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Cordless Phones with High Tech Batteries? 52

Posted by Cliff from the I'm-getting-sick-of-NiCad-too dept.
ewieling asks: "I will be replacing my current corless phone soon and was wondering if there are any cordless (not Cell) phones that have something better than a NiCad battery. My current cordless phone had great battery life when I first bought it, but soon the battery life degraded until now I only get about 10 mins of talk time out of it. I tried to avoid the 'memory' problems of NiCad batteries, but I still get very little talk time now. My current cordless phone is a high end (at the time I bought it) Panasonic with a keypad, LCD display, speaker phone and headset jack on BOTH the base station and the cordless handset and uses the 2.4 Ghz range, but it still only has a NiCad battery. Can anyone help me find a good cordless phone with the above features that uses better battery technology."
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Cordless Phones with High Tech Batteries? More

Cordless Phones with High Tech Batteries?

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  • Comment removed (Score:3, Informative)

    by account_deleted ( 4530225 ) on Monday October 07, 2002 @03:36AM (#4401249)
    Comment removed based on user account deletion
  • Nickel Metal Hydride batteries last longer than NiCd batteries.

  • There are different philosophies, but how are you avoiding your NiCad's memory problems? My Sony 900MHz is maybe 3-4 years old now and its batteries still last as long as they did when they were new--standby at around a week. I don't talk hours on end but they last a lot more than 10 minutes. I basically let them drain until they're dead then swap them with the second battery charging at the base.

  • Just change the old nicads. (Score:5, Informative)

    by Gordonjcp ( 186804 ) on Monday October 07, 2002 @03:40AM (#4401258) Homepage
    They're really cheap. You can get replacement cordless phone batteries from most decent electronics shops for a couple of pounds - sometimes they're actually cheaper than similar-sized ordinary nicads.
  • From my use of batteries and what I've read on the matter, here are a couple of suggestions:

    1. Use Nickel Metal Hydride (NiMH) batteries - I'm sure there will be a thousand posts on this.

    2. Keep you batteries charged!!! With NiMH, if the battery is discharged it looses hydrogen at the anode and thus looses capacity. With NiCads, it means the deactivation of reactants which yields the same results. That means keep the phone on the charger when not in use.

    3. If you feel the batteries are loosing their capacity to recharge, the best thing to do is to drain them completely and recharge them at least twice.

    Just my two cents ;)

  • Solutions: 1) Don't charge so much. 2) Discharge. (Score:3, Informative)

    by Futurepower(R) ( 558542 ) on Monday October 07, 2002 @04:06AM (#4401323) Homepage

    See my previous post about how to have less trouble with NiCad batteries:

    Solutions: 1) Don't charge so much. 2) Discharge. [slashdot.org]

    Someone responded to that post with a link to a PDF file. The PDF file contains interesting information, but is too detailed for most people. It mentions that often the memory effect isn't really memory effect, but another process that has the same cure.

    I agree that it is good to replace the NiCads with NiMH batteries. But it is possible to live with NiCads if you observe their limitations. It is possible that a particular device designed for NiCads will not charge NiMH batteries well.
    • NiMH batteries are very sensitive to being reverse biased. If you discharge your pack all the way down, you WILL kill it.

      My advice is to forget about memory effects. You're not likely to see them anyway. Worry more about running the pack all the way down and destroying a cell with a reverse bias. Keep the thing charged all the time if you can.

      • There was no mention of discharging NiMH batteries. There would be no need to do this, since they don't have memory effect.

        The discussion was about discharging NiCad batteries perhaps once a year. This was recommended in the RCA NiCad design manual.

        • Re:NiCad, not NiMH (Score:3, Informative)

          by ivan256 ( 17499 )
          Let's put this falsehood to rest already:

          NiCd Batteries do NOT have "memory" [repairfaq.org]
          • I posted the same thing a while ago, and it turns out that practically speaking, NiCd batteries do not have memory. But technically, if you have the right equipment to discharge batteries to exactly the same level over and over you can develop a memory.

