Originally posted by SkyWatcher
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To wit, it seems to me (in my ignorance) if we are trying to run CFLs (hundred volts and above) from batteries (ones to tens of volts), a switcher PSU transformer which runs a transistorized device (ones to tens of volts) from mains (hundred volts and above) could be used backwards and have something at least light up enuf to take data.
But it seems like everyone here is salvaging the cores and rewinding the coils -- I will have to go back thru the forum posts and find out why.
Boosting voltage from a battery to run a 120V LED lamp, which just has to knock it back down to 2 volts or so internally, doesn't make a lot of sense to me. CFL elements are damned cheap (I have a pile of dead CFLs and I bet you do too), the phosphor area of ONE of them is probably equivalent to 1,000 white LEDs, and various of you have demonstrated dimmability and close to half-brightness with 2W of drive.
Commercially available CFL bulbs use way more power than they should, because just as a car's engine must be sized for its maximum load, so too a CFL's ballast 'must' be sized for creating the starting voltage. To save costs, the ballast's components are non-adaptive, and dissipate this extra energy once the lamp is lit.
I know deriving luminosity data is an inexact science, but I would suggest that any posting of results include some lumens/watt figure. For example, I have an old germanium solar cell-based photographic light meter that I will be using, placed at some reference distance from the bulb.



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