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  1. H

    Worlds largest battery...

    Cool! I recall a getting a tour of the national fuel cell research center in Irvine a few years ago (which at the time I believe could claim the largest fuel cell array in the world). Even the resistor banks were a sight to behold. I love macro engineering.
  2. H

    L91, 14500, CR123 on a plane?

    I fly with similar stuff (usually an SF-CHROMA-MIL and lots of 123 type batteries and Li-Ion rechargables) in my carry-on, never gets a second look, even when it's entangled in a rats nest of cables. In fact, the only thing that seems to get their attention is (occasionally) is PC boards not...
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    Opinions on rechargable batt for GPS

    Man, everyone has one of those 60csx's (me, too). Great GPS unit. Another vote for Eneloops if you use it moderately often, Li-AA cells if it's going to sit in a backpack or glove compartment for infrequent emergencies. I get about 16 hours on a pair of Eneloops, with the backlight on (at a...
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    Bench Supply Recommendation?

    CC is "constant current". It's basically a current limit for the output. If the load tries to exceed the current limit you set, it will drop the voltage (down to zero if need be) to limit the current drain to the value you set. Or you can think about it the other way; the power supply will...
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    Bench Supply Recommendation?

    Well, the specs seem comparable to what you'd want in a good supply. I've never seen one (the HP/Agilents pretty well are the standard in these parts), so can't speak to how well they hold up. The smaller and lighter package is nice, assuming its rugged. One thing that seems to be a slight...
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    Carbon-Zinc Batteries - Still Useful?

    Actually, it's not clear to me if carbon-zinc chemistry is inherently more likely to leak that alkaline, but certainly I remember lots of "heavy duty" D-cells ruining the flashlights of my youth. None of the weird industrial carbon-zinc batteries I use have leaked, on the other hand/
  7. H

    Carbon-Zinc Batteries - Still Useful?

    In some very low-current applications, carbon-zinc cells can outperform alkaline in terms of energy density. (Though Li probably would outperform either, although that's available in fewer form factors). There are some battery form factors that to this day are only available in carbon-zinc...
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    Bench Supply Recommendation?

    Also, I'm not sure why you think the HP/Agilent E361x supplies are made in China. It's possible some of them are, but of the nine that are in my field of vision at the moment six are labeled as made in Korea and three are labeled as made in Singapore. Neither of those places, last I checked...
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    Bench Supply Recommendation?

    I have a stack of HP and Agilent bench supplies, mostly E3610As and a few 3611A's. Several have been powered on and under load almost 100% of the time for something like 12 years. I've never had anything go wrong with one. The 3610A is THE industry standard workhorse electronics lab DC bench...
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    Recommendations for good electronics books?

    My two favorites: The in-depth classic is Horowitz and Hill's Art of Electronics. The digital stuff is out of date, but it remains the best practical introduction to analog circuit design in print. Not for the squeemish, though. This is a serious, big, no-nonsense book aimed at engineers...
  11. H

    3M vs. Batteries.com Li battery patent case

    Ah. the story seems to have been updated since I posted it. Originally is said lithium, not lithium ion, and didn't say anything about laptop batteries. I guess this is more limited that I had thought it might be, and probably doesn't affect many of the cells we use here.
  12. H

    3M vs. Batteries.com Li battery patent case

    According to this Reuters story (which probably requires an NY Times free account to read), batteries.com just agreed to stop infringing a patent owned by 3M on some sort of Li battery technology. No idea what specific product(s) might be involved or what they are branded under...
  13. H

    Lithium D's...anyone use?

    Heating is a consequence if high (relative to other battery technologies) internal resistance. But I believe your cell is different from the cells in the original post (which are the ones I've used), and yours advertises LOW internal resistance, so this is clearly not an issue here. Edit: it...
  14. H

    Lithium D's...anyone use?

    If you're drawing 500mA from one of those, you're wasting a lot of the energy heating up the battery itself, so it's not really an optimal use of these cells. If all you care about is the shelf life, it may be reasonable tradeoff, but there are probably now significantly better alternatives...
  15. H

    Lithium D's...anyone use?

    I've used them in a few devices, mostly medium-size things that can't be accessed or maintained (e.g., entirely encased in weatherproof epoxy) once installed. They are 3.6V, have rather high internal resistance and can't be reliably used with more than about 2 in series, so are not a direct...
  16. H

    WHY did they stop manufacturing Nickel-IRON batteries :(

    Just for the record: Actually, a telco CO battery array must deliver VERY high current when the float charge is removed (among the highest steady state loads batteries are routinely used for, in fact). You definitely don't want to be nearby if a CO battery shorts. Individual local loops are...
  17. H

    DMM CAPTURE MEASURE AMP PEAK??

    Jim, All the mAH rating of a battery directly tells you is how much total energy it stores. It doesn't directly tell you the maximum current it can deliver. For that, you need to know the internal resistance. The less internal resistance, the higher the peak current that can be delivered...
  18. H

    DMM CAPTURE MEASURE AMP PEAK??

    OK, I think I've got a sense of what you're doing now, although I'm a bit fuzzy on the details.. Thanks for the explanation. First, an aside. The mAH rating of your batteries doesn't have anything to do with how much current they deliver in an instant, only with how much total energy they...
  19. H

    DMM CAPTURE MEASURE AMP PEAK??

    By the way, you can get a rough idea of the maxium inrush current of some (but not all) lamps by measuring it with an Ohmmeter, but you'll find the answer unsatisfying. I just measured a 50W 24V halogen lamp that I had lying around. We'd expect it to have a steady state draw at 24V of about...
  20. H

    DMM CAPTURE MEASURE AMP PEAK??

    No, you haven't said what your purpose is. I'm not trying to give you a hard time. I'm actually trying to help you. I understand that you want to measure the inrush current. But what you haven't told us is what you're going to use that measurement for. How can anyone offer an opinion as...

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