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Power Hardware

Why Is a Laptop's Battery Dearer Than a Lawnmower's? 427

Barence writes "PC Pro's contributing editor Paul Ockendon has bought a new lawnmower powered by lithium-ion batteries — part of a recent flood of such lithium-ion-powered garden and workshop tools which are taking over from NiCd and NiMH thanks to lighter weight, longer life and lack of the pernicious 'memory effect.' This is pretty much the same battery technology used in laptops, mobile phones and MP3 players, so volume manufacture is already established. Yet laptop manufacturers charge more per Watt-hour than lawnmower makers. This blog investigates whether such a seemingly ludicrous situation can be justified."
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Why Is a Laptop's Battery Dearer Than a Lawnmower's?

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  • by Anonymous Coward on Tuesday December 15, 2009 @11:26AM (#30444478)

    That's the free market. If people are willing to pay $50 for cell phone batteries then that is what you charge, otherwise you're leaving money on the table.

    Look on amazon, you can get cell phone batteries from reputable companies for far, far less.

    And cell phone accessories is an even bigger scam. I wanted another usb cable for my blackberry. From my cell phone company they would charger $30. BestBuy was similar.

    I bought one on amazon for $0.39. Yes, 39 cents for a genuine usb cable (+2.50 shipping). Chargers are $0.99.

    Look, even the genuine stuff comes out of the cheap factories in China, and you're being gouged if you don't shop around.

  • Re:Size matters (Score:5, Informative)

    by robkill ( 259732 ) on Tuesday December 15, 2009 @11:27AM (#30444482)

    This was mentioned in the article, but not as size, but weight. The power to weight ratio is more important. Density of the individual battery cells, and continuous use vs. burst usage also come into play.

  • by bzzfzz ( 1542813 ) on Tuesday December 15, 2009 @11:32AM (#30444566)

    It's the main reason they replaced nicads in most applications.

    http://en.wikipedia.org/wiki/Memory_effect [wikipedia.org]

  • Re:Price Fixing? (Score:4, Informative)

    by captaindomon ( 870655 ) on Tuesday December 15, 2009 @11:45AM (#30444796)
    Price Fixing is not at issue here. Price fixing is only when multiple manufacturers decide to raise a price simultaneously, which is illegal because it is bad for competition and the end consumer. Price fixing only works with commodities that are highly fungible http://en.wikipedia.org/wiki/Fungible [wikipedia.org] i.e. gasoline or LCD tvs. With laptop batteries, price fixing isn't necessary because you can't buy a Toshiba battery if you need one for a Dell. Laptop batteries aren't fungible.
  • by Snap E Tom ( 128447 ) on Tuesday December 15, 2009 @12:10PM (#30445210)

    The guy from Sony answered it: size, weight, and output differences. Would someone actually critique that instead of talking about markets, price settings, and conspiracy theories?

  • by Anonymous Coward on Tuesday December 15, 2009 @12:25PM (#30445454)

    I think you are conflating the difficulty of make laptop batteries with the ability of China to deliver goods that actually perform at the task they claim.

    From batteries that catch on fire,
    to drywall full of toxic coal ash,
    to plastic products that are so thin they bend or break when used as intended,
    to pet food containing toxic melamine,
    to cough syrup containing anti-freeze,
    to mechanical toys whose tolerances are so poor that gears chatter instead of engage,

    Chinese products are always cheapened one or two degrees past the point that they function.

    Our stores are now full of the pathetic junk that we used to look down up the Communists for having.
    We just have more choices of junk that they did.

  • Re:Not Greed .. (Score:3, Informative)

    by blackchiney ( 556583 ) on Tuesday December 15, 2009 @12:26PM (#30445466)
    There is a standard set of sizes for Li-Ion batteries. I cracked open my laptop pack and what I saw was 6 cells of slightly larger than AA cells. A little bit of searching and I found a supplier where a pack of 10 cost $50 w/ shipping. There was space in the case for 2 more so I upgraded the pack from 6 to 8 and adjusted the wiring and thermal probes to match.
  • by amorsen ( 7485 ) <benny+slashdot@amorsen.dk> on Tuesday December 15, 2009 @12:40PM (#30445732)

    I believe the reason is actually another.

    Laptop batteries sold separately are generally sold after the laptop was purchased, or at least after the decision was made to purchase that particular laptop. People don't generally spend the time to price out more than 2 laptops including all options before picking which one they want, they usually look at the base unit price. Therefore the laptop manufacturer has a monopoly (or close to a monopoly, at least, for some things you can get third-party components) on the sale of laptop options like batteries. A monopoly means being able to charge what the item is worth to the buyer, instead of only being able to charge a little more than the productions costs like in a market with perfect competition. The only challenge is to avoid scaring the cheapskate buyers away that you only make a small profit on without lowering the price for everyone, but differential pricing is solving that "problem".

    Options and spare parts are generally examples of market failures.

  • by Sandbags ( 964742 ) on Tuesday December 15, 2009 @01:02PM (#30446148) Journal

    Yea, look at the battery design of the newer LiPo battery packs, like those used in the Macbook. Each cell has a chip attahced that monitors output, heat, and charge state, and the charging cuircuit in the battery intelligently detects which cells charge/discharge faster than others in order to gain max charge performance as well as a better balanced output load and use closer to 100% of the energy on a flatter discharge curve. This prevents components on the motherboard (which get hot) from having to do this using active resistance, and extends battery life as well. There are entire little computers in battery packs now, and they're getting smarter. many also have buttons that show active charge states even when the battery is not connected. Since power is not based on a curve, but a flat line, traditional battery measuring techniques (like the old meters on AA and C energizer batteries that detect output and heat a wire), don't work. to know the battery state, one must know the number of minutes it;s been running for at a given output, based on the last known charge cycle. it has the be calculated, and the battery itself has to internally understand when to thell the PC to stop charging, or when it's running low.

