Dashcam Audio, Power and Memory Choices

Audio Recording

Some dash cams record sound as well as video.

Audio can be helpful – for example, if the other driver says that you failed to indicate a change of lane, or that you were indicating a turn which you did not take, it is probable that an audio recording will hear the sound of the indicator alert (or not).  It can also report on your state of mind and behavior (in terms of whatever comments you might be making), although that type of reporting may or may not be positive!

Audio recording can potentially be a problem in states that require consent from all people being recorded – with that consent being necessarily obtained prior to the recording starting.  It isn’t so much a problem in terms of recording things like the sound of a crash or of a car’s tires squealing around corners, engine revving, and that sort of thing; the problem instead might come from an unexpected source – the passengers in your car.  You might think “of course my friends and family won’t object” but if you’ve not obtained their agreement in advance, you’re creating a legal loophole that, in a high stakes case, the attorney for the other side might exploit to get your recording designated as illegal and therefore made inadmissible as evidence.

So, if you live in (we think) CA, CT, FL, IL, MA, MD, MI, MT, NH, NV, PA or WA, you either should disable the audio recording or let your passengers know.  It is probably sufficient to have visible signs in your car rather than have to ask people every time anyone gets in your car “do you mind if my dash cam records anything you say in the car”.

Some type of sign also helps you with the video recording itself – instead of having it become an awkward issue, you can simply have a tiny (but clearly visible) sign explaining you are filming both sound and picture to protect you in the case of an accident and any doubt/dispute about who was at fault.

Power Source and Connections

There are primarily three sources of power for your unit, and four types of connector between the power cable and the dash cam itself.

The three sources of power are :

Hard-wired :  You might need to hard-wire your unit into the vehicle’s electrical system if your accessory connector outlet switches off when the vehicle’s ignition is turned off, but you wish to leave the unit on all the time so as to (hopefully) get a record of any damage to your vehicle even when you’re not present in the vehicle.  We discuss the practicality of that feature on the page about advanced dash cam features.

Needless to say, hard-wiring the unit in to your vehicle’s power lines is a slightly more complicated process than just plugging it in to something.  We generally take the easy way out in such cases and pay an auto-electrician to run the wiring and connect whatever it is up for us, and that installation process invariably adds another $100-$200 to the cost of the unit.

Cigarette lighter type adapter :  An easier approach than hard wiring is to have the power cable terminate in a cylindrical round cigarette lighter type plug.  If you already need to use your power socket for something else, you can get adapters that convert one socket into two or three sockets.  They are inexpensive (from about $10 and up on Amazon) and some of them offer both cigarette lighter type sockets and also USB charging sockets too.

Of course, in most cases, this means that when you turn your car off, the dash cam loses power and won’t provide standby vehicle monitoring.

USB adapter :  The third choice is a power cable that ends in a USB connector, looking for any type of USB power source.  This is our preferred approach.

It means you can conveniently power the dash cam in other situations too – you probably have an external power pack for your phone and other devices, and USB ports on your laptop and maybe other electronics too, as well as dozens of wall chargers that you’ve accumulated over the years.  So if you want to experiment with the unit and understand its controls and how to best configure it, somewhere other than in the car, it is easy if the unit wants a USB power source, and more difficult if it requires a cigarette lighter shaped 12-14V power source.

It is easy to get a cigarette lighter adapter for your car that converts to a USB power socket, or more commonly, to two or three such sockets, – indeed, we use one that ends in four USB power sockets.  It is amazing how easy it is to need all four sockets – one for your phone, one for a passenger’s phone, one for a music player, and one for a dash cam.  Maybe you need one with six sockets!

At the other end of the dash cam’s power cable is of course a connector to plug into the dash cam itself.  Hopefully the cable is generously long so you can route it around the outside of the windshield if you wish, minimizing its visibility (and also making your dash cam itself more discreet – as we discuss in the section on self incrimination and other legal matters, it is better to be discreet about the presence of a dash cam).  A standard “long” cable seems to run 11′ – 12′ or so in length with most units, and that is usually plenty long enough.

We’ve seen several different types of connectors at the dash cam end of the power cable.  Astonishingly, some use the old fashioned mini-USB type connector.  Most use the more modern micro-USB connector.  There’s also a slow trend towards the new USB-C connector.

We don’t down-check a unit solely for having a mini USB connector, but it does make us wonder why any current model dash cam would be using a connector that has been obsolete and seldom used for at least five years (the micro USB connector came out in 2007).  What else might be old “underneath the hood” as well, in such a case?  There is definite value in having a modern unit with modern electronics, because it will probably consume less power and therefore is less likely to overheat in summer, or run your battery down if you choose an “always on” function.

In addition to these three somewhat standard type of connectors, some units use a proprietary connector.  That’s definitely a bad thing – it locks you into the dash cam manufacturer if you need to replace the cable in the future.  And you just know that a proprietary cable is going to cost at least twice as much as a generic industry-standard one.

Memory Card Issues

There are three things to consider when adding a memory card to your dash cam.

Capacity :  How much storage do you want on your card?   Some people automatically believe that bigger is better, and buy the largest card they can find/afford (and also possibly limited by the ability of the dash cam to accept very high capacity cards).  Micro-SD cards are so very cheap these days, with Amazon selling 16GB and 32GB cards for about $5 – 8, 64GB cards for about $11, and so on.

The thing is that while your camera might use as much as 5 – 10 GB per hour of recording, it doesn’t matter.  Your camera is recording a series of perhaps three minute video clips, one after the other after the other, in a continual process of recording.  When it has filled up the card, it goes back to the beginning, and then starts overwriting the clips, from the oldest to the newest.

What that means is the dash cam is automatically always keeping the last some hours of recorded video.  The only reason to have a larger capacity card is if you want to have more hours of recorded video kept.  But why would you want to do that?

If something happens that you feel a video record is important to keep, the easiest (and most prudent) thing to do is, at the end of that event, including continuing to record any interactions with other drivers and police, etc, you simply take that card out of the camera and keep it safe and separate.  The accident itself will only require a minute or two of recording.  Usually there’s no relevance to look at your driving history three or six hours before the accident (which might well have been on an earlier day or even week); indeed, if anything, on the basis that if you look hard enough you’ll find something, the less driving history that is stored, the fewer opportunities there’ll be for embarrassing footage.

Maybe, three days ago, you didn’t come to a complete stop when going through a stop sign.  Maybe two days ago you went through a light that was changing to red as you entered the intersection.  Maybe earlier today you accidentally glanced at your cell phone while driving.  A desperate attorney for the other side in any legal action could use those events to suggest that you are generally a risky bad driver, and so therefore, somehow, you must have been at least partially at fault in the accident that transpired.

So our advice is to get a small capacity card, not a high capacity card.  An 8GB card might be more than adequate so as to capture the last hour or so of footage.

Data Transfer/Write Speed

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Data Integrity

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Please Keep Reading

This is the fourth part of a seven part series all about dash cams, and supplemented with specific dash-cam reviews, too.  If you arrived from somewhere else, there’s a list at the top of the page showing all the articles.  And if you’re reading sequentially, the next page is about assorted other considerations and choices when you’re choosing the best dash cam for you.