Rechargeable Batteries - Yes or No? 896
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?"
Nickel Metal Hyride (Score:5, Informative)
Batteries (Score:5, Informative)
Those batteries keep their energy for 3 months at a time easily, when I am not on vacations or otherwise using the camera.
If it helps... (Score:1, Informative)
NiMH - accept no substitute. (Score:5, Informative)
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.
Ray O Vac (Score:5, Informative)
All kinds. (Score:4, Informative)
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:NiMH (Score:5, Informative)
Re:NiMH (Score:3, Informative)
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 common form factors I mentioned above, and are more expensive.
Recycle (Score:5, Informative)
Re:Winner: most underrated comment! (Score:1, Informative)
You misunderstand the purpose of the over/under moderations.
They exist merely for the purpose of anonymous modslapping from the editors.
You'll notice a comment that makes a good, well thought out point - but is contrary to slashbot groupthink - will dissappear to -1 Overrated, with no other moderations done. It's not a troll, flamebait, offtopic, or redundant - but it is something slashdot doesnt want heard, so out damn spot.
You'll notice idiotic rambling zealot comments, like "I think gentoo is awesome and RIAA is stupid!" get whacked up with Underrated mods. Same thing. Such comments add nothing, and would be left at 0 if they were not put on a pedestal by the editors.
Whenever you see overrated or underrated moderations, that's an editor shaping the conversation towards his viewpoints.
iGo Juice (Score:4, Informative)
Walmart anyone? (Score:4, Informative)
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)
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)
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.
NiMH by far, and retrofittable to NiCad stuff (Score:5, Informative)
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.
Have used many over the past 20+ yrs... (Score:1, Informative)
These days I'm using a few diffrent ones in my Oly C-2100 digital SLR... The Oly ones that came w/ the camera are starting to show their age, but still hold an ok charge in a pinch. I've been most happy with the latest Energizer brand AAs NiMH (still in the Oly charger). The Energizer NiMH AAs are no more expensive than the Energizer High output Lithiums at most stores, and for the old Walkman (still in service, but for biking now) and my camera, the rechargables are great.
just my $0.02 US
Re:put dead batteries in sun for more life (Score:2, Informative)
Heat.
It increases the rate of the reaction, allowing the battery to supply more current. It also works if you roll them back and forth in your hands for a while. I had to learn this trick while living just south of the Yukon border. Cold weather stops the reaction, and your batteries can't provide enough current.
This trick works for both rechargeable and disposable batteries, as long as they're not completely dead.
Re:NiMH (Score:2, Informative)
The second reason LiIon batteries are superior is because of their discharge characteristic. They tend to hold their voltage until almost completely discharged, then the voltage drops like a rock. This is great for portable electronics that require a relatively stable voltage supply to operate. NiCd and NiMh batteries have discharge curves closer to that of a standard Alkaline AA, in that the voltage tends to fall as the battery discharges. This means that the actual amount of time the battery is good is less, since some of the stored energy can't be used because the voltage on the battery isn't high enough for the electronics to use.
Re:lower impedance (Score:3, Informative)
The Great Battery Shootout (Score:5, Informative)
Battery FAQ (Score:5, Informative)
Rayovac Renewal - Avoid Energizer Accu (Score:2, Informative)
I chose Rayovac Renewal because it was the first rechargeable alkaline battery made. My grandfather actually picked it up before me, and he's usually the last to touch a new invention! He does like to be efficient and save money, though.
The batteries do wear out over time, though. I have a few bad batteries mixed in with my good batteries, and so sometimes I put in newly recharged batteries and they don't last as long as they should. If I had it to do over again, I would number each battery in sequence when they were purchased, so I would know which batteries are getting old and could throw them out. Now, I have no real way of knowing which are old and which are new, because they all look the same.
Rayovac Renewal puts out the full 1.5 volts per battery (AA, AAA, etc.).
Avoid Energizer Accu! I learned this the hard way. They only put out a lousy 1.2 volts per battery! That's just 80% of the voltage you're supposed to be getting. This is borderline fraud!
