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Technology

A Cordless Phone's Major Problem - Dealing w/ Batteries? 53

Posted by Cliff from the coping-with-technology dept.
Brian James asks: "I am sick to death of cordless phone batteries going dead at the drop of a hat. And with frequent recharging they tend not to hold much of a charge. Replacement often equals the cost of a new phone altogether... so what's the point? Ultimately I wish cordless phone manufacturers would design a phone that used standard rechargeable batteries, preferably with 2 battery bays and a switch that allowed you to switch over to the fresh set when one set starts to go dead (of course, I don't see this happening any time soon). Is there any way to modify a cordless phone such that I can run the handset off of standard batteries? I don't care how 'cheap and dirty' it ends up, I just need to know I can pop in a fresh battery and call the guy back, without waiting 8 hours for it to charge up." A few cordless phone manufacturers do have a clue. Some phones allow you to charge an extra battery in the base while the other is being used by the phone, which works well (I have a Sony 900Mhz model that does this). It would be interesting to see if someone has done what the poster has asked, however if you'd like to recommend a cordless phone that keeps downtime to a minimum, I'm sure such would be appreciated.
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A Cordless Phone's Major Problem - Dealing w/ Batteries? More

A Cordless Phone's Major Problem - Dealing w/ Batteries?

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  • some older phones pre-800MHz are much better than most news dealing with batters they last longer.
  • What would be nice is a cordless phone with a recharging system built into the machine. That way, you just set it down and while you're not using it, it recharges itself.
    • Huh? This is exactly how rechargeable cordless phones work. If you set it down into its cradle, it recharges while not in use.

      No wait -- Are you suggesting that when I set the phone down on my desk, nowhere near the cradle or any source of electricity, it should somehow recharge itself by simply drawing electricity from the ether?

      An interesting idea, but not yet practical. See, e.g., the movie "The Quiet Earth" [1985].

  • In my expirence (Score:4, Informative)

    by seann ( 307009 ) <notaku@gmail.com> on Saturday May 11, 2002 @03:05PM (#3502937) Homepage Journal
    at Radioshack, I've dealt with people like you over and over again. They bring back their nickle Cadium based phones a few weeks later, and tell me it's dead. I then say "heres your new battery" and they buy it.

    Now when the old couple comes in with the pre-1980's cordless phone, and I tell them the batter is 40-60$, I generaly ask if they want a new phone.

    So I bring them over to the wall and show them the selection of phones with a lithium-ion batter in them, and I tell them about how if they keep charging their old battery (nickle cadium) it will damage the battery, but instead with these lithium-ion phone batterys, give them one good charge on your first use, then recharge them any time you wish!

    The same thing is with my cell phone, the Sanyo SCP-4000. Not a spectacular phone, but the default lithium-ion battery that comes with it is a god send, I recharge it every night with no fear of the battery dying.

    So in short I tell you, pick a cordless phone that has a lithium-ion battery in it, instead of a nickle cadium, or nickle metal hydrate (the latter is your next best alternative).
    • I also used to work at Radio Shaft, and most customers buying a cordless phone would ask me about the battery and how to keep it charged. I finally got to the point where I would just tell them before they asked. My speach went something like this: When you get the phone home, charge it for a good 24 hours. When you wake up in the morning, take it off the cradle and put it back before you go to sleep. Replace the battery after a year. (insert shameless plug for the service contract that would replace the batteries for free for 3 years) But you know what? I never followed my own advice. I leave the phone on the charger all day and all night. In the rare instance that I have a long phone conversation, the battery never dies or even complains. The battery in my current phone (admittedly, quite an old phone) is about a year old and I have had several long conversations in the past week without any problems at all. I am really curious to know what people are doing to these things that cause them to ask this question in the first place.

  • dyi (Score:4, Informative)

    by elfkicker ( 162256 ) on Saturday May 11, 2002 @03:09PM (#3502949)
    You can always make your own to save yourself a few bucks. Of course, it's probably more trouble than it worth. But, if you're the DYI type check out http://www.rccentral.com/guides.asp?ATCL_ID=51

    That'll give you a little primer on what's involved. It's geared towards hobby RC cars, but you could adapt this for phones pretty easily.

    I also make it a point to stay with NMH batteries when possible. They actually get batter after a little use, and no need to drain them completely before you charge them again.
  • preferably with 2 battery bays and a switch that allowed you to switch over to the fresh set when one set starts to go dead
    You won't need "two battery bays" and switch, because if you had that much room for batteries, then you could just connect your power cells in parallel and not have to switch between the 2.

