How Does a Dash Cam Work?

Credit: Nextbase Series 2 dash cam (Source: Nextbase)

Dash cams are like home security cameras for your car. They’re great at capturing incidents, like someone rear-ending you while you’re stuck in traffic, or even someone vandalizing your car when you’re not around to see it. But if you’re new to dash cams, you may want to know how they work before you invest in your own.

In this article, I’ll explain how dash cams work on a basic level, both how they record and store footage so you can access it and use it in an insurance claim, a police report, or even a particularly fun session of car karaoke.

How Dash Cams Work

A dash camera, or a dash cam for short, is a security camera that you mount on your car’s dashboard or just inside the windshield. It records either the outside of the car through the windshield, the inside of the car, or both, in some cases. Not only can it provide evidence for car accidents or crimes, but it can also deter crime before it happens. An ounce of prevention is worth a pound of cure, as they say!

While dash cams are becoming more and more advanced, here are the basic components you’ll find with all dash cams on the market:

• Camera: The most important component, of course, is the camera itself, which works like any other security camera and can record in 720p HD, 1080p HD, or in the best cameras, 4K.
• SD card: An SD card or a micro-SD card is responsible for storing the footage locally. Some SD cards upload to cloud storage, creating redundancy that ensures you don’t lose your footage just because your camera or card is stolen.
• Power source: Typically, dash cams are powered by the car’s battery, but occasionally, there’s a separate power source, like an external battery. The power source matters because if a camera is hardwired into the car, it will stop recording when the engine is turned off. If there is an external battery, however, it can record even if the engine is off, for example, when you’re parked and someone sideswipes you.
• Mount: The camera needs to be physically mounted to the dashboard or windshield, so there will usually be some sort of adhesive.
• Night vision sensors: Finally, some cameras have night vision sensors which allow the camera to record clear footage at any time of day. If you want night vision, look for cameras with High Dynamic Range (HDR) or Wide Dynamic Range (WDR) so your recordings aren’t limited to waking hours.

Now that you’re familiar with the components across all dash cams, get to know the three main types of dash cams, based on what exactly they record:

• Front-only: Also known as single lens, a front-only camera is mounted to the front windshield and shows the front of the vehicle only, as the name suggests.
• Dual-channel: A dual channel camera shows both the front and back of the car, recording your passengers in addition to the street.
• Cabin-view: Finally, best paired with a front-facing camera is a cabin-view, which records the cars besides you along with your passengers.

All of these components work together to record onto an SD card, which uploads to cloud storage. Some cameras lack an SD card altogether and upload to cloud storage directly.

How Long Does a Dash Cam Record For?

The amount of time a dash cam records for depends on the amount of storage, which is measured in gigabytes or GBs. Based on my experiences testing out dash cams, here is a chart of how long cameras record for based on their storage size.

The higher quality the video is, the more storage space it takes up. That’s why I’d recommend getting an SD card with at least 128 GB of storage at a minimum. Especially if you’re only depending on an SD card and not other cloud or local storage, your footage will rewrite itself once the storage fills, so you could lose important footage if you don’t back up your files regularly or lock the footage, possible with some dash cams.

So when exactly does a dash cam start and stop recording? It depends on the dash cam itself as well as its setting, but there are a few main options:

• When an incident occurs: Some cameras have motion sensors that allow it to start recording only when an incident occurs, like someone taps your bumper. This is often referred to as “intelligent recording” and can occur even if your car is off, given the dash cam is powered by an external battery.
• When your car turns on and off: If your dash cam is dependent on your car’s power, it will turn on and off with your engine, recording only when your car is on. Although you won’t have to worry about replacing the battery, you could miss out on recordings of incidents that occur when your car is off, like a hit-and-run.
• Always: Finally, some dash cams record 24/7 continuously. Of course, this uses the most storage, but at least it means you won’t miss an incident.

Typically, you can make your camera record manually either by pressing a button on the device itself or by using the camera’s smartphone app.

How to View Your Dash Cam Footage

You can view your dash cam footage in two ways:

• Local storage: If your camera uses an SD card, you’ll have to upload the footage onto another device, like a smartphone, computer, or tablet, and watch it there.
• Cloud storage: Or, if your camera automatically uploads its footage to cloud storage, you can view it more easily via a smartphone app.

I’d recommend choosing a dash cam with cloud storage. Although you may have to pay monthly storage fees, cloud storage can’t be stolen, unlike a physical SD card, and it makes it less likely your footage will be overwritten. An SD card on the other hand, will be overwritten once it runs out of space, and if someone steals the card, your footage is gone forever (or at least until the police recover it, if ever.)

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