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10 year lithium 9V Batteries?

Discussion in 'Pickups & Electronics [BG]' started by gimmeagig, Mar 29, 2006.

  1. I just saw at Home Depot a 9V Lithium battery for smoke detectors that is supposed to last for ten years.It looks like a regular 9V but is quite a bit lighter and costs about twice what an Alkaline battery costs.
    Would such a battery work for a bass preamp?Has anyone here tried one?How much more life would I get out of such a battery?Is there any reason not to use Lithium?
  2. scottbass

    scottbass Bass lines like a big, funky giant

    Jul 13, 2004
    Southern MN
    Batteries have two main failure modes - depletion and passivation. Depletion is when the two materials (annode and cathode) have exchanged so many ions the potential voltage between the two drops below some threshold level...maybe 8.5 volts or something like that. Passivation is when there are still plenty of ions left to exchange, but a film or skin has built up over one of the materials that prevents efficient ion exchange from happening.

    Depletion is accurately predicted by measuring the total current put out over time. The units of this measurement are amp-hours. Every battery is rated for a certain number or amp-hours. After it has put out it's allotted number of amp-hours, the materials are depleted and the voltage drops below the threshold level.

    Passivation happens to batteries that are NOT putting out bery much current over time. Either they are sitting completely idle (shelf life) or they are putting out a very small trickle of current - such as in a smoke detector. The factors for passivation are time, temperature and LOW current draw.

    As you can guess, passivation is not an issue for a battery that is putting out significant current over time. In that case, it's useful life is completely a matter of its time-to-depletion, as measured in amp-hours.

    A 10-year lithium battery is good at fighting the effects of passivation in low-current applications such as smoke detectors. It will not last anything close to 10 years if it is called upon to put out reasonable current, like if it in your active bass preamp or an effects pedal.

    The only way a 10-year lithium battery will last you significantly longer than an alkaline battery is if you don't play your bass very often. In fact, I'm pretty sure it actually has a lower amp-hour rating than an alkaline battery, so it will actually have a shorter life if you play your bass more than an hour or two per month.

    Look at the lithium battery package (or visit their web site) and see what the amp-hour rating is. Compare that to a normal alkaline battery. If it has twice the amp-hours, it is worth twice the price. Or if you hardly ever play your bass, it might last longer due to less chance of passivaiton.

    Me - I buy (alkaline) Duracells or Energizers when they're on sale and change every battery once a year.
  3. Thanks for the explanation.The Lithiums jooked kind of futuristic so i got curious.I guess I'll stick with alkalines.I do play a lot and I change mine about every 6 months,just to be on the safe side.
  4. chucko58


    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    That's funny, the lithium 9Vs I'm using will last as long as 3-4x a typical alkaline. See here. Combine that with the shelf life advantage and a higher output voltage over the life of the battery, and I'll use them in everything they'll fit.
  5. scottbass

    scottbass Bass lines like a big, funky giant

    Jul 13, 2004
    Southern MN
    Yeah - I see your lithium has 1.2 amp-hours at an average current draw of 9 mA vs a Duracell's typical 0.6 amp-hours at an average current draw of 10mA. That would be just about twice the expected lifetime before depletion for your lithium compared to an alkaline. Plus lithiums will last longer in the package due to slower passivation.

    They're a good deal unless they cost more than double.
  6. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Yep. Not for nothing do a lot of digital cameras use rechargable Li-ion batteries and get a lot of shots out of a single charge - where using the strongest Everreadies or Duracells would only get a fraction of the shots before needing to be deep-sixed.
  7. JansenW


    Nov 14, 2005
    Cambridge, MA
    Here's a web page about a rechargable 9v Lithium Polymer battery:


    Comparing costs:

    Top 9v alkaline (540 mAh capacity): $2 each
    10 Year Lithium (1200 mAh capacity): $5.00 ($=2.5 alkaline batteries)
    Rechargeable (100's of times) NiMh (250 mAh capacity): $12 + $20 (charger) = $32 ($=16 alkaline batteries)
    Rechargeable (100's of times) Lithium Polymer (400 mAh capacity): $15 + $35 (charger) = $50 ($=25 akaline batteries)

    I wonder how these would compare in actual usage.
  8. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Well, in a digital camera it doesn't take long to find out that over-the-counter NiMh AA are many many times cheaper than Alkalines. And you don't end up running out of power so danged fast.

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