Rechargeable battery question

If it were mine I'd retro-fit a single battery made from lithium Ion cells with two buck converters to give your two supplies.

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Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
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Reply to
~misfit~
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The two supplies don't share a common ground.

Reply to
John-Del

You might want to try H-type nickel battery strips like this: Ideally, you want mostly nickel strips, not nickel plated steel, but I've managed to make it work. I couldn't find any H-Type pure nickel strips on eBay.

With an ordinary strip most of the current goes through the strip, with less current going through the stainless battery can. With an H-type strip, the electrodes straddle the slot. This increases the resistance of the strip as the current now needs to go around the slot. That results in a larger portion of the current going downward and through the battery can.

I'm not sure using brass for electrodes is a great idea. I've never tried it. The resistivity of copper and brass are: copper 1.7*10^-8 ohm-meters brass 8.0*10^-8 ohm-meters making the resistance of identical wires roughly 4.7 times higher for brass. If you look at photos of commercial spot welder electrode tips: methinks you'll find that most of them are copper, not brass.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

I've had no issues replacing Ni-Cds with Ni-mH for vTech cordless phones. A pack with 3 AA batteries in series. I have extra connectors and wire now. 5-7 year life.

Reply to
Ron D.

Perhaps that's what I meant by line two of the quoted part... "I wouldn't use it for anything high current tho..." Somebody nitpicked my use of the word, "weld" with brass. I'll rephrase...

One can use an energy pulse directed through hobby store brass sheet cut into strips to effect a connection to a cell very easily, but the resistance is slightly higher precluding use in applications that require high current, and may pose corrosion issues in unfavorable environments, otherwise it is easy to do and works well for many applications for those who don't have sophisticated spot welders, a supply of the proper tab media or a desire to 'school' the poor fool who made the suggestion with links to basic principles and value a working battery higher than nitpicking the suggestion that someone use something imperfect in their eyes. Methinks thou dost protest too much. Brass is perfectly adequate for a metal detector.

Stated another way...If I didn't have workable alternatives, there'd be no reason for me to post. Scientists like perfection. Engineers are happy when it gets the job done.

Reply to
mike

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