Atomic I/O letters column #106

Originally published 2009, in Atomic: Maximum Power Computing
Reprinted here June 16, 2010
Last modified 03-Dec-2011.
 

Atomicans vs Batteries, Part XXXII

I know you've covered the slow death of laptop batteries in detail before, but I'm curious what would cause them to die very quickly.

When I first purchased my name-brand laptop computer the original battery pack would give me plenty of useable power. After 18 months of moderate use I was starting to get noticeably less and less capacity from the battery, until about 6 months later it was cactus. Fair enough, I'd had a good run with it so it was high time I got a new one.

I decided to have a try at an eBay cheapie. I knew it probably wasn't going to last as long as an (extremely expensive) OEM unit, but I was planning to upgrade to a new laptop in less than a year anyway. When the battery arrived I was quite pleased with it, getting just as much time out of it as the original.

However, after only 5 months it started to lose capacity... quite dramatically. Within the space of about a week it went from taking a 100% charge down to only about 10%, hardly enough for me to even shut down the laptop if the mains had failed.

Since the dealer was Australian I tested their "1 Year Guarantee", and much to my surprise they actually honoured it. The replacement didn't fare much better, only getting 6 months of use before it, too, died a quick death inside a few days.

What would cause this rapid decline in capacity?

I know non-genuine battery packs probably don't use cells of the same quality as OEM but I don't understand why they'd go from 100% to zero in such a short space of time. I was expecting a much more gradual decline like with the original pack. Maybe the electronics in the pack died instead? Perhaps Windows was lying to me all along?

Michael

Answer:
I can't give you a really confident answer to this question; as you say, there are a few possibilities.

In decreasing order of probability, I'd say:

1: The cells in the battery were old when you bought it,

Lithium-ion cells used to commonly crap out only a couple of years after they were manufactured (though even then, a very few LiI cells lasted much longer). Today, they're likely to last better, but still not nearly as long as, say, NiCd or NiMH cells. If you buy a "new" battery that's been on the shelf for a couple of years - entirely possible, if you've got an older-model laptop, or one that uses the same battery type as older units - that battery may have a very disappointingly brief life, and the loss of capacity over time may be as dramatic as you've experienced.

It's also possible for a brand-new battery to be assembled out of cells that've been on the shelf for a couple of years, with the same result.

(The very cheapest dealers on eBay for certain categories of gear, like memory cards and thumb drives, have for some time now been 100% scam artists, because fake goods can drive real ones right out of the marketplace. I would not be surprised if eBay also had a burgeoning population of people selling super-cheap batteries which they know very well have been assembled out of five-year-old cells.)

Lithium-ion cells also age faster when it's warmer, so laptops often bake their batteries into an early grave. The hotter the weather, the worse the problem - I wouldn't be surprised if the same cells had significantly lower lifespan in Australia than in, say, the UK. (Except for any batteries that actually freeze, which ruins lithium-ion cells.)

For optimal shelf life, store lithium-ion batteries at 15C and 40% charge. Have your butler charge them very carefully, and then gently place them in your battery humidor.

2: The battery's still OK, but the charge-monitoring hardware is deranged, and won't let the battery discharge, or charge, fully. This is what's happening when someone reckons "cycling" a lithium-ion battery brought it back to health.

If discharging as far as it'll let you and then recharging doesn't help (and that's not something you should otherwise do, as lithium-ion prefers frequent shallow discharging), then there's nothing more you can do.

3: Some lower-level problem, like the laptop's charging circuit isn't working properly.

4: Something really off-the-wall, like crud on the battery contacts.

 

Cable origami

In my line of work I install copper and optic fibre cabling that has varying levels of minimum bend radius. The copper networks (Cat-5, Cat-6) usually get a performance hit against them if the bend radius is not met, or the cable gets kinked a few times during installation.

Do typical PC cables, like SATA and IDE cables, suffer a performance hit or slowdown if I bend them too tightly in trying to get a really neat case install?

Chris

Do not attempt at home.
And now, I shall make a crane sitting on a chrysanthemum.

Answer:
Yes, there are minimum permitted bend radii for internal PC data cables. Bend them too sharply and you can damage them. I wrote about this in a letters column a while ago.

If you're lucky, an excessively sharp bend will fracture a data conductor and stop the cable from working at all. If you're not lucky, you can end up with a dodgy cable that throws data on the floor from time to time. Then error-detection in the various protocol levels involved in moving data to and from drives usually copes with the problem, and just gives you a somewhat slower drive than you'd otherwise have. But every now and then, some bad data will get through, and cause crashes or subtly munged files.

(I wrote a bit on this subject in this piece, about over-long and "rounded" PATA cables, back in the distant past when we didn't yet have the retronym "PATA".)

Ribbon cables are a special case, when it comes to bend-radius limits. They don't really bend at all in one plane, but they bend really well the other way, and, as you say, often have quite sharp creases folded into them to get them to neatly turn a corner. They demonstrably usually work fine like that, though the definition of "fine" may include "wound down by Windows to some awful PIO transfer mode to make the errors stop".

Exactly how sharp is too sharp a bend in a ribbon cable depends on who you ask. Real Army-uniform razor creases are definitely asking for trouble, but it's easy to find recommendations that go far the other way.

According to NASA, for instance, permanent bends in ribbon cable should not have a radius smaller than ten diameters of the individual wires, including the insulation.

Standard 40-conductor PATA cable has wires a little less than a millimetre in diameter, so the NASA spec dictates quite a large radius; the bend's diameter will have to be about the same as that of a five-cent piece (or a UK 5p, or a US penny).

