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Rechargeable Batteries - Yes or No? 896

Posted by Cliff
from the they-keep-going-and-going-and-going dept.
TheFifthElephant asks: "I currently use quite a few devices that require various size batteries and I feel horrible just tossing them when they die. I saw a recharger at a retail store today and was thinking to myself how much waste it would reduce by using rechargeable ones. Which units have you used happily and/or which units have you heard of/read about satisfying someone else? Are the more expensive units better? What chemical rechargeable batteries last the longest/recharge the most?"
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Rechargeable Batteries - Yes or No?

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  • by Gherald (682277) on Tuesday July 29, 2003 @05:46PM (#6564581) Journal
    Use Potatoe/Lemon batteries!
    • by NETHED (258016) * on Tuesday July 29, 2003 @05:50PM (#6564638) Homepage
      Everyone, DAN QUAYLE is a slashdot reader!!
    • by Hogwash McFly (678207) on Tuesday July 29, 2003 @05:58PM (#6564780)
      You say Tomayto, I say Tomahto, you say Potatoe, we spell it correctly... ;)
    • by Anonymous Coward on Tuesday July 29, 2003 @06:13PM (#6564963)
      I don't see why people worry about batteries.

      Hell, if you want to reduce your impact on the environment, try a few other sacrifices:

      1) Adopt instead of breed.
      You might as well adopt one if you plan on having kids (at least as ONE of them). If you don't feel adoption is your civic duty, they'll just accumulate and become a local nuisance. Then you'll need to pool your money with local businessmen, and hire off-duty cops to "clean up" the problem.

      2) "Disposable diapers"
      Need I say more?

      3) Of course... don't expect a woman to give up this convenience while you parade around in a HumVee and a mow your lawn with a 20hp rider tractor. Otherwise you're forcing the burden on someone else.

      4) Actually, you need a "push mower" like the old days. Save money and slim that fat ass of yours.

      5) Lawn?? Plant a fucking tree you egotistical prick. You can still plant grass that's not harmful to the environment... it's called NATIVE grass. You'll not find it at the nearest local golf course...

      6) Trees mean you don't need to water your lawn.

      7) Or CHEM-LAWN(tm)
      Actually, if you're stupid enough to lay toxic chemicals on your lawn, you have penis-size issues.

      8) Don't listen to me... you'll end up spending more money on viagra...

      Moderators: If the above ON TOPIC SARCASM offends your sensibilities, go ahead and mark me as Flamebait or Offtopic. The meta moderators will get you...

      I know some of you will agree though :-)

      • by Anonymous Coward
        2) "Disposable diapers"
        Need I say more?

        Yes you do. What is a bigger problem for the millions of people living in LosAngeles: Disposable diapers or the lack of drinking water due to a million cotton diapers a week needing washing?
        • by stekman (575167) <stekman@sedata. o r g> on Wednesday July 30, 2003 @08:33AM (#6569626) Homepage
          The amount of water used in the process of makeing diapers exceeds the amout of water when you wash diapers (if you fill the machine up). The a weight of garbage from one average kid using diapers is 1000kg. The energy from transporting the garbage, makeing the diapers and transporting the diapers to the shop exeeds the energy to clean the diapers by serveral times. An average kid uses 5000diapers. That is about $1500. A set of cloth diapers costs about $35. We have used cloth diapers for both our girls. It was really good and as they feel that they are wet when they pee, they stopped using diapers a lot sooner then the other kids at kindergarden.
      • by slyxter (609602) on Tuesday July 29, 2003 @07:53PM (#6565952) Homepage
        I like how you feel the need to threats at random moderators that are completely anonymous to you 3 lines after you mention others having issues with their penis size.
      • by matt-fu (96262) on Tuesday July 29, 2003 @09:07PM (#6566558)
        I know you're being sarcastic but..

        4) Actually, you need a "push mower" like the old days. Save money and slim that fat ass of yours.

        Actually, I have a "push mower" (it's called a reel mower [cleanairgardening.com]) like the old days. It's actually lighter to push around than a regular gas mower since there's no engine, with the added benefit of getting to experience the "fresh cut grass smell" the entire time rather than only after you're finished. The only downside is that you can't let your lawn get out of control. You have to keep up with it because the mower won't cut grass that's longer than four inches or so.

  • by Soothh (473349) on Tuesday July 29, 2003 @05:47PM (#6564583)
    I use monster brand and it does me well, I hear there are better though. Monster costs quite a bit thought but so far works great for me, and seems to recharge pretty fast

    • EZONE! (Score:5, Informative)

      by g00bd0g (255836) on Tuesday July 29, 2003 @09:21PM (#6566663) Homepage
      More than you ever wanted to know about battery tech. Keep an eye on the emerging Lithium Polymer batteries @ roughly 3X the current NiCd and NiMh power/weight and power/size batteries. I use them in my micro R/C helicopter instead of the oringal NiMh and get 3X the run (was 5 now 15 minutes) with less than 1/2 the original battery weight (1.75oz vs 3.75oz). These are gonna be cost effective in the next 10 years or so, making a 100 mile range EV very easy and cheap. This is what they are using in the current solar racers. Environmentally friendly as well! Oh the original question? 2000mah NiMh all the way.
    • by ball-lightning (594495) <spi131313@yahoo.com> on Tuesday July 29, 2003 @10:00PM (#6566908)
      Why is this modded funny? There really is [crutchfield.com] a monster brand of battery.
  • NiMH (Score:4, Interesting)

    by sterno (16320) on Tuesday July 29, 2003 @05:47PM (#6564586) Homepage
    I use NiMH batteries for my wireless mouse, and my camera. Got a simple charger over at radioshack, and it works quite well. The batteries provide equivalent if not better power than alkalines and though they cost more up front, are definitely cheaper in the long run.
    • Re:NiMH (Score:5, Informative)

      by Anonymous Coward on Tuesday July 29, 2003 @05:50PM (#6564646)
      NiMH batteries are great but they have the downside of losing charge very quickly "on the shelf" so you can't keep a bunch of charged MiMH batteries ready to use.
      • Re:NiMH (Score:5, Funny)

        by poot_rootbeer (188613) on Tuesday July 29, 2003 @06:29PM (#6565157)
        NiMH batteries are great but they have the downside of losing charge very quickly "on the shelf" so you can't keep a bunch of charged MiMH batteries ready to use.

