Physics Professor Uses Super Math Skills To Investigate Classic Question Of Generic vs. Brand Name Battery

It’s a good thing there are physics professors around to do all the complicated math when we need questions answered, otherwise how would we know if it’s worth it to buy name brand batteries? We would never know, is the answer. checked out the work of Professor Allan from Southeastern Louisiana University, who had some burning questions about how much energy was burning how fast in cheap dollar store batteries versus the more expensive name brands. He blogged about his investigation and came up with some interesting observations.

The lure of generic brands has proved appealing to consumers with tight budgets, from cereal to prescription drugs, toilet paper to socks.

But when you’re trying to power a device, the amount of power delivered from the battery for the length of time you need it is important, and Prof. Allan found, through various mathematical equations and science-y type things, that the more expensive brand batteries like Duracell and Energizer keep up the juice longer than the cheapies.

So then it’s a question of what you’re using — a flashlight works just fine with a cheaper generic because it doesn’t need as much energy, and the fall off in power won’t affect its use too much. On the other hand, if you’ve got a Wii remote or a complicated device that needs lots of juice for a long period of time, go for the pricier brands.

And of course, when you can, buy in bulk to save even more money. No need to let that Wii remote go dead!

A Physics Professor Asks: Are No-Name Batteries a Better Value Than Major Brands? [Time]


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  1. FatLynn says:

    What about rechargeables? I think those are actually cheapest in the long-run, no?

    • PHRoG says:

      Yup, $15 gets you the batteries and charging station for two Wii-motes and it promptly pays for itself. ;)

    • Marlin says:

      Just about to say the same.

      The “pre-charged” ones are cheap enough now we even use them in remotes.

      • hoi-polloi says:

        We’re in the midst of that transition. I’ve been loving rechargeable AAs rather than my play-and-charge for my 360 controller. Before long, I’d guess all of our AA and AAA batteries will be rechargeable, and we’ll need just a few spares to swap out during charging. We have a few flashlights that run on C or D batteries, but we’ll probably deplete our old stock before buying rechargeable spacers for them.

    • powdered beefmeat says:

      rechargeable are great but their “charge” drops off quickly – especially in high power devices like the Wii.

      • Marlin says:

        Not the pre-charged ones. The older ones do that and are not good in remotes and itmes that don;t get used right away.

      • dulcinea47 says:

        Not in my experience- I’ve been using rechargables (Duracell pre-charged) in my Wii remotes and they seem to last about as long as the non-rechargeable kind.

    • aleck says:

      Yes. ENELOOPs FTW!!!

    • CubeRat says:

      Has anyone else noticed that the rechargeable AAs are a tiny bit larger than disposable batteries?

      I have some of the tap lights that the rechargeables don’t fit in. I just discovered this in the wind storm 2 months ago, I lost power for 4 days. The batteries worked great in the radio and flashlights, but it was a supprise. (yes, my emergency kit now has disposable AAs).

    • duncanblackthorne says:

      The only rechargeable batteries currently available are NiMH (Nickel-metal hydride), and there are downsides to them. Anything larger than a AA has the same capacity as a AA, and the AA’s and AAA’s have a smaller capacity than a non-rechargeable AA or AAA, and most importantly: the voltage of rechargeable batteries is 1.2 volts, NOT the 1.5 volts of a non-rechargeable. Some devices won’t even work properly with rechargeables. Also, they don’t last forever either: they only have so many discharge/recharge cycles. Overall they’re not a great solution, or you’d see everyone using them.

      • eigenvector says:

        Unless they don’t work in a device (a problem I’ve never had), they are still the better buy. After a few charges, you’ve already gotten your money’s worth.

        More people should use them. Buying a cheaper pack of one-use instead of a pack of multi-use for roughly double the price makes no sense. Overall, I don’t see people making good spending decisions, so I don’t expect saving money on batteries any different.

        I save so much money now that I use rechargeables. When they start losing their charge quickly, I rotate a fresh set into my collection.

      • MJDickPhoto says:

        um check your source then.

        Sealed Lead Acid
        NiCad (Nickel Cadnium)
        NiZN (Nickel Zink)
        Li ion (Lithium Ion)
        Li ion Polymer (same as Li ion, but cheaper and more dependable)
        Silver Oxide (expensive, and hard to come by)

        • KeithIrwin says:

          The NiZn ones on the market should be avoided, though. They’ve been losing their capacity fairly quickly, and this, when combined with a charger which charges them until they reach a given capacity (which they might be unable to do), results in them getting overcharged and dying. It’s not necessarily an inherent flaw in the overall idea, but the ones on the market now should be very strictly avoided. That’s why the few places which are still selling them are doing it at a very steep discount from the original price: they’re just clearing out the remainder of their defective inventory. They might, in the future, bring better NiZn batteries to market, so in the long run, they might be a good idea, but right now they’re to be avoided unless you want a battery which only lasts for as few as five or six recharges before it dies.

