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BS: modern rechargable batteries
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Subject: modern rechargable batteries From: Zebedee Date: 16 Feb 01 - 05:19 PM This is a bit obsure, but someone might know... Recently I've bought several things: phone, razor, organiser etc. which have rechargable batteries. In each case, I'm told that I should let the batteries run dry before recharging to extend battery life. This is impractical, as the power running out at any time could be most inconvenient. My television manual says that I should unplug it every night, but 10 years on, still works having been plugged in all the time. Is it the same with mobile batteries? Ed
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Subject: RE: BS: modern rechargable batteries From: Zebedee Date: 16 Feb 01 - 05:23 PM in other words, can the manufacturer's advice be ignored? |
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Subject: RE: BS: modern rechargable batteries From: Bert Date: 16 Feb 01 - 05:27 PM No. Well yes, you can ignore it if you like but when you recharge the battery before it is completely run out it's capacity will be lessened. So each time it gets less. The trick is to keep a spare set of batteries. |
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Subject: RE: BS: modern rechargable batteries From: Zebedee Date: 16 Feb 01 - 05:41 PM Bert, Thanks, but how much less? From what you are saying, I'll eventually reach the point where I won't have any charge at all. If that happens in 10 years, fine. If it's going to happen in 10 weeks then I'll be bothered. Ed
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Subject: RE: BS: modern rechargable batteries From: Bert Date: 16 Feb 01 - 05:43 PM It's just a small percentage each time but it varies on just how much of a charge you leave in the battery. The more charge you leave in the sooner the battery becomes useless. |
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Subject: RE: BS: modern rechargable batteries From: Bill D Date: 16 Feb 01 - 06:13 PM ummm...the answer is slightly different depending on whether you use NiCad...(Nickel-Cadmium) NiMH(Nickel Metal Hydride)...or even Lithium Ion The NiCad do need some more careful discharging, but the NiMH batteries have very little 'memory' problems....I am using NiMH in my digital camera now, and they are supposed to be good for 1000 charges and you don't need to run them all the way down ( a search in Google will get you MUCH more than you want to know_) |
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Subject: RE: BS: modern rechargable batteries From: Bill D Date: 16 Feb 01 - 06:22 PM for example...http://www.weeno.com/art/0599/49.html |
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Subject: RE: BS: modern rechargable batteries From: mousethief Date: 16 Feb 01 - 07:23 PM For NiCd batteries, I just use 2 sets, and hook the half-used set up to a small device I created using a battery case and a small DC engine purchased from radio shack. This decharges them all the way, and then I pop them into the charger. Voila! No "memory" problems. |
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Subject: RE: BS: modern rechargable batteries From: catspaw49 Date: 16 Feb 01 - 07:47 PM What Bill said. I recently converted everything to the NiMH's and they are much better simply because they don't have to be fully discharged. I don't care what the "experts" say on this one, the NiCads just wear out way too soon if you don't go through the discharge completely. My Video Camera battery was down to the point it would only stay charged for 2o minutes tops, and that was after trying to ALWAYS discharge it completely. Go with the NiMH's and a recharger. Our digital camera, which eats batteries right and left, has a lot longer life with them. Spaw |
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Subject: RE: BS: modern rechargable batteries From: Bernard Date: 17 Feb 01 - 06:30 AM A lot of the problems are down to the charger itself. 'Fast' chargers will 'cook' the battery if over-used, but some chargers are 'intelligent'. 'Intelligent' chargers will fast charge, and change to a 'trickle' charge when the battery reaches optimum volts. Some 'intelligent' chargers also have a 'discharge' feature, which can be used to 'cycle' the battery and remove the 'memory'. As for complete discharging, some NiCads will not recharge once totally discharged, although you can often find the cell that is faulty, and give it a short 'boost' charge of about double the voltage for a few seconds, after which it will accept a charge normally - until it is run 'flat' again. The phenomenon of 'reverse' charging is the problem - once a cell reaches zero volts, it will start to reverse-charge if the rest of the cells in the battery have not also reached zero volts. This is why a failing battery seems to suddenly lose its capacity - one cell is sapping the energy from the rest. 'Reverse charging' means exactly that - the terminals will, for a short time, be reversed: '+' becomes '-' and '-' becomes '+'. This is because cells in a battery are connected '+' to '-' in series. Instead of stopping at zero, the cell continues into a negative state, and will start to get hot, although they are designed to 'fail safe' rather than cause a fire.