        Is that the "Secret of NiMH"?

      • by Ruie (30480) on Tuesday July 29, 2003 @06:47PM (#6565336) Homepage
        Radio shack has a nice page about different batteries [radioshack.com].
      • Re:NiMH (Score:5, Insightful)

        by shellbeach (610559) on Tuesday July 29, 2003 @07:50PM (#6565916)
        NiMH batteries are great but they have the downside of losing charge very quickly "on the shelf" so you can't keep a bunch of charged MiMH batteries ready to use.

        This is not the case in my experience. I have used 650mAh AAA NiMH batteries with my Palm IIIx for about three years now. I have two sets of batteries (so one can recharge while still using the old set) and when travelling for long periods of time (several months) I've just charged both sets and used the second set a month later. There was a small loss of charge, but it wasn't a big deal.

        Sure, you can't charge the things up and leave them for half a year. But when are you ever going to need to do that? In the very worst case scenario, you could always pack a travel charger - they're small and light.

        I don't think I could begin to count the money I've saved by not having to change two sets of Alkaline AAAs each month (well, actually I could - it's several hundred dollars as opposed to an initial outlay of $40 for the batteries and the charger). And the capacity of NiMH batteries keeps getting better - you can now get 650mAh AAAs and 1850mAh AAs just about everywhere, which is a huge improvement on rechargables five or ten years ago

    • Re:NiMH (Score:3, Informative)

      by edgarde (22267)
      For consumer batteries in conventional form factors (AA, AAA, C, D & whatever a 9-volt is called), you basicly have Nickel-Metal Hydride (NiMH), and Nickel-Cadmium (NiCd). Neither last as long as disposables, but NiMH last substantially longer, and are more environmentally friendly (i.e. they don't contain lead or mercury). Downside: NiMH costs more.

      RadioShack [radioshack.com] sells both kinds.

      Lithium ion batteries ... uhm, exist but I know nothing about them. They have advantages over NiMH but don't come in the comm

      • Re:NiMH (Score:4, Funny)

        by dnoyeb (547705) on Tuesday July 29, 2003 @06:17PM (#6565020) Homepage Journal
        I use NiCd and NiMH. The NiCd are old ones that are still good and I wont toss em till they die.

        My son has lots of electronic toys, I fill all with rechargables. I put rechargables in anything that gets frequent use, and use standards in things that dont.

        frequent use:
        kids toys
        pager
        remote controls
        vibrator
        Rotating Tie-rack
        non-frequent use:
        smoke detector
        battery-backups
        Flashlight

        You find Li batteries in equipment that tends to be charged daily. From the daily charge I highly suspect they don't hold charge too well, but they probably have high life cycles. Probably why they don't go in pagers and other stuff that does not have a built in charger.

        Cordless telephones
        cellular telephones
        Cameras
        computers
        PDAs
      • Re:NiMH (Score:3, Informative)

        by KiahZero (610862)
        Don't buy from RadioShack, buy from GreenBatteries [greenbatteries.com]. I've shopped with them before, and gotten great deals... haven't seen $2.75 each for NiMH AAs in 12 packs at WalMart. Unfortunately, they don't seem to have the common form factor Li-Ion batteries either, but I've been sastisfied with the NiMH so far.
    • Re:NiMH (Score:5, Informative)

      by lars_stefan_axelsson (236283) on Tuesday July 29, 2003 @06:10PM (#6564922) Homepage
      I use NiMH batteries for my wireless mouse, and my camera. Got a simple charger over at radioshack, and it works quite well.

      About chargers, understand that there are two types out there; timer controlled and -deltaV controled.

      You want the -deltaV controlled, which monitor the voltage on the battery to sense when they're fully charged. The timer controlled chargers, will overcharge the battery, and nothing kills batteries like overcharging.

      Now it turns out that for low amp applications, even a simple charger will get enough performance out of the batteries, but for more serious applications such as digital camera, a real charger could tripple the number of cycles you'll get out of the batteries.

      Also, watch out for 'micro processor controlled.' While all -deltaV chargers will have that on them somewhere, it may also mean timer controlled (as in there's a micro processor keeping time somewhere).

      There was a good test this spring in the Swedish equivalent of Consumer report, but unfortunately it's in Swedish (and you have to be a subscriber). The noteworthy point was that not all -deltaV chargers are created equal, one undercharged, so you may want to check around. Expect to pay serious money for a serious charger. The good ones in the test were $100-$200 in Sweden, you'd pay perhaps 50%-75% of that in the US (I don't really know the battery charger market).

      P.S. Use NiMH. Better for you, and no memoy effect. With a -deltaV charger you can easily top them up if you've had them on the shelf for a while (they'll lose their charge in a couple of months when stored).

  • Nickel Metal Hyride (Score:5, Informative)

    by Alan Cox (27532) on Tuesday July 29, 2003 @05:47PM (#6564588) Homepage
    I'm using NMH batteries for just about everything battery powered in the house nowdays. NiCad's dont last as long and are very bad for the environment. The batteries I have claim to be good for several hundred cycles, which at the current rate is going to be about 30 years ;)
    • by kzinti (9651) on Tuesday July 29, 2003 @06:04PM (#6564857) Homepage Journal
      I'm using NMH batteries for just about everything battery powered in the house nowdays. NiCad's dont last as long and are very bad for the environment.