80-wire ATA cables - which have the same actual signal wires, but with earths interleaved between all of the signal wires to reduce interference at Ultra ATA/66 data rates - have wires only about half a millimetre in diameter, so the NASA spec for those gives a bend diameter about that of a pen. (But the connector's own strain-relief bend is, on the same NASA page, obviously rather tighter!)

The NASA spec tries to make the cable work just as well bent as it does flat, even for extremely high bandwidth and/or great lengths of cable. An 18-inch PATA cable connecting a UDMA/33 DVD burner in a PC doesn't need to be treated this carefully. (You could probably grind a 34-wire floppy-drive cable in a mortar and pestle and still have it work.)

So, as ribbon cables fade out of the PC scene, I suggest you just refrain from putting sharp creases in them, or in SATA or even power cables, for that matter. Fold cables as gently as is possible to achieve the routing you need, or just hook 'em in place with cable clips, gently-applied zip-ties, Velcro ties or whatever. (If you're using a lot of nylon cable ties, consider getting a cable-tie "gun"; it'll automatically tighten the tie and then neatly snip off the sticky-out bit. If you wind the tension wheel control down to minimum, you shouldn't crush any cables.)

Whatever you use, don't crush folds flat just to stop a cable drooping a bit. And remember that if a drive seems to be going weird, a creased cable may be the cause.

(The classic mysterious version of this problem is the cable that wasn't creased, until you slid the side panel back onto your computer and accidentally crushed the cable between the panel and the frame.)

 

Always wax your registry after cleaning it

Are registry cleaners worthwhile?

I don't mean those ones with the late-night TV or pop-up ads that tell you your computer will be 2743X faster if you clean all the Satan out, like all those fake-antivirus ads. But I use Crap Cleaner to get rid of temp files and stuff, and it's got a registry cleaner option, and that never seems to have hurt anything.

But did it do any good? What's really the point of these things?

Sam

CCleaner's registry cleaner

Registry cleaners certainly LOOK as if they do something useful...

Answer:
The Windows registry is a giant pile of software settings, for the operating system itself and for most of the applications on it. You name a configuration change in your computer - including minor automatic updates - and it'll at least change a registry "key" somewhere, and probably add some new ones.

But when configuration changes remove something, they usually don't mop up all of the registry changes that thing made.

Enter the registry cleaner. It whips through all of the many tens of thousands - or hundreds of thousands - of registry entries, and looks for all of the things that don't seem to be needed any more.

Pointers to old versions of files that've been replaced by newer ones, and then deleted. File extensions that something took note of, but which you've never associated with an application. Settings for software you've uninstalled. Breadcrumb-trails about files that some installer used, but then deleted.

And then the registry cleaner deletes all those things. (After showing you a giant list of stuff that you don't know what it is, and asking you if it's all right to get rid of it all.)

And then, almost always, everything is perfectly fine.

As a general rule, none of the "reputable" registry cleaners, like the one in Crap Cleaner (which was delicately renamed "CCleaner" a while ago), ever do any harm. Heck, you can still run a 1997 version of Microsoft's own "RegClean" on Windows 7, and I don't think it'll trash anything. (I still don't recommend you try it, though.) I've run registry cleaners umpteen times over the years, and I can't remember one ever making a computer any worse than it was already.

But that doesn't mean that all of this is actually worthwhile. The steadily-growing registry was one of the many things that all worked together to force people to keep reinstalling Windows 98, but every Windows version since then (let us not speak of Windows ME) has had a whole different registry system, in which the size of the registry has close to zero impact on anything. Software does not have to spool through the registry from the beginning, searching for the entries that apply to it. The only thing that really takes longer, today, if your registry is gigantic and full of meaningless cruft is... backing up the registry.

It does take up more space, but now that an utterly Gargantuan one-gigabyte registry occupies less than ten cents worth of disk, who cares?

A more worthwhile kind of registry cleaner is the one that's part of anti-malware software, and tries to weed out the poisonous tendrils of the ever-more-devious crapware foisted upon the Windows world by diseased minds. But that sort of registry scrubber expressly isn't looking for entries that aren't connected to anything any more. It's looking for unholy Gordian knots of nonsense-named cloaked programs that all try to guard one another from the extermination they, like their authors, richly deserve.

I think unnecessary registry cleaners may have gotten a boost from Windows Vista, because Microsoft really outdid themselves there. An old WinXP system's registry might be 25Mb in size; an unremarkable Vista box's registry can easily be 400Mb.

(This may have something to do with "registry virtualisation", in which apps that don't use the registry properly have their out-of-spec calls redirected to new, in-spec locations, while the OS strings them along and pretends everything's the same as it was. Windows 7 does all this stuff too, though, and Win7 registries are generally less than half the size of Vista ones.)

No registry cleaner ever actually makes a normal registry all that much smaller, anyway. Actual miraculous improvements from just cleaning cruft out of the registry are only found in the glowing reviews on get-your-honest-reg-cleaner-reviews-here.com, whereon are promoted umpteen dodgy registry cleaners, all with get-rich-quick affiliate schemes...

 

This is a reprint of a column originally published in Atomic: Maximum Power Computing magazine here in Australia. The e-mail address for the I/O column is io@atomicmpc.com.au, but I can't answer all of the letters I get.

If you're not an Atomic reader, then sending mail to their letters address is somewhat perverse. Use this alternative instead.

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