            Regular users are not likely to ever develop a memory in a NiCd battery.
          • Whether it is the memory process or another process that causes the degradation, the cure is the same. I doubt that the person who wrote the question cares about the exact process.
            • Whether it is the memory process or another process that causes the degradation, the cure is the same. I doubt that the person who wrote the question cares about the exact process.

              The cure is NOT to switch battery types, it's to charge your batteries correctly.

              Instead of looking for a phone with a "high tech" battery, he should be looking for a phone with a high quality charger.
        • Right, but someone out there will replace their NiCd battery with NiMH. Then they will run a pack all the way down. Then they will start crying when their NiMH pack dies after 10 charges because they reverse biased a cell in the pack.
    • Do not discharge packs of batteries below 1 volt/cell. (Nominal NiCd/NiMH voltage is 1.2V, so don't drop a 4.8V battery below 4V, for example)

      Going beyond this will run a great risk of a cell reversal and your pack is DEAD.

      Discharging individual cells to 0 is a different story. Don't do this often though, but it might help to do it occasionally.

      NiMH batteries can be charged by NiCd chargers in certain cases. Specifically, slow chargers. Many such chargers are designed to safely continuously charge NiCd batteries even past full. (Almost all "smart" chargers apply a small trickle charge continouously after stopping. Slow NiCd/NiMH chargers supply this current at all times).

      I believe a lot of phones fall into this category. In general, if it takes 14 hours to charge your NiCd, it'll be safe to use the same charger to charge a NiMH. (It'll take 20 or more hours though). Most cordless phones require 10+ hours of charging before initial usage.

      • Andy,

        You said, "Do not discharge packs of batteries below 1 volt/cell."

        I've discharged NiCad (not NiMH) batteries to zero volts numerous times, with no problems. My original post that started this thread suggested discharging with a 510 Ohm resistor. This is such a slow discharge that apparently it causes no problems. It may take 48 hours to completely discharge a battery, so this is a method for people with backup cells.

        However, you are bringing up an important issue. The discharge should be very slow. A slow discharge is NOT the same as using an appliance until the batteries are dead, or putting the batteries in a flashlight until they are dead.

        I also would also guess that most NiCad slow chargers would charge NiMH batteries. NiMH fast chargers should not be used with NiCads because the normal charge rate of NiMH batteries is higher.
        • Be careful...

          Usually in a battery pack the cells are pretty well matched. But no match is perfect. The problem with this is that in such a case, one cell may hit 0 volts before the others. Once this happens, that cell is forced to continue "discharging" itself by the other cells in the pack. Problem is it can't discharge any more without being seriously damaged. This is what a cell reversal is - If a cell reversal happens, you've lost the pack.

          It doesn't matter if it's been discharged slowly or not, a reversal is a reversal.
  • These phones also have replaceable batteries.
    They have very good reception and sound quality, as well as a respectable speaker phone function on the handsets and a 200 number memory.

    However, in all other respects they suck hard. This is mainly because the UI is counter-intuitive and very unresponsive.

    There is some kind of serial interface on the base station, which I assume could be used for synchronising the phonebook with a PC, but in their wisdom Philips have denied us that facility and you have to use the crappy UI to peck in each entry.

    What really gets me about these DECT phones is that they are mostly similar to cellular models from the same manufacturer but they are always stripped of the most useful functional extras.

    There. I've said it.

  • Old batteries are dead batteries (Score:5, Informative)

    by adolf ( 21054 ) <flodadolf@gmail.com> on Monday October 07, 2002 @06:01AM (#4401534) Journal
    From the tone of your article, the phone itself sounds like it is relatively old.

    Nicad batteries wear out. This is normal. They're also the cheapest and safest rechargable batteries you're likely to find, bar none.

    So, just replace them. Find a well-stocked Panasonic phone dealer (amazon?) and get the genuine article, or just pick up the appropriate off-brand replacement at the department store of your choice.