      Agreed.

      According to a very long article/discussion I read somewhere (sorry, can't remember the URL), NiCd batteries are easily damaged by overcharging, which tends to reduce their capacity over the life of the battery - and there is no so-called "memory effect".

      I use NiMH batteries in my digital cameras and love them. I have a set of 1450 and 1600 mah AA's; 1600 was the best capacity available when I bought them, but today you can find 1800 and 2000 mah capacities.

      One problem with NiMH cells is that they don't hold a charge very well on the shelf - in other words, if you charge up a set, set them aside, then pick them up weeks or months later, you're likely to find that they've lost much of their charge (can't recall how fast that "shelf-drain" occurs). So I keep one set in the camera and one set in the charger. I've had both sets of batteries about 3 years and charged them hundreds of cycles, and I think I've noticed a bit of a decrease in effective capacity over that time, but not very much. NiCd cells would have died an aggravating death by now.

      The lithium-ion batteries in my iPod and Dell laptop seem to have both good capacity and shelf life, but the laptop batteries died after a couple of years and I had to replace them... VERY expensive. I hope the iPod battery fares better.
      • by afidel (530433) on Wednesday July 30, 2003 @01:36AM (#6568169)
        The iPod uses a lithium polymer gel pack, despite what people claim it can eventually degrade enough that it exhibits similar symptoms to memory (I think this is mostly due to exposure to excessive heat). There is a company that sells a replacement for the battery in the series 1 and 2 iPod's that are actually higher mAh rated then the Apple origionals.
    • by JoeCommodore (567479) <larry@portcommodore.com> on Tuesday July 29, 2003 @06:08PM (#6564903) Homepage
      I use NIMH in my digital Camera (an older Olympus D-460) and they are great. I keep two sets in my camera bag, the NIMH and a standard high-quality alkaline set, Normally I use the NIMHs till they are low (which can be several days of moderate camera usage) and then swap in the standard batteries and continue till I can get the NIMHs recharged. Recharging takes a few hours but once charged they are ready for hours more work. With this the 'normal' batteries last for a few months of occasional use.

      If you are using them on something you depend on (camera, camcorder, etc.) It would be prudent to have a set of high-quality standard cells for backup like I do.

      NICADs historically develop a memory problem and may not hold much of a charge later on (not that they hold much in the first place from my experience). NICAD technology may be different now, so choose your rechargable batteries sensibly.
      • by kzinti (9651) on Tuesday July 29, 2003 @06:34PM (#6565195) Homepage Journal
        There is no such thing as a NiCd memory effect [repairfaq.org].
        • by evilpenguin (18720) on Tuesday July 29, 2003 @06:40PM (#6565246)
          The memory effect is a myth (as your link indicates). I have talked to several chemists and electrical engineer involved in battery design and manufacture and not a single one I've talked to thinks there's anything to it.

          The advice you are given by people who claim the "memory effect" exists is to periodically run your batteries flat. I am told by these chemists and engineers that the more often you "deep cycle" your rechargable batteries (of any type, lead-acid, Ni-Cd, NiMH, Li-ion, whatever), the shorter the total AH life of the battery, guaranteed.

          Put those puppies on the charger as often as convenient, and NEVER run them out flat if you can avoid it.
    • by gotr00t (563828) on Tuesday July 29, 2003 @06:11PM (#6564950) Journal
      Remember that Rayovac sells rechargable akaline batteries as well, and like Ni-MH, are not AS bad for the environment as Ni-CAD.

      Moreover, they do have a distinct advantage: they're cheap and of high capacity, though not good for many recharge cycles. While a pair of Ni-MHs cost about $8, a pack of 4 rechargable akalines costs about the same price. Like regular akaline batteries, they have pretty high capacity (about 2200(I think) mAh for a AA, compared with the low 1000's range for most Ni-MHs), and actually come charged, with a long shelf life without discharging itself.

      I use these batteries for most of the things that don't work with Ni-MH (graphing calculator, small electronic devices), as these have the usual 1.5 volt, instead of the 1.2 volt on most rechargables. Their downside is the fact that they can only be charged 10-20 times before they leak (the package said 40).

      • by caouchouc (652238) on Tuesday July 29, 2003 @06:21PM (#6565064)
        about 2200(I think) mAh for a AA, compared with the low 1000's range for most Ni-MHs

        I've got a bunch of 2100 mAh NiMH AA's, so they're catching up. :)
        They do have the distinct disadvantage of discharging themselves, but it's not a problem at all when you use them as much as I do. They're also good for a lot more recharge cycles than alkaline.
      • I was just going to mention these.

        Their characteristics are very different from other types of rechargeables. Alkalines have no memory effect -- in fact, they like being recharged from part-full, and last much longer this way than if fully discharged.

        So whether they're suitable depends very much on how you use them. I use them in my handheld computer; I set the battery monitor to remind me when they get below about half-way. This works really well; it means that I get plenty of warning to change them,

    • by WTFmonkey (652603) on Tuesday July 29, 2003 @06:18PM (#6565030)
      They can't be that bad for the environment, I mean those little Cadmium Cream Eggs are SO GOOD around Easter-time.
  • Batteries (Score:5, Informative)

    by theedge318 (622114) on Tuesday July 29, 2003 @05:48PM (#6564599)
    I have an old olympus camera that came with Ni-MH AA batteries and a battery charger ... it has lasted me near 4 years.