      • MaxH42 thinks RecordStoreToughGuy got a raw deal says:

        You do know that an alkaline battery only outputs 1.5v when it’s fresh, and eventually drops below 1.2v, while a NiMH battery will output 1.2v through almost all of its usable life, right? The only devices in which that might make even a small difference are flashlights with incandescent bulbs, and devices that pull in or transmit a signal, and for those, you’d have to change the alkaline about halfway before it dies to have it come out ahead.

      • Tunacrab says:

        People don’t use them because misinformation like this keeps being repeated. Modern-day rechargeables are vastly superior to the rechargeables of yesteryear. They last much longer in high-drain devices and are almost always the better, more economical choice for electronics. The only problem with NiMH batteries is their rate of self discharge (they lose about a percent of their charge every day, even not being used). This makes them a poor choice for slow drain devices like wall clocks and remotes, stuff that can go for years on one or two batteries.

        My digital camera lasts about twice as long using rechargeables as compared to alkaline.

  2. Don't Bother says:

    On the other hand, if you’ve got a Wii remote or a complicated device that needs lots of juice for a long period of time, go for the pricier brands.

    Seriously. I use the generics from Fry’s, and they go dead within a week in a Wii remote.

    • PHRoG says:
      • Don't Bother says:

        Trust me, if it weren’t to play one game (Skyward Sword) I would have. But I had a few lying around, and it was the first time in a year I had turned it on.

        If I were in the habit of using it, I agree : )

    • Outrun1986 says:

      I have to agree the Wii remote is a battery hog. I think it also uses power when its left off, so you need to take the batteries out of it when you are leaving it for more than a few days. I also find that the Wii remote likes to drain one battery while leaving the other one totally full which is a waste if you do not have a battery tester to figure this out. The Wavebird did this as well (drained only one battery), but batteries with that were hardly an issue, as 2 AA’s would easily last you a couple years even if you played a lot. Ironically you can’t just put one battery in, it needs 2. I can put one battery in my Microsoft mouse and it will work.

      If you are playing Wii a lot this is a problem. I played one game session of endless ocean blue world. I have to admit that the game was a very good game and I ended up playing it for about 5 hours without stopping which is actually quite unusual for me. However when I was done the Wii remote batteries were in the red, and I had them charged before I played, so they only lasted 5 hours before needing to be charged again. I have the La crosse charger from Amazon so that is not the problem.

      On the other hand I can put 2 of my cheapest generic rechargables in my Xbox 360 controller and it will last me weeks and weeks. I can get 40 hours or more from rechargables in my Xbox 360 controller, not to mention the time the controller is on the shelf and these are no name dirt cheap rechargables.

      • Don't Bother says:

        I have to agree the Wii remote is a battery hog. I think it also uses power when its left off, so you need to take the batteries out of it when you are leaving it for more than a few days

        You are so correct. I don’t use what my friends and I call the “Wiimote condom” because I have to constantly take the batteries out and put them back in.

        I also heard Ocean Blue was a good game, but I never have played it. Would you recommend it?

        • Outrun1986 says:

          Its endless ocean blue world, there is also the first endless ocean, but I have no idea if that is any good as I haven’t played it. I have played blue world though and its an amazing game! Definitely get it but stock up on batteries or charge your batteries before you play!

  3. rmorin says:

    The lure of generic brands has proved appealing to consumers with tight budgets

    No. You don’t need to have a tight budget to understand that with some products, the generic is a better value.

  4. pop top says:

    Surely you’re joking Professor Allan.

  5. TheMansfieldMauler says:

    the more expensive brand batteries like Duracell and Energizer keep up the juice longer than the cheapies

    The December 2011 issue of Consumer Reports had battery comparisons (AA size), and while Duracell Coppertop was the best alkaline, Energizer alkalines came in rated next to last I believe – below several generics such as Costco brand.

    • PHRoG says:

      I’ve never verified the truth in this, but one day at Costco the Duracell rep was at Costco and I had intended on buying batteries. So I asked him what he thought a better value was, to which he said, “We make Costco’s batteries…they’re the same thing.”.

