EV charger types and how much power you actually need

An electric vehicle battery only stores direct current, so somewhere along the chain a conversion has to happen. What separates the two main charging types is where that conversion takes place.

In alternating current charging, which is what homes use, the unit on your wall is not really a charger: it is a control and protection device that delivers alternating current to the vehicle and communicates with it. The actual charger sits onboard the car, and it does the conversion. That is why the maximum home charging power is set by the vehicle, not by the wall unit: you can install a higher-powered point and the car will still accept only what its onboard charger allows.

In direct current charging — fast public stations — the conversion happens in the station, which feeds direct current straight to the battery, bypassing the onboard charger. That is what allows far higher power, and also what makes those units large, expensive and appropriate to commercial installations rather than homes.

The practical consequence is simple: for a house or a private parking space, the conversation is always about alternating current. If someone offers you fast DC charging for residential use, either they misunderstood the case or they are overselling.

The international standard IEC 61851-1 defines charging modes according to how the vehicle connects and what protection and communication exist between the two ends. This is not a distant technicality: RETIE explicitly references it as one of the two valid routes for installing a charger in Colombia, alongside section 625 of NTC 2050.

What separates one mode from another is the degree of communication and protection. In the most basic modes the vehicle plugs into a conventional socket through a cable with an in-line protection device, with no dedicated installation. In the mode corresponding to a fixed charging point, there is a dedicated circuit and the equipment talks to the vehicle to negotiate available current and cut off if something goes wrong.

That negotiation is the difference that matters. A fixed charging point knows how much current it can deliver and tells the vehicle, which adjusts. A cable plugged into a household socket knows nothing about the circuit behind it: if that socket shares a line with the fridge and the air conditioning, nobody is watching the sum.

This is why habitually charging from a conventional socket is the practice that causes most problems. It can work for months and fail on the day the loads coincide, because the weak point is not the vehicle but the wiring and protections of an installation never designed to deliver high current for hours on end.

The connector is not a design choice, it is a consequence of which car you own. Vehicles sold in Colombia come with their inlet as standard and the charging point has to speak that language, not the other way round.

In alternating current two connector families coexist, one of North American origin and one European, and vehicles of both are on Colombian roads. In direct current, fast charging standards differ again, and some combine the AC and DC sections into a single combined connector.

The practical advice is not to memorise names but to ask for the data before buying anything: which connector your vehicle carries and what maximum AC power its onboard charger accepts. With those two figures any serious installer can propose compatible equipment; without them, any proposal is guesswork.

One detail that saves trouble: many charging points are sold either with a tethered cable or with an open socket. The open socket accepts whatever cable each vehicle brings, which adds flexibility if you change car later or if there is more than one at home.

Here lies the most expensive and most common mistake: sizing by the maximum power the vehicle accepts rather than by the energy that needs replacing.

The honest calculation has two numbers. The first is how much energy you use per day, which comes from your daily mileage and the vehicle's consumption per hundred kilometres. The second is how many hours the car sits parked and plugged in, which in normal domestic use means overnight. The power you need is the first divided by the second, plus a margin for losses.

With that calculation in front of them, many people discover that a moderate charging point is more than enough: if the vehicle sits still for ten or twelve hours each night, spreading the charge across that window is plenty, and it is gentler on both the battery and your electrical installation.

Going higher only makes sense when the usage pattern genuinely justifies it: high mileage, short parking windows, several vehicles sharing one point. And even when it does, the limit is usually set by something else: the capacity of your electrical service, which is what the site survey checks.

A modern charging point can do rather more than deliver current. Two features genuinely change something, and it is worth asking for them by name.

The first is time scheduling: charging in the windows that suit you rather than starting the instant you plug in. The second, and more important in a home with a tight electrical service, is dynamic load management: the unit measures total household consumption and reduces charging current when the rest of the installation is drawing heavily, preventing the main protection from tripping.

That second feature is often what allows a charging point to be installed without upgrading the service, which tends to be the most expensive item in the whole project. It is worth asking explicitly whether the proposal includes it and what it requires, because it normally needs an additional meter in the panel.

If you also have, or are considering, solar panels, a third feature links the two: charging preferentially from solar surplus rather than drawing from the grid. It is not essential, but it is why many people find it makes sense to plan both installations together.