    Those batteries keep their energy for 3 months at a time easily, when I am not on vacations or otherwise using the camera.
  • by Directrix1 (157787) on Tuesday July 29, 2003 @05:48PM (#6564607)
    I find the batteries that hold the greatest charge the longest are the magnetically levitated in a vacuum flywheel electric motor.
  • by douglips (513461) on Tuesday July 29, 2003 @05:48PM (#6564611) Homepage Journal
    These batteries kick serious booty. In my digital camera, a single charge outlasts even the best disposable batteries by a factor of 2 or 3. In about a year I've already saved more in disposable battery cost than I spent on the charger and cells.

    Definitely worth the investment. I have Panasonic brand, but only because that's what they had at Costco. I doubt that there is a big difference between brands of similarly-rated cells.
    • look for the rating. (Score:3, Informative)

      by twitter (104583)
      Compare prices by the rating. If the rating in milli-Amp-hours (mAh) is not on the battery or packaging, you don't want it. If you know your device's current draw, you can make a reasonable guese at how long your batteries will last. Conversly, you can get your device's average current draw from how long your batteries last. Wal Mart has reasonbly priced high capacity NMH. Between that and a fancy Radio Shack charger, I have few battery problems.

  • Don't sweat it (Score:4, Insightful)

    by skryche (26871) on Tuesday July 29, 2003 @05:48PM (#6564615) Homepage
    Batteries are tiny tiny compared to what gets thrown out. (Like CDs: yeah, the world landfills are filling up because of AOL.) And they stopped putting mercury in 'em so they aren't even that bad for the environment.

    You want to make a difference? Drive an efficient car (if you must drive one at all) and recycle what you can.

  • Ray O Vac (Score:5, Informative)

    by buckeyeguy (525140) on Tuesday July 29, 2003 @05:49PM (#6564616) Homepage Journal
    Have had good results with 1800mAh NiMH RayOVac AA-size batteries in cameras with flash. Havne't used them for much else yet. Had less satisfactory results from Radio Shack-brand NiMH ones. YMWV.
  • by Anonymous Coward on Tuesday July 29, 2003 @05:49PM (#6564620)
    "Which units have you used happily and/or which units have you heard of/read about satisfying someone else?"

    My wife has this vibrating thing, something Rabbit, she's always saying it satisfies her...
  • lower impedance (Score:3, Interesting)

    by Alain Williams (2972) <addw@phcomp.co.uk> on Tuesday July 29, 2003 @05:49PM (#6564633) Homepage
    Although rechargables seem to have a slighly lower nominal voltage than the equivalent disposable, I am told that they have a lower impedance (resistance). The result is supposed to be a risk to some equipement. This is why some things have the label ''do not use rechargable batteries''.

    However, I have always ignored the above and never had any kit die as a result of using rechargables.
    • Re:lower impedance (Score:3, Informative)

      by alienw (585907)
      The lower impedance cannot possibly cause a risk to equipment unless said equipment is extremely badly designed. The reason for the labels is usually the lower voltage. Sometimes, the equipment will shut down long before the battery is exhausted, simply due to the lower voltage.
  • All kinds. (Score:4, Informative)

    by RatBastard (949) on Tuesday July 29, 2003 @05:49PM (#6564635) Homepage
    I've used all kinds of rechargables, from cheap Radio Shacks and Mallorys, to expensive Sony units. They are all pretty cose to the same, save for newer lithium-ion batteries.

    I keep enough batteries in the chargers to replace the batteries in every device at the same time. And it does save an amazing amount of money in the long run. Most of my rechargables last for five to seven years before they stop being able to hold a charge.

    The only batteries I have not replaced with rechargables is AAA-size. At that size the rechargables don't hold enough charge to be worth it.
    • Re:All kinds. (Score:3, Informative)

      by Elvisisdead (450946)
      I've used AAA in everything from my infra-red keyboard to the ultra-mini MagLite. From my experience, the NiMH ones I have (Radio Shack) last about as long as alkaline.
  • Recycle (Score:5, Informative)

    by marshac (580242) on Tuesday July 29, 2003 @05:50PM (#6564652) Homepage
    You know, you can recycle your dead batteries, right? When I worked at Radio Shack a long time ago, we took in dead batteries and sent them off to be recycled. I'm not sure if this was just my store, or a company wide thing, but there are free recycling services out there.... so don't throw them away!
  • iGo Juice (Score:4, Informative)

    by BWJones (18351) on Tuesday July 29, 2003 @05:51PM (#6564669) Homepage Journal
    I have been using the iGo Juice [ententeweb.com] to power my Powerbook and peripherals and find it to be quite the appealing solution including charging handhelds and cell phones when I travel. The iPod gets charged through the Firewire port (awesome idea), so other than that, I'm set. All of these devices appear to use Lithium Ion batteries and have decent performance, (especially the Powerbooks).

  • by warpSpeed (67927) <slashdot@fredcom.com> on Tuesday July 29, 2003 @05:52PM (#6564679) Homepage Journal
    Rechargeable Batteries - Yes or No?

    [ ] CowboyNeil charges my battery

  • Walmart anyone? (Score:4, Informative)

    by RealBeanDip (26604) on Tuesday July 29, 2003 @05:53PM (#6564695)
    For AA batteries, go to Walmart and pick up the NiMH rechargables at 1800mAh and a charger. I think you can get a combo pack (4 batts and charger) for something like $12, which is a heckuva a good deal. These batteries last and last and last.

    The 1800mAh batteries are an absolute requirement for digital cameras. Using standard alkalines, I would get just over 30 digital pics in my Toshiba camera. Using 4 1800 NiMH, I get about 200 before needing a charge.

    I also use them in my FRS radios and GPS, and they last forever.

