Posts by ilmari

Re: Cool

When overcharged or overdischarged, the li-ion cell starts dissolving its copper, and producing metallic lithium. When the dissolved copper precipitates again, there's no telling where it ends up. If a shunt forms, it might cause localized heating and set off thermal runaway. As for metallic lithium, needless to say, it's highly volatile. The damage is accumulating.

RC Hobby people get relatively frequent battery fires, a consequence of running batteries without protection circuitry, and running batteries hard, making their base temperature already high, before builtin or evolved defects come into play.

Re: "Change in plan for vertical-landing Falcon 9 rocket stage"

Falcon 9 flying as planned and as expected for maximum payload to GTO. A change in plan would have been if first stage tried to re-enter atmosphere in a controlled manner somewhere halfway to Africa.

As for space race breakthrough, is the author talking about this being Turkmenistan's first satellite?

Re: "Landed Fine"

In the 60s, the rockets fell/tumbled out of control and crashed into the ocean each and every time, well, except for the times they blew up on the pad. This still happens today, and rocket debris washes up on shores in south america. SpaceX is doing something new trying to do a powered softlanding.

Re: Another vapour-ware

Actually, your almost 3000mAh AA is made by some "computer wizard" with label editing "skills", changing 2000 to 3000 because "everyone else is doing it".

In the Li-on space, typical capacities for the classic 18650 size cell have gone from less than 1800mAh to today's 3100-3400 mAh for the premium cells from premium manufacturers, a doubling in capacity.

One thing that annoys me is how media frequently reports on "breakthroughs" in making a battery that charges in 5 minutes. Such Li-Ion batteries already exist, the capacity penalty you take for quick charge isn't even that big (Compared to supercapacitor capacities). Dumping that much power in 5 minutes requires some nice fat cables and chunky charge electronics, though. Your average usb cable would turn into a glowing white noodle in seconds.

If media reported on car tyres like they report on battery tech, every week there'd be a sensational post reporting on a new innovation, a new tyre that is rounder and not square. Every month there'd be reports of amazingly low friction tyres promising to save 75% energy, the boffins are calling it "railway". A couple of times a year there'd be reports on "out of the box" thinking derived "innovations", pht wings on the car, "inventing" the "aeroplane", and tyres are only used a short portion of the travel. Stick legs on the vehicle so it walks, no tyres needed at all, and no road infrastructure either, all problems solved forever!

Re: short term benefit

I tried one of those too, but it was like watching a rsa key fob tick.

And yes, it had no clue about power factor, so it thought laptop power brick eats double what it really does, and idling wallwarts were overestimated by a factor 10 or so..

Re: Its about time 2G was dropped from coverage maps / statistics.

What good are fines, if operators aren't allowed to build coverage anyway?

How about maps of "We've set aside money to improve coverage here, but unfortunately we haven't received permission to do so"/"blocked by nimbys"

Re: Poor Oisin

JC in anger management therapy? Now that's a tv show I'd watch, especially if it includes segments such as "staying calm driving behind pensioners in caravans".

I don't think any other country equated smart meters with remote control, everyone else is doing "advanced meter".

One directive I don't see mentioned on thereg though, is the one requiring damages and refunds for power outages. It has caused a building boom in Sweden and Finland atleast, with grid operators hurrying to bury electric cables underground so they don't need to pay out so much compensation for outages during storms.

Re: Capacitors - caveat observer!

Also, grounding yourself seems like the last thing you'd want to do.

Intel's graphics is the most popular graphics choice for PCs, makes sense to integrate it in their mainstream offer.

AMD moving to 16nm wont make you happy, by that time Intel will be measuring node size in atoms rather than nm. Both companies make CPUs that are "good enough", anyway.

On my asus transformer from about the same time era, chrome (and to a lesser extent firefox) spends much of its time writing to the slow emmc. I believe the N7 was also plagued by an extremely slow emmc with around 1-4 WIOPS performance?

This issue is something that has persisted with browsers for a longer time, across platforms. firefox was notoriously slow on Linux, due to the way it wrote cache and browsing history with sqlite. This issue is amplified further on flash based storage, where each tiny write triggers a 8 megabyte read-modify-write cycle. sqlite, being a database ish thing, is paranoid about dataloss, and makes sure the data is on physical storage after each step, with the end result that appending a new url to browser history, to a storage medium where every write request regardless whether it's 50 bytes or 8 megabytes takes on the order of 1 second to complete, you're looking at several seconds just to add to browsing history, let alone disk cache for images etc...

