What Is the Difference Between 35W and 55W Ballasts?

Many moving parts must work together properly for your car’s headlights to function. While many kinds of HID bulbs (or high-intensity discharge bulbs) are available, there is a difference between 35w and 55 ballasts. Ballasts are small units that operate and hDouse the electrical arc in an HID bulb that allow a car’s headlights to work.

Some similarities between 35W and 55W ballasts include:

  • People install both with an extra relay harness for protection.
  • Usually, both consist of anti-UV quartz.
  • Most recent HIDs are water and dust-proof for a greater lifespan.
  • Both are high-intensity discharge bulbs.

What sets them apart?

  • 35W requires less power, runs less hot, and may work better for your machine.
  • 35W has a better bulb life and won’t need replacing as quickly.
  • 55W offers maximum brightness and glare.
  • 35W is typical for drivers, states, and manufacturers.

The most critical point to consider is that 35W is legal in most states, while 55W may not be. That should factor into your decision because you may only be allowed to use one.


Which Is Brighter?

 35W bulbs draw from that many watts of power. The bulbs will look bright and be the color they are supposed to, including white, blue, purple, red, and others. The most common and legal color is often white with varying watt HID.

55W bulbs used with 55W ballasts will also look nearly three times brighter but slightly dull. The higher wattage of the bulb, the less intense the color appears.

One valuable difference between 35W and 55W ballasts is the increased risk of electricity, brightness, and damage with a 55W HID. However, there are some cases where a 55W would work best for your car, so keep that in mind.

HID Bulbs and ballasts should go together. For example, 35w bulbs work with 35W ballasts, and 55W bulbs with 55W ballasts.

55W becomes less efficient since the bulb may become too hot and doesn’t offer better light. It may seem brighter at first glance but is usually less efficient when compared to the 35W.

The law of diminishing returns holds with 55W ballasts because as the watts increase, the lumens do too, but gradually the “increase” seen as valuable diminishes over time. As a result, many people prefer the 35W.

It is vital to note that light from a 50W ballast compared to a 35W ballast will be 50% brighter. The quality of the color will decrease due to the increased amount of wattage and power needed.

A higher Kelvin amount for the light does not necessarily mean it will be brighter since the brightest thing we know of is the Sun is 5800K. Any more than this for your headlights causes brightness loss and eye strain.  

Purpose of 35W and 55W HID Kit

An HID kit or system works when a high-volt energy current reaches the HID bulb. That electric current must travel in an arc to get to your car’s headlights. This system allows them to function expectedly. 35W HID bulbs are usually the standard for HID systems because 55W HID bulbs are not usually what their specs claim.

A relay harness connects the HID system to your car’s battery. Your car’s lights will then draw power from the car battery rather than from the rest of it. 35W and 55W ballasts are popular options for car light HID systems, but there are other options in the middle, such as 40W, 45W, and 50W.


Which One Do I Need?

35W ballasts trump the 55W ones for efficiency and lifespan, but higher temperature and “brightness” are qualities of the 55W. A high-powered ballast such as the 55W can work effectively and correctly. However, you must pay careful attention to how you use it.

You need good ventilation for the 55W ballast since the unit can reach such high temperatures. 55W might be too much to handle and cause permanent damage if the wiring gets too hot.

The risk of technical issues and heat damage can draw some away from the 55W ballast, but it might be what your high-powered car requires.


Now that you know the difference between 35W and 55W ballasts, we hope this information will help you decide which works best for your vehicle. We will happily answer any questions if you are still uncertain or require further assistance.

At Underground Lighting, we are the experts in top-rated HID lights and can help you find everything you need. Call us today at (718) 701-8433 with any questions and learn more about our fantastic products!