On-Board Charger (OBC)

Because on alternating current the vehicle sets the limit, not the charge point. The on board charger has a fixed maximum rating, so a car with a seven kilowatt charger plugged into a twenty two kilowatt point will draw seven, and a single phase charger on a three phase supply uses one phase only. That is normal rather than faulty. If your vehicle has always charged at a given rate and now charges more slowly, the question becomes whether it is derating, which is different.

That the fault is on the alternating current path, which the on board charger owns. Rapid charging bypasses the charger entirely, feeding the pack directly from the charge point's own converter, so a vehicle that rapid charges normally has a healthy pack and healthy contactors. Look at the alternating current pins in the inlet, the charging cable, the supply itself and then the charger. Test with a different cable and charge point first, since supply faults are common.

Several possibilities, and the charging log usually names the stage. A supply that cannot sustain the current trips its own protection. A charger that is derating because it or the pack is too hot reduces current and may stop. A communication fault between the vehicle and the charge point ends the session cleanly. A fault in the charger itself stops it abruptly. Try a different charge point before anything else, since domestic supply and installation problems account for a great many of these reports.

Specialist repairers handle some units, and the manufacturer route is replacement. Inside are power semiconductors, magnetics, capacitors and control electronics in a sealed cooled housing connected directly to the high voltage system, and diagnosing to component level requires equipment few workshops have. Where a reputable repair service exists it can be considerably cheaper. What is not viable is opening the unit without training, since it sits on the high voltage bus and retains charge after shutdown.

It is the ability to take energy out of the pack and produce ordinary alternating current for appliances, tools or camping equipment, usually through an adapter that plugs into the charging inlet or through a socket in the vehicle. It requires a bidirectional charger and the software to support it, so it is a feature rather than a given. Where a vehicle offers it, the same unit that charges the pack runs in reverse, which is why this category names the charger as bidirectional.

A charger sits alongside the other high voltage electronics in value, above a sensor or a contactor and below a traction pack, and it is usually quoted rather than priced as a standing listing. The head of this page carries the live range for the category. Before committing to one, get the charging fault properly attributed. A damaged inlet, a tripped supply, a failed pilot circuit or a cable fault all present as a car that will not charge, and each of those is a much smaller bill than the charger itself.

Yes on current vehicles. The unit arrives without the vehicle's configuration, and its software has to match the rest of the network and the vehicle's charging strategy, including any bidirectional functions the car supports. Some vehicles also require the charging parameters to be set for the market. Confirm that your workshop has the diagnostic access and correct software before the part is ordered, since an uncoded charger will not charge the vehicle at all.

Because the pack limits what it will accept, not because the charger has weakened. Cold cells accept current poorly, so the vehicle reduces the rate to avoid damaging them, and it may spend energy warming the pack before raising the current. This is most obvious on rapid chargers. Preconditioning while still plugged in, or driving to the charger with preconditioning active where the vehicle supports it, removes most of the delay by bringing the pack to temperature first.

With the portable cable supplied for the purpose, and with an installation that is up to it. A domestic socket was never designed to deliver near its rated current continuously for hours, so the risks are in the socket and the wiring rather than in the vehicle. Use a socket in good condition on a dedicated circuit, avoid extension leads and reels, and if the plug or socket becomes warm, stop and have the installation checked. A dedicated charge point is the better answer.

Only where the OE number and software variant agree. Charger rating follows the vehicle specification, communication protocols follow the platform, and the mounting, cooling connections and high voltage terminations follow the installation. A unit that fits mechanically but reports a different rating either refuses to code or charges incorrectly. Read the number from the existing unit, quote your vehicle identification number, and have the reference confirmed before anything is dispatched.

There is no service interval and no wear mechanism in the mechanical sense, since nothing moves. What ends their life is thermal stress, moisture at a connection, or damage from a supply side fault such as a severe voltage surge. Keeping the cooling path healthy, using sound charging equipment and dealing with charging faults rather than repeatedly retrying are the only meaningful things an owner can do, and they are worth doing given the replacement cost.

Yes. On board chargers are ordered by number and by market, because single phase and three phase units differ and so does the software behind them, which is why an enquiry is the usual route. Send the label reference with the vehicle identification number. Confirm what the workshop needs to do afterwards, since many replacements require configuration before the vehicle will accept alternating current at all. If the fault appeared after a charging incident, ask for the input fuse and the connector as well, because damage at the inlet frequently accompanies a failed charger.