Devices that have strict voltage requirements, like digital cameras, just will not run at all with Energizer Accu. It might be tolerable for flashlights and old radios, which can be a little dimmer/quieter while still working fine, but for any modern electronic device it will cause problems.
Devices with Energizer Accu will run for a very short time, if at all, as their voltage starts at 80% of normal and not at 100%. So, if the device requires something like 75% of rated voltage in order to function correctly, you will only have 5% of headroom with Accu versus 25% for a normal battery. So, assuming that batteries drop voltage at the same rate, your device will fail five times faster with Accu!
Accu does have one advantage, though. They do make a "9-volt" (really 7.2V) rechargeable battery. Rayovac Renewal does not make this battery, to my knowledge, so I am forced to use Accu for various devices that require a 9V battery.
If they made a true 9V Rayovac Renewal battery, it would make me happy!
A few tips (Score:5, Informative)
- 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!Re:Nickel Metal Hyride (Score:5, Informative)
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.
Re:NiMH (Score:3, Informative)
I don't own any lithium cells, other than the ones in cellphones, but based on my cellphone experience I'd say they probably charge quickly too. If you go with NiMH you can get 1 hour fast chargers for them, which is certainly good enough for my needs right now. Those chargers won't charge NiCads tho, so be careful.
Also, can't help but note... if you've got a AA battery that's putting out 3.6 volts, I'd say you've got quite a defective battery. An AA battery is supposed to put out 1.5 volts, plus or minus a small fudge factor. You'll likely blow LED's in an LED flashlight if you double the voltage like that... imagine what it can do to other stuff.
Battery Tests (Score:4, Informative)
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.
Lots of facts &comparison data f/ imaging-reso (Score:2, Informative)
http://www.imaging-resource.com/ACCS/BATTS/BATTS.H TM [imaging-resource.com]
An important snippet from that page:
I use a digital camera (Minolta Dimage 7Hi) and I use his recommended ones: Powerex 1800 batteries and the very effective Maha C204 [imaging-resource.com].
eBay (Score:2, Informative)
Re:Get NiMH or better (Score:2, Informative)
Personally, I have used the Maha brand battery and charger and have been happy with them.
Alkaline rechargeable (Score:5, Informative)
The alkaline starts out at around 1.63 volts and discharges to around .9 volts before it is considered dead. The NiMH is flat at 1.2 volts. For some apps, the NiMH battery comes up "low battery" (like in my friend's pager) because the pager may consider an alkaline discharged to 1.2 volts as about done with. So you have to find out if 1.2 volts per cell will run your appliance.
The other thing about the NiMH is that it self discharges -- it is even worse than the NiCad, only it isn't supposed to have the memory effect that a NiCad has (the camcorder which doesn't fully discharge the NiCad which means the NiCad never ever seems to ever recharge and ever run the camcorder).
Now for the alkaline rechargeable. They say you can put ordinary alkalines in one of those chargers -- tried it and it won't burn the house down, but it won't hold a charge, or it will recharge but have really high internal resistance on discharge. I guess you have to pay for those fancy Renewal batteries if you want to recharge an alkaline.
OK, here's the deal. A fully charged alkaline is over 1.6 volts (none of this 1.2 volt business), and it is supposed to hold its charge forever (I measure .01 volt per day degradation). The rub is that you can't discharge them (ha, ha). What I mean is that if you use them in a flashlight and discharge them until the light gets dim, you have discharged them down to that .9 volt, and you are lucky to get one or maybe two recharges (if that) out of them. The trick is to discharge them only down to 1.5 volts and then freshen 'em up in the charger. Apparently they only like to be discharged a little bit and then recharged as soon as possible -- I use D-cells in a couple of flashlights (a 4-cell Mag and a 2-cell ordinary flashlight). If I use a flashlight on a project (like to change a dead car battery at night, or to poke around a crawlspace, I recharge them as soon as I can). I am told they will live (Rayovac data sheets) nearly forever that way.
BATTERY BRAND SHOOTOUT (Score:5, Informative)
Re:All kinds. (Score:3, Informative)
Just researched this... (Score:5, Informative)
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.