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Subject: RE: BS: modern rechargable batteries From: John J at home Date: 17 Feb 01 - 08:25 AM I understand if Nicad batteries are discharged to abt 1.1v per cell, the battery life will be optimised. A bit of messing with diode / zener diodes and resistors should come up with a satisfactory discharge circuit. Telefunken came up with a clever IC for conditioning Nicads. I can't remember the part number. Basically it's an externally programmable device which pulse charge / discharges the battery / cell until the correct charged condition is attained. I may have data on it at work if anybody is interested, but be aware that construction of such a conditioner / charger requires some electronics construction knowledge. Data may be available on the internet, although I don't know if Telefunken (also known as 'Temic' I think) have data on the web..I still use Nicads, but I am replacing them with Nickel Metal Hydrides as they die. Hope this is of interest. John PS Hiya Bernard, I'm just getting back into life again. 'spose I'd best tell everyone I'm up and about!JJ |
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Subject: RE: BS: modern rechargable batteries From: Liz the Squeak Date: 18 Feb 01 - 07:50 AM That's all well and good, but what happens when your charger gets knackered? LTS |
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Subject: Charger... From: Bernard Date: 18 Feb 01 - 04:06 PM Didn't know this thread was about horses.... |
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Subject: RE: BS: modern rechargable batteries From: Lonesome EJ Date: 18 Feb 01 - 04:58 PM Wow, you folks are giving the old Radioshack dude (me) a lesson on rechargeables. This is what I see... NiCads are fairly durable under normal temperature conditions, and used in a device not subject to electrical spikes. Even when abused, as in the common situation of the cordless phone which is always put back in the cradle (charger), the NiCad will last from 6 months to four years. Other applications, and in particular camcorder use, seem to contribute to a faster decline in the NiCad storage. This decline can be remedied by either recharging batteries in what is known as a Charger/conditioner, which depletes battery storage before re-charging, or by using a depleting external device like the small dc motor someone mentioned above, or a small wired bulb. NiMh batteries were introduced as the perfect rechargeable battery because they did not manifest the "memory" power decline of NiCads, but I am selling as many replacement NiMh cellular batteries as I did NiCad, which makes me wonder. I believe that NiMh batteries are more vulnerable to temperature variations and possible overcharge/overheat scenarios than are NiCads. I'm still not convinced the NiMhs are worthy of the fact that they are twice the price of NiCad. LithiumIon is the newest technology to be marketed and so far I don't have much history with them. |
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Subject: RE: BS: modern rechargable batteries From: Zebedee Date: 18 Feb 01 - 05:12 PM Everyone, Thanks for your replies. Helpful and much appreciated. Ed
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Subject: RE: BS: modern rechargable batteries From: GUEST,Simon Date: 31 Jul 02 - 07:12 AM My nephew has a game boy advance, which states in its instructions not to use nickel cadmium rechargables, why is this? |
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Subject: RE: BS: modern rechargable batteries From: GUEST,JTT Date: 31 Jul 02 - 07:36 AM What good advice - thanks! My digital camera runs through batteries in no time, even though the batteries are quite new, and even if I leave them in the camera, and leave the camera turned off. Obviously I need to get an "intelligent" charger (any other names for them?) and two sets of NiMH batteries. Thanks! |
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Subject: RE: BS: modern rechargable batteries From: GUEST Date: 31 Jul 02 - 07:47 AM Simon - not sure if this applies, but when I bought a digital camera the other day I was told to use NiMH rechargeables because they supply a higher voltage which the equipt requires. May be the same with the game boy. |
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Subject: RE: BS: modern rechargable batteries From: nickp Date: 31 Jul 02 - 07:54 AM That may be the case - a 1.5 volt NiCad will actually be 1.2 volts and would drop below the 'best' operating voltage range faster. |
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Subject: RE: BS: modern rechargable batteries From: GUEST Date: 31 Jul 02 - 08:11 AM try this. |
