Run 12 volt lights in 24 volt coach in series?

Scott & Heather · January 31, 2016, 10:34:26 AM

My 102C3 appears to be setup by the previous owner with 12volt brake lights set up in series...I think. Is this possible in a 24 volt coach?

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Jim Eh. · January 31, 2016, 10:42:53 AM

I thought that was how all 9s and 12s were done?

Scott & Heather · January 31, 2016, 11:29:16 AM

My 9 is entirely 24 volt lighting except the headlights which are center tapped off the batteries. Rear brake turn and running lights as well as clearance lamps are all 24 volt. The 102 has 12 volt brake tail and turn signals and headlights too. I know for a fact they came 24 volt originally so I contacted the previous owner. He said he seems to remember wiring the 12 volt tails in series which is how R&M fiberglass said to do it when he installed their caps. I'm having issues with the tails and trying to sort out if it's even possible to run 12 volt turns, tails, running lights in series on a 24 volt coach?

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jmblake · January 31, 2016, 12:05:59 PM

Scott, how about something like this http://www.grote.com/products/44070-24-to-12-volt-converter-converter/ I was going to go that route till I found 24 volt led stop and turn lights.
Jason

Scott & Heather · January 31, 2016, 01:34:01 PM

That would be useful for sure. May have to look into those more.

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Brian Diehl · January 31, 2016, 01:44:44 PM

Scott - running two 12 volt lights in series is perfectly fine. This creates a 24v circuit with each light getting 12 volts. This works perfect when the lights are both the same (resistance in each bulb is the same). The only real drawback with this setup is that if one bulb burns out both light bulbs quit working. I have several LED lights in my house system wired this way without any issues. Taillights work exactly the same when wired in series.

Scott & Heather · January 31, 2016, 02:54:32 PM

Ok that's exactly what I needed to know. Thanks so much Brian. So, toad lights....you know where I'm going with this.... ;-)

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RJ · January 31, 2016, 06:47:01 PM

Scott -

You might want to double-check the voltage feeding the taillights and turn signals, as well as the clearance lights

I seem to remember reading somewhere that around your vintage coach, MCI went to all 12v exterior lighting.

Or maybe it started with the "D" models. . .

Luke might know, too.

FWIW & HTH. . .

Scott & Heather · February 01, 2016, 12:11:44 AM

And the plot thickens. You're killing me. I am pretty sure the lights are wired in series because of some issues I have been having with them. It makes sense. Plus the original owner telling me he remembers wiring them in parallel. I don't think they went 12v on exterior lighting until probably D coaches. Mine is a 1992.

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sledhead · February 01, 2016, 01:47:24 AM

under the drivers window .the elect. panel has a relay for the running lights . I changed the 24 v to 12 v and replaced all my top running lights to led 12 v . as for the brake lights , I made up a new aluminum panel with new 12 v led lights 2 per 12 v off the 24 v feed . for toad lights I used a 4 wire to 5 wire converter off the brake , running lights . so all led lights now ( 5 years ago I made the change )

dave

gumpy · February 01, 2016, 02:04:11 PM

Yeah, it's possible. As long as you have two lights in the series. Turn signals get a bit complicated because of this. You just have to have 2 turn signals on each side.

Maybe a better solution would be a toad converted that you can use to drive your 12 volt lights. That's what I do on mine.

Initially, when I converted all my clearance lights to LED, I set them up in series on the original 24v feed. They all burned out within a year or two, but I think they were just
plain crappy lights, because I replaced the rears and ran them off the 12v from the toad converted and they burned out, too. So I need to find a better LED and then
set them all up off the toad converter.

Scott & Heather · February 01, 2016, 04:52:30 PM

Ok. I plan on just using 24 volt leds but I just wanted to be sure that I was chasing down the right issue here

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Scott & Heather · February 02, 2016, 10:40:57 AM

One more question, let's say, for instance, I have two 12 volt LED tail lamps...and the last one in the series somehow has an issue and shuts off. Does this then allow 24 volts to surge into the first one in the series and burn it out? Forgive my lack of understanding here.

Lee Bradley · February 02, 2016, 11:18:58 AM

Most of the leds are 10 to 30 volts so even if you got a 24 volt feed, they should be OK.

Scott & Heather · February 02, 2016, 01:25:01 PM

Ok. Thanks. I'll choose LED's accordingly

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