    While it certainly wouldn't be impossible to design a cordless phone that used rechargable lithium cells, noone seems to market such a beast to the consumer. Probably because lithium batteries are very good, very light-weight, and also very expensive. They also tend to react explosively to mistreatment during the charging cycle. Stay away from lithium rechargables in devices not expressly intended to use them. [FWIW, Motorola Startacs have a microprocessor in the battery pack itself, expressly for the purpose of lawsuit prevention - I imagine most/all other companies do the same thing, but I've never taken apart any other Li-Ion packs.]

    You might be able to change the nicad cells with NiMH, but you're not likely to get any net benefit from the exercise. Besides, NiMH suffer severe stamina problems after being charged for too long at one time, which is something that chargers designed for this type account for, and your cordless phone does not.

    So. With NiMH, you'll have to remove the cordless phone from the base after no more than 12 or so hours of charging, followed by a substantial drain before the next re-charge. Unless you're able to do this every time you charge it, and are able to train your friends and family to do the same, I'd avoid a NiMH retrofit, unless you anticipate and accept that permenant battery damage will result. [At least they don't tend to explode, like lithium batteries do...]

    And at any rate, if you had the discipline to follow such strict procedures, you'd have plain old, cheap NiCads that last forever, just like me.

    I've got a 4-year-old, vanilla, Uniden 900MHz analog phone. It works well, having great audio quality at long distances through any number of obstructions.

    I replaced the stock battery after a year or so with whatever compatible type Sears had at the time, and things have been golden since.

    Tricks:

    I use the phone until it's either inoperably dead, or starts in with its low-battery song and dance (blinking light, funky stutter ring when someone calls). When this happens, I place it on the charger, and leave it there until at least the next day. When I feel like using it again, anywhere from six hours to six days later (depending on alcohol intake), I keep it off the charger until it is once again dead. The whole cycle takes from 5 days to just over a week, depending on use.

    Those who are keeping score will note that I've got three years of outstanding service from a cheap Sears battery. It takes a slight effort to keep things in-check, but the system (as a whole) is reliable and predictable, which is really all that matters.

    That all said, I echo your sentiment: I've got a Nokia cell phone with their smallest available lithium battery. I only ever use it with the cheap, third-party charger I have in the car, which cooks the battery completely in just over an hour. Routine fast charging like that is supposed to always be bad for batteries. But Lithium batteries seem to Just Work(tm) no matter what I do to them, and I still get great talk time and days worth of standby. Must be that microprocessor...

    I'd love for a cordless phone manufacturer to start using modern battery systems. I'm even willing to pay extra for it the convenience of not having to bother with the proper care and feeding fo the battery.

    Even my UPS, a Best Ferrups 850, maintains its sealed lead-acid battery (a Panasonic) automagically. Once every 1 or 2 weeks, it'll switch over to battery power for a few minutes at a time. It then tops off the battery again and resumes keeping it on float charge. This is all part of the normal care and feeding of a lead-acid battery (your car does it with its battery, too, by virtue of you running the starter motor), but most UPSs don't do it at all. OTOH, I suppose this is no ordinary UPS [powerware.com], but why can't phone manufacturers adopt at least semi-modern battery technology? NiMH would be a good, safe, and inexpensive start. Even my RioVolt came with a pair of AA NiMH batteries, and enough smarts to avoid abusing them.

    Good luck!

    • >So. With NiMH, you'll have to remove the cordless phone from the base after no more than 12 or so hours of charging, followed by a substantial drain before the next re-charge.

      Sorry, but no need for this. NiMH has no memory effect.

      And an advantage of NiMH is that its charge lasts much longer than NiCd
      • I never said NiMH batteries suffered from memory effect, just that they have issues with being cooked too long in the charger.

        Try it sometime.

        NiMH and NiCads each have very similar charging voltage and current, so it's quite possible to use NiMH batteries in a NiCad charger.

        Here's what you'll need:

        A set of NiCads, a set of similar NiMH, and two examples of the same type of (dumb, timerless, non-smart, plain-old-voltage-source) charger, such as that found on a cordless phone base.

        Load one charger with NiCads, and the other with NiMH, and make the chargers charge for 12 or 14 hours - whatever seems typical for that battery capacity in that charger.