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Subject: RE: BS: modern rechargable batteries From: John J Date: 31 Jul 02 - 01:01 PM The only reason I can think of for recommending the use of NiMH or NiCd over primary cells (other the very major economic reason) is that they have a very low impedance which allows you to pull large amounts of current (measured in Amps) from them. The cell voltage is rather lower at around 1.2v per cell. EG: A PP3 9 volt primary (= not rechargeable) battery is made up of 6 x 1.5v cells = 9 volts. a PP3 NiCd or NiMH is made up of 7 x 1.2v cells = 8.4 volts. Sometimes, but not always a problem. Cheers, John |
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Subject: RE: BS: modern rechargable batteries From: treewind Date: 31 Jul 02 - 01:13 PM Here's another version of the story about NiCds and NiMH and 'memory': To keep the battery in good condition, you need periodically to discharge it fully. In between it doesn't matter very much what you do with it (other than overcharging at too high a current which causes damage by overheating). In particular it's not necessary to discharge it fully every time you use it. For NiCad you should do this discharge exercise once a month. All the gory details at http://www.cadex.com Anahata |
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Subject: RE: BS: modern rechargable batteries From: EBarnacle1 Date: 31 Jul 02 - 01:58 PM I have been carrying spare batteries for my cell phone so that I can run them to dead and recharge them at my convenience. Some of my friends just run with the one that came with the phone. So far, this system has given me more life than any of the friends' systems, both with NiCad and NiMh batteries. The problem is similar to one we grew up with. If you pay attention to the batteries in your flashlight or other electrical equipment it will be around when you need it. |
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Subject: RE: BS: modern rechargable batteries From: Pied Piper Date: 01 Aug 02 - 08:53 AM I use a high capacity 150mAh NiMH PP3 replacement in my Deger electronic Chanter. They last about 2/3 as long as Alkali batteries, and cost 6.99 Sterling. I have 2 which I alternate. The manufacturers say they can be re-charged up to 1000 times, but assuming this is pretty optimistic a more realistic figure might be 500 times. At my present playing rate a battery lasts 1 week, giving me a lifetime of 10 years each. 20 years for £14 (plus the cost negligible amount of electricity), not bad with the cheapest Alkali batteries being £2 each.PP |
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Subject: RE: BS: modern rechargable batteries From: GUEST,cocoadragon@yahoo.com Date: 14 Nov 02 - 10:41 PM ...ummm after ten uses my new NiMH are only good for one hour of play in my new mp3CD player. they are suppose to be be good for a minimum of ten hours recharge. I was thinking of taking them back. the two devices i own, a game boy advance and the forementioned mp3 cd player, have failsafes that cut them off before all the power is gone. :-( LOL and i dont have a light bulb, a dc motor orconditioner. ( i think McGieyver must of came over and "borrowed" some things to make one of those weapon detection devices our goverment has been using to sniff out the iraqies persidential palaces...) So is my best option to return the batteries and buy the pack with batteries and a charger for ten dollars more or or put down an extra twenty dollars to get the "quick charger" which someone above said has it's own set of problems? |
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Subject: RE: BS: modern rechargable batteries From: JohnInKansas Date: 14 Nov 02 - 11:24 PM For standard shapes, put your batteries in a flashlight and turn it on. Take them out and recharge when the light goes out, or gets dim enough to see "coils" in the filament. Each of the battery types does produce a different "cell voltage" so some equipment may work better with one type than with another. NiCd batteries probably suffer most from memory effects, although they're pretty good for high discharge rate stuff. The biggest problem with Ni-MH batteries is that they're vented (usually right next to the + post) and may corrode the battery contact or the terminal in the device you use them in. If you're having problems with a reasonably new battery, it's likely that a good buff on the terminals will help - although if you rip the plating off the terminals they'll just corrode faster next time. A little bit of corrosion can cause an incredibly high resistance. The main problem with Lithiums is that they have a tendency to explode (or at least set something on fire) - very rarely, but at least 3 laptop mfrs have had major recalls in the past few years because of it. They're probably the most "touchy" about using a charger designed specifically for the battery, especially since their frequently in "multi-cell" packs - with a lot of multis. There was a fairly long thread about this not too long ago, but I'm nursing one of my other PCs through a rather long download. Maybe later. John |