    I've also used various brands of NiMH's besides the Walmart specials and haven't seen much difference in quality.
  • In a word: yes (Score:3, Informative)

    by jandrese (485) * <kensama@vt.edu> on Tuesday July 29, 2003 @05:53PM (#6564708) Homepage Journal
    I picked up some NiMH (Rayovac's in case you care) batteries a couple of years ago and I've never gone back. I use them in my digital camera (where I get about 300 full res (1760x1168) pictures out of the 4AAs. I use them in my Palm VIIx (a battery hog in the best of days) where they easily last as long as the Alkalines (there's even a feature in PalmOS to switch the battery meter over to NiMH). Even when you consider the inital cost ($12 for 4 AAs), they quickly pay for themselves (I've taken ~3000 pictures on the 8 AAs I bought for the camera and recharged the palm batteries more times than I can count) with only half a dozen recharges.

    One thing to be careful of is that the batteries do lose a bit of life over time, although my original sets seem to be holding up quite well. Also, rechargeable in general seem to leak charge faster than Alkalines, so they're not really a wonderful idea for long life low draw devices like remote controls.

    Don't bother with NiCad. They have sucked from Day 1. I've never tried the rechargeable Alkalines. When you buy a charger, make sure you get one that supports NiMH, not all of them do.
  • Environment (Score:3, Informative)

    by spoonist (32012) on Tuesday July 29, 2003 @05:54PM (#6564716) Journal

    Please do not just throw away dead batteries. Please recycle them [rbrc.org].

    I use tons of NiMH batteries in my various gadgets.

    The prices aren't the best, but REI [rei.com] has all you probably need right here [rei.com].

    Battery Barn [batterybarn.com] has some good prices.

  • by swb (14022) on Tuesday July 29, 2003 @05:56PM (#6564734)
    NiMH rechargables. You should have no problem finding 1800mAh AA cells, and these hold up quite well to frequent charge/discharge cycles. I've been using them for about 4 years and they can take quite a pounding.

    What's even better is that a lot of cordless stuff with NiCads can be converted to NiMH by making your own battery packs. Internally many of the packs are just a few AA cells soldered together.

    If you do this, look for places that sell flat-top and soldertab batteries. Some of the cartridge-type battery packs won't fit the normal button-top batteries, and soldering can be hard on the cells if you try to solder directly to the cell itself.

    I did this with my Uniden 900 Mhz DSS phone. Before it would go ~90 minutes on a fresh (new and fully charged) NiCad pack. Now I can get over 2 hours of talk time, leave the phone out of the charger over night, and still have it be perfectly usable the next day.

    I was concerned about the charging system, but not any more. A friend has done this for a long time (NiCad->NiMH conversions) and hasn't had any problems, and neither have I.
    • That's great, but never ever consider doing this with lithium-ion cells. Their recharge cycle must be precisely controlled, or they turn into pretty decent torches. Lithium-ion devices are heavily tested and regulated.

      NiMH cells are great, they always last me around 3x longer than the best alkalines I can buy. So if I charged them once, used them, and threw them away, I'd be breaking even. Every additional charge is just icing on the cake.
  • by rigmort (584960) * on Tuesday July 29, 2003 @05:56PM (#6564740)
    "...which units have you heard of/read about satisfying someone else?"

    My wife seems to be "satisfied" by energizers while I'm away...

  • by egg troll (515396) on Tuesday July 29, 2003 @05:58PM (#6564776) Homepage Journal
    Imaging-resource.com did a great review [imaging-resource.com] of a ton of rechargeable batteries. The electronics geek in you will enjoy his breakdown of how he conducted the tests.
  • Battery FAQ (Score:5, Informative)

    by meehawl (73285) <meehawl.spam@NoSpAM.gmail.com> on Tuesday July 29, 2003 @05:59PM (#6564795) Homepage Journal
    This is a very comprehensive Battery Guide [buchmann.ca]. [buchmann.ca]
    The mention of NiMH on a battery pack does not automatically guarantee high energy density. A prismatic NiMH battery for a mobile phone, for example, is made for slim geometry and may only have an energy density of 60Wh/kg. The cycle count for this battery would be limited to around 300. In comparison, a cylindrical NiMH offers energy densities of 80Wh/kg and higher. Still, the cycle count of this battery will be moderate to low. High durability NiMH batteries, which are intended for industrial use and the electric vehicle enduring 1000 discharges to 80 percent depth-of discharge, are packaged in large cylindrical cells. The energy density on these cells is a modest 70Wh/kg.
  • A few tips (Score:5, Informative)

    by PurpleFloyd (149812) <zeno20@attbPASCALi.com minus language> on Tuesday July 29, 2003 @06:02PM (#6564821) Homepage
    I've used rechargables for quite some time now, and they do seem worth the extra cost. A few things I've learned:
    • Buy a good charger. Cheap ones can fry batteries, take longer to charge, and can go up in smoke easily. Also, make sure it can charge NiMH batteries as well as NiCDs; if you have high-drain devices like digital cameras, then you want NiMHs, and probably don't want to pay for a new charger for 'em. Expect to pay $30-$50 USD for a decent one.
    • When you buy batteries, look at the milliamp-hour rating. That's the capacity they can hold: for example, an 1800 mAh AA could supply (theoretically) 1 mA for 1800 hours, 1800 mA for one hour, or anything in between. While mAh ratings do tend to be stretched a bit (the tests are performed under the most favorable circumstances possible), it's the best guide you can get to how long the battery will last in the device you plan to use.
    • Don't buy more battery than you need. Your TV remote probably doesn't need expensive 2200 mAh NiMHs, so put in cheaper 800 mAh NiCDs.
    • You'll be better off buying online than anywhere else. I've had good luck from several companies, but note that the "Energizer" branded batteries are relabeled and marked-up generics; you can get better batteries, cheaper if you go with other companies.
    • Get extra batteries. You should have a few sitting around for when something important goes dead; don't just buy what all your devices need. Get a few extra of each type you use, or just keep alkalines around to use while recharging.
    • Don't be too hard on your batteries. Many good chargers have a "fast" and a "trickle" setting; don't use the "fast" setting unless you absolutely can't wait overnight. Fast charges are hard on batteries; once or twice won't hurt much, but repeated fast charges can cause a significant drop in total battery life.
    • Finally, if you have some high-drain devices and want to get more battery life, try hacking something onto the AC adaptor. A good guide to doing this with your digital camera is here [dansdata.com]; the principles are pretty much the same for anything else that has an AC adaptor socket.
    Good luck!
  • Battery Tests (Score:4, Informative)

