How a dashcam works
A dashcam mounts to your windscreen, draws power from the 12V socket or a hard-wired circuit, and begins recording the moment the engine starts. It writes video to a memory card in a continuous loop of short chunks, typically one, three or five minutes each, and once the card is full the oldest chunk is overwritten by the newest.
A built-in G-sensor detects sudden braking or impact and locks the current and surrounding chunks so they cannot be overwritten. That automatic locking is the mechanism that quietly preserves the footage of an incident while everything else loops away in the background.
Does a dashcam record when the car is off?
By default, no. A camera powered from the 12V socket switches off with the engine, so it only records while you are driving. That covers the great majority of what most drivers need.
To keep recording while parked, the camera needs continuous power and a feature called parking mode, which requires hard-wiring to a circuit that stays live, or a separate battery accessory. Parking mode watches for motion or impact while the car is unattended, with a voltage cut-off to protect the battery.
The main types
There are four broad types. A single-channel camera records only the road ahead and suits drivers mainly worried about head-on or side incidents. A dual-channel adds a rear camera at the back window and is the most commonly recommended setup for South African conditions, covering rear-end and lane-change disputes.
A triple-channel adds an inward-facing cabin camera, common in rideshare and commercial use, and a 4G-connected camera adds a SIM that uploads incident clips to the cloud automatically. Each of these has its own dedicated guide; the short version is that dual-channel is the sensible default for most private drivers.
Resolution and field of view
Resolution decides how much detail the footage holds, and the practical baseline is Full HD, which keeps number plates legible at normal following distances. Higher resolutions add clarity and longer-range plate capture at the cost of larger files, with a mid-step option sitting usefully between the two.
Field of view describes how wide the camera sees, with a range around 120 to 170 degrees being typical. Wider captures more to the sides but distorts the edges slightly; the resolution-versus-storage and the field-of-view trade-offs each have their own detailed guide.
How the footage reaches you
The footage always lives first on the memory card in the camera, and the simplest way to view it is to remove the card and read it on a computer. That is all a basic camera needs.
Many cameras add Wi-Fi, letting you connect a phone app to review and download clips without removing the card, which is convenient rather than essential. Connected 4G cameras go further and push incident clips to the cloud automatically, so the key footage can reach your phone even if the camera itself is lost.
The disadvantages, honestly
A dashcam is not free of downsides. It is an upfront cost plus some ongoing upkeep, mainly replacing the memory card periodically, and a poorly fitted unit drawing power around the clock can strain a battery. A camera on the windscreen can also be a target for a smash-and-grab if left visible.
There is an even-handedness point too: the footage records what happened, not only what helps you, so it can show your own fault as readily as someone else's. For most drivers these drawbacks are small against the protection, but they are real and worth weighing.
Which type fits which driver
A low-mileage driver in a lower-risk area may be well served by a single-channel camera, while most metro drivers benefit from dual-channel given how common rear-end and lane-change disputes are. Rideshare and commercial drivers lean toward triple-channel and connected systems for the cabin view and evidence backup.
The honest summary is that dual-channel with GPS is the right default for the typical South African driver, with parking mode added where theft and parked-damage risk is higher. The dedicated guides on configuration, resolution, installation and insurance cover each decision in depth.