It sucks walking out to your car in the morning finding your battery dead. Does ignition interlock drain car batteries? Some ignition interlock device customers worry about the effect their device will have on their battery. But is this a valid concern?

Simple answer: No. Your interlock device will not drain your battery.

First, a little lesson in electronics

If you leave your headlights on overnight or you leave your trunk open or you don't close your door all the way, you're often greeted the next morning with a dead battery. But lights draw a decent amount of energy from your battery. Just for the sake of providing an example, let's assume you have four 100 watt lights on a 12 volt system, your battery will need to supply 33 amps. If your vehicle has a 65 amp alternator, 33 amps for headlights is a big deal even when the vehicle is running. When your car (and therefore alternator) isn't running, that can eat up your battery power quickly. 

Ignition interlock devices work with, not against, car batteries

Ignition interlock devices draw less than ¼ of an amp while the vehicle is not operating and ½ of an amp when it is preparing for a breath test. This is a very minimal amount compared to even your car’s stereo or clock.

Many vehicle accessories, such as your clock, radio, the internal memory of your engine computers, or your cellphone charger, draw a minimal amount of electricity. Leaving your headlights on overnight or not closing your trunk completely will cause your car’s battery to drain much more than these electrical accessories. When you have an ignition interlock device installed into your electrical system, the device will draw a tiny amount of power from your car’s battery but it is not enough to drain your car battery totally.

Keep your battery charged

When your car is running, your alternator recharges your battery. So generally when your car is running, the amps being pulled from various devices is less of an issue. But if you leave your car parked without starting it for several days, the alternator is not recharging the battery. This can contribute to a dead battery especially if your battery, alternator, or both are defective or old.

Your car may not start if you do not use it for a while. Your accessories are constantly using your car’s battery, so if you are not keeping the battery charged by starting your car regularly, your battery may die. Make sure you are using your vehicle regularly to maintain its battery power. Even if you're not driving, start it and let it run for a while. Don't forget you're still responsible for any breath tests requested by your ignition interlock device.

What if my battery does die?

If your vehicle’s battery does die, it is typically because of an old battery or a defective alternator which are not due to the ignition interlock device. If this occurs, you may need to visit a mechanic to troubleshoot the problem after you get your car jumped and running. Just make sure your mechanic is aware you have an ignition interlock device so they know to contact us before working on your vehicle. And make sure to maintain very accurate records of all mechanical issues and work while your interlock is installed.

Checking your current battery voltage with the ignition interlock device

With Smart Start of Louisiana, clients have an easy way to check their car battery’s current voltage right on their ignition interlock device screen. To check your car battery’s voltage, press the pound (#) sign then the number 2 on your device’s keypad. If your battery is below 12 volts you may want to charge or change your car battery. Our team is always standing by to help if you use a Smart Start ignition interlock. If you ever have any questions about your ignition interlock, feel free to call us at 1-866-447-8686.

Need an ignition interlock?

With friendly technicians providing the best care to you and your vehicle and a 24/7/365 customer care center for any questions during your program, fulfilling your ignition interlock requirement will be a seamless and easy process. And whether your questions relate to car batteries or monitoring authority reporting or meeting your program's requirements, we're here to help. Schedule your installation appointment today by calling 1-866-447-8686 or save 20% by filling out our short online contact form.