Friday, February 11, 2011

Excellent led replacements for 921 wedge RV incandescent bulbs

NOT a very flashy title. Sorry. But you'll REALLY want to know this, and you simply CAN'T easily find this out on the web.

The light bulb we are trying to replace is called a "921" light bulb with a "wedge style base". This bulb runs on 12 Volts DC (all/most RV systems operate on this system). This 921 wedge bulb consumes about 18Watts of electricity. I'm thinking this puts out about 280 lumens (hard to find GOOD data on this). So the efficiency of this type of bulb is 15 Lumens per Watt, which is fairly low for an incandescent.

921 incandescent 12 volt wedge base light bulb
921 wedge style light

The application I tested the LED replacements is pictured here. Notice that any light only needs to send out light in a half circle (180 degrees) :

rv lighting application needing only 180 degree light

Acceptable led light replacements for rv lighting 921 wedge style bulb

  • - WLED-WWHP10-DAC : $14.95 each : this WARM WHITE color tone LED light is almost a perfect replacement for the 921 wedge. There were two 921's in the fixture and I replaced it with two WWHP10-DAC's. So you can see I replaced about $3 of lighting with around $30 of lighting. I still think it is cool. I can tell you that the LED color tone is VERY VERY close to the 921. Also I can tell you that I think the WWHP10 was just slightly brighter and the color tone was actually just enough whiter to illuminate the area a little bit better. I was very pleased. The specs say the LED light bulb would put out 98 lm.  I'll follow up on that later and verify. The current draw is 0.2 amps so the total power consumed would be 2.4 Watts. ASSUMING that my eyes are NOT lying when I say this is equivalent to the 921, we can probably use 280 Lumens as the reference, then the efficiency of this bulb would be near 116 lumens per watt. I don't understand how the mfg got 98 lm / LED in their specs? But I'm pretty impressed overall.
  • - T10 Wedge 380 : Another warm white bulb, but arranged for 360 degree light. Puts out 380 lumens and it fully replaced another 921 application. These are $17.95 each, but have many more LED's on the 'bulb'. Significantly brighter than the 921. WE highly recommend.
As I find out more decent replacements, I'll list them here.


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