Recent content by billw

fenix-store
  1. B

    Batteriser - Wonderful Alkaline Helper or This Weeks Smoke & Mirrors?

    There is also the reality that most voltage-sensitive electronics that run on batteries these days probably already contain a boost-mode voltage regulator... It saddens me to see people with apparently reasonable credentials selling apparent snake-oil :-(
  2. B

    Got a 5000mAH King Kong 26700 and it's at 1.9V!

    Re: Got a 5000mAH King Kong 5000mAH and it's at 1.9V! Um... I haven't been paying attention for a while. Is over-discharging something that is supposed to make an Li-ion cell dangerous to charge? In my somewhat limited experience, an over-discharged cell just won't charge at all. I would...
  3. B

    driving 3 watt UV leds question

    You need a new driver, or more than 1 UV LED. The "minimum" output voltage of your current driver (20V) is far above what is needed for a single UV LED, and it (almost certainly) won't properly regulate the current...
  4. B

    Whoa! Philips selling LED arm !

    "Dutch electronics giant Philips on Tuesday said it was selling a majority stake in its LED and car lighting arm to a consortium led by China-based GO Scale Capital investment fund in a deal worth $2.8 bn." http://news.yahoo.com/philips-sell-major-stake-led-car-lighting-arm-060651818.html
  5. B

    Help finding true UV led strips

    400nm *is* "purple", pretty much. The problem is finding LEDs with a shorter wavelength, adequate output power, and non-jaw-dropping price. :-( (For example, the "BLB" class fluorescent UV "Black Lights" have emission peaks around 350-360 nm)
  6. B

    Replacement for old 6 foot T12's needed

    A high-output 4ft dual T5 or T8 would probably exceed the light output of the 6ft T12. You could probably do two offset 4ft single T5 "bare" fixtures inside a dual 6ft "fancy" fixture, if you're wanting to keep the external appearance.
  7. B

    A general explaination of LEDs and circuit theory (with visuals)

    For example, if you were to put a particular charge on the plates of a air-gap capacitor, and then increase the separation between the plates, that would increase the voltage you would read between the plates. (This makes sense. The plates are oppositely charged, and attract each other...
  8. B

    A general explaination of LEDs and circuit theory (with visuals)

    Voltage doesn't have anything to do with "density"; a single electron can be at an arbitrary voltage; it's an energy thing. Like lifting a rock in a gravity field; the higher the rock, the more energy it has. The more energy an electron has, the higher it's voltage. Both the rock and the...
  9. B

    UV leds with low visible emissions?

    I'm looking for some relatively cheap UV LEDs with less visible emission. The cheap eBay 400nm LEDs are too much visible purple. 380-385nm LEDs would probably work fine, except the ones I tried seem to have packaging that fluoresces at that frequency, so they emit a relatively significant...
  10. B

    Just how damaging are disposable batteries to the enviroment?

    Yeah, what they end up doing with mandatory recycled things is "questionable." We had "battery recycling" containers at work, usually in the "Break Rooms." "terrific", I thought. Concentrating the supposedly toxic waste in the same room with the fridge and microwave, where people store and...
  11. B

    Just how damaging are disposable batteries to the enviroment?

    My understanding is that a lot of primary battery technologies used to contain some small amount of mercury compounds (that increased shelf life.) Most manufacturers seemed to remove the mercury about the same time as some communities started requiring that (alkaline) batteries be recycled...
  12. B

    What's the SAFEST NiMH charger?

    Pointers? Ditto. I was under the impression the NiCd/NiMH chargers were pretty close to inherently safe (especially compared to Li-any), since the batteries have aqueous electrolytes, the metal/etc is relatively unreactive (compared to the Li/CoO in most Li batteries.) Sure, it would be a bad...
  13. B

    re: 25w or 40w candleabra replacement (LED or CFL) that is not ugly or expensive

    Re: 25w or 40w candleabra replacement (LED or CFL) that is not ugly or expensive I have some of the costco LoA LED candelabra bulbs, and I sorta like them. 18x SMD LEDs on a central post (4 sides plus two on top), rated 2.5W and (only) 135 lm. Substantial heatsink. They're not dimmable at...
  14. B

    Does anyone make primary Lithium C and D cell batteries?

    Saft seems to make an LiMnO2 (3V) D-cell rated to 4A continuous discharge. http://www.saftbatteries.com/Produit_LM_M_cell_ranges_302_254/Language/en-US/Default.aspx#DL2 (But I can't find anyplace that sells them.) Tadiran is the famous maker of low-current cells with the distinctive purple...
  15. B

    How do you charge up unprotected 18650 cells from 0V?

    In my experience, the average "dead" laptop battery pack will have a couple cells that read zero volts (and are responsible for the pack being "dead"), and a rather larger number that still read 3 to 4.2V and may be of "reasonable" quality. I haven't actually measured such cells' capacity and...
See more

Latest posts

Top