Re:Nickel Metal Hyride (Score:5, Informative)
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.
Re:NiMH (Score:5, Informative)
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).
Re:put dead batteries in sun for more life (Score:2, Informative)
Depends on the application (Score:4, Informative)
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.
Rechargeable AA are getting really good (Score:3, Informative)
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.
Re:NiMH (Score:1, Informative)
look for the rating. (Score:3, Informative)
Re:NiMH (Score:4, Informative)
NiCd and NiMH batteries hold their terminal voltage until almost completely discharged too, they are both actually slightly better than Li-ion in that respect. They will also work will at current draws of up to 1C for NiCd and 2C for NiMH with no loss of performance.
The Lithium batteries that can do 2.5Ah @ 3.6 volts in an AA form factor aren't even rechargable.
Jason
ProfQuotes [profquotes.com]
Re:NiMH by far, and retrofittable to NiCad stuff (Score:3, Informative)
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.
NiMH/Li-Ion (Score:2, Informative)
.
Re:What about rechargable akaline? (Score:4, Informative)
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.
Re:NiMH (Score:4, Informative)
Not every charger, actually. Check yours to learn wether it has this 'keep alive' feature.
Re:NiMH (Score:5, Informative)
But Alkaline batteries have high internal resistance, so they're not terribly useful in high-current devices like my Kodak digicam. That high resistance causes the batteries to heat quickly, and because resistance increases with heat, it gets worse the longer you use the device. The voltage drop across the resistance causes the output voltage to drop, and before long it can drop below a useful voltage. In high-current devices, NiMH and NiCd batteries work much longer than alkaline batteries, in part because they don't heat as much.
This isn't just theory; I've tried alkalines in my digicam, and they don't last for more than a handful of photos, not nearly as long as my usual NiMH cells. So I can use alkalines, but only in a pinch. For low-current devices like a CD player, alkalines may last as long as NiMH or NiCd, but when they're done you have to throw them away.
Charge cycles and self-discharge (Score:5, Informative)
(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.
Re:Rechargable Alcalines (Score:5, Informative)
-Matt
Re:Nickel Metal Hyride (Score:2, Informative)
They'd last a few hundred re-uses, but you'd have to swap them every three weeks as they passively discharge themselves faster than the PDA will. They're designed for more high-drain devices, like video cameras, game & audio devices, etc...
NiMH batteries (Score:5, Informative)
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!
Re:Nickel Metal Hyride (Score:5, Informative)
I buy mine from... (Score:2, Informative)
I have the Maha C204F charger and I love it. It has been *very* gentle to my batteries. I have had the best luck with the 1800mAh Powerex batteries, but I see they have the 2200mAh available now as well.
I can't recommend NiMH batteries highly enough for high-drain devices like digital cameras; they last longer than alkaline in such applications. But for low-drain devices like remotes, I disagree with some of the posters' suggestions to use them. They self-discharge at a much greater rate than alkaline and are unsuitable for such applications (unless you like finding dead batteries in your remote every few weeks... been there, done that).
Please note that it's getting much easier to recycle the non-rechargable batteries now; I save mine up and take them to the local transfer station where they gladly accept them for recycling. Probably not as common in areas with lower population densities, tho.
Cheers,
- Leo
Re:Nickel Metal Hyride (Score:4, Informative)
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.
When I die, bury me with my NiMH batteries! (Score:2, Informative)
A couple of notes:
Energizer (Score:3, Informative)
Comparison of various batteries. (Score:5, Informative)
Re:NiMH (Score:3, Informative)
Re:NiMH (Score:4, Informative)
- The voltage drop of the LED is unrelated to the voltage of the battery; the battery voltage just needs to be greater than the drop across the LED for the LED to light.
- For a given brightness of LED, the current needs to be the same; it wouldn't be enormous for a higher voltage. In theory, the LED is a short circuit anyway, to the current is whatever the battery can put out regardless of voltage (at least for the split second until the LED fries.