    • Outrun1986 says:

      I can definitely see this as being true. I have had a couple sets of energizer rechargeable batteries and they were easily the WORST batteries I have ever had in my life. They would charge up in my La Crosse charger but they would discharge in about 30 min or an hour! Moreover, they cost more than the generic rechargeable batteries which actually worked! I am not the only one who has had this experience with energizer.

      Because of this I can’t see their batteries lasting any longer than ray o vac or duracell, or the costco or sam’s bulk batteries. You are paying for the Bunny marketing when you buy energizer. Radio shack enercell batteries are also rebranded duracell batteries if I remember correctly. Some duracell rechargeable batteries are also rebranded sanyo eneloops, if you can find the ones with the white tops vs black tops.

      I also have a second hand set of duracell rechargables (they were not mine originally), they aren’t even the most modern kind and they aren’t LSD cells. After refreshing them with my charger, I have them sitting in my old digital camera and I have never seen a set of batteries last longer in that camera. I can pick the camera up months later and the batteries will still be charged. These are batteries that have been abused too in the past.

      I know way too much about batteries.

  6. Dr. Ned - This underwear is Sofa King Comfortable! says:

    I think EGM a long while back did some tests on battery life for the Nintendo DS to see what disposable battery was the best value for money price/performance wise. While the energizer and duracell high end batteries had the best life, the Rayovac brand had the best cost/performance ratio.

  7. GuyGuidoEyesSteveDave‚Ñ¢ says:

    “It’s a good thing there are physics professors around to do all the complicated math when we need questions answered, otherwise how would we know if it’s worth it to buy name brand batteries? We would never know, is the answer.”

    Is that an indictment against Consumer Reports?

  8. homehome says:

    I know those cheap batteries in BB that work a long time, better than almost all the namebrand ones. I think they’re dynex.

  9. Outrun1986 says:

    Different types of batteries for different devices. Have a digital camera that sucks batteries, sanyo eneloop rechargables for sure. TV remote that doesn’t have a back light, ok to but those dollar store batteries in it, they will last well over a year if not longer. The ones with lights in them suck more batteries so you probably want alkalines for those. You wouldn’t want rechargables in your remotes, its just not cost effective.

    Most toys don’t use much batteries unless they have a LCD screen but if its just lights and sounds a pair of alkalines will probably outlast the life of the toy. I buy tons of second hand toys and the alkalines in them were barely dented as far as capacity is concerned. With more high drain toys like a leapster you should be getting rechargable batteries.

    Its best to get your batteries in bulk packs, they are infinitely cheaper than the 2-4 packs stores charge a premium for. A bulk pack of alkalines from Sam’s or Costco will probably last a long time. Don’t buy too many batteries, batteries expire and they can leak so just buy what you need and watch the expiration dates. I have had brand new batteries in the package leak.

    A lot of electronics come with built in lithium ion batteries these days, so AA’s aren’t as big of a concern as they were in the past. You will need them to power your Wii remotes and Xbox 360 controllers however, so you should definitely be getting rechargable AA’s for those. Getting rechargable AA’s for those is much cheaper than buying the proprietary batteries and charge kits that all the stores are happy to sell you. I use generic cheap rechargables in my Xbox 360 controllers and they last 40 or more hours.

    You also need a good charger though for rechargable AA’s or else your batteries will not perform, so invest in a $30-40 La Crosse charger from amazon, there are other good choices too instead of buying the cheap stuff that you see in the store.

  10. Swins says:

    Maybe check with Consumer Reports before suggesting enegizer

  11. unpolloloco says:

    Yeah….this study doesn’t take rate of discharge into account. Different devices draw at different rates and different batteries will give more total energy depending on the rate of discharge.

  12. nugatory says:

    To give an example of where generic’s don’t work: electronic paintball markers.

    I’ve got a smart parts electro paintball marker. If I put anything other than Energizer or duracell 9v, the gun will not fire. With generics, the power light will come on and it’ll make clicking sounds, but basically misfires.

  13. maruawe says:

    This was learned in the process of using various electronics with both types of batteries by my daughter at nine years old and proven in our remote controlled cars and motorcycles and even in a helicopter later. So this news is not new knowledge but a recap of old knowledge.
    i am sure that we were not the only people that studied this affect on batteries

  14. Bugley says:

    My impression is that the cheap batteries are more likely to leak.

  15. Torchwood says:

    I don’t need super math skills to tell me that Kirkland brand of 40 AA batteries sold at Costco is a good buy.