        After this, measure the capacity of each set of batteries. A small flashlight and a stopwatch will work fine for this (but don't let things discharge completely - that's another type of abuse, altogether). Record your findings. The NiMH battery will probably last somewhat longer than its NiCad counterpart.

        After that, repeat the experiment using the same batteries, except increase charging time to one week instead of half of a day. The NiMH batteries will lose substantial capacity during this time, which you'll see with your stopwatch. The NiCads will still have similar capacity to what they did during the first experiment. Record your findings, and realize this:

        No technology is perfect. Repeat it over and over until it becomes clear. No technology is perfect. No technology is perfect. No technology is perfect. Once you get that to sink in, start with the following: Nothing is what it seems. Nothing is what it seems. Nothing is what it seems.

        After a few months of this, perhaps you'll be able to emerge from Marketroid Consumerland and join the rest of us thinkers.

        While it's true that NiMH batteries do not suffer the same "memory effect," per se, of NiCads, they are not without their own particular problems and quirks. Chief among these is how susceptible they are to damage from being charged too long. They also leak (self-deplete/drain/reach maximum entropy) faster than NiCads, discharging themselves relatively quickly while not connected to anything at all.

        • >Chief among these is how susceptible they are to damage from being charged too long

          This is what smart chargers are for.
          • > This is what smart chargers are for.

            Clearly. And in the context of the article (did you even RTFA?), there is no "smart charger" to be had. This makes the point rather moot, don't you think?

            And now for something completely off-topic:

            Have you ever, even once in your life, agreed with someone in an upfront manner, or admitted that you were wrong?

            Or are you one of those people who are always right, and will always state fault with what someone else is saying, even when there's a chance that you're not right and that the other person's statement is without flaw?

            Just curious.

    • I agree with what you are saying except for stating NiCads are safe (cadmium) which makes disposal a problem. Some people don't care about toxic metals such as cadmium and mercury, but its enough to be regulated:

      Explanation Of Carcinogenicity: CONTAINS CADMIUM [7440-43-9] WHICH IS LISTED BY NTP AND IARC AND REGULATED BY OSHA AS A CARCINOGEN.
  • I've had a Siemens Gigaset 2415 (plus another 2400 handset) for the last couple of years and it takes two standard AA NiCad or NiMH rechargables. I'd be careful about inserting NiMH batteries into any old phone, since they have different charging characteristics from NiCADs. Still, even with NiMH the phone doesn't have a great talk- or standby-time, maybe two to three days standy. It seems that the current generation of digital cordless phones aren't as power thrifty as they could be, most 900 MHz analogs would beat them in terms of battery life. At least that's my experience and what I've heard of some other phones as well.

  • Battery Bashing (Score:4, Insightful)

    by evilviper ( 135110 ) on Monday October 07, 2002 @07:53AM (#4401744) Journal
    I hate battery bashing...

    There is nothing wrong with your NiCads. They can be just as powerful, and be recharged just as many times as LI & NiMH. In fact panasonic made 1100mAH AA NiCad batteries (if only they'd boosted the voltage as well, they could have been Alkaline Killers).

    The problem is simply stupid NiCad chargers. People know that they can handle being overcharged, so everyone has something about as complex as an AC adapter to charge them.

    LI & NiMH batteries just get the good quality rechargers. That's why they fare so much better. The only legitimate complaint about NiCads I've heard, is that they don't have keep their charge for months at a time like other batteries. That may be true, but it's not a big of an issue all that often.

    Anyone care to hazard a guess as to why rechargable battery makers don't put out 1.5V rechargeable batteries and kill off alkalines once and for all?
    • I'd imagine the reason they don't kill off alkalines, is cause they're still making a killing on them?
      • Well, that's the obvious first answer that comes to mind. I could be wrong about who owns who, but I don't think the main Alkaline battery manufacturers are associated with the rechargable battery manufacturers. So, if they aren't mutually owned, some payola might possibly be changing hands.
    • Anyone care to hazard a guess as to why rechargable battery makers don't put out 1.5V rechargeable batteries and kill off alkalines once and for all?

