Nothing stopping you from having more.
I have 2 on my Terrano. 1 on each side of the spare tyre to light up either side.
I also have a LED light bar on the front (wired in as a fog light) along with 2 spot lights. With all the lights on, driving along a dark country road is brilliant. The LED bar has heaps of spill which makes cornering better, and the spotties give the throw for long range vision. The light bar puts out better light than the headlights Lo beam but not as good as Hi beam. Low speed crawling along a river bed or farm track, the LED bar is fantastic. Foggy nights however, the LED light is far too white and simply creates a white blanket out front.
The quality of LEDs are getting much better. Decent brands are very good quality but horrendously priced. Cheaper Chinese lights are available much more reasonably. Quality of bracketry and bolts leaves much to be desired though. My light bar came from Aliexpress and was landed for under $75ND.
Bookmarks