Recent content by mattheww50

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  1. mattheww50

    Garmin GPSMAP64S or GPSMAP66S?

    In looking at the specifications the only difference that is likely to be important is the display. The 64S has 2.6 inch 160x240 display, the 66S has a 3 inch 240x400 display, so the 66s display can show a lot more detail. The 66S has 16gb of memory for maps and tracks, the 64S has 4Gb, I...
  2. mattheww50

    what light is your go to light when you need a bunch of lumens from a handheld night

    Haikelite Q30 with Samsung 30Q's. Don't think is really 12000 lumens, but it is certainly a large number, and far beyond what any single 18650 light can deliver!
  3. mattheww50

    Cordless power tools

    Generally the Lithium Ion batteries have much better storage characteristics then NiCd's in terms of self charge. However when stored for long periods of time at high charge states, it actually does tend to reduce the life of the cell. The major impact of Lithium Ion cells is on total weight...
  4. mattheww50

    15 year CD-R video archival test

    The more serious long term problem is the availability of devices that can actually read old media. Try finding an 8 inch floppy drive these days. Early in my career in the computer industry one of my users brought me a tape. He said he needed the data on it. It was from a Bendix G15 computer...
  5. mattheww50

    So how come 26650 batteries don't have higher mAH ratings?

    As others have pointed out, there is no large industrial demand for the 26650 cell. The demand today is for the 18650, but that is moving to the 21700. That big demand pays for extensive R&D in the hope of creating a product that can gain market share and profits in the high volume market, so...
  6. mattheww50

    What did you do for runtime before LEDs?

    For really long runtimes, you just used a lot of big batteries. I have a fluorescent light that takes 8 x D size NiMh, even 10 years ago those things were about 10ah each, so you have 100 watt hours, and gives pretty long run times even on fairly large sources. The big problem I used to have was...
  7. mattheww50

    identify: NiCad or NiMh?

    To be honest, I don't think it makes any difference whether they are NiCd or NiMh. The output and charging characteristics are virtually identical, the NiMh cells invariably have higher capacity (and often much higher, early AA NiCd's were typically 450-550mah). I'd rebuild the pack with NiMh...
  8. mattheww50

    Why yes, it was dark in that nuclear reactor (25 pics)

    About the only thing you can do with a partially finished nuclear power plant is convert it into a fossil fuel plant. That actually happened at Cincinnati Gas and Electric about 35 years ago with the Zimmer plant. There was still a huge loss on the project, but it was nowhere near as bad as it...
  9. mattheww50

    Most efficient flashlight ??? (AA & or 18650)

    Re: Most efficient flashlight ??? (AA & or 18650) In general, the higher the voltage you start with, the more efficient the light is likely to be. Higher voltage means lower current, and the losses are proportional to I^2 x R, so doubling the voltage cuts the current in half, but...
  10. mattheww50

    Fireflies E07 (1x21700, 7x 90+ CRI emitters)

    These units are now being shipped, I ordered a yellow with Nichia LED's, and received tracking information yesterday. www.usps.com confirms that China Post has the parcel. Given the realities of shipping this time of year, I don't expect to see it until after New Year's however.
  11. mattheww50

    Geiger counters, radiation detectors, lets see 'em

    Tritium does NOT produce gamma radiation. Tritum Decays via Beta emission, which is simply an electron, and it is at very low energy (18kv), which is less then the energy of most of the electrons that were used in cathode ray tubes like TV sets. Most color television used something between 20...
  12. mattheww50

    Lithium Primaries AA & AAA

    As I recall there were some Canon Film SLR cameras that depended upon the internal resistance of the Alkaline cells to operate correctly. The way the camera sensed that the roll of film had come to an end was that the drive motor stalled attempting to advance the film. That caused the camera to...
  13. mattheww50

    Question about NiMH AAA cells

    Most NiMh and NiCd cells have a high self discharge rage sometimes as high as 1-2% per day, so they discharge whether you use them or not. Also remember that one of the features of these cells is the voltage remains the same almost regardless of cell charge state, and NiCd or NiMh cell will...
  14. mattheww50

    Nitecore TM03 vs Klarus xt11 gt?

    The thing that is likely to cause you the most grief with TM03 is the only way to get full output with a specially modified 18650 cell only available from Nitecore, and I am not even sure it is still available. The TM03 really pushes the limits for continuous draw from 18650, which is why...
  15. mattheww50

    Most efficient >=100W equivalent bulbs in 2018

    The problem isn't brightness, it is how long the lamp lasts for me, I concluded the return on investment was going to be long after the 21st of Never.
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