      Could it be the half-cell voltage conspiracy?

      • Could it be the half-cell voltage conspiracy?

        That would be a plausable explanation if you assume every single engineer who has ever worked on rechargable batteries, is a TOTAL MORON.

        Last time a checked, two batteries can be hooked up in serial, thus providing higher voltages. So, it's just a matter of making two, half-height, AA batteries at 0.75 Volts a piece, and you've got yourself a Rechargeable, 1.5V, 1100mAH, AA battery.

        Of course, I'm positive that I'm the first person to EVER have thought of that bit of basic electrical engineering... </sarcasm>
        • When's the last time you ever saw an alkaline battery that put out .75 volts? Do you understand what a half-cell is?
          • When's the last time you ever saw an alkaline battery that put out .75 volts?

            Never. Why? Perhaps you do not understand what I'm saying?
            • So, it's just a matter of making two, half-height, AA batteries at 0.75 Volts a piece

              If you make a half-height battery it'll be 1.5 volts. Do you know what a half-cell voltage is?

    • Re:Battery Bashing (Score:1, Informative)

      by Anonymous Coward
      Anyone care to hazard a guess as to why rechargable battery makers don't put out 1.5V rechargeable batteries and kill off alkalines once and for all?

      It has something to do with the chemistry of the battery. It's been a while since I took chemistry so someone chime in with corrections if needed.

      Most every battery work in the same basic manner in storing the charge in an electro-chemical process. The charge is stored in the creation of a bond and then released as the bond breaks. The difference is in the elements used in the reaction. The different elements each have a different "voltage" associated with it which is based on where it lands in the periodic chart. The futher apart they are on the table the greater the voltage that can be produced in the reaction. The elements used in an alkaline cell are spaced 1.5 volts apart, a Ni-Cd cell uses elements spaced 1.2 volts apart and so on. A 9 volt alkaline battery just has 6 cells inside to achieve the rated 9 volts, similarly with a 12 volt car battery and other true batteries (not "cells" which are commonly called "batteries").

      So to answer your question why someone doesn't just make a 1.5 volt rechargable is because the chemistry becomes too complex to fit in one little cell and still get a reasonable capacity. It is easy to make a "one-shot" alkaline because the reaction only has to go one way. It's kind of like storing heat in wood, it's easy to burn the wood for heat but it's more complex than heating up the ashes to get the wood back to a burnable form again. To get a cell that could recharge easily meant choosing elements different than those used in a traditional alkaline cell, ones with a different natural voltage difference.

  • Swaping Batteries (Score:3, Informative)

    by north.coaster ( 136450 ) on Monday October 07, 2002 @08:40AM (#4401903) Homepage

    Let's assume that you're replacing the phone for reasons other than the amount of talk time that the current battery is providing you with. As others have pointed out, if talk time is the only problem then replace the darn batteries and move on... :-)

    If you're buying a new phone, look for one that uses standard size AA rechargable batteries, instead of a proprietary battery pack. A phone that can handle NiMH batteriers is somewhat preferable to ones that can only use NiCAD batteries, but since NiMH batteries cost more I'm not sure that they are really worth the extra cost.

    There are several advantages with standard size AA rechargable batteries. One is that you can purchase replacement batteries from any good electronics shop. Another is that if talk time consinues to be a problem then you can always buy a second set of batteries and an inexpensive stand alone reconditioning charger, and swap batteries back and forth between the phone and the charger. Note that the charger should have a reconditioning circuit (cheap ones don't).

    There are several good inexpensive chargers on the market. I use a MAHA brand charger, which I purchased from Thomas Distributing [thomas-distributing.com]. I have used it to recharge both NiCAD and NiMH batteries with good results.

    /Don

  • The Gigaphone is 2.4Ghz, handset has integrated speakerphone, callerID 50 number memory. Expanable, with sperate charges for each handset you add to the system. Basesets come as a plain, digital answer, speakerphone. Speakerphone works well, with few complaints from callers.

