I have some extra backup lights installed on my truck, each with a 100 watt bulb.

I want to add two more of them, so it would be 400 watts total.

Can the 14gauge wire I ran to them support this current draw?

Also, what size fuse should I be running?

Thanks guys

 

well 400w divided by 12v gives you a 33.33 amp current draw, so no the 14 ga is not big enough. You should use at least a 10 ga wire, preferrably an 8, with at least a 40 amp fuse.

 

Thanks,

Right now with my 200 watt lights I have it fused at 15amps, never blow once.


I think I will run another 14g wire out back for the additional two I want to add.

 

Defently going to blow your 15amp fuse with 400w lights...I dont get how u havent with your 200watts of lights. Thats gonna be drawing allmost 17amps...

 

Depends on the length of the wire.

 

Pray tell, what do you need 400 watts of light to the rear for back up lights??? 200 is a lot. You can run a maximum of 20 amps for 18 ft on 14 ga. wire. Since you're not running near 18 ft., a second 14 ga. wire for the additional 2 lights should do fine, although if I were doing it I'd probably run a 10 or an 8 ga. to run all of them, but I tend to believe in over kill. You do need to increase the fuse size though. Generally fuse at least 125% of draw, I prefer at least 150%. Means you should have AT LEAST 20 amp fuses on EACH line. If you have 'em on for very long at a time, I MIGHT go 25 amp.

 

^x2 Have any pics? I'm really curious to what this looks like

 

I can't imagine how fast you'd need to go in reverse to need 200W of lighting, much less 400W. He must have the hammer down. Maybe this is for a midnight demolition derby.

 

Looks like this is a good thread to ask a backup light question.

What would be the largest size backup lights I can install on my 09 F150, which can be spliced into the OEM backup light wire?

I have seen some low profile driving light which were like 55w or 100w each.
Would I have to install a relay and fuse?

I wonder if there are any low profile LED backup lights which are much lower power consumption, I've only seen big ones which dont look good as they really stand out.

Also, It would be great if we can get Blackjack to post some photos, with just the oem lights, 200w light, and 400w light so we can see the difference??

 

Your original back up lights (and hense wiring) are not a very high wattage at all, so you're not going to be able to run even a 55 watt off of those wires, definitely not a 100 watt. Why would you need a relay unless you ran a heavier wire (or wires) to carry the load? If you're going to run that kind of lights, you need to run heavier wire (or wires) and THEN a relay and fuse it at the source (presumably the battery). The are definitely LED's that you could run off of your back up wires, but they are gonna cost you a lot more money. How about the LED bulbs that you use in place of the original bulbs, a lot brighter and NO additional wireing, relays or fuses?

 

Code58: Thanks for your help.

Would you be able to let me know which LED bulb would work for me and possibly where to get it from?

Since we are on the topic, would you know if I can do the same to my headlight bulbs? If so, please advise which ones.
I wonder if it is possible to get ones that give that bluish hue.

thanks