  16. scoutermac says:

    I found I buy which ever is cheaper, energizer or Duracell. I gave the rechargeable a try for a while and they would not hold a charge long either. I bought some cheap batteries from Big Lots once and they were worthless.

  17. Hi_Hello says:

    i would be nice to get a list of store name and who actually made the battery. I know a lot of brand battery make store brand too.

    I avoid batteries sales…each time I buy them, they don’t last that long.

  18. Such an Interesting Monster says:

    It also depends upon the battery type. Duracells and Energizers are alkaline. Most of the batteries I see in dollar stores are zinc carbon or chloride which are poor choices for electronics, but perfectly fine for other things.

    Rechargeables are great, and I use them myself, but I often wonder their true cost, i.e., the purchase price along with the cost of the power needed to charge them.

  19. 5seconds says:

    I have sworn off regular batteries. We can’t throw away batteries here, you have to have them recycled, so I keep my dead batteries in a box. I haven’t been motivated to take them to be recycled, so I have been saving them for 6 years. When I look at the waste in that box, and the chemicals etc. I feel kind of disgusted.

    I have been slowly buying up Eneloop batteries when I see a good price ( and am replacing all of my alkaline. Soon I won’t have any alkaline in my house at all (except for the 9v in the smoke detector)

  20. cameronl says:

    Thanks for the link an blog about the article about the study. /sarcasm

    Follow the link to the original Wired story and you find this:

    1. “Study” looked at Engergizer, Duracell and ONE generaic dollar store battery. Not a great sample.

    2. THIS is at the end of the article:


    It should be clear that I usually fly by the seat of my pants. I pick up some cheap batteries at a store and I just assume they are alkaline. Apparently not. The dollar-store batteries I used say ‚Äúheavy duty‚Äù. The interwebs tell me these batteries are zinc chloride and not alkaline. Oops. Anyway, even though they are different types of batteries, I can still compare the cost per energy. So‚Ķ”

    So…. dollar store Heavy Duty batteries don’t last as long as name brand alkalines… duh.

  21. Krazycalvin says:

    I honestly believe that this test is a lot easier than they made it. Get a digital camera that uses double A batteries and do the comparison test by snapping off pictures until it dies.

  22. yurei avalon says:

    I love my rechargeable AAs, but they just don’t work for everything. They work great in keyboards and mouses but my 360 controllers refuse to work with them and their performance in digital cameras is so-so.

    • Outrun1986 says:

      Mine work in the 360 controllers just fine and I have tried various brands, all were cheap generic brands. They still last about 40 hours in the controller, aka they last a LONG time. I don’t use a headset, but I have no idea if that makes a difference or not.

  23. Razor512 says:

    Overall useless, because it doesn’t tell you which is the current best to get. And to figure it out, you don’t need high level math, all you need is batteries from all different brands, then measure the capacity of each battery and compare it to the cost of the battery

    While ever gives the best cost to power ratio is the best battery.

    For rechargeable batteries, you take batteries from each brand, measure the capacity of each (you will almost never get advertised capacity), then measure how many recharges it can handle before failing then compare that to cost to find the best rechargeable.

  24. phsiii says:

    When the kids were little, I used Costco batteries in their toys simply because I knew they’d leave the suckers on and run ’em down: when they did so, I wasted a cheaper battery. Yeah, I know, “Use rechargeables”. This was a while ago, and NiCds sucked too badly…

  25. Mr Grey says:

    Harbor Freight –

    I have very good results with Harbor Freights rechargeable batteries. The green ones, and the black ones are the best (black better than green IMHO)

    NEVER NEVER NEVER buy the ORANGE ones.

  26. DrPizza says:

    “It’s a good thing there are physics professors around to do all the complicated math when we need questions answered, otherwise how would we know if it’s worth it to buy name brand batteries? We would never know, is the answer. ”

    I guess if you feel that way, then a good choice of a career might be something far away from math and science. Maybe head into journalism or something. The “complicated math” is high school level mathematics that an average high school student should be able to handle.

    “through various mathematical equations and science-y type things” translates to “I’m not smart enough to understand what he’s talking about. My brain hurts.”

  27. The_Fuzz_53 says:

    How about Nickel-Metal Hydride rechargeables?

  28. ldillon says:

    The main problem I have with rechargeable batteries in my bike headlight is that they go dead without much warning leaving me (literally) in the dark.

    • Razor512 says:

      get the sanyo eneloop batteries, they last longer than any non rechargeable AA battery that I have used, and they hold their working voltage longer so while they may only be 2000mAh, they can run my camera longer than my 2700mAh sony batteries. The same goes with flashlights.

