Late last year a few of us took apart the standard CFL 120Vac screw in bulbs and connected the tubes to 12Vdc ballasts from other devices. Scanners, battery CFL lights, battery powered flouresent droplights, etc...
My 12Vdc droplight ballast (8watt tube) worked pretty well lighting a standard 120Vac 26watt CFL tube using 24Vdc untill I reversed polarity and fried a mofset or power transitor or something.
Well tonight I was playing again with CFL and DC.
GE soft white 100 ( 00262 package number for 3 pack) 26watt CFL supposed to be equal to 100 watt, 1700 lumens work. However, basically same "Light Of America" CFL does not work so far.
This bulb lights up well on 60Vdc and appeared to put out some good light! NO MODS, I just screwed it into a normal table lamp and wired the plug to the 60Vdc battery bank, flip switch and it turned on fine. This was a low amp bank (about 1.3amp) and I had already been playing with a 100watt incadesent bulb so the bank was not full charged.
I don't have any power use tests or figures, but it worked if others want to try it. Also I don't have anyway to compare light output from DC and AC bulbs other than use them both and look at them.
At 35VDC it does not light well. Somewhere around 34-40Vdc or so I have to play with it a bit to light it. This is a bulb that resembles a corkscrew, and at low volts the bottom turns of the tube light a little. If I wrap my hand around the bulb it lights up most the time. Sometimes I grab the bulb and it tries to light but not quite, touch my finger inside the tube turns and it lights. Once lit it has stayed lighted down to 30VDC although you can see lower volts is making less light of course. I never ran the batties low enough that the light actaully went out yet.
I thought this was very interesting myself and that others may also want to try various things with this light! My battery packs are dead now and I am charging them from a high volt low amp genny, nice winds tonight here. $5 motor, $40 in magnets, getting 0.25-0.5amps into 100V battery bank, 25-50watts kinda disapointing. Not very good at 48V and it stalls out bad at 24V, but at least it runs good at 60Vdc and above.
My thought on this was if the voltage were bumped up from 48Vdc to 60Vdc or higher to start the light then it may work well at 48Vdc. For a $2-$3 bulb it may make a nice 48Vdc CFL light. Perhaps something simple like charging a capacitor in a lamp fixture to give a voltage boost when first turned on just to get it lit?
Anyway just thought I'd pass on that the GE CFL is working on the 60Vdc fine sofar with no mods if anyone wants to play with it. I don't have any CFLs less than 26watts, a 15watt may work better or on lower volts or may not?