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Subject: RE: BS: modern rechargable batteries From: GUEST,Sliceablepoem Date: 19 Mar 03 - 12:01 PM Bateeries are charachteriesed by capacity, power density and energy density (both gravimetric and volumetric). I would be grateful if anyone can explain the meaning of power density and energy density. Kadir |
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Subject: Tech: modern rechargable batteries From: Genie Date: 19 Mar 03 - 01:06 PM Thanks for all the info, folks. It's especially good to know that I don't have to totally discharge my NiCD batteries before EVERY recharge and that I SHOULD occasionally discharge my NiMHs fully. One potenital problem with NiMH batteries, I've recently been informed (and found through experience), is that they LOSE THEIR CHARGE quite rapidly, compared to alkaline and NiCD batteries, when they are not in use. What this means is: a - if you charge them up a few days or weeks ahead of the time you'll need them, they may not have the juice you need when you go to use them. b - if you "top them off" before each use -- which requires some vigilance --, you are replacing power that has in effect been flushed down the drain. c - Due to their propensity for losing power, they may not be the best batteries to keep around for emergencies-- unless you have a solar powered recharger. Genie Just a thought for Joe O: Shouldn't this thread be considered "Tech" instead of "BS." A lot of us music makers use rechargeable batteries in our tuners, amps, guitar pick-ups, etc.,--not to mention the computers we use visit Ye Olde Mudcat Café--so this thread is definitely relevant to music. |
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Subject: RE: BS: modern rechargable batteries From: Bev and Jerry Date: 19 Mar 03 - 03:03 PM Slice: As a recovering engineer I (Jerry) will try to answer your question in English. Power is the amount of electricity being used at any given time. A 100 watt light bulb uses 100 watts of power when it's on. Energy is power multiplied by time so if a 100 watt bulb is left on for 10 hours it uses 1000 watt-hours, or 1 kilowatt-hour. Gravimetric power density is the number of watts per unit of battery weight measuered in watts per pound or, in the case of the kind of batteries being discussed in this thread, milliwatts per gram. Gravimetric enerty density is the number of watt-hours per pound. You probably will never care about these measurement unless you're designing a spacecraft or are extremely sensitive to the weight of the device in which the batteries go. Volumetric power density is the number of watts per unit of battery volume measured in watts per cubic inch. Volumetric energy density is the number of watt-hours per cubic inch. If your shopping for a battery, the volume and shape of the battery is determined by the device you're putting it in. So, the higher the volumetric energy density, the more energy the battery will have and the longer it will last. Likewise, the higher the volumetric power density, the more the battery will be able to deliver at any time. This can be important in certain high power applications like digital cameras. The amount of current being delivered by a battery at any monent is measured in amps (milliamps). If you multiply that by the battery voltage at that time you will get the battery power discussed above. Capacity is the amount of current multiplied by the time it's delivered and is measured in amp-hours (milliamp-hours). The relation between current and capacity is similar to the relation between power and energy except that the battery voltage has been eliminated from consideration. Did this make it better or worse? Bev and Jerry |
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Subject: RE: BS: modern rechargable batteries From: JohnInKansas Date: 19 Mar 03 - 03:20 PM Kadir A battery "contains" a certain amount of energy, and a "high energy density" battery contains a (relatively) larger amount of energy within a smaller weight or volume. A battery with a "high power density" is able to deliver its energy rapidly (i.e. at high current), even though the total amount of energy it can deliver may be more or less than the "high energy" battery of similar size, shape, weight, or volume. If the information you are looking at does not have "pictures" of "discharge curves," you may be assured that it was written by the advertising department - and not by engineering, so it's fairly safe to assume that it's meaningless marketing hype. The one