, never to the nominal class alone.

Repair note: we verify both the charger's cut-off voltage and the pack's BMS behaviour together — a charger that is correct on paper can still be the wrong partner for a custom pack.

Fast / High-Current Chargers — 5A, 10A, 15A

What it is: larger fan-cooled chargers delivering 5A, 10A or 15A for bigger packs — 32Ah lead-acid sets and large lithium packs — and for commercial and delivery fleets, where a bike that charges in half the time earns its keep.

The trade-off: charge time falls sharply, but the pack runs warmer and a battery charged at maximum rate every day will age faster than one charged gently. Fast charging is a tool for when time matters, not a default — and both the pack and its connector and cabling must be rated for the current.

Heat management: these units depend on active fan cooling. Vents must stay clear, and a fan that stops is a repair-now fault, not a run-it-anyway one.

Repair note: fan and thermal faults are the most common service items on high-current chargers; we repair them and load-test at full rated current afterwards.

Smart / Intelligent Chargers

What it is: chargers with a controlled multi-stage profile and a display or indicator panel that shows the charging stage and reports faults, instead of a single LED that simply changes colour.

Protections: automatic cut-off at full charge, temperature monitoring and protection, and reverse-polarity and short-circuit protection — the features that make unattended and overnight charging safer.

Pulse / repair mode: many smart chargers add a pulse mode for sulphated lead-acid batteries — packs that have lost capacity after sitting discharged. It can recover some of that capacity on a sulphated pack; it is a recovery aid, not a guarantee, and a battery that has physically failed will not come back.

Repair note: we service smart chargers at board level, including their sensing and display circuits, and confirm the charge profile behaves correctly on a real pack after repair.

Motorcycle & Car 12V Battery Chargers

What it is: small clamp-on chargers for ordinary 12V batteries — the starter and accessory batteries in motorcycles and cars, and the same 12V blocks used in small backup systems.

Two sizes cover almost everything: 1–2A tender and maintenance chargers that keep a motorcycle battery healthy through weeks of standing, and 4–8A smart chargers that charge and then maintain a car battery. Most modern units are automatic — connect, select the battery type where the unit asks for it, and the charger manages the rest.

Repair note: the same matching rule applies here — use the mode that matches the battery, and a 12V charger is never a substitute for the 48V–72V traction chargers above, or the other way round.

Diagnosis Before Anything Is Replaced

A red fault light is the charger reporting a problem — but it does not say where the problem is. It can be inside the charger, in the cable and gun, or in the supply and protection upstream. We test all three before a single part is ordered, so you never pay to replace a healthy component.

Board-Level Repair, Not Just Part-Swapping

Many charger faults live on the control board — a failed power-supply stage, a damaged relay driver, a burnt contactor coil circuit. Where it is sound practice, we repair the board at component level instead of replacing the whole unit, and safety-critical parts are always replaced with the correct rated part.

Dedicated Circuit & Correct Cable

Dedicated circuit: the charger gets its own circuit from the distribution board — never shared with sockets or other loads.

Cable size: sized for the charger's full continuous current and the length of the run — voltage drop matters on long runs. As a guide, a 7.4 kW wallbox typically needs at least a 6 mm² copper run, and larger chargers or longer runs need more. The size is calculated per installation, never guessed.

Protection, Earthing & Load Check

Protection — RCD/RCBO, Type A or Type B: every charger circuit needs residual-current protection. Type A is the minimum where the charger has built-in DC leakage detection (6 mA); where it does not, Type B protection is required, because DC leakage from an EV can blind a basic Type AC device. We fit the correct type for the charger being installed.

Earthing: a verified earth connection is mandatory — the charger's safety functions and the car's own checks depend on it. Earth resistance is tested, and improved where it falls short.

Load check: before installation we check the home's total capacity — main breaker rating, existing loads and phase balance — so the charger can be added safely, with load management fitted where the supply is tight.

Safe Charging Is a Correct Installation

With a fixed wallbox on its own protected circuit, charging — including overnight charging — is exactly what the system is designed for. The risks appear with damaged equipment and improvised setups, covered in the notes below.