LED lights with normal lights on same circuit

[bowmaga]

Can you install LED lights and normal bulb lights on the same circuit?  For example, my buddies RV, he went out and purchased some new LED running light, to replace old school faded, broke, ugly normal lights, and installed them. But they are also tied in with the tail light and turn signal lights.  Will this mess with the flasher, or anything else?  This works, but he's trying to track down an electrical gremlin, and I'm wondering if that might be part of the issue.  I thought I remember being told you can't mix the two, but that could have been part of a bus dream.

Greg

[Sean]

There is no reason why LED and incandescent lights can't be on the same circuit, so long as they are the same voltage rating.

Conventional bi-metal flashers may not work at all or may flash at the wrong rate if too many incandescents are changed out for LEDs.  LED-compatible flasher modules are available to fix this problem.

-Sean
http://OurOdyssey.BlogSpot.com

[bevans6]

As Sean said, they are fundamentally compatible.  On my MCI there is a relay based circuit in the brake lights that is supposed to light up the dash light when the brake lights are on.  If one brake light is out, the reduced current makes it so the dash light doesn't light up.  With my LED brake lights, there is comparatively speaking virtually no current, so the relay doesn't work and the dash light never lights up.  So you can run into funny little things like that.

Brian

[JohnEd]

Yes, of course...what Sean said.

Your running lites ARE NOT on the same circuit as the brakie and turn.  The bake and turn may be on the same filament or they may be separate.   But, they aren't flashing when the turn sig is on.

The flasher, the common ones, use heating of a metal strip to open and beak the circuit.   Simple, reliable and cheap.  When you drastically reduce the current flow, as a LED does, the flasher never sees the current it expects and never flashes.  

I wish I could give you a part number or source but I got nutt'n.  Help will arrive and anyway, now you know what you are looking for.  

[Len Silva]

The heavy duty flashers used on trucks and buses are not dependent on load current to set the duration.

[Ncbob]

When Fred Hobe installed my LED Tail, Stop and turn lights (I have a 24V System on that circuit) He installed 50 Ohm resistors on the groun d side of each lamp and prompted me to keep at least the incandescant side flashers should I decide to go LED in the front turn Signals.

Something tells me that it's the load of the incandescants that make the old flashers work so I keep an eye on the lights just behind the front wheels.

S'all I know....it works.

NCbob

[PCC]

Exactly, Mr. Bob. As long as there is enough current/load to cause the flasher to do its cyclical thing, it will work, and all the LEDs you add will not make a difference, as long as there is enough current passing through the flasher to make it open and close the circuit.

I have three incandescants on each side, and will be making all the rest LED (as I can afford the changeover). Makes for a great light show when using them at night !!

[Ace]

I purchased 9 individual LED assy's for the rear of my H model Prevost and didn't add or change anything to the circuits other than remove the old incandescent bulbs and wire in the new LED's! They stop, they blink, and they turn on with the rest running lights. It might also depend on your application!

[JohnEd]

Ace,


What Len said is the most probable cause for your failure to fail miserably.

The heavy duty flashers used on trucks and buses are not dependent on load current to set the duration.

I guess all we have to do is find a schematic for that sys and the flasher.  Tanks

[belfert]

Despite Grote saying my existing electronic flashers would likely work with LED lights they do not.  When I turn left the lights flash at a different rate than when I turn right.  The left side still has a few regular lights and it flashes at a normal rate.  The right side is al LED and flashes at some wierd rate.  I bought some new LED compatible flashers from Grote, but I have not installed them yet.

I have a wierd system with two signal flashers.  I can remove either one and the whole system still works.  I assumed one was for each direction.