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Comment: Re: Star Wars! (Score 4, Interesting) 253

by mirix (#49162621) Attached to: 20-Year-Old Military Weather Satellite Explodes In Orbit

These ran NiCd cells. Here's some TL;DR from NASA about a variant of NiCd they use(d), not sure if it applies here.

http://www.nasa.gov/offices/oc...

Short notes:
Fancy NiCd, Higher density and sealed. They rely on precise chemistry to be hermetically sealed units (lean on one element, for limiting and only O2 production).
High pressure at full charge (~60PSI at room temp), higher if things go south, Pressure drops with charge state.
Excess discharge causes hydrogen production.

So, tin can, pressure changing with charge cycles (metal fatigue over many cycles?), H2 production, O2 production... maybe there is some chance for catastrophic failure there.

Comment: Re:Perhaps it wouldn’t pass today’s .. (Score 2) 286

by mirix (#49077111) Attached to: 1950s Toy That Included Actual Uranium Ore Goes On Display At Museum

I'd imagine more harmful to ingest/inhale uranium ore... in addition to radioactivity, uranium is also a heavy metal like lead. (in both senses of the term "heavy metal".)

However most ore is quite weak, with 1% being pretty decent... I think it's economical to mine it as low as 0.1%. A few mines in Canada are near 20%, though (which I suppose is related to Canada being the biggest producer... 1/5th the ore is end product, instead of 1/1000th!). Ore will often have lead and such in it as well (decay products), which is also toxic.

Comment: Re:consumerism wins! (Score 2) 294

by mirix (#48995857) Attached to: Radioshack Declares Bankruptcy

It might be different in the US, but in Canada they always had terrible stock. So if your thing didn't have a broken lamp or speaker, or a dead battery - you were SOL, as they didn't carry anything else.

There's so much different silicon now that it isn't really feasible to stock even a small portion of it in every mall anyway, so most anything you fix you'll have to order in parts for...

It would have been more reasonable when I was a kid (and they only stocked a whopping 3 transistors and zero fets then, too).

Comment: Re:What happens to these at the true end-of-life? (Score 2) 143

by mirix (#48541467) Attached to: Using Discarded Laptop Batteries To Power Lights

Lithium cells are pretty benign in general. There are a few variants in chemistry, the worst would probably be the cobalt based ones. (others use various combinations of iron, nickel, manganese, and phosphorous, which are pretty tame). Though the cobalt variants are quite common.

NiCd is far worse, cadmium is fairly nasty... much more than cobalt.

Comment: Re:sorry, all my laptop batteries are dead (Score 2) 143

by mirix (#48541451) Attached to: Using Discarded Laptop Batteries To Power Lights

In every 'dead' laptop battery I've torn down, one cell (or pair, in parallel) is totally kaput, and the remaining cells retain at least 50% of their nameplate capacity. Protection circuitry will lockout recharging of the whole pack, which wouldn't work with the dead cell anyway.

So the battery as a whole is utterly useless for the laptop, but 2/3rds of the cells or more have some life left in them, for other purposes.

I imagine a lot of the too-cheap-to-be-true off-label replacement laptop batteries are in fact combinations of two dead ones, with the remaining functioning cells rewired into one working (but lower capacity) pack. Certainly seems about right judging by the performance of them, anyway.

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