Adding led lights...relay or not

[jcummins]

My L4330 has two 25 watt bulbs in front that are blocked by the RR fishplates weights I put on the front weight bar. I plan to replace them with 2 18 wat LED light bars Amazon.com: Signstek 2*18W CREE LED Flood Light Headlight Work Light Lamp off Road High Power ATV Jeep 4x4 Tractor off Road Light Fog Driving Bar Rree Truck SUV Car IP67 Waterproof Dustproof Shockproof (Black): Automotive.

I don't plan to use relays, just disconnect the OEM lights, tie them directly to the LED light bars. Unless I find that Kubota used rediculously small wiring for the headlights that is. Just in case I bought a couple of these when I bought the LED lights, so I'm prepared either way: Amazon.com: Absolute USA 2 In-line ATC Fuse Holder, 2 Relay RLS125 12 VCD Automotive Relay SPDT 30/40A and 2 SRS105 12 VDC 5-Pin Relay Socket: Car Electronics

Good luck!

Well one of my relays was bad....so I bought the deal you posted. Actually pretty good price considering what all is included.

 

[FTG-05]

JC, you helped me out a couple months ago, glad I could at least slightly return the favor!!!

[beer] (or however you do it.....

 

[jcummins]

JC, you helped me out a couple months ago, glad I could at least slightly return the favor!!!

[beer] (or however you do it.....

Hey...it's what this forum is all about. Kind of a go to spot in researching stuff.

 

[mx1alex]

Amp draw on 12v LEDs is very small. IMO no relay is needed. I had 6 50w LED flood lights running on a 24v system on my boat wired on one switch with no relay.

 

[jcummins]

Amp draw on 12v LEDs is very small. IMO no relay is needed. I had 6 50w LED flood lights running on a 24v system on my boat wired on one switch with no relay.

I actually don't think so either, except for the circuit I'm pulling from. It takes little effort to add them, so I'm going to.

Nice bow fishing setup. Many years ago, I was wanting a setup like that. To dang old now.

 

[quarencia]

I'm surprised by many of the comments about LED current draw. Maybe I'm interpreting what people are saying incorrectly, and if so ignore what I'm about to say.

Watts = Volts X Amps (for DC circuits)

This is true regardless of what type of device you are using. A 55 watt LED draws the same amps as a 55 watt halogen bulb. Size switches and wire gauge accordingly. A 55 watt LED is more efficient and will put out much more light than a 55 watt halogen bulb. Conversely, because the LED is more efficient, it will produce much less heat than a 55 watt halogen bulb.

A 70 watt LED light bar draws 5.8 amps (70 watts/12 volts). A 5.8 amp circuit should use 14 gauge wire up to 10' to 15' wire length. If the wire run is longer you should use 12 gauge wire. Two 70 watt light bars and you should use at least 12 gauge wire up to about 15' of wire. These recommendations vary slightly depending on the source, but you can see that just because it's an LED does not make current draw and wire size insignificant.

Get this wrong and you could get lucky and have no problems or you could melt a wire, short it and blow a fuse. Although unlikely, the worst case scenario of undersized wiring is a fire. Please don't assume just because it's an LED fixture that it doesn't draw much current.

 

[quarencia]

Amp draw on 12v LEDs is very small. IMO no relay is needed. I had 6 50w LED flood lights running on a 24v system on my boat wired on one switch with no relay.

To add to my previous post, 6 50w LED flood lights draw 12.5 Amps on a 24 volt system. In a 12 volt system, these lights would draw 25 Amps! That's a lot of current. Better plan for it.

 

[gladehound]

Watts / Volts = Amps
72 / 12 = 6
36 / 12 = 3

So with all of the lights you are looking at you will only be at 12 amps. The switch will handle it just fine. Now the trick will be finding a circuit on the vehicle that will handle the extra draw.
I like to take the draw back to the fuse box where you might be able to tap into an empty lug on the switched side of the box. Mind you, I'm not tapping into a fused circuit, I'm going to the main bus bar. The new line needs an in-line fuse.

I used these switches on my tractor light install. I had to go to the fuse box with the front lights as they drew nearly 25 amps. For the rear lights I tapped into the existing wiring since they only drew 3 amps.

Wow! That's a lot of forward facing light on that ROPS! 25 amps on 12volt LEDS will give you ~20,000 actual lumens. Or about 10x brighter than your average car head lights. Does it ever blind you if you turn around with the front lights on?

 

[gladehound]

I just installed 4x18 watt LEDs today. The tractor had a 10 amp "work light" fuse with wire terminating at the rear of the tractor. I wired 2 x 20 amp rated toggles each running 2x18 watt LEDs (2 front 2 rear). Each switch will only ever see 3 amps (36 watts for 2 lights divided by 12 volts). I don't see any possible way to fry the 20 amp rated switches or hurt anything upstream of the 10 amp fuse with 3 amps per switch and 6 amps total going through the fuse. If there is a short causing a current spike the fuse should blow before the switches. So I did not use a relay.

However, this thread got me thinking... I'm don't know much about this stuff, is there any benefit from adding a relay in my situation (as described above)? If so, I can't think what that benefit would be so help me out!

 

[Garandman]

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A 70 watt LED light bar draws 5.8 amps (70 watts/12 volts). A 5.8 amp circuit should use 14 gauge wire up to 10' to 15' wire length. If the wire run is longer you should use 12 gauge wire. Two 70 watt light bars and you should use at least 12 gauge wire up to about 15' of wire. These recommendations vary slightly depending on the source, but you can see that just because it's an LED does not make current draw and wire size insignificant.

This is a good point. DC systems have significant voltage drop as length of run increases. There are charts available to help calculate. I use a book on marine DC wiring.