exception, where somewhat meaningful information is available at the consumer end is for automotive batteries, where you will often find a "total capacity," stated as the total number of "ampere seconds" that can be discharged (at, typically, 12 volts) at a specified level of current - before the voltage falls below a standard minimum value. This is an "energy capacity," although you'll have to separately divide by battery volume or weight to get a density. For the automotive battery, you'll also find a "cold cranking capacity" which specifies the maximum current that can be "taken out" over a standard period of time, without reducing the voltage below a standard minimum value. This is effectively a "power capacity," which, again, you can divide by battery "size" to get a "power density." Without knowing the specific specification applied to the measurement, it is meaningless adspeak. If you can find the standard test specification used to determine that a particular battery deserves its "high capacity" designation, then the specification itself will tell you what it means. For most "consumer" batteries, the test specification is the procedure developed by the manufacturer that makes his own batteries "look better." John |
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Subject: RE: BS: modern rechargable batteries From: GUEST Date: 25 Mar 03 - 04:45 AM Hey guys, they are the type of answeres I had been looking for. Thanks. Kadir |
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Subject: RE: BS: modern rechargable batteries From: Dave Bryant Date: 25 Mar 03 - 05:37 AM Slight thread drift - For many years it was the general opinion that electric cars would never really be viable because of the weight of batteries required. Nowadays, thanks to the research that has been used to find technology for powering Mobile Phones, Portable Computers, and Digital Cameras etc, we are a getting much closer to that goal. It doesn't seem as though the motor industry tried very hard to solve the problem in the last 50 years ! |
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Subject: RE: BS: modern rechargable batteries From: JennyO Date: 25 Mar 03 - 10:23 AM Gee I wonder why? (drifting further) Could it have something to do with oil, money, power and things like that? |
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Subject: RE: BS: modern rechargable batteries From: JohnInKansas Date: 25 Mar 03 - 10:43 AM Dave Bryant - The technology for powering Mobile Phones, Portable Computers and Digital Cameras has virtually nothing to do with the development of potential "batteries" for electric cars. Those technologies remain mostly poor choices for vehicle power. The "batteries" being used for the few "electric" vehicles that are beginning to appear bear little resemblance to them, and have been developed as separate technologies because the motor industry has tried very hard to produce marketable products using secondary power devices. A look at the questions and comments in this thread alone should dispell the assumption that the batteries to which you refer have been "perfected" for reliable performance in high-usage and high-power density applications. If anything, the transfer of technology appears likely to go in the opposite direction from what you imply - since there appears to be a good chance that automotive research may lead to fuel cell power in your portable computer within a few years, in a spin off of methods developed primarily by the automotive industry. John |
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Subject: RE: BS: modern rechargable batteries From: Mr Red Date: 26 Mar 03 - 06:12 AM FWIW toy car racwers only use NiCad because of the lower internal resistance. NiMH has a lower memory effect (from part charge) but even Lion batteries are not immune to memory effect, it may be small but not unnoticeable. The Lion batteries on my camcorder have all but given-up after 3 years but I was warned that the particulaer Sony camera "hammers the batteries" particularly on single shots. More modern devices are kinder on the batteries but they still suffer from charge discharge cycles. NiMH have a life of half that of NiCad for the same hammering. |
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Subject: RE: BS: modern rechargable batteries From: Bernard Date: 26 Mar 03 - 12:48 PM The biggest problem with batteries for electric cars is the very fact that they need charging! Okay, the car itself may have negligible emissions when in use, but the power station providing the power to charge the batteries certainly hasn't! So it's really more efficient for the vehicle to generate its own power... Until that side of the problem is satisfactorily addressed, I suggest that there isn't really a lot to be gained (apart from PR!) from using battery powered vehicles! Ho hum! Back to the drawing board!! |