    by Daikiki (227620) * <daikiki AT wanadoo DOT nl> on Tuesday July 29, 2003 @06:04PM (#6564860) Homepage Journal
    NiMH batteries last a factor 2-3 longer than NiCd batteries, are less environmentally unfriendly, and lack the memory effect that made people hate rechargeable batteries in the first place. What this means is that a fully charged MiMH battery will last as long, if not longer, than a regular alkaline battery in the same application. Capacity of batteries is rated in milliamp hours. A penlight rated at 2000 mAh will, in theory, provide 2 amps of power for an hour. It goes without saying that bigger is better.

    This guy [imaging-resource.com] has tested several dozen different types of NiMH penlights for use in digital cameras. Although there are many other uses for the things, this seems to be one of the more common and at least vaguely representative of what to expect.

    When choosing a charger, make sure it supports, and is set to charge NiMH batteries. Running a NiCd cycle on them will yield unsatisfactory results. There are fast chargers available that will charge your batteries in as little as an hour and it's commonly accepted that these don't harm the batteries much.
  • by NetMasta10bt (468001) on Tuesday July 29, 2003 @06:07PM (#6564899)
    I too use NiMH batteries, and I highly recommend them. But when I first started using them I skimped on a cheap 'dumb' charger which can overcharge/overheat batteries and it takes 8 hours for a charge.

    I recommend a smart charger like the Maha C204F from Thomas Distributing [thomas-distributing.com]. They have all sorts of batteries at great prices (not affiliated just a happy customer).

    This charger also has a conditioner feature that will help bring those older batteries back to life (the ones that you were using the dumb charger on before!).

    Batteries that I've charged with this charger last 3x as long in high drain applications like in my GPS unit.

    • I've had the same charger for about two years, the thing is great. Plus the optional car charger cord makes this even better (although I had to run a constantly hot fused feed to my cigarette lighter).

      One thing about NiMH, they need to go through about 3 dicharge/charge cycles before they come up to full capacity.

      The place where I bought mine says to keep your batteries in a sealed bag in the freezer [greenbatteries.com] when not in use, they self-discharge about 40% in about 30 days [greenbatteries.com] at room temperature.
  • by linuxwrangler (582055) on Tuesday July 29, 2003 @06:15PM (#6564990)
    NiCd and NiMH have somewhat lower voltage (~1.2v) than alkaline (~1.5v) but they also have a far lower internal resistance so if you short a NiCd/NiMH you can get far more current than if you short an alkaline.

    NiMH also self-discharge quite rapidly - several percent/day. In some apps the self-discharge drains the battery faster than the device does. This also makes them lousy for emergency uses unless they are always on charge.

    The upshot of this is that if you have a very low draw app like noise-cancelling headphones or a radio-only walkthing then you may want to stick with alkaline as they last weeks to months anyway and the loss of 0.6v (for 2 cells) may cause problems.

    You may also want to stick with alkaline for certain very high-draw apps. Some halogen high-intensity flashlight bulbs specifically recommend against using rechargables. They are designed for use with alkaline and without the limiting factor of the internal resistance of the alkaline battery the bulb will pull too much current and burn out quickly.

    On the other hand moderately high draw things like digital cameras are perfect for NiMH. The high draw depletes the alkaline to a point that it can't supply enough current in short order - a couple dozen pictures in my camera. NiMH will power it for a couple hundred. Unless your use level borders on "never", rechargables are the way to go for cameras, flash units, handi-talkies and similar devices.

    Beware of chargers that recharge pairs of batteries, however. I recently had some old NiMH batteries that I thought were dead (~12 pix per charge). I had been using the Kodak charger that I got with my camera - it charges cells in pairs. Unfortunately if cells are out of balance it doesn't work well.

    I bought a PowerX charger and after a couple charge cycles the batteries were working great again - and they are almost 5 years old.

    The PowerX has gotten favorable reviews from ham operators and camera buffs. It has two charge cycles so if you don't need a charge RightNow! you can switch to a slower setting to prolong the life of your battery. Also, each battery is on an independent channel so each battery gets an appropriate charge and you won't be driven crazy when you have an oh-so-common 3 battery device. After charging it switches to a trickle mode to keep the battery topped-off. I've only had mine for a couple of weeks but so far it beats the heck out of my old chargers. Comes with a car cable, too.
  • From 650ma for the original shitty nicads to something like 1850ma for the latest generation of Nickle-metal-hydride.

    The 1850ma batteries last long on a charge than the best alkaline batteries do new, and you can recharge them a thousand times or so, with no memory effect. The original 1650ma batteries I got with my Fuji camera still gave a full charge two years later when the camera was stolen.

    I never buy disposable AAs for anything anymore, instead I have a bunch of AA NmH.
  • by TFloore (27278) on Tuesday July 29, 2003 @06:24PM (#6565092)
    Rechargable batteries are wonderful things. Like a lot of other /. readers, I have a pocketful of AA NiMH batteries. There are some things you should be aware of with rechargables before you jump into them, though.