- There is a current limiting resistor in series with the LED, which according to Kirchov's voltage law has the rest of the voltage dropped across it. So in that case, you know the resistance and voltage dropped across the resistor, therefore you know the current through it, and by Kirchov's current law, you know the current through the LED.
Now, it should be fairly obvious that the larger the voltage dropped across the resistor, the more stable the current will be against slight changes in battery voltage. Therefore, you want a relatively large voltage potential dropped across the resistor (at least as much as across the LED) to keep the current stable. That means the voltage of the battery should be at least double the voltage drop of the LED.Jason
ProfQuotes [profquotes.com]
Re:NiMH (Score:2, Informative)
Re:Screw the environment you posers (Score:3, Informative)
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?
Re:A few tips (Score:3, Informative)
As for using a timer, that's not a bad idea. In fact, the cheapo chargers than much of the world uses use a simple timer-based circut; they don't bother monitoring anything except whether there's something in the battery bay that passes current. However, this causes problems: if the charger or battery is malfunctioning, then it can zap a good battery, or pump too much current into a faulty battery and perhaps even cause a fire hazard. Most of the "smart" chargers are intelligent enough to detect faults in their own circutry and in the battery and will refuse to charge if things don't look right (like, say, the battery is passing 2000 mA). Using a timer is a good solution if for some reason you can't use any other charger, but I'd be in the market for a new smart charger if I just had a NiCD charger and lamp timer.
Overcharging is one of the fastest ways to kill any rechargable, be it NiCD, NiMH, LiIon, Pb-Acid, or anything exotic. As long as you're careful, however, overcharging can be avoided fairly easily.
Re:What about rechargable akaline? (Score:3, Informative)
Re: What about rechargable akaline? (Score:3, Informative)
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, and don't get caught out with flat batteries. Also, alkaline batteries generally have a larger capacity than other rechargeable types, and can be much cheaper.
OTOH, they're not so good for devices which need a very long battery life, or which don't give any indication of battery charge. You can also get problems with some types of battery leaking slightly when recharged -- I haven't found this dangerous, but it can corrode the recharger's terminals slightly, leading to contact problems.
In short: well worth trying if your intended usage is suitable. Oh, and pretty much any alkaline batteries are suitable, not just the Rayovacs. (I know Duracell, Energizer, EverReady &c claim they're not rechargeable, but then their sales would plummet if they did!) I find that the top-of-the-range Duracells are best; although the extra cost isn't really worth it if you're just using them once, for recharging they last for many more charge cycles, which makes them more economical in the long run.
Re:MOD PARENT DOWN (Score:3, Informative)
The datasheet is right here [energizer.com] for NiMH. That is a very flat horizontal curve until the cliff right at the end. For comparison, the Alkaline curve is here (look on page 2) [energizer.com]. That curve drops steadily throughout the life.
Jason
ProfQuotes [profquotes.com]
Avoid fast chargers (Score:1, Informative)
I recently purchased a Vanson V6988 charger: too late I discovered that this piece of crap can't do slow charges, plus, it simply fails to detect the end of charge voltage dip on about 70% of all the cells I try to charge with it, thus keeping them on charge for extra long times and overheating them as hell.
All cells are almost new and get fully charged in a good ol' c/10 slow charger.
Get a slow charger, and more batteries if you need them often.
Re:NiMH-link to a very informative review (Score:2, Informative)
Re:NiMH (Score:2, Informative)
You must be joking. I have a pile of panasonic NiMH batteries that I got at costco a couple of years ago. I keep a couple of spare sets in my camera bag for my flash, and they've kept a full charge for over a year.
Re:Recycle (Score:4, Informative)
Re:A few tips (Score:2, Informative)
Actually, it doesn't neccessarily mean that. It means it can supply a nominal amount of current (specified by the manufacturer) for a nominal number of hours... which happen to multiply to 1800. You will never ever get 1800 hours or 1.8A for an hour... For example, from my handy databook Panasonic says their mAh ratings for NiMH batteries are at a discharge of 0.2C (C=battery rating in mAh). So a 1800mAh NiMH is only 1600mAh at a discharge rate of 360mA (ie. it will last 5 hours).
