If you’re thinking about buying a dash cam and wondering “Can a dash cam drain your battery at night?”, then you’ve come to the right place. Yes, a dash cam can drain your vehicle’s battery, but only under certain circumstances.
In this article, I’ll discuss the specific scenario in which a dash cam can drain your car’s battery.
Understanding How Dash Cams Are Powered
In general, there are two main places a dash cam might be powered: hardwire kit or car charger. A hardwire kit connects your dash cam to your vehicle’s fuse box while a car charger plugs into your car’s cigarette lighter, which is subsequently powered by your car’s fuse box.
The main difference between a hardwire kit and a cigarette lighter is that a hardwire kit contains an internal circuit that detects when your car’s starter battery drops below a certain voltage and stops drawing power which causes your dash cam to turn off. A car charger typically only draws power while your car is running.
Scenario 1 – A Cigarette Lighter With Constant Power
If you’re powering your dash cam via a cigarette lighter and it has power even when your car is off, then it definitely has a chance of draining your battery to the point where you will need to jump your car to get it to start.
However, this is typically only applicable if you’re running parking mode on your car, where the dash cam is going to be active after your car is turned off.
Car chargers have no circuitry to detect when your starter battery’s voltage drops below a certain point. As a result, if your dash cam is plugged into a cigarette lighter that is always hot, then it will keep pulling power until your car’s battery has no power left to give.
This typically isn’t a problem since most cars have the cigarette lighter on an accessory fuse, which means it only receives power while your car is running or the ignition switch is in the “ACC” position.
It’s really easy to determine whether your car’s cigarette lighter have constant power. You just plug a car charger into it while the car is off and see if provides power to whatever you’re trying to power.
If it does provide power, then you may want to wait 15-20 minutes to see if your vehicle eventually cuts power to that circuit as some cars are designed to provide power to ACC circuit for a short time after the car is turned off.
If there’s no power to the cigarette lighter, then you can be confident your dash cam isn’t going to drain your car battery.
It’s possible to use a cigarette lighter with constant power to power your dash cam without draining the battery, but you’re playing with fire.
If you wanted to do this, then you would need to driver your car enough each day to restore the amount of current your dash cam uses while the car is parked.
If you don’t happen to drive your car for a day or two, then you may end up not being able to start your car. The amount of time you could go with a dash cam on an always hot circuit and not driving your car is highly dependent on how old your battery is, how much current your dash cam draws, and the state of charge of your battery when you turned it off.
I really don’t recommend doing it, but it is a possibility. I’ve done a similar thing with a DC/DC charger in the past when I installed it, but forgot to buy a relay to cut power to it when the engine was off. Even though the charging function is turned off, it still consumes some power to keep things like the Bluetooth connection going.
I was constantly worried about if I was going to run my starter battery down, even though I knew from my use of a dash cam hardwire kit I had about 16 hours before the battery voltage would even hit 12.2V
Scenario 2 – Dash Cam Wired Into The Fuse Box without a Hardwire kit.
If you buy a dash cam that accepts 12V directly, then it’s very possible to drain your car battery if you wire it directly into the fuse box without a hardwire kit. This will largely depend on if you wire it into an always hot circuit or into an accessory/ACC circuit.
If you wire it into an always hot circuit, then there is nothing to prevent the dash cam from drawing power and it will do so until your battery doesn’t have any juice left in it. This is basically the same scenario as your cigarette lighter being wired into an always hot circuit with the only difference being where your dash cam is getting its power.
If you wire it into an accessory circuit, then your dash cam will turn off when you turn your car off.
Scenario 3 – Hardwire Kit Set With Too Low of a Voltage Cutoff
Hardwire kits typically come with a switch that lets you select the voltage at which you want them to stop drawing and supplying power to your dash cam. Typically these voltages are 12.4V, 12.2V, 12.0V, and 11.8V. Depending on the battery voltage chart you look at, the state of charge that corresponds to these voltage levels are:
- 80% state of charge at 12.4V
- 60% state of charge at 12.2V
- 50% sate of charge at 12.0V
- 30% state of charge at 11.8V
Again, these are just ball park figures, but they get the point across. The lower the voltage cutoff setting you set, the lower your drain your car’s battery. Lead acid batteries don’t like to be kept as fully charged as possible.
If you let your dash cam run your starter battery down to 30% consistently, then you’re adding a lot of wear on your battery and eventually you may run into a situation where your battery can’t start your car from that level of charge.
Most people with dash cams recommend that you don’t go below a setting of 12.4V or 12.2V because of the extra wear on the starter battery below those levels.
As you can see, it’s draining your battery with a dash cam is a valid concern, but it’s only going to happen under certain conditions.
If you avoid wiring your dash cam into an always on circuit without a hardwire kit or plugging it into a cigarette lighter outlet that’s always on, then you don’t really have to worry.
If you’re using a hardwire kit make sure to set the voltage cutoff to 12.4V or 12.2V or be comfortable with the fact that you’re sacrificing some of your battery’s service life, above what you’re already losing at 12.4V or 12.2V, to enable your dash cam to be powered longer while your car is parked.
If you have questions or comments leave them below and I’ll be sure to respond to them.