Ever since flash storage started appearing, programmers stopped caring about how they write stuff to disk, because "no moving parts, it's instant so I don't have to care". SSDs only started working like that, through the use of large Arm cores and massively complicated firmwares (that still today occasionally mess up), around the era of Intel M-25 and ocz vertex. Today if you're not careful, you'll get an emmc that still behaves as poorly as the one in N7.

Probably the only company that pays any attention to the issue is Motorola, with the use of f2fs, a filesystem which tries to make life easier for the emmc, boosting performance.

Re: Too Small?

Am I the only one who never swaps sd cards?

I put in a card in my phone, and it stays there until it is obsolete or upgraded to the next faster, bigger, affordable version.. The old one's data copied over and never used again.

Re: MS Might Share Some Blame

I recently discovered the hard way, that restore usb media created in windows refuses to work on empty harddrives, ir if the partition table is corrupt. In other words, if HD is screwed, you're screwed.

However, to my delight, I discovered hidden deep on Microsoft's website a tool which creates Win8 install media battery downloading from ms. You have to pick 32/64 bit, language, and edition correctly, and the resulting usb key will install W8 on a PC with the correct W8 key in bios.

Re: Interesting

Bye bye per cpumodel benhmarks is already a relity for low power intel CPUs. They're primarily limited by TDP, as in actual power use and not overheating, and the PC maker decides if they want to limit CPU to 4.5W or 11W, or anywhere in between. Add ontop of this efficiency variation from cpu to cpu too.

Also for desktop CPUs, overclockers were buying many haswell i7 from different places, hoping to get one from a "good" batch known to overclock well, and returning if batch lottery didn't play out well. All of the CPUs meet (and exceed) the performance promised by intel, but some exceed it with huge margin.

Re: From the Whitehall Home for the Hard of Thinking

(Not in UK)

Re farmers using technology that works.. Couldn't agree more. As part time tech support person, the most complex networks/LANs I've encountered with farmers. Recently one told me "I really regret not signing up the cow for fibre optic internet when I had the chance".

He has fibre to his own house, and a point to point 54Mbps wifi link to the building with the cows some 200m away. There's a "visitor/casual" wifi and lan, and a "infrastructure" LAN, plus home lan+wifi. The infrastructure part of the network is where the milking robot, feed silo management, and god knows what sits. This is, of course, available to him on his smartphone and PC realtime. If a cow gets in an argument with the robot, his phone buzzeds and he can look at the situation and have the robot shoo the cow or bribe it with treats or whatever.

.. But it'd work much better if it wasnt behind a 54Mbps bottleneck.

As for government services? Dump all the paperwork and receipts with specialists that can decode and speak governmentese..

Re: It is Elite from 1984, only even more so.

They coukd do like EA/Maxis did offline singleplayer mode (which is apparentky different from online singleplayer), where they basically just freeze comnodity prices and availability, makkng them static.

Re: Not pirates - just because you don't carry along a CD player anymore...

Initially this levy was set up to "compensate" lost revenues when people were using this newfangled gizmo called tape recorder, ti record radio broadcasts for later and feared repeated playback.

This was later extended to casettes, vhs and beta casettes, writable CDs and DVDs, harddrives in PVRs, eexternal harddrives (but not internal hd when bought separately, and nit empty external hd cases), etc.

It's still known as "casette levy" in Finland.

(Typos, because i don't have a real keyboard)

Liithium-Ion polymer batteries are in the form of a soft pouch, often surrounded by a hard case for extra protection, though devices with non-removable batteries use the device casing itself for that.

"Regular" Lithium-Ion batteries are cylindrical metal cans, where instead of the polymer keeping the components pushed against eachother, the metal container exerts mechanical pressure on its contents.

Cylindrical cells are the most common type used for laptops, with the 18650 size being the most common. (18mm by 65mm). Yiur typical laptop battery has somewhere between 2-9 of these cells, in various parallell and series arrangements. A battery management, protection, and sometimes, "tell laptop this is genuine expensive battery"-chip complete the battery pack, which is then encased in hard plastic.