It is till the best guide for battery capacity though...
One other tip - NiMH batteries only generally last a maximum of 2 years or 500 cycles. So when they get that old, you've saved yourself tonnes of money already - just recycle them and get new ones rather than trying to bleed every last bit out of them...
RipVan100 (Score:3, Informative)
I still have the green Sanyo "industrial grade" cells I originally bought about 2 years ago, and I've been buying more since for other purposes. The charger (lightning pack 4000) is also excellent. I can't necessarily recommend the newer batteries they've stocked, but I definitely recommend the charger and the green-jacketed Sanyo batteries - they consistently perform well for me, and most reviews note that they perform BETTER than several NiMH battery brands with higher mAh numbers (they're only 1700 mAh).
New standard for AA battery? (Score:2, Informative)
Umm the standard for the AA sized battery is 1.5v - you go sticking batteries that put out two and a half times the expected voltage into sensitive devices and they will
I do like LiIon batteries, although I have never used them in the AA form factor (just in laptops.)
Different battery options (Score:4, Informative)
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.
Battery choice depends on environment. (Score:5, Informative)
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.
NiMH == all the same (Score:5, Informative)
So, if you buy NiMH, you don't have a lot of choice in the matter. This is NOT to suggest avoiding NiMH, which is a superior battery in many situations - just to inject a note of realism.
As for the original poster's question, surely there is a website out there with vast amounts of statistical data on the various brands (and types!) of batteries?
I like NiMH as it is relatively easy (and safe) to recycle. However, keep in mind that NiMH can lose up to 2% of its charge per day sitting on the shelf. NOT a good choice for that emergency flashlight.
Re:NiMH (Score:2, Informative)
For consumer batteries in conventional form factors (AA, AAA, C, D & whatever a 9-volt is called)
They're called 9v batteries. And the other ones on your list aren't batteries, they're cells. A battery is a collection of cells.
So a 9v battery has 6 1.5v cells in it.
Is it any wonder my wife calls me Mr. Pedantic?
Some more tips. Avoid Rayovac! (Score:3, Informative)
A lower capacity cell will have thicker electrodes, which conduct more easily and will last through more charge/discharge cycles. Ideal for applications like camera-flash units that draw very heavy current. You'll just have to charge them more frequently.
The higher-capacity cells would be more suitable for low-drain devices, like portable music players, or cameras that don't see much flash use. Their higher internal resistance doesn't pose a problem when the power draw is low.
Another thing to be aware of is that many chargers go into a blitz charging mode on startup, blasting heavy current into the batteries for the first hour, before backing off, taking a reading, and determining how much further charging is needed. This makes sense if the charger is plugged in constantly, and only drained batteries are tossed into it. It only becomes a problem in situations like mine: I was running a little 4xAA charger from the inverter in my vehicle, which would cycle on and off with the engine. Leaving batteries in the charger would cause them to get blasted every time I turned the car on, shortening their life dramatically. Don't do that. Now before I shut off the engine, I peek at the charger to see if it says they're charged. If so, I take them out and toss 'em in a cupholder, so they don't have to endure further charging. Keeping a spare set in my vehicle has proven indispensable though.
Avoid Rayovac. I got a Rayovac "3 in 1" desktop charger, which advertises the ability to charge NiCd, NMH, and rechargeable alkalines. Then I threw in a set of four Rayovac NMH AA's. A few hours later, I discovered that they'd gotten so hot during charging, their labels had warped and peeled, exposing the bare metal can underneath. They still work fine, holding plenty of charge to be useful, but the bare metal means I can't use them in certain devices' battery compartments because of shorting concerns. I put a set of ancient Radio Shack NiCd's in it, and it cooked them too. They were probably dead anyway, but the point is, the Rayovac charger doesn't have a thermal cutoff, which it should! Curiously, this charger works just fine on my other batteries, even AAA's never get more than warm during charging.
Ironically enough, another set of Radio Shack "high capacity" NiCd AA's from the same era work just fine, in the Rayovac charger and others. Because the NiCd chemistry has a lower self-discharge than NMH, they're ideal for occasional-use standby duty. Those old cells sit in my Mag Lite.
