A 55W light bar draws 4.5 to 5 amps while a 120W LED bar will draw around 10 amps of current. LED light bars are a rising star in the field of automotive lighting. When someone dresses their vehicle up for off-roading, light bars are likely one of their initial choice of auxiliary lighting. It is also possible to get the perfect one that matches your vehicle setup since they come in different shapes and sizes.
But it is always necessary to know the amount of current and power that your newly bought LED light bar will use. Speaking of LEDs, I should also mention that they draw really low energy compared to the traditional incandescent and halogen light bulbs.
So, even though light bars often contain over 20-pieces of LED beads, you don’t have to worry about having your battery drained during an off-road journey.
How Efficient are LED Light Bars?
If we compare LED lights with incandescent bulbs, we can find a major difference in energy usage. The former uses almost 85% lower electricity compared to the latter. The difference is too high as well between LED and halogen. But why so?
Halogen lights use the same method as incandescent and heat up their filament using current. Most of the electricity gets lost in the form of heat in the process. We only get 5% of it as light. Hence, touching a lit halogen light can burn your fingers.
On the other hand, LED lights use a semiconductor consisting of a positive and a negative terminal. While the negative side contains electrons around its layer, the positive side has free slots.
Applying an electrical charge to the structure can change the position of the electrons from the negative to the positive side, creating light. If you look at it, there is no heat involved here. Hence, no energy gets wasted in the form of heat.
When combined with a heat-dissipation system, LED light bars almost always stay cool to the touch.
Because of such a process, LED light bars are more efficient than halogen and HID. They also last a long time for the same reason.
How Many Wattages LED Light Bars Use?
Wattage is the unit of power that your light bar will be using to produce its light output. Having a higher wattage is convenient, but it will also drain more current. When you drive with your light bar on, the vehicle alternator recharges the bar by itself.
However, if the wattage usage is higher than your system can output, it can drain your battery and is not ideal. Usually, you can find LED light bars with 120W on the market. It is the least amount for decent visibility.
If you want to keep it in an affordable range but get a better brightness output, you can opt for a 240W one. Depending on the manufacturing, a light bar with such power can generate around 20,000 – 30,000 lumens. Light bars can have as high wattage as 800W.
Note that the wattage of a light bar depends on the LED number and types as well. For instance, CREE LEDs are famous for providing higher brightness with similar power as other LEDs. Also, a 20” light bar will generally have a lower wattage than a 32” one (unless the former uses high-quality LEDs than the latter).
What Voltage Do LED Light Bars Use?
Most LED Light bars that I came across are manufactured to run on 10-30V output. When driving the vehicle, the alternator supplies a voltage from 13.5 to 15V. Although, the cabling wastes some of it. So, most light bars on vehicles use around 12-13.5V.
Now, you can apply the ohms law here to calculate the amp draw of the bar. If it is a 120W light bar running on 13.5V, it will draw around 8.89 amp. A 240W one on 14.7V will drain 16.33 amp. Simply divide the wattage with the voltage it runs on.
If we conclude it all, LED light bars can have a wide range of current draw, depending on their power. Higher wattage means more amp draw. If you use a 120W bar, which many use, you can expect between 8.89-10-amp use.
I suggest using 120W LED bars only off-road. For on-road use, go for a lower-powered one. Some states do not allow LED bars on-road and require you to put a cover on them when on the street.