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#91
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Is there any good non-rechargeable headlights anymore?
On Mon, 15 May 2017 06:06:27 -0700, sms
wrote: On 5/13/2017 4:52 PM, Jeff Liebermann wrote: On Sat, 13 May 2017 16:33:40 +0000 (UTC), Ralph Barone wrote: "A thing of beauty and a joy to behold." Not quite... I beg to differ. The uglier it looks, the better it works. When I see a beautiful work of mechanical art, I suspect that something important has been sacrificed to gods of art and beauty. It might be a joy to behold, and simultaneously be pure hell to operate. It's much like concept bicycle designs, which (to me) are generally quite beautiful, but also impossible to ride. Form follows mal-function: http://802.11junk.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html Incidentally, the Maglite in the photo is no more. I tried to use it last night and discovered that the D cells had leaked and are now corroded and firmly stuck in the flashlight tube. Sniff... Time to join the 21st century. Get yourself to Costco. Most of my Maglites are 20+ years old. (The company is 38 years old). Some were repaired for switch problems under the lifetime warranty. Try that with what's available today. However, I don't think I'll live another 20+ years, so I'm currently buying cheap junk flashlights on eBay. Costco is currently selling Duracell flashlights. https://www.costco.com/Duracell-2-pack-LED-700-Lumens-Flashlight-.product.100319990.html 700 lumens seems slightly less fanciful than the previous 1000 lumen claim. I haven't tested any, but I don't believe that 700 lumens from 3ea C cells is possible. Assuming a typical 75 lumens/watt LED, the battery would need to deliver 700 lm / 75 lm/watt = 9.3 watts. 3 cells is about 4.5volts, so that's: 9.3 watts / 4.5v = 2.1 amps From the data sheet at: https://www.costco.com/Duracell-2-pack-LED-700-Lumens-Flashlight-.product.100319990.html a single C cell is essentially dead drawing 2A for 15 mins. 3 cells in series at 2A have the same 15 min discharge time. The light probably operates much longer than 15 mins, which suggests that the 700 lumens is still rather fanciful. From the reviews section: Great illumination, nice design. I just wish the flashlight worked. I've had 8 of these, and every single one ceased working anywhere between 1 week and 7 months after purchase. ... The replacements I received from the vendor's customer support all were DOA. The real problem is the alkaline battery which does badly at the high currents needed to run a really bright LED. A large flashlight these daze should be using some flavor of LiIon or at least LSD NiMH batteries. Duracell is using these flashlights as a gimick to sell alkaline batteries. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#92
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Mag lights
On 5/15/2017 9:41 AM, Jeff Liebermann wrote:
On Mon, 15 May 2017 06:16:07 -0700, sms wrote: On 5/14/2017 7:22 PM, Jeff Liebermann wrote: True. I retrofitted my various 2D and 3D Maglites with aftermarket LED conversions. The reflector design was obviously all wrong but worked well enough to be usable. There are now Maglite conversion kits which replace everything from the light bulb, to the entire head assembly. Convert your film camera to digital too: http://www.siliconfilm.com/ $700. For that, I can buy a fairly decent digital camera. The sensor size is not specified, but I doubt it will cover the entire 36x24mm frame size. http://www.siliconfilm.com/faq.htm http://www.siliconfilm.com/fov.htm Resolution is 1.3 megapixles (1280x1024 in 36 bit color) but no clue if that's the sensor resolution or if it has been upscaled from a smaller sensor. Probably useful for someone who has a large investment in a compatible film camera system. It never came to market other than some prototypes. There were so many issues with it that of course it was never going to work. |
#93
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Is there any good non-rechargeable headlights anymore?
On 5/15/2017 10:11 AM, Jeff Liebermann wrote:
snip The real problem is the alkaline battery which does badly at the high currents needed to run a really bright LED. A large flashlight these daze should be using some flavor of LiIon or at least LSD NiMH batteries. Duracell is using these flashlights as a gimick to sell alkaline batteries. And I had one of the Duracell 4C models which self-destructed with NiMH batteries. |
#94
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Is there any good non-rechargeable headlights anymore?
