Review on 💡 10-Pack Super Bright 921 LED Bulbs for RV, Camper, Trailer, Motorhome, Marine Boat Dome Interior Lights - Natural White 3500K by Sal Muniz

In contrast to many replacement LED lamps, they do not have a switching power supply. Instead they appear to have multiple groups of diodes arranged in a current mirror pattern. If you're looking for quiet bulbs that don't produce all kinds of RF noise, these are the bulbs you *need*. The tubes have a full wave rectifier built in, so they are non-polarized (so you can wire them either way and they'll still work). These lights work in a very wide voltage range from less than 11V to over 14V which is good as I intend to use them for dry camping and on land. Note, however, that the current (and light output) doesn't increase appreciably with higher voltage since these are current mirror designs, and you're just increasing the amount of heat generated. While this makes them less efficient than a switching power supply, they are still much more efficient than any incandescent/halogen bulbs and more efficient for dry camping (when battery voltage is lower) when efficiency is most important. 300mA when first turned on and drops to 260mA depending on how hot they get. (Always keep LEDs as cool as possible, they put out more light per watt when operated at a lower temperature). As with many LED lamps, the lumens are too high. Using a regulated power supply, I lowered the input voltage to about 9.5V at 270mA. Any smaller value and the current started to fall, suggesting that only about 9.5V is being applied to the diodes (probably it's 3V Vf in series of 3 series) and the rest is going to the full-wave rectifier and mirror transistors current as the voltage increases. . 9.5V * 0.27A = 2.6W. Assuming 120 lumens per watt (the best industry standard is 150 lumens per watt) they produce about 310 lumens. While that's significantly less than the advertised 684 lumens, it's still very bright. And since there are so many LEDs compared to other lights, they provide better heat dissipation and probably more light. These bulbs have replaced incandescent halogen bulbs which used 18 watts and put out less light than these, so I'm more than happy with them. Finally, an added bonus: All LEDs appear to be housed in a series current reflector, protecting against catastrophic failure. Many switchable LED lamps contain diodes connected in parallel and if one of them burns out, the device connected in parallel with it will also burn out. RF noise they are worth.