    They have the great range you expect from 2.4, and I've seen a newer 5Ghz version.

    Best of all, NiMh batteries. I've had a 4 handset system for 2 years, and the only problem I've hand is forgetting to put the handset on the charger for a few days. When this happens....I reach for the base, and grab the spare that sits there on charge. Swap, and go.

    Works great
    • same system for me, I agree that these batteries work great. Range is decent (base station on the ground floor covers upstairs, basement, and about 30 feet outside the house). I had to get used to the quality, sounds like there's just a little extra background noise when you're listening. Belt clips and headset jacks are standard, another cool feature. Speakerphone feature standard on all phones, and that works quite well.
      Worst thing: I'd like the option of each handset maintaining its own individual memory list (that's the way it is now) OR the base station maintaining the list. Programming 20 numbers into 3 phones sucks (at least you only have to do it...uhm, three or four times).
      Intercom feature works well, but I'd like the handsets to be able to automaticly go off hook, like the base station does.
  • I have had a couple of Ericsson 260 cordless DECT phones [ericsson.com] with NiMH batteries for a couple of years. They work very well and have no problems with memory effect (unlike our previous cordless with NiCads).

    Recommended if you can get them in the US.

    • You're quite the subversive, aren't you? You didn't even mention that this phone runs Linux [linuxdevices.com]!

      -Peter
      • You're quite the subversive, aren't you? You didn't even mention that this phone runs Linux!

        This really should be modded "Funny"...

        Read the article again. It is the new cordless Screen Phone HS210 that runs Linux. I'd be very surprised if the 230 or the 260 is running Linux. It would be vast overkill for the functionality they have.

  • I will be replacing my current corless phone soon...

    Coreless? Kind of like the string-and-tin-cans? Those have poor amplication, but you never have to worry about the battery life. ;)
  • My VTech VT1421 (touted as the smallest 900MHz cordless phone) uses a NiMH battery; while probably a far cry from a Li-Ion battery, it's certainly better than a NiCd. The phone's base includes a charger so you can have a spare charged battery there in the (unlikely) event the phone's battery dies (it lasts about a week without recharging) and you absolutely need to talk. A fancy plus is that, if the power goes out, the base draws power from the spare battery, so you can keep on using the phone.

    Now, chances are the VT1421 is already discontinued, but do look into vtech's line; i guess if they used NiMH on the VT1421 a couple years ago, they're still using it on newer phones.
  • I refuse to buy a cordless that doesn't have quick-change batteries and a charger in the base. When the current battery is run down I swap it with the one in the base. NiCads last a coupla years and then I replace them.

    The big advantage is that the phone doesn't have to spend a lot of time on the base. The base can be out of the way and the phone where it's convenient.

    My next cordless will likely be a Panasonic, which takes standard AA batteries. A coupla sets of NiMHi will be just as convenient and even easier to replace.
  • 900mhz (analog I guess, did not realize they where making household cordless phones digital);

    about, err, 6 or 7 years old, maybe a bit older.

    No clue what battery type it has in it.

    Never had to change. Just hang it up on the charger when done talking.
  • I work from home doing tech support so I'm sometimes on the phone for 8+ hours a day. Oviously I don't need to be on the cordless the entire time. I think what I'm going to end up doing is replacing current base station and handset with one that supports two handsets, that way I can have one charging while I'm using the other one. --Eric
  • li ion phones do exist, at least we have them in europe. yes, cordless and not cell. they're not easy to find, and yes, they are a bit expensive, but i have a sony i bought in 1996 (one of the first li-ion cordless phones on the french market) that still works like a charm today. problem: it works like crap in the states due to the phone's circuitry. u.s. phones work fine here though... otherwise, when i worked on an ambulance in ny we had to "de charge" the batteries for our batteries every now and again. maybe there's a service for this in the states that does this for cordless phones? easiest is still to replace the battery, but i wonder about panasonics since i have friends who had the same problem and replaced the battery, but the new one wore down in less than 6 months to the same talk time (roughly 5 - 10 minutes). maybe it's just panasonic?

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