Tim Thomson said:
Does anyone know how much a 1156 12 volt auto buld draws?
What would a 120 volt CF bulb draw on the 12 volt dc side of one of
those cheap crappy tire inverters 75 watt and 400 watt. (rated at 9
watts 120 vac)
This is an RV project..........
The 1156 incandescent draws about 2.1 amps at 12.8V =27W, and provides about
400 lumens for an efficiency of 15 lumens per watt.
An F8T5/CW Fluorescent draws about 0.8 amps at 12.8V =10.2W, and provides
about 400 lumens for an efficiency of 39 lumens per watt. That's over twice
the efficiency of incandescents.
Those inverters generally claim an efficiency of about 75-90%. Check to see
if the inverter draws current when it's not under load. That should still
save you a good deal of power in the long-run over an 1156 bulb.
I have installed some 15W 110V fluorescent strip lights on the ceiling and
walls of my RV, plugging them into small 75W inverters, and they seem to
work quite well, but they don't start as easily, and buzz more loudly than
when running on regular AC.
I'm still waiting for good and affordable white LEDs. At present, they are
very expensive, not much more efficient than incandescents, and the harsh
violet-white light isn't particularly easy on the eyes.