    It would be nice to have solar cells to help compliment the amount of power from the battery. I don't expect that you'll get much power out of the solar cells, but every bit helps.
    • If the parallel set starts going dead there no backup. Two battery bays allows you to know that something needs to be switched at the same time providing full funtionality. I think that it would be nice to have the bodies of almost everything consisting of mostlty solar cell material.
      • Two battery bays allows you to know that something needs to be switched at the same time providing full funtionality.
        Oh, okay. I didn't realize that you guys didn't get any warning. With the Nokia 5190, you get a beep when you've got only about a quarter of the power left. It'll repeat over and over again every few minutes. The only time that I've had a connection drop on me was when I forgot to recharge the battery, even with the beep. That was my fault, of course.

        I could now see a benefit to having a seperate battery instead of one big one or two in parallel. An idea would be to have two batteries in one battery case. When the first one goes dead, you take it off and leave it in your pocket. When you empty your pockets at the end of the day, you say to yourself, "Oh yeah, I have to recharge this.".

        I'm not sure that I would need a feature like this, but it would help some people, based on the battery type and the way that they use the phone.
  • when my batteries get low and i need to talk to someone, i just plug it into the wall while i talk... it charges and i talk at the same time...

    i have your basic motorola startac... its not like i am out of business when my batteries are dead... its not any more inconvenient than a normal telephone used to be... i just look at the batteries as being a luxury to have them at all... the important part is the ability to talk from anywhere.

  • Siemens Gigaset (Score:3, Informative)

    by ivan256 ( 17499 ) on Saturday May 11, 2002 @03:14PM (#3502963)
    Not only are the siemens gigaset phones well featured, but they also take 3 standard NiCad rechargeable AA batteries. I haven't had them wear out yet, but at least I know it'll be cheap and easy to replace them when they go.

    • Re:Siemens Gigaset (Score:3, Informative)

      by zsazsa ( 141679 )
      I also have a Siemens Gigaset (An older model 2415, which I got CHEAP on closeout at Staples.) It came with two standard Panasonic 600mAh AA NiCad batteries. After looking at the manual, I saw that it could take NiMH batteries. Awesome! 2-3x More capacity and no more stupid memory effect!

      I got a couple 1800mAh Powerex batteries from Thomas Distributing [thomasdistributing.com] and the phone has worked great. After weeks of on-hook/off-hook type usage, it can go for a LONG time without charging with no memory effects.

      With standard AA NiMHs, you can keep a spare set sitting in the charger if you need em.

      It's a freakin' cool phone, too.

      Ian
      • Actually the "Memory effect" (Which isn't really the memory effect at all [drexel.edu]) isn't really a problem with the NiCads in the gigaset, since it has an excelent charger that was designed correctly. They are lower capacity then the NiMh batteries though.
        • We have a Siemens Gigaset too, and we've never had battery problems with it. Remembering how much trouble we had with our previous phone and knowing the Gigaset uses NiCd batteries, I bought NiMh batteries right from the start, to prepare for the NiCds to give up. I've never needed them though. The NiCds keep working perfectly, and now I use the NiMhs in my cordless mouse.
    • I also have Siemens Gigasets (4015 & 4010). This phone (system) really is a geek's phone. I say system because you can go buy more phones and "register" them to your internal phone system (think about it like adding a PC to your LAN).

      It does all the stuff you'd expect out of a "high-end" phone (voice mail, intercom, caller ID, headset port, phonebook, etc), but its also really sleek looking (no antennae on the outside :)! If anything it reminds me of a cell phone. Anyway, its got a ton of features and I've often wondered if it was hackable... there just has to be things you change in there if you only knew the codes. :)

      Back to the poster's desire for a phone that runs off of AAs, this phone is a champ in that department too. It takes NiCD and NiMH... which was a huge selling point for me, as I've thrown away 3 cordless phones in the past few years due to dying/dead batteries. Plus, since I've got other stuff in the house that uses rechargable AAs, its really convenient.

      • My favorite feature is the 'DID' feature. I have a message that plays when I get called that asks marketers to hang up and tells everybody else to press '*'. It annoys the few people who actually want to call me, but it has stopped all but one of the telemarketers that used to call me all the time.

  • Ok, I just have to complain! (Score:3, Insightful)

    by c.r.o.c.o ( 123083 ) on Saturday May 11, 2002 @03:14PM (#3502964)
    I never did this before, but this takes the cake! Exactly how is a cordless phone battery life of any importance? News for Nerds, Stuff that Matters?

    First of all, the betteries died on all the cordless phones I've ever had. However, it was never more than just a fraction of the cost (less than CAD$20 on a CAD$200-something phone). However, none of them died sooner than 3 years. By that time I was usually tired of the phone, or significantly better ones came out.

    Second, maybe I'm not an average phone user, but I never ran out of batteries on any of my cordless phones. I have a Sanyo 900Mhz, and the longest conversation I had lasted 3 hours, on the hands-free speaker (works out really well to coordinate attacks in RTCW). And this is with a 3.6V 600mAh battery.