  • Re:Conratulations. (Score:5, Informative)

    by CrimsonAvenger ( 580665 ) on Tuesday December 15, 2009 @01:33PM (#30446760)

    The Phillips head screwdriver is inferior to TORX heads any day of the week.

    The Phillips head was developed for use in automated manufacture - it's designed so that the machine driving it will tend to slip the slots rather than over-torque the screw.

    And for that purpose it works really well.

    What it wasn't designed for is screwing by hand, where any other design works better.

  • Re:Not Greed .. (Score:5, Informative)

    by homer_ca ( 144738 ) on Tuesday December 15, 2009 @01:35PM (#30446788)

    Laptop batteries all use a standard cell which is slightly larger than AA. What you need are unprotected 18650 Li-Ion cells. You can find made in China cells for $3/ea from places like DealExtreme.

    Just keep in mind you assume all the risk yourself when you rebuild Li-Ion packs. The cells aren't intended to be sold to end users because they must be certified together with the electronics that protect from overcharging and discharging. That said, there isn't nearly as much specialization in cell selection as some posters imply. 18650 cells may be rated for different capacities, but they're all compatible with any other 18650 charger. Just don't mix new and old or different capacities.

  • Re:Size matters (Score:3, Informative)

    by smellsofbikes ( 890263 ) on Tuesday December 15, 2009 @01:37PM (#30446844) Journal

    If the batteries are next to your balls, I don't think you are using the lawnmower in an approved manner.

    Whole different meaning to "whacking off".

    I had a friend who worked in the ER in a fairly redneck-filled state. I asked her about the weirdest accident she'd ever seen and she said they'd brought in her *cousin*, who had actually managed to injure his penis (and leg and hand and other bits) with a lawnmower.

    There was a moment of silence, and then everyone hearing the story said "HOW??!?"

    She said "I think alcohol was involved..." but that was all we ever got.

  • Re:Not Greed .. (Score:4, Informative)

    by cheesybagel ( 670288 ) on Tuesday December 15, 2009 @01:52PM (#30447136)
    There are standard sizes for rechargeable lithium ion cells. But different laptops use packs with different numbers of cylindrical 18650 lithium-ion cells [buy-laptop-batteries.com].
  • by sjbe ( 173966 ) on Tuesday December 15, 2009 @03:18PM (#30448426)

    that's where the theory of capitalism fail, if every laptop owner know that it has been ripped of money for nothing in return
    than, maybe, market would work (and low the price),

    Your logic is flawed. If the laptop buyer is offered a price and agrees to it (absent coercion) the laptop buyer has de-facto decided that the value of the product being offered was a fair compensation for the money tendered. A fair deal is one that both parties are willing to agree to - this is the definition EVERY economist you're likely to ever meet uses.

    Furthermore not every laptop buyer wants the same things so their willingness to pay is going to be different. There are some products that sell for prices far beyond what I'd be willing to pay for them and that's ok. The fact that we might pay different prices for the same thing is ok in general because odds are the product is worth different amounts to the two of us. Every time you go into a store and decide to buy or not buy something, you are conducting a negotiation. If too few people are purchasing something at a given price, the price will eventually be lowered. This is how markets work. Sellers adjust prices to match buyer's willingness to pay but the only way to get that information is to offer a price and see if the buyer is interested.

    The biggest flaw in your logic however appears when you turn your logic around. If you don't pay as much as possible for your purchases aren't you "ripping off" the sellers who worked hard to provide you that product?

    but the main component that influence the market today are publicity and obfuscation of real characteristics and flaws of product not informed comparison of products, where intelligent and informed people could decide if they want more reliable, more durable or cheaper product of a certain kind and, buying it, influence the market production.

    Nonsense. There is more information available about products today then there ever has been. I'm guessing you've never tried to sell very much because marketplaces are ruthlessly efficient at adjusting prices to match buyers with sellers. Collectively people are extremely good at deciding what sort of products they want and influencing the market. Individually being informed about your purchases is YOUR responsibility. If you choose to not inform yourself, that is your fault and no one else's. I can't decide for your what you want in a product or what your are willing to pay for it. Only you can decide that.

  • Re:Not Greed .. (Score:3, Informative)

    by Anonymous Coward on Tuesday December 15, 2009 @03:48PM (#30448788)

    My experience with Chinese 18650 cells is that a lot of them are crap. The stuff made for RC cars and power tools is usually the worst. Samsung, Moli, BostonPower, Sony all make pretty good cells.

    Also you will find that many laptop packs will run the batteries in a series-parallel arrangement. The cells in parallel need to be matched as closely as possible - ideally from the same lot code. Otherwise what happens is that the weaker cell of the parallel cells will essentially control how much energy goes in during charging, so when the weak cells says "I'm done", the charging will stop leaving the stronger cell with too little charge and the whole pack dies a lot sooner than it otherwise would.

  • Re:Not Greed .. (Score:3, Informative)

    by dangitman ( 862676 ) on Wednesday December 16, 2009 @03:33AM (#30454778)

    Laptop batteries all use a standard cell which is slightly larger than AA.

    That's not true at all. Some laptop batteries use flat-packed lithium polymer cells, not cylindrical cells.

I THINK MAN INVENTED THE CAR by instinct. -- Jack Handley, The New Mexican, 1988.