F3528002 Natural White LED RV Ceiling Double Dome Light (Fixture Double 921 Wedge 12v)

I've been using the double fixture for about 4 years now powered by SLA batteries. I got tired of replacing leaking cheapo SLA batteries every year, so I now have them hooked up to a Buck Converter that is powered by a 4S Lipo with the output voltage of the DC-DC converter set to approx 11.2V.After doing some testing, here is some information I compiled on these fixtures:Each PCB seems to be segmented into 4 sections...each section is comprised of a 9 LEDS (strings of 3 series LEDs wired together in Parallel) and a Constant Current driver circuit built out of discrete components (2 transistors, 3 resistors). There is also a diode that seems to exists for reverse polarity protection.The seller's specs for an input voltage range of 11-18V is mostly accurate with one major caveat...anything over ~11V seems to be a waste. Because of the CC driver circuit, the brightness of this fixture does not really increase after you've hit 11V...and excess voltage is bled off as heat into the transistors and resistors in the CC circuit (mostly in the transistor that has it's Base is connected to the LED string). I believe this is because the CC Driver is built similarly to a Linear Voltage Regulator. The CC circuit seems to be tuned to ~0.170A or so. The Voltage across the LEDs need to be ~2.90V for this current. The Forward Voltage of my LEDs were 2.6V.My fixtures seem to work all the way down to 9.5V with a significant decrease in brightness starting below 11V. Brightness was measure using my smartphone's sensor.Some Data I collected (per PCB, 2x for a dual fixture...all values are approximate):[ Input Voltage | LED Voltage | PCB Input Current | Power | Transistor Temp | Lux ]09.42V | 2.75V | 0.059A | 0.56W | 27C | 2000 Lux11.00V | 2.89V | 0.166A | 1.82W | 36C | 5000 Lux12.00V | 2.85V | 0.165A | 1.98W | 40C | 5000 Lux14.23V | 2.90V | 0.170A | 2.42W | 44C | 5000 Lux17.50V | 2.90V | 0.170A | 2.98W | 51C | 5000 Lux

These worked out great as replacements for our class-C RV, which came with fluorescent fixtures.They are very bright. I think that they are significantly brighter than the old fixtures.I really like that they have two switches so that they can be turned on one half at a time. We are replacing all lamps with LEDs to reduce power consumption, as to allow us to "boondock", running off batteries-only during the night. Not needing the high brightness of both lights lets us save the extra power.I do like the quality of light. They are a nice color temperature. Not being overly warm as to be yellow, nor cool to being blue, which can be quite common with LEDs.The reasons for 4-star ratings:Like another reviewer noted, I also received a fixture with the wires backwards as far as polarity. Which also gets me to the light panels which come with the unit... So many of the LED replacement lamps come with drivers that can work with any polarity. I was surprised that these were polarity dependent. Since we were putting these in permanently, it was easy to mark the fixture and note the polarity issue during install... and just flipped wires.One other thing is that they are really bright. The lenses are clear textured plastic, with an absolutely clear area directly straight down. I would like an option to order these with a "frosted" white lens. They tend to have a bit of glare when sitting across the RV.I am hoping that these will last for the lifetime of the RV. The fixture is setup to take a standard lamp base, but comes with an interesting LED panel that secures to the fixture with a screw. The lamp is very nice, but I have not found a listing for a replacement lamp on Amazon that identically matches.

So as others have said the light is very bright. Much more so than my old unit - which instead of a clear cover like this one had one of those white plastic ones. I replaced one light with this dual model, and another one with a single one. Both were very easy to install. Note that in my motorhome the red wire on the light went to the black on the coach, and the black on the light went to the white on the coach.The housing is off-white (not bright white as the picture shows) and that matches well with my other lights. The housing is a bit smaller, but can be placed in the same position as the old one. My ceiling has a fabric material, so I can see the outline of the old light and two small indents where the screws were from the old fixture. I can live with that and it may be better over time (it is indented from the pressure of the old light). Note that the covers were tricky to remove on the dual fixture. Take your time as for some reason on both sides of the fixture one side of the cover was easy to slide, but the other stuck. Took my time and wiggled it quite a bit and got it to come off. Easier to get on and off now.I have only had it installed for a couple of days, so no real use yet. Due to the brightness I will likely not replace all the fixtures. We will see how that works out after I do some camping. I did replace one in the main cabin, one in the hall, and expect to get one more double unit for the bedroom.Very satisfied so far!