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Subject: RE: BS: modern rechargable batteries From: GUEST Date: 27 Mar 03 - 05:11 AM I have found various battery types: Sealed lead acid Alkaline Alkaline manganese dioxide zinc Carbon zinc Alkaline zinc air Silver Oxide zinc Zinc Chloride Zinc mercury oxide battery Manganese alkaline Nickel metal hydride (NiMH) Nickel cadmium (NiCd) Lithium manganese dioxide (Li/MnO2) Lithium ion Lithium thionyl chloride Lithium Polymer Lithium Sulphur Lithium Photo Mercuric Oxide Most of it is secondary (rechargeable) batteries. I would be very happy if anybody can give me or tell me where i can get some information about these batteries. thx Kadir |
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Subject: RE: BS: modern rechargable batteries From: Bernard Date: 29 Mar 03 - 07:42 PM Mercury-based batteries are banned in most countries, and have been replaced with a silver based equivalent which is significantly more expensive. As I understand it, neither are sold as 'rechargeable'. It has been a myth for a long time that 'ordinary' cells are not rechargeable. Although they will not 'cycle' as many times as 'rechargeable' cells (typically no more than 20 cycles), using an 'intelligent' charger I have had good results - the cost of the charger being recouped fairly quickly. The cost was about 30 quid (45 dollars?), which meant I had to charge a couple of sets of AA cells fifteen times to make it worthwhile. Okay, I had to plug it into the mains, but that cost is negligible. The principal is simple - they cannot be charged with straight DC current, it must have an AC component which is assymetric - charge and slight discharge - which prevents dendhrites (crystals) forming on the anode. Sorry about the over-simplification! Hah! You also have to be careful to watch out for signs of leakage. The explosion warnings are propaganda from the manufacturers to dissuade recharging - a properly made cell is designed not to explode, or they wouldn't be allowed to sell it!! |
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Subject: RE: BS: modern rechargable batteries From: JohnInKansas Date: 30 Mar 03 - 01:06 AM Bernard - The possibility of recharging the typical carbon-zinc cells has been discussed, and I'm sure you're aware of - and careful with - the hazards. Corrosive leakage is probably the worst that will happen. One of the worst hazards reported is with the Lithium Ion (rechargeable design) batteries popular in Laptop computers and other small handhelds - which do have a record of exploding under improper(?) charging conditions. Several laptop mfrs have had extensive recalls due to "flaming machines," but the battery mfrs have managed to do pretty good damage control, so not much has been published about it. It appears (based on scanty reports) that the problem only occurs when there are manufacturing defects in the batteries, but it's still something to watch out for. I personally avoid leaving my Li powered portable "on charge" if I'm not around to watch it. John |
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Subject: RE: BS: modern rechargable batteries From: Bernard Date: 30 Mar 03 - 06:40 AM Tetchy today...?!! ;^) |
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Subject: RE: BS: modern rechargable batteries From: Schantieman Date: 30 Mar 03 - 08:59 AM So - have I got this right? Standard, relatively cheap. old-fashioned zinc-carbon dry cells can be recharged? What sort of device produces this asymmetric (?sawtooth?) current? Steve |
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Subject: RE: BS: modern rechargable batteries From: JohnInKansas Date: 30 Mar 03 - 01:48 PM Schantieman - People have been recharging zinc-carbon cells for at least 50 - 80 years, judging from the ads in the old Popular Science magazines for dry cell chargers. It was more often done before cells designed to be recharged were available. It can be done, and some claim good success with it; but you do need to watch the condition of the batteries carefully. I haven't found it worth the extra effort required; but I'm sure someone (come on Bernard) with some experience with doing it will be along soon. John |
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Subject: RE: BS: modern rechargable batteries From: Bernard Date: 01 Apr 03 - 01:18 PM Click here for a UK company, or do a Google search for 'charge zinc carbon batteries', which is how I got that link. I have a circuit somewhere for building one, but ready made ones are so cheap it isn't worth the bother. The wave form is a sine wave, but (in simple terms) doesn't go 'down' as far as it goes 'up'. It's also referred to as 'dirty DC'. |