Really, for standby jobs, the best chemistry is rechargeable Alkaline. They have almost no self-discharge, so they can sit for months on end and still be ready for service. I've got a pair of Renewal AAA's in my laser pointer, I think I've charged them 5 times in the 5 years I've owned them. (BTW, it's worth the extra bucks for a laser that takes standard batteries. After you've replaced those button cells 2 or 3 times, you begin to see why.)
You should check out Isidor Buchmann's excellent book [buchmann.ca] on the subject. After a free "who are you?" registration, you can read the whole thing on line.
P.S. Anyone know an outfit that rebuilds Lithium-ion laptop batteries?
Re:Screw the environment you posers (Score:5, Informative)
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.
EZONE! (Score:5, Informative)
My battery history (Score:2, Informative)
Great because it charges rechargeable alkaline, NiMH, and NiCd [not 9Volt form factors, but the standard AAA, AA, C and D batteries] and it won't overcharge them.
I have three or 4 pairs of NiMH for my digital camera [works great in there] and Talkabout radios. Have a couple sets of rechargeable alkalines for stuff like remote controls [long idle time in those]. Don't have any NiCd...too many problems with battery memory which the NiMH doesn't have.
The best battery I've seen was the Kodak Lithium Ion 3V [single battery in the form factor of two AA's]. It ran the camera for three months before I replaced it with the rechargeable NiMH.
Just my $0.02
Re:Nickel Metal Hyride (Score:2, Informative)
I'm not sure about over charging, but they used to have problems with filing to get a full charge if used before they were fully charged. This has been fixed in the last couple years, though.
Re:I use monster brand (Score:4, Informative)
More on "memory" (Score:4, Informative)
Re:NiMH (Score:1, Informative)
Because of the short shelf life, NiMHs are best used in high-drain devices like digital cameras, GPS receivers, cel phones, etc. They are _not_ good for things like TV remote controls and clocks that don't use much power because you lose more power to leakage than to the device. In these applications, good old-fashioned NiCds work better.
Lithium-ion batteries pack a punch, but they're expensive, and they require external circuitry to prevent overcharging, as overcharged Li-ion batteries tend to explode. For this reason, they tend to be used only in special applications. In the consumer world, they are most commonly used by hobbyists in custom RC cars and airplanes.
Lithium polymer batteries are a step above Li-ion. They don't require the extra circuitry, they're very light-weight, and they can be made in almost any shape and size. They don't even need a metal case. They more often resemble a bag full of jelly! But because of their high price, they are very uncommon in consumer applications. However, I expect we'll see more Li-polymers appearing in weight-critical applications in upcoming years...such as in electric cars and bicycles.
-- A battery enthusiast
Re:NiMH (Score:3, Informative)
Not if you want decent battery life, it shouldn't.
I think you'll find most "advanced" LED flashlights use a small PIC and utilize PWM to regulate the LED current rather than wastefully throwing away any battery voltage in excess of the LED's forward voltage.
And if they don't use a microcontroller, they use a battery arrangement as close to the forward voltage of the LED so as to maximize available life.
In other words, in such an application it's fine if the LED current varies significantly over the discharge of the battery, because it means a much longer usable overall battery life.
For reference, I have a Photon Micro-Light (a popular brand of small LED flashlight) which uses no resistor (or PWM) whatsoever. Just two watch batteries in series connected directly across the LED.
Re:Save the environment.. (Score:2, Informative)
Panasonic makes most of the cells any way (Score:4, Informative)
Rechargeable Alkalines are no more... (Score:3, Informative)
I liked 'em so much I went back to Target to find more and discovered that they're not carried there anymore. Nor at Radio Schlock. Nor at a bazillion other places. I think Ray O Vac is trying to phase them out.
It's too bad -- rechargeable alkalines do something the others don't: last a long time in the drawer. It takes years for an RA to self-discharge; about 30 days for a NiCd.
(The upshot is that any NiCd you don't store in a a charger is empty when you actually want it).
