Emergency generator??

But ACv lights don't need a battery charger?

ACv halogen lamps will blink, even thru those lil hatteras transformers when some Air units cycle on or DCv halogens change while on charger or mains alternators.

Our fix, Replace the ACv transformers with ACv to DCv power supplies and run DCv LED lamps.
These power supplies or drivers keep the LEDs at a constant level and still use very little current.

12v LED have better dimming qualities than 24v LED. Also, best to still run the dc power through a transformer designed for the LED bulbs by the manufacturer. Third party dimmers , like those made by Blue Sea, don't provide quality dimming control. At low setting the darn things flicker. There's actually a science here that needs to be followed...

The boat has combination of dimmers.the guest rooms had small dimmers modules called I-something that were not working with LEds We just removed them as nobody was using them anyway and rewired the boxes. The master and all other areas have an older Lutron system which works fine with LEDs.

it s always a bit hit or miss.

problem with an 24 VAC system is that you need compatible bulbs which are harder to find. When I replaced the antique halogen stern floodlights I had to use DC - AC converters for the Lumitec fixtures to work

I served the circuits with 24v DC. My next step was to swap to 12v bulbs and install a small sept down 24-12 for the circuits. The Vimar momentary rocker switches control the driver. Next step is to experiment with a different driver. I haven't gone there yet. Need to research options. Blue Seas is not the answer for the LED...

It's kinda crazy to think that I need to step power up from DC to AC with a transformer just so that the led bulbs can properly dim...

My guess would be because by the time you've got even half a dozen bulbs on a single circuit you could be pulling 600+W, requiring ~25A @24Vdc. This affects wiring size and generally complicates installation. Not to mention an adequate 24Vdc battery/charger/distribution system. The same lighting @120V requires ~5A so much more capacity on a 14AWG wire with 15A breaker.

Still guessing, it's because AC-AC voltage conversion has been easy for a very long time. Nowadays we have all kinds of little black (blue?) boxes converting AC-DC, DC-AC and even DC-DC which likely weren't available during initial construction.

As these were originally all incandescent, the AC fixtures are probably rated for ~100W bulbs and the DC for ~20W.

Re: outlets, if 120Vac circuits (probably 15A?) are being run to those spaces anyway I could understand combining lighting if higher wattage bulbs are needed there.

on older boats, about pre 2010/2012, all lights were pretty much halogens / xenon. On bigger boats, it s a long wire run from ER where batteries are usually located so voltage drop was a concern.

when I took over the 110 I run, it still had xenon bulbs… about 350 of them. At 10-20w each, that’s about 5KW total…. It took me a while to find and test AC compatible warm white LEDs that would work as is, with the Vince dimmers used in guest rooms and the Lutron system used on the main deck and PH/Slylounge. What a PITA

each guest room had a control box with 2 to 3 120VAC to 24VDC transformers which would power the lights and dimmers. I guess three were needed because of the incandescent draw… only left one in each box for the LEDs

It turned out the dimmers couldn’t handle the low draw and we had to put in an incandescent bulb in the box. Pretty stupid so I ended up removing all the dimmers all together and requiring each box . Nobody ever used them anyway…

What really scares me is the aging Lutron system. If that fails, we loose most of the lights and because there are no traditional wires between the Lutron system and the various switches, we can’t get rid of it. In an emergency we d have to manually connect each circuit in the Lutron box.