Review on SRRB 12 Volt Replacement LED Bulb BA15s 1141/1003 / 1156 Dome Light Fixture for RV Camper Travel Trailer Motorhome 5th Wheels and Marine Boat - Enhanced 3.0W Natural White Illumination by Dan Toliver

This was a direct fit for the [previously] incandescent porch lights on my small 16 foot RV. Polarity doesn't matter with this bulb; It runs on AC or DC power, so it must have a full-wave rectifier. It consumes only 2.5 watts. So if you're running on battery, you should expect it to last significantly longer than an incandescent bulb (6 watts). Can't comment on durability yet as I've only just installed it, but the LEDs shouldn't burn out in everyday use at rated voltage, so I'm optimistic.