Is a relay needed for 120w LED light bar?

vilguy · Sep 20, 2015

yeah spots or lightbar... its pretty much the same. Its just lumens and the positioning of them. If you have chequerplate on your bonnet it can make it a bit worse as there are some angles on the plate which are just right to reflect it back into the cab, but its only minor. There is so much light projected forward that you don't even notice.

Mcclegend · Sep 21, 2015

I watched a video on youtube it might of been an Andrew Pierre-white and he was say about the glare back off the bonnet and it he just stuck down some mat black vinyl on a little of his bonnet and it helped.

I wonder if it makes a lot of difference is the "spot" LEDs are in the middle and the "flood" led at the edges or the other way round, I've seen both for sale.

Paul D · Sep 21, 2015

I painted my bonnet chequer plate (It came with the cp fitted) matt black, which has made a huge difference.

timtheenchanteruk · Sep 22, 2015

Personally I'd uprate the cable too and use a 15A fuse, you may find a 10A fuse (IF the LEDs are actually running at the full 120W) doesnt last long, LEDs have a huge inrush current.
EG a 7W fitting from Halers has an inrush of over 30A, 12V units are no different, the inrush is in the LED.

Saltlick · Sep 22, 2015

Inrush? Not heard the term before...
Off to google then

huffhuff · Sep 22, 2015

timtheenchanteruk said:
Personally I'd uprate the cable too and use a 15A fuse, you may find a 10A fuse (IF the LEDs are actually running at the full 120W) doesnt last long, LEDs have a huge inrush current.
EG a 7W fitting from Halers has an inrush of over 30A, 12V units are no different, the inrush is in the LED.

Well, it's in now and with 25amp (28 strand) cable. The cable that the unit is fitted with doesn't look any higher than what i've used, if anything, it looks less likely to handle whatever an 'inrush' is

This is the current that flows in a short time period just after the first switch on of a cold lamp. With cold I mean that the lamp has been off for some time, enough to have the major capacitors and eventual coils empty with regard to energy.

Inrush currents is a known phenomenon for (heavy) motors. These motors are inductive loads that during a relative long period of time (several cycles of the grid, sometimes up to 250 ms) can draw a current that is significantly higher than the steady state current. This higher peak current needs to be delivered by the power grid and fuses, switches and cables need to be able to handle this current without shutting down the application.

http://www.olino.org/us/articles/2013/10/22/inrush-current-for-led-light-bulbs

timtheenchanteruk · Sep 22, 2015

The cable will be fine, the fuse may not tho but you'll be safe to upgrade it if need be (cant find a curve for car fuses)
Inrush is basically the "startup current" as just as flourescent lights have a higher current demand for a second or so till they light, so does LED, what many people dont realise is its can be many many times greater than the rated operating current. whilst this is more prenounced in AC applications, its still present in DC too,

Is a relay needed for 120w LED light bar?

vilguy

Do'er of stuff and the like

Mcclegend

Well-Known Member

Paul D

Old, nackered 'n broke, but the Landy is fine . :)

timtheenchanteruk

Well-Known Member

Saltlick

Well-Known Member

huffhuff

Well-Known Member

timtheenchanteruk

Well-Known Member

Similar threads