12v spotlights on 24v truck?

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=137131
Printed Date: April 27, 2024 at 10:00 AM

Topic: 12v spotlights on 24v truck?

Posted By: 2-stroke
Subject: 12v spotlights on 24v truck?
Date Posted: August 21, 2014 at 12:31 AM

I'd like to install a spare pair of 12v spotlights on my new 24v truck.

They have a normal 12v H3 globe and two wires coming out the back, no electronics, just a simple lens, globe, reflector type spotlight.

I'm guessing that it's as simple as replacing the globes for 24v H3 ones but I want to check that there is not some other factors to consider.

Thoughts anyone? :)

Replies:

Posted By: oldspark
Date Posted: August 21, 2014 at 5:28 AM

Assuming they are halogen, no problem.
Being a similar power but at 24V means half the current so any 12V spot wiring will be fine.

Posted By: 2-stroke
Date Posted: August 21, 2014 at 9:06 AM

Great, thank you Oldspark :)

Posted By: i am an idiot
Date Posted: August 22, 2014 at 9:44 AM

Have you thought about just running the 12v devices in series?

Posted By: oldspark
Date Posted: August 22, 2014 at 11:32 AM

That's likely to have grounding issues & hence blow one bulb since H3s are single wire with base GND and most reflectors are grounded, else can easily be shorted to GND.

If the bulbs were 2-wire or isolated, if one bulb dies, both die. And if they have unequal resistances...

Posted By: i am an idiot
Date Posted: August 22, 2014 at 8:33 PM

He said he has 2 wires coming out of each socket.

Posted By: oldspark
Date Posted: August 23, 2014 at 10:03 AM

Good point, but if it's a metal reflector bonded to metal body etc. (Tho I did miss the 2 wires part posted_image

.)

PS - plus I question startup & imbalance issues that take one well over 15V etc. It's not like linear components (resistors, caps etc) nor like 2 series 12V for 12V DRLs.
Series 2x12 for 24V is a good idea in a pinch and may work fine, but I'd be inclined to buy 24V bulbs & keep the 12Vs as spares for 12V lights.

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