    (Mostly AA specific)

    First, make sure your battery-powered device is rated to handle rechargable batteries. Alkaline AA batteries are nominally 1.5volts. "Fresh" batteries will probably test to 1.56volts in a digital multimeter. NiMH AA batteries are nominally 1.2volts, and will usually test as 1.26volts freshly-charged. If your device has a voltage meter (if it shows "battery power remaining" it does) then you need to be sure it can handle running with the different voltage. My old family-band radios (some motorola model, don't remember which) were made assuming alkalines at 1.5volts, and gave noticably less powered-on time with NiMH batteries than with Alkalines. The batteries still had juice in them, but were putting out a slightly lower voltage than the radio wanted, and the radio turned itself off.

    Second, all rechargable batteries (except possibly lead-acid/gel-cells) have a normal charge cycle rating. This means, effectively, that they can be recahrged that many times, and then they stop holding a charge, the chemistry inside breaks down after that many charge cycles. By chemistry:
    NiCad = 500 charge cycles.
    NiMH = 400 charge cycles
    Lithium Ion = 350 charge cycles

    After you recharge them that many times, expect them to become noticably less useful. This is part of why laptop batteries are only warranted for a year, incidentally... 350 charge cycles, 350 days of charge/discharge (about a year), and you have a battery that doesn't last nearly as long as when it was new. This is also why people that buy laptops like intelligent chargers, and don't recharge immediately upon reconnecting to a wall regardless of charge remaining. Recharge based on charge % remaining, and the battery lasts a lot longer, so wait until the battery gets below, say, 85% charge, and it will last 2-4 years instead of one. Intelligent chargers in laptops will check the charge remaining automatically, and only charge when it drops below a given threshold.

    Third, you have different self-discharge rates with different batteries, aka, the shelf life. Alkalines are really good here, they have a quite long shelf life, usually measured in years.
    NiCads are less good than alkalines, and especially with the multi-cell NiCad packs where you are concerned with polarity reversal, you want to recharge your NiCads every few months, to keep the charge level above a certain minimum where one cell in a pack might get too low, reverse polarity, and basically kill your multi-cell battery pack.
    NiMH batteries self-discharge at about 1-2% per day. Yes, a "freshly-charged" battery that is left on a shelf for a month will be down by 25-50% charge. This is environment dependent, of course, varying with temp and humidity mostly.
    Lithium Ion batteries have about the best shelf-life of rechargables, about the same as NiCads, really. Still nowhere near alkalines, though. (Again, leave your laptop sitting on a shelf for 3 months, you'll probably have a dead battery. Be aware, and plan accordingly.)

    With all this said, I still love rechargable batteries, and use them whereever they fit the device specs.

    Oh, and fair warning, if you travel outside the US. Most of the cheap NiMH chargers you see in Walmart and everywhere else are US voltage only, they work with 110V 60Hz AC ONLY. If you are travelling anywhere outside the US and Canada, get an international charger, that can handle 50/60Hz and 110/120/220V. You'll be much happier, and not unpleasantly surprised when your charger gets very very warm and then suddenly stops charging. Bear in mind that the carribbean, while very near the US and supposedly US power specs, has crappy power regulation on wall plugs, and you'll want an international charger there too. Just another thing to be careful of.
  • NiMH batteries (Score:5, Informative)

    by pbegley (84849) on Tuesday July 29, 2003 @06:27PM (#6565136) Homepage
    I replaced over 100 batteries used in our household (three daughters, geek father) with NiMH. No problems at all. I get the next to highest mAh rated batteries from Thomas Distributing (just a happy customer) and I use an Altek 5798 charger. The tri-state LED's give a good status on when its done charging.

    I had a few go bad over the past few years, but I know several sets have had hundreds of charges.

    The last AA set I got were 2000 mAh and they are great in my Fuji digicam.

    www.thomasdistributing.com - don't let the 'web designer on acid' interface bother you, they have always had the best price and reasonable delivery. I even like the 'free gifts' (synth chamois car cloth, plastic battery holders).

    Hope this helps!
  • Energizer (Score:3, Informative)

    by _iris (92554) on Tuesday July 29, 2003 @06:44PM (#6565303) Homepage
    I've had a wonderful experience with the Energizer Rechargables [energizer.com], using the wall charger by the same name. I was given the charger and a set of batteries. I'm still on the same set of batteries (which I mostly use for my Olympus D-390 digital camera). I've recharged them about 8 times and they haven't lost any lifespan between charges (my old Rayovac Renewable system suffered from this).
  • by frovingslosh (582462) on Tuesday July 29, 2003 @06:54PM (#6565404)
    First of all, use NiMH batterise, avoid NiCads. NiCads have much lower capacity, and use very toxic materials. NiCads might still be of some use in very high current situations, but overal are obsolete (but people are still willing to sell them to you).

    Also, when buying NiMH batteries, pay attention to the mAh rating, which is how much power they hold. AA NIMH batteries might range from 1200mAh or lower to 1950 mAh (the best capacity I've bought so far). This gives you a good indication of how long the batteries will last between charge; clearly there is a big difference out there. And the more expensive batteries do not always have the greatest capacity.

    On chargers, there are a lot of different and bad chargers out there. The worst never shut off, just tell you to be sure you only charge batteries for x hours. If you forget and overcharge you can destroy the batteries! Also, if the batteries were not completely discharged then you can overcharge and destroy the battery even if you charge for only the time stated.

    The next worst chargers have a simple timer in them and do shut off after x hours. But they still can overcharge a battery if it wasn't fully discharged, or if you try to charge a lower capacity battery. And if you get a higher capacity battery and try to charge it, it will not fully charge.