      PS the average store bought name brand alkaline battery is only around 800mAh, and the cheap off brand ones will give you around 400mAh or less.

  29. marc6065 says:

    I know the cheapo batteries do not last as long in my butt vibrator than the name brand ones.

  30. nearly_blind says:

    Unbelievable! If the editor read the original article by the professor he would find that he posted a correction (that make’s him look like an idiot).
    Consumerist, please remove this.
    After reading the Time arcticle in the link, I noticed that the Time didn’t mention what type of battery the dollar store battery tested was. If it wasn’t alkaline like Duracell and Enegizer then of course it would not work as well, everyone knows that. The Time article linked to what looks like the original article in written by the professor himself. At the bottom of that wired article there’s an Update, where the professor basically says, “Oops”, the dollar store batteries were not alkaline, I goofed up. Basically he spent all this time and effort that alkaline batteries work better than cheaper heavy-duty batteries.

    When I first saw the headline I was very interested because I always buy generic long-life alkaline batteries that I have read and found through experience basically work as well as name brands and cost about 50% less.

  31. Not Given says:

    My wireless mouse eats AAs like they’re going out of style.

  32. esc27 says:

    “a flashlight works just fine with a cheaper generic because it doesn’t need as much energy, and the fall off in power won’t affect its use too much”

    This may be true for cheap mag lights, but my nice, barely pocket sized, 200 lumen tactical light can go through a pair of CR123’s in just a few hours and the “fall off” when it drops out of 200 lumen mode is significant.

  33. medfordite says:

    I personally have preferred Duracell for my digital camera which just eats batteries up. I can more often than not get a couple of good months of occasional use with those. Tried Energizer and had poor results.

    On my Apple Magic Mouse (Very Notorious for being a battery sucker), I put in Energizer Rechargeables. Within 2 weeks, either alkaline or Rechargeable, I can get the same results. The Payoff for me is to not have to run out and buy batteries so often.

    Then in my remotes for the TV, Blu-Ray, DVD, etc… I use dollar store variety batteries. Low drain, no worries. :)

    I remember seeing on a TV special one time that both Eveready and Duracell, both make batteries for other companies including store brands but never divulge as to who they make them for.

    • Outrun1986 says:

      I think Enercell is rebranded duracell, enercell is sold at radio shack. Someone here also said the costco batteries are just rebranded duracells. I know that some sanyo eneloop rechargable batteries are also rebranded as duracell rechargables, these will have white tops vs black tops.

      If you don’t have a costco membership or are lacking a costco in your area I believe radio shack does sales on enercell batteries if you need a lot of batteries.

      Based on this I would suspect that energizer makes the Sam’s club batteries (member’s mark brand), because the only battery Sam’s seems to carry is Energizer so its likely they have an exclusive contract with energizer..something like that.

  34. Kuri says:

    My family fell for the cheaper batteries trap a few times.

    The worst was when they picked up a huge pack of VERY cheap generic batteries at of all places a trade center. Popped two into my discman, which I had then, and they lasted maybe through the first chorus of a song then died.

    I’ve sworn by Rayovac ever since, as they seem to last the longest for me.

  35. shthar says:

    I could have saved this guy a lot of time.

    The heavier the battery, the longer it lasts.

  36. Elgog Partynipple says:

    Battery’s are all about the chemistry. If a battery is Alkyline then it will last a long time for “High drain” applaictions like electronics and have a shelf life of about 4 years. If it’s a Lithium battery like Ever Ready’s Advance Lithium AA’s (non-recharable) it will be good for high drain applications and have a shelf life of about 12 years. If it’s a carbon cell or Heavy Duty battery then it will have a short life, not be good for high drain applications and have a shelf life of less than a year.

    It doesn’t matter whose battery you use, buy them based on the chemistry. Rayovac, Coppertop or Ever Ready alkyline batteries all have about the same life and performance.
    Currently, if you can get an Alkyline battery for about $0.50 each or less then it’s a good deal. packages of 2 or 4 batteries typically sell for about $0.75 or more per battery. Quantity packs of 20 to 30 batteries are about $0.50 each battery or less. The shelf life for these batteries is about 4 years for alkylines and 12 years for Lithium. So stock up for as many batteries as you may need over that time period when you see a sale. This article didn’t really give enough information about what they were talking about. It’s important to take in to consideration the type of battery and the application it is intended for. It’s all about the chemistry.