Rechargeable alkaline (Score:4, Informative)
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.
Re:All About the Same (Score:1, Informative)
Actually, Taiwan == China, though not Taiwan === China. Just about any thing made in Taiwan (especially steel products) are actually made in PRC then finished in Taiwan. For decades most companies in Taiwan have shipped as many factories as they could across to providences in China. Their labor is extremely cheap, the government is willing to let them do about anything, and the Taiwanese gov't is pretty lax in country of origin decisions. So in this case, the batteries are likely made in PRC and then painted (if that) and packaged in Taiwan.
Re:Save the environment.. (Score:2, Informative)
cut down your energy use you pigs! (Score:2, Informative)
Zen says, 'information....' (Score:3, Informative)
With industry claiming that one set of rechargeable double-A batteries can be charged up to 1000 times, even before you consider the environmental impact of switching to rechargeable batteries, the economic arguments for using them are very convincing.
In my experience, a set of current generation rechargeables cost no more than two to three times what a set of comparable quality disposable batteries do and even if the advertiser's claims with regard to the number of recharging cycles are wild lies--exaggerated by a factor of one hundred--you *STILL* make out like a bandit by using them. As far as I'm concerned, they're the smartest thing going.
Down to brass facts, or, 'more than you ever wanted to know...'
Current rechargeable batteries are an imperfect technological compromise between alkaline batteries and cheaper disposable battery technologies. As such, you find that even the best rechargeables tend to be somewhat underpowered in terms of the voltages they generate. Disposable and recharable double-A batteries share form factors, but the rechargeable is designed to sustain a slightly lower voltage than the disposeable--when you read the fine print on a sampling of rechargeable double-A's, you find that nearly all of them are rated for 1.25 volts instead of the disposable's 1.5---and in some applications requiring a higher voltage, rechargeables might not be all they're cracked up to be. Personally, I have never seen this to be the case.
For a lot of people who thought about buying rechargeables years ago and rejected the idea, one of the things that put them off was having to charge their batteries all night for units that didn't have anything like the stamina of disposables. This is simply no longer true. Rapid chargers are available from a number of well-recognized companies which will rapidly impart an almost full charge to them, often in as little as one to two hours.
The stamina of rechargeables has also improved over the last few years. Rechargeable batteries are rated according to their maker's claim that their batteries will put out useful voltage over time. This is measured in thousandths of an Ampere per hour (aka, milliampere hours, sometimes abbreviated, mAh) with the number of mAh forming the cornerstone of the company's marketing efforts. In theory, the greater the number of mAh on the battery's label, the longer it will last in high-drain devices like digital cameras, where rechargeables are pretty much imperative if you want to avoid going broke while you poison the local groundwater.
Back in the bad old days, rechargeable batteries were nasty beasts with little to offer. You had to be organized and disciplined to use them. They were expensive. They took all night to charge and compared to a set of Duracells alkalines, they were bad joke. All of that has changed. I use rechargeables exclusively in applications ranging from my portable reading lamp to my digital camera and I couldn't be happier.
Names to look out for at your local electronics outlet include, Sony (more for their charger than their batteries), Duracell, and Power2000, who have just come out with a double-A battery that they claim offers a 2100 mAh of power, which, if true, put them at the top of the heap.
Happy trails.
Re:All About the Same (Score:2, Informative)
http://www.lewrockwell.com/spectator/spec79.html [lewrockwell.com]
Re:Screw the environment you posers (Score:5, Informative)
Rayovac NiMH charger - Stay away! (Score:3, Informative)
People there are big fans of Maha chargers. They just released one that has an individual charge controller for each cell, which means that you can charge non-matched batteries safely, AND you don't have to charge 2 or 4 at a time - You can charge 1 or 3 if you wish.
As to the types of batteries out there:
Alkaline - Reasonably long shelf life, high internal resistance. Good for low-current applications like TV remotes and HP48 calculators. Gentle discharge curve.
NiCd - Toxic, lowest capacity rechargeables. Lowest internal resistance, which is why they're still popular in R/C cars because of their insane current handling capabilities. Flat discharge curve with a steep dropoff at the end.
