What Is A Headlight Ballast

In this article, we’re going to explain what a headlight ballast is, what it does, and why it is important if you’re upgrading your vehicle’s headlights

When you upgrade from halogen to HID technology, it’s not a question of simply replacing one type of headlight bulb with another. It is critical to make sure you install the correct ballasts along with the new headlight bulbs.

Installing headlight ballasts is a little more complicated than simply flipping the lightbulbs, but they fulfill an important role in providing better road vision at night and also improving the look of your vehicle.

Read on, as we explain.

Headlight Ballast: Explained

The basic function of a ballast is to provide the voltage to start an HID lightbulb. And once the bulb is shining properly, a ballast maintains an adequate electrical current flow to keep the bulb burning steadily.

If you don’t use a ballast the bulb will still work, but the current will be unregulated and uneven, and the result will be a much shorter lifespan for your bulb. The fluctuating current will also mean uneven lighting on the road ahead.

Normally HID bulbs don’t work on DC power, so the ballast also acts as a DC-to-AC converter. That means you can use your car’s DC power source to light the bulbs.

If your car came out with halogen lights, it is completely possible to upgrade to HID, but then a ballast becomes essential. These are available in HID conversion kits. They typically contain wiring, mounting elements, and ballasts, along with the HID bulbs.

If you upgrade with a kit like this, your HID conversion will be 100% successful.

If you’re wondering about the term – Canbus – this is the electrical circuitry in your vehicle that facilitates communication between the different electrical and electronic components.

The reason this is important is not every car comes standard with a Canbus system. If your vehicle has a standard Canbus system, and you install an HID kit, your Canbus may become erratic because HID bulbs use less power than halogen bulbs. The result can be a constant error message that signals an issue with your headlights, depending on how your car’s warnings are configured.

If your car does come standard with a Canbus system, make sure you install Canbus ballasts or a Canbus kit.

The best recommendation we can give if you’re considering an upgrade from halogen to HID is to always choose quality over price. In this case, it is important because a premium ballast will give you up to 5-years of trouble-free service, while lesser units are proving themselves to be less reliable all the time.

So, the rule of thumb is a high-quality product with a good warranty.

Headlight Ballasts and Wattage

While there are various factors to consider when you’re thinking about an upgrade from halogen to HID, most kits will have this preconfigured for you. This takes the guesswork out of the equation.

Make sure you’re up to speed with the required wattage for your vehicle, though. This is a critical factor when you purchase a ballast and will determine the intensity of light your HID bulb ends up producing.

The most common configurations for HID ballasts are 55 and 35 watts respectively. 70watt units are available, but that is probably overkill for everyday use.

A parting shot

All things considered; a proper headlight upgrade is always a great idea. And taking your car’s headlights up a notch from halogen to HID will only improve your safety and driving comfort.

But once you start making aftermarket modifications to your vehicle (and face it, this upgrade is one) making sure everything you add is compatible with everything that is, becomes super important.

Our suggestion is to not be in a hurry. Make sure you understand what kit would be a perfect fit for your vehicle. If you’re not sure, ask. Also, instead of buying the components separately, get a kit. They are easier to install, and they come with instructions.

Road safety is becoming more important than ever. This is the one upgrade you can make to your vehicle that will improve your safety on the roads, provided you do it systematically, with the correct planning, and a meticulous installation.

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Richard Nickleson is the author and owner behind Headlight Reviews. He first started the site as a hobby to share his insights on car parts and specifically headlight bulbs, but it soon ballooned and now he writes on all topics surrounding headlights bulbs. If you've got a bulb question, contact Richard here.