    My rule of thumb is that I never use a charger that insists on charging batteries in pairs. Such chargers cannot sense individual cells, which would allow them to stop charging each cell when it is fully charged. There are a few chargers out there that do sense individual cells and shut off properly though. I think Best Buys sells one for about $30. However, the $9.99 Ray-O-Vac NiMH charger sold at WalMart does this fine. I'm not a Ray-O-Vac fan at all, but I do use and recommend this charger.

    And take batteries out of any charger when charged, never trust chargers that promise to keep batteries ready by trickel charging them. I've had them cook batteries.

    Again, I want to stress that one should never use chargers that do not sense individual cells and that have to charge in pairs. I have several (I just got one with the 1950 mAh batteries I bought recently) but never use them (I bought the batteries and recharger just to get the batteries, the price was right). Don't risk your expensive batteries to a cheap charger, it will seem to work fine for a while, then you will find that all of you batteries have started leaking and failing.

    Remember to look for and pay attention to that mAh rateing when buying batteries.

    In applications where the battery might last for years (TV remote control for example, or garage door opener) do not use rechargable batteries. Use Alkaline batteries in these applications; rechargeables will loose their charge too fast, and alkalines are the best choice (I have a garage door opener with the same alkaline battery in it for 19 yeras now).

    And thanks for asking here rather than doing a simple Google search on the topic.

  • by Anonymous Coward on Tuesday July 29, 2003 @08:14PM (#6566129)
    Standard disposeable alkaline batteries have very good capacities but also high internal resistances, so they don't do well in high-drain applications.

    NiCD batteries have lower capacities than alkaline, but they have miniscule internal resistance and can push an unbelievable amount of current. I'm getting about 45 amps of current from 1700 mAh NiCD battery packs in one of my RC planes. These batteries deliver close to 100% of their rated capacity even at insane drain levels like this. Downside to NiCD's is that they discharge at about 1%/day, so they are useless for stuff like clocks and calculators, etc.

    NiMH have almost the same capacity as alkaline and almost the same internal resistances as NiCD. They are sure to replace NiCD since some new high-drain types can equal NiCD performance. These also self-discharge pretty fast.

    Li-Ion are a completely different chemistry. Alkalines push 1.5v/cell. NiCD and NiMh push 1.2v/cell, which is close enough for drop-in replacements. Li-Ions are 3.6v/cell, so they are not really practical in replacing 1.5v alkalines. Li-Ions oxidize over time, so they lose capacity. Useful life for something like a laptop battery is 2-3 years or somewhere around 300 cycles. Li-Ions lose efficiency very fast as current draw increases.

    So, to sum things up:
    In clocks, calculators, smoke detectors and other long-run, low-current devices, use alkalines.

    In high drain devices like digital cameras, flashlights, electric motors, NiMH are probably the best bet.

    For insane current draw, use NiCD. Sanyo R-cells can push > 100 amps!

    Use lithium only in devices designed for it. A NiMh/NiCD charger can and will explode a Li-ion.

    Good luck.
  • by dann0 (555381) on Tuesday July 29, 2003 @08:25PM (#6566214)
    Is operating temperature a concern? NiMH batteries are not so good in low temperatures, so don't use them in a GPS on your Everest Expedition.

    What about space/weight/charge density? Lithium Ion batteries have a higher energy density than NiMH and NiCads, but they require more intelligent (read: expensive) chargers, as they are often microprocesser controlled.

    Current Drain? NiCads can deliver more current than NiMH batteries.

    Access to power supply? Weight and size of chargers? NiCad batteries are the easiest (after Lead Acid) to recharge, so the charger could be lowcost and small sized. You can charge a NiCad quite well with just a dc power supply and an appropriate voltage dropping resistor, just make sure that you time the charging to match the capacity. You can't jury-rig chargers for Li Ion batteries and you have to be very careful for NiMH cells (you really need to detect the voltage drop these guys display when nearing charge completion and trickle charge from that point onwards).

    Also, contrary to what others have posted, not all batteries of the same kind are created equal. Stick to name brands (Sanyo batteries have been very good for us) - they tend to last a little longer. Maybe they have more pure electrolyte or electrodes?

    Avoid rechargable alkalines. It will end in tears.

    Good luck with your decision.
  • More on "memory" (Score:4, Informative)

    by Daniel Rutter (126873) <dan@dansdata.com> on Tuesday July 29, 2003 @10:08PM (#6566961) Homepage
    Someone's already linked [slashdot.org] to one of my pieces about batteries, so I need only pimp Dan's Quick Guide to Memory Effect, You Idiots [dansdata.com] :-).
  • by axelbaker (167936) on Tuesday July 29, 2003 @10:49PM (#6567229)
    Panasonic is (as far as i know) the largest maker of battery cells in the market. They make excellent LiO and NiMH cells. NiMH are probably the best bang for the buck, as they are a direct replacement for regular alkaline batteries. Lithium are great if they will work in our device as they are lighter, and wont be destroyed if you accidentally let them heat up or get too cold. Down side is LiO cost a lot more.
  • by CustomDesigned (250089) on Tuesday July 29, 2003 @11:01PM (#6567291) Homepage Journal
    I bought some rechargeable alkaline batteries and a charger. They recharged a few times, then leaked. Since the whole reason to pay a premium for rechargeable alkaline was that they wouldn't leak like regular alkaline, I put some regular alkaline batteries in the charger. They might leak a little more often than officially rechargeable, but not much.

    So now I just buy regular alkaline and recharge them until they start leaking, then throw them out. Recharging before deep discharge gives the longest battery life for alkaline. I had a set in my RC car that I recharged after every play session, and they lasted for two years (with several sessions a month).

    If batteries leak badly, I clean up the discharge with white vinegar and baking soda.

Things are not as simple as they seems at first. - Edward Thorp

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