When a laptop battery fails, it's usually because one set cells in series arrangement has died. The entire pack is limited by its weakest participant. I recently disassembled a dead 6 cell battery. It was arranged as 2P3S, that is, 2 cells in parallell, 3 of these pairs in series. 1 pair was totally dead, had leaked, and its mechanical protection had severed its internal connections. Must've been running hot! Anither pair had so-so performance, and one pair had excellent performance.

Now, laptop battery recycling already takes place in China. Enterpresing people obtain dead laptop batteries, crack them open to harvest the cells that still function a little bit, and reuse them to make "new" laptop batteries. Thesd are sold on ebay, at significantly lower price compared to official genuine packs. The plastic casing, labels and holograms cost cents to make, and are not reused.

The cells nit reused for laptop packs, are given a new shrinkwrap, a fantasy capacity label, sometimes a circuit board is added, and then sold on. There's a significant market with e-cig users and fancy flashlight users, for cylindrical li-ion cells. It's remarkable that such a market exists, considering that no reputable manufacturer willingly or knowingly sell "bare" li-ion cells, thry always require the cells to be either built into a device, or buolt into a battery pack, and measures in place to prevent charging by anything except the designated charger. As such, one can consider all "lose" cells for sale a bit dubious.

Re: The trouble with OCZ

This is wise also when it comes to usb drives and sd cards.

Re: Sorry, I can't get excited about NASA's 'new' 1960's Mercury/Gemini/Apollo Space Program v2.0

In terms of actual rocket science, they're keeping the actual good bits of the space shuttle, the SRBs and the space shuttle main engines.

As they don't need to fly any single-orbit missions anymore, they don't need huge wings anymore. The buge wjngs of the shuttle were needed so that on a single orbit polar mission, the shuttle could use its wings to compensate for the earth rotating underneath it, so it could return in a single orbit to its launch site. The air force wanted that, but no missions were actually flown.

Without wings, they can place the orbiter ontop of the rocket, and not have piece of foam and ice smash into it on take off.

The first SRBs to fly will actually be reused from the shuttle, and have flown before. They don't plan to reuse them anymore. If it doesn't pay off, don't do it.

The space shuttle main engines are phenomenal still today, their fuel efficiency is 1.7 times better than that of Saturn V.

Of course, politicians will probably cancel the SLS, which is the most useful bit of all the associated projects...

Well, Nasa pioneered skip aerobraking. Kerbals and ESA use skip lithobraking :)

Re: @b166er

Buying a drilling rig to just make one hole is very silly.

As someone living in the Nordics, where groubd source heatpumpd are now withib top-3 modt popular heat source for new or newly renovated houses, i csn tell you the hole doesnt cost that much.

Roughly speaking, changing to gshp is a 15kE investment, of which roughly 5k goes to the dude that comes over and parks drilling rig in your yard and naps for 2days as the machine works away.

Oil heating running costs on the order of 3-5kE annually, electric even more.

Wood fired central heating needs something on the order of 3-5ha of forest for comfort, and 2-4 weeks of work put into it, to harvest and process the "free" fuel.

Rules of thumb for renovations or new houses: 100cm of rock wool above and below, same or atleast 60cm on walls. Forced air ventilation with heat exchanger (or even a heat pump), and underfloor heating. Underfloor heating allows system temperature to be kept at around 40C instead of 60-80C as with radiators. Lower system temperature boosts overall efficiency considerably.

Re: Plus ça change, plus c'est la même chose

I cant wait until the day Steam games are all kn the cloud. I wouldnt have to worry about constantly upgrading the gaming rig, wouldnt have noise and heat problems in the gaming room, the gaming room could be repurposed.. And, best of all, I wouldnt need to get out of bed to play a game if it ran on, or was streamed to a phpbe, phablet or tablet device..

Re: Do not write off the low-cost Series 40 featurephone platform

Part of why Nokia failed, was that they did not realize quickly enough that calls are no longer the primary purpose of phones, and that call quality and battery life arent that important either.

Re: Crap Battery

I bet you nonzero amount of currency that the real reason is novelty wearing off, and you doing less power intensive tasks on it. Or no longer blocking antenna with hand, or your operator boositng coverage.