Dual voltage lighting

[Smartstream]

Has anybody seen or heard of a dual voltage light? I have a light fixture over the dining table that is 110 volts. It has 3 bulbs and is very bright. I took one bulb out to make it a little more comfortable. The other problem is it is the only light in the dining area.

It occurred to me it would be interesting to remove one of the bulb sockets and install a 12 volt bulb socket with a separate 12 volt switch. It seems to me to be a simple solution. I seem to recall seeing similar items but I can't find any so it may be my imagination. I would guess there might be safety issues but the fixture is mounted under a wood cabinet and each voltage would have it's own ground and be isolated.

Anyway just putting it out for thoughts and opinions. I'm not an electrician so I seek information from those who know more. Thanks in advance for your comments and opinions.

[overlander63]

Just so you know, you don't ground 120vac light fixtures. 12vdc needs one power and one ground.
Also, if you are just concerned about the lights being too bright, why not swap the bulbs for a lower wattage version?

[Paprika]

Given that it's the only light in the dining area, unless you're always plugged into shore power (which was probably the norm 37 years ago when the rig was built), a 120V lighting fixture in a trailer sounds less than useful.

Yes, you could add a single 12 V bulb, but wouldn't it make more sense to convert the whole thing to a 12 V LED fixture, so it would work all the time, whether you're plugged in or not?

Making the swap shouldn't be hard. There are plenty of good 12V LED fixtures on the market... or if the one in your '82 is a classic style, and you want to keep it, you can refit it with all 12V LEDs (be sure to get "warm white" ones). That's what I'd do, anyway.

[uncle_bob]

Hi

If you *really* want a dual voltage setup, they *do* exist. They are built into fancy boats so certain areas are lit regardless of the power source available. They carried the practice over to lighting a variety of areas in some boats.

Plan on spending a *lot* for one of those fixtures (like a couple hundred bucks).

Bob

[kidjedi]

I'm not sure I understand the point of a dual voltage light... or any lights being 120v for that matter. If you're plugged into shore power, all your 12v stuff works. Also, you can wire "regular" 120v fixtures to 12v and just buy 12v LED bulbs (they make them that look just like regular old light bulbs"). All my lights are vintage 120v fixtures run with 12v wiring and 12v LED bulbs.

[rmkrum]

Yup. Most big fancy boats ran a 12 or 24 volt DC system with huge battery chargers, engine mounted alternators, auxiliary AC/DC generators, and AC shore power. The electrical panels were rather complicated to do all this.

My dad was a captain on private yachts all his life. I helped him deal with this stuff and came to understand the simplicity of a single DC system.

A single 12 volt system with decent batteries, solar power, and a good converter is easy to manage. My only complication is a manual transfer switch to select either the front generator input or the OEM side input for shore power.

The rest of the system is 12 volt DC and takes care of itself essentially. Still need 120 volt AC for air conditioner but that’s about it. We can run on solar and batteries without shore power until we runs out of fresh water or gray or black tank space...

[A W Warn]

Originally Posted by Smartstream

Has anybody seen or heard of a dual voltage light? I have a light fixture over the dining table that is 110 volts. It has 3 bulbs and is very bright. I took one bulb out to make it a little more comfortable. The other problem is it is the only light in the dining area.

It occurred to me it would be interesting to remove one of the bulb sockets and install a 12 volt bulb socket with a separate 12 volt switch. It seems to me to be a simple solution. I seem to recall seeing similar items but I can't find any so it may be my imagination. I would guess there might be safety issues but the fixture is mounted under a wood cabinet and each voltage would have it's own ground and be isolated.

Anyway just putting it out for thoughts and opinions. I'm not an electrician so I seek information from those who know more. Thanks in advance for your comments and opinions.

Some 12v DC light bulbs have the same Edison base as a 120v AC bulb. Did you actually measure voltage or assume based on the way the bulb looks? I have a couple 12v incandescent bulbs from one of my earlier Airstreams that looked like normal 120v bulbs, but had 12v DC printed on the end of the bulb..

examples>https://www.amazon.com/s?k=12+volt+e...l_6mkjd89g3s_b

[Smartstream]

Thanks for the responses. I know it is 120 volts because when we first got the coach we couldn't figure out how to turn the light on. Finally one day we plugged the power cord in and the light suddenly worked. The coach by the way is a 345 moho. It was ordered as a shell and built into a mobile chemical test lab. We bought it at an auction after it had been converted to an RV. It is configured similar to a factory 345 but there are subtle differences and no plans or diagrams to follow. Learning what does what has been interesting.

Anyway back to the light it is brass edged glass panels and I kind of like it. After I took one of the bulbs to dim the light a bit the thought crossed my mind to convert that socket to 12 volts. It seemed like an interesting idea. After reading your responses it's makes more sense to convert the entire fixture to 12 volts. It was obvious but the idea never occurred to me. Again thanks for the help.

[uncle_bob]

Hi

While you are playing around, consider converting everything to 12V LED lighting ...

Bob

[55AS]

I have no 120 volt lights in my trailer. All fixtures are either 12 volt marine type or 120 volt fixtures converted to 12 volt with LED bulbs. They work all the time regardless of power source and are very bright.