On 5/15/2017 9:30 AM, Jeff Liebermann wrote:
snip https://en.wikipedia.org/wiki/Eneloop Using 4th generation numbers: AAA 3 cells * 800 ma-hr * 1.5v = 3.6 watt-hrs AA 2 cells * 2000 ma-hr * 1.5v = 6.0 watt-hrs For a light that you're using every day, there's no upside in the Eneloop batteries. They reduce self-discharge with a separator that is thicker, decreasing the volume of chemicals. But if you're charging every day anyway, self-discharge is not an issue. Also, the Eneloop Pro AA are about 2500mAH and there are non-low-self-discharge NiMH cells that deliver 2700mAH. The Eneloop Pro AAA are about 950mAH. |
#95
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Is there any good non-rechargeable headlights anymore?
On Mon, 15 May 2017 10:26:17 -0700, sms
wrote: On 5/15/2017 10:11 AM, Jeff Liebermann wrote: snip The real problem is the alkaline battery which does badly at the high currents needed to run a really bright LED. A large flashlight these daze should be using some flavor of LiIon or at least LSD NiMH batteries. Duracell is using these flashlights as a gimick to sell alkaline batteries. And I had one of the Duracell 4C models which self-destructed with NiMH batteries. That makes me wonder what marginal circuit Duracell used for an LED driver. The LED driver is suppose to be a current regulator matched to the LED power rating with a PWM modulator for controlling brightness. As long as the driver can handle the applied voltage, the current should be the same for alkaline and NiMH batteries. My guess(tm) is that: 1. Duracell did something stupid, like use a 3 cell LED driver (4.5V max), in a flashlight with 4 cells (6.0V max). 2. Maybe the NiMH batteries actually delivered enough current to drive a really bright LED but cooked the LED driver by dissipating too much power. 3. Didn't use power saving PWM to control brightness, but instead used an inefficient linear regulator. Got a photo diode and an oscilloscope? Try looking at what the dimmer circuit is doing. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#96
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Is there any good non-rechargeable headlights anymore?
On 5/15/2017 4:30 PM, Jeff Liebermann wrote:
snip And I had one of the Duracell 4C models which self-destructed with NiMH batteries. That makes me wonder what marginal circuit Duracell used for an LED driver. The LED driver is suppose to be a current regulator matched to the LED power rating with a PWM modulator for controlling brightness. As long as the driver can handle the applied voltage, the current should be the same for alkaline and NiMH batteries. My guess(tm) is that: 1. Duracell did something stupid, like use a 3 cell LED driver (4.5V max), in a flashlight with 4 cells (6.0V max). 2. Maybe the NiMH batteries actually delivered enough current to drive a really bright LED but cooked the LED driver by dissipating too much power. 3. Didn't use power saving PWM to control brightness, but instead used an inefficient linear regulator. Got a photo diode and an oscilloscope? Try looking at what the dimmer circuit is doing. There had to have been a board in there because there were multiple power levels, and flash mode. The light came on very bright, for a few seconds, before destroying the LED or the driver. |
#97
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Is there any good non-rechargeable headlights anymore?
On Mon, 15 May 2017 17:14:28 -0700, sms
wrote: There had to have been a board in there because there were multiple power levels, and flash mode. Yep. Something like this: http://www.ebay.com/itm/222134093111 The light came on very bright, for a few seconds, before destroying the LED or the driver. Sounds about right for overheating. Over voltage would blow it up instantly, while overheating takes some time. The usual culprit for overheating is lousy heat sinking on the LED or regulator circuitry. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#98
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Is there any good non-rechargeable headlights anymore?
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#99
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Is there any good non-rechargeable headlights anymore?
On Monday, May 15, 2017 at 3:22:28 PM UTC-7, sms wrote:
On 5/15/2017 9:30 AM, Jeff Liebermann wrote: snip https://en.wikipedia.org/wiki/Eneloop Using 4th generation numbers: AAA 3 cells * 800 ma-hr * 1.5v = 3.6 watt-hrs AA 2 cells * 2000 ma-hr * 1.5v = 6.0 watt-hrs For a light that you're using every day, there's no upside in the Eneloop batteries. They reduce self-discharge with a separator that is thicker, decreasing the volume of chemicals. But if you're charging every day anyway, self-discharge is not an issue. Also, the Eneloop Pro AA are about 2500mAH and there are non-low-self-discharge NiMH cells that deliver 2700mAH. The Eneloop Pro AAA are about 950mAH. This sounds like exactly the thing for a bicycle headlight. |
#100
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Is there any good non-rechargeable headlights anymore?
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