So Do Auxillary LED Lights Need A Relay.

[drizler]

I see more and more things seem to have relays these days . I never used any on my old tractors but I don't want to be frying anything on a 2014 Massey with all it's computer goodies either. I plan on adding just a pair of 18 watt square mounts forward and probably a separate rear facing work flood on a separate switch. So what's the standard installation of lights like this you guys have run?

 

[wploetz]

Your old tractors drew a lot more watts than the LEDs. 18 watts is 1.5 amps at 12 volts so as long as your switch and wiring can handle that, your golden.

PS: You might consider using inline fuse holders when you wire the auxiliary lights.

 

[kthompson]

Agree with the above but on different issue, if you have bugs...try to mount the flood light as far as reasonable from you. kt

 

[k0ua]

Lets discuss the reasons to use relays. One reason is because switches to handle higher currents can be more expensive that relays to handle that same current, but another good reason in automotive applications is because placing a relay closer to the source of power (the battery in this case) or the path from the source of power to the load (the lights in this case) can allow you to run a minimum amount of large wire and you only have to run a small control wire for the coil.

But when LED lights came on the scene, this changed up the thinking somewhat. They draw significantly less current than either halogen or conventional incandescent bulbs. Now it is possible to run fairly long supply and load wiring to the dashboard for switch control and back to the lighting without significant voltage drops and not needing wiring gauges nearly as large..

So long way around and complex answer for a simple question, but Yes you should be good to go without using a relay.

 

[PILOON]

Most toggle switches can handle 10 amps (quality ones).

As to fuses or breakers you always want to have protection as close to the battery as possible mostly to prevent shorting that starts fires.
SO, # 16 wire, better still 12 or 14 using a 10 amp protection (fuse or CB) will CYA, always as close as possible to the source (battery).
LED's draw so little amperage that any toggle switch can be used without a relay.
If the protection device cannot be near battery source just be sure that wire up to the protection device cannot short to ground (use protective sleeves and/or tie the wires off so that they can not chafe and short to ground).
Sleeves and grommets (in holes) plus tie wraps to isolate from metal works OK.
Just remember that fuses and CB's have to be the weak link in a circuit otherwise that wire becomes a heater element if it shorts to ground.

Headlights generally use a relay as the current draw is way over that magic 10 amp level but with LED's the draw is always below that 1o amp level.

 

[KyleH]

If you are replacing existing lights (or adding to a prewired oem circuit for halogen lights) with leds I wouldn't worry about a relay, but I like to use relays most of the time when adding lights (or whatever) because it can extend the life of the switches by reducing current passing through them. Each time a switch is turned on and off there is an arc, very small, but the greater the load the more damage it does each time, this normally takes a long time to add up to anything that would cause problems, but sooner or later the contacts will be blackened and not conduct as well, heat will build up and cause a failure. Switches are not cheap if you are going with oem style ones to match your tractor. For example I added two switches to my B2650 and used Kubota switches like the TLB models and they are around $55 each plus tax, so it makes sense to use a relay to reduce the current and extend the life of them as much as possible.

Also, spend the extra money to get weather sealed relays and connectors. I use Deutsch or weather pack and dielectric grease along with heavy wall heat shrink that has the glue to keep water out. Doing so can save a lot of headaches down the road by reducing the likelihood of corroded wires. As a mechanic, I've spent a lot of time tracing wiring issues and a lot of the time it's due to people cutting corners or trying to reduce cost, or my favorite is finding green spots where somebody probes the wires with a test light, huge no no these days as the copper is not like it used to be when exposed to the elements.

 

[petegoud]

I might take a little issue with the 'most toggle switches can handle 10 amps'. I've replaced too many '10 amp' switches that have failed when being used in circuits drawing 7-8 amps. Cheap switches perhaps. Relays are really the best way to go.

 

[k0ua]

I might take a little issue with the 'most toggle switches can handle 10 amps'. I've replaced too many '10 amp' switches that have failed when being used in circuits drawing 7-8 amps. Cheap switches perhaps. Relays are really the best way to go.

A lot of the small toggle switches are just rated at 6 amps. One just needs to look carefully at the ratings and not work so close to the ratings.

 

[Midniteoyl]

The other, important, reason relays are used is to keep high amperage circuits out of the cockpit/cab. If a device malfunctions, or a short were to occur in a higher amperage device, the fire and smoke will be away from the user/driver.

 

[Industrial Toys]

No point installing a relay if it isn't required. But I would install yet another fuse, even though the circuit you are using is probably already fused.

As far as bugs go. A friend told me on the weekend that a Retrofit lighting contractor told her, that LEDs have the benefit of not attracting bugs. I told her, that the new LED light we installed in the garden seems to attract Bugs just fine. Is it a (color)temperature issue by chance?