NiMH - Almost identical to NiCd except non-toxic, double the capacity, and somewhat increased internal resistance. Excellent for medium to high-discharge-rate devices such as CD players and digital cameras. Same basic charging algorithm as NiCds, although the charger must be aware of minor differences between NiCd and NiMH batteries. Both will actually start DROPPING their voltage as they are charged beyond capacity. Modern smart chargers detect this, but the peak and subsequent drop are much smaller with NiMH, requiring a more sensitive charger.
Lithium - Extremely high capacity, current handling capability, and the longest shelf life. Most are 3v, although I've seen 1.5v "Lithium" AAs (might not actually be lithium.) Non-rechargeable
Lithium Ion - Rechargeable, high capacity, high current handling ability. Very lightweight. Unfortunately quite flammable. Between the low internal resistance and flammability, it is not legal to sell bare Li-Ion cells in the U.S. to someone not licensed to work with Li-Ions. Almost anyone you buy "cells" from in the U.S. (such as www.onlybatteries.com) indicates that the cells are sold in a pack with some sort of protection circuitry if you read the fine print. (This circuitry cuts off the battery if a short circuit is detected, preventing the batteries from exploding.)
Lead-Acid - An oldie but goodie. Highest energy density per unit volume, but horrible density per unit weight. DIRT CHEAP. Still used when enormous capacity and current handling ability is needed at minimal cost. (Read: Car batteries.) A number of variants exist. Standard car batteries have very thin electrodes designed to maximize surface area for maximum current handling ability. These types don't like being discharged very deeply. "Deep cycle" cells have thicker electrodes, allowing them to be cycled more deeply but with less current capacity. (Still quite a bit, and nowhere near as deep as any other rechargeable chemistry.) "Gel cells" are a deep-cycle variant that uses a gelled electrolyte. These are much safer and can be sealed, which makes them optimum for situations where the battery might get wet or tipped over. (Automotive lead-acids are vented and cannot be safely tipped over.)
Re:All About the Same (Score:3, Informative)
The majority of "generic" non-rechargeable batteries sold in the U.S. are made by the same "major" manufacturers. Unless the ink used to print the brand name on the battery is somehow causing a performance increase, any apparent performance improvement is probably due to good advertising.
However, among the major manufacturers (and therefore also among the brands of "generic" battery they OEM), there are differences in construction that make some batteries better for some tasks than others.
While working at Kodak, I found that Kodak's Supralife AAA batteries lasted noticeably longer in my Palm than Duracell or Energizer. When I installed a program that tracked battery voltage, I found that the Supralife batteries' voltage declined in a very predictable curve, where Duracell and Energizer tended to fluctuate, sometimes causing the Palm to decide the batteries were near death when they still had useful life. This was several years ago, and the battery formulations may have changed.
The best advice with disposable batteries is: try a few different brands and find out what works best among the brands in your area, in your device, the way you use it.
Re:All About the Same (Score:3, Informative)
Many people don't know that electronics that says "don't use rechargeable batteries", it's because of the voltage. In those, you're fine using alkaline rechargeables.
In many cases you can use NiMH rechargeables and it'll work fine. Electronics is remarkably tolerant to low voltage levels. However, if you read your warranty on many of those devices, you'll find that you void it if you use rechargeable NiMH batteries. With rechargeable alkalines, you don't need to worry at all. It also makes the "battery meter" on electronics work correctly, say, on a Game Boy Advance, where the LED goes from Green to Red at about 1.35V, and then off completely by 1.2V. Rechargeable alkalines show normal behavior. Palm Pilots as well, though Palms can change their battery meter to read NiMH rechargeables.
And don't get me started that NiMH rechargeables lose charge over time by bleed away, and alkalines don't. So NiMH batteries are useless if you want to just leave them in something for a while.
Short answer: Rechargeable alkalines have several advantages over NiMH, which is why you can still buy alkaline rechargeables. NiMH is almost purely better than NiCad, which is why you can't buy NiCad much anymore (plus I think NiMH is friendlier to dispose of).