    My advice? Get a better phone. None of the GE 9or the likes) crap. Frm my experience Sanyo, Sony, Panasonic make good phones. It would be pointless to get a phone with rechargeable batteries. Especially since a good set of 4 NiMH are pretty much the same price as the original phone battery.

    And here's an afterthought: if you dislike cordless phones so much, why not use one with a wire? They still have those, you know?

  • Corded Phones (Score:3, Insightful)

    by finity ( 535067 ) on Saturday May 11, 2002 @03:27PM (#3503021) Homepage Journal
    Well, I see your point about how annoying it is when cordless phone batteries die, and I agree completely. What I don't understand is why you would wait 8 hours to call someone back because your battery dies. Don't you have any phones with cords that plug into the base? Just use one of those when your cordless dies.

  • Solutions: 1) Don't charge so much. 2) Discharge. (Score:5, Informative)

    by Futurepower(R) ( 558542 ) on Saturday May 11, 2002 @04:07PM (#3503184) Homepage

    I'm surprised no one else has said this:

    Nickel Cadmium cells have 2 unfortunate limitations: 1) They have a "memory effect". 2) Charging them all the time makes them old very quickly, and makes the memory effect much worse.

    So, this is what you do: 1) Don't charge the batteries all the time. I have two ATT 900 MHz Cordless phones. (I bought one for $30 at Costco, and the other for $5 at a garage sale. These are not expensive phones.)

    I charge the batteries for about 6 hours once a week. I regularly talk for 3 or 4 hours in one phone conversation, and I have never had problems with the battery going dead. I've never switched phones in the middle of a conversation, either.

    If I have a conversation lasting more than 20 minutes, I charge the phone then, also, after the call.

    This is how you tell if you should stop charging a NiCad battery: It becomes warm. That is because all of the charge energy goes into making heat after the battery is fully charged. Before the battery fully charged, some of the charge energy goes into charging the battery, of course.

    Don't worry about overcharging a little. A few extra hours, even 10 extra hours, in one or two charges a month seems to make no difference. It is 24-hour, 7-days-a-week charging that causes the problems.

    2) The memory effect can be completely cured by discharging the battery completely. To do this, buy a 510 ohm, 1/4 or 1/10 watt resistor (an electronic component) at Radio Shack or an electronics parts store or an electronics surplus store. Remove the battery. Just push the leads of the resistor into the contact sockets of the battery (where the contact pins normally go), and leave it for 12 hours. Once the battery is discharged, it will no longer have the "memory effect" and will be as good as new, or 95% as good as new. Then, recharge the battery until it is fully charged (when it becomes especially warm).

    The memory effect works this way: It causes the battery to discharge rapidly, even though there is a small load. The memory effect causes the battery to have a "shallow discharge curve", they say.

    Lithium Ion and Nickel Metal Hydride batteries do not have memory effect. However, they also get old faster if they are constantly charged.

    This is reliable information. I was an electronics designer in past years, and I have talked to an RCA battery engineer about the exact parameters of NiCad memory effect.
    • There is no memory effect in NiCd batteries** the real problem is lousy charging systems overcharging the batteries. This heat the NiCds and causes to vent electrolyte.

      Short form:

      Long (and accurate) from ARRL:

      http://www2.arrl.org/tis/info/pdf/119470.pdf

      ** At least not for ones on earth -- there is a real memory effect for slow charging and discharging NiCds in orbit. But unless you phone is in a satellite in orbit this won't be a issue .

      Solution: Don't put the phone back in the cradle until it needs a charge.

      ALWAY keep a regular (loop powered) phone in your local loop. You can always pick up with it when you battery is dead oer when power is out (and the base is dead).

      And Radio Shack carries a lot of cordless phone batteries (I had the same problem with a VTech 900Mhx cordless -- now on its third battery).

  • I have one of these phones. They ship with two detachable batteries. I always have one battery in the charger and the phone on someplace else in my apartment. When the battery pack has a low amount of charge while I'm using it, the phone will start beeping and I then find the fully charged battery and swap them out. This can be done with a minor interruption in the phone call. But it doesn't disconnect the person I'm talking to, so as soon as I attach the fresh battery, I can start talking again. I bought it at a Sam's Club store for about $30.

  • Ni-Cd memory a MYTH (Score:3, Interesting)

    by PD ( 9577 ) <slashdotlinux@pdrap.org> on Saturday May 11, 2002 @05:44PM (#3503528) Homepage Journal
    http://www.repairfaq.org/ELE/F_NiCd_Battery.html

    This FAQ explains the whole thing.

    The REAL thing to watch out for is completely discharging a pack. The first cell that goes dead will be driven in reverse by the other cells. That's bad news, and it kills that cell.

    Apparently NiMH batteries are even MORE sensitive to this than the NiCd batteries.

    So, charge your phone often. Don't let it run all the way down.
    • I don't know who modded the parent up, but the poster failed even to read the URL he mentioned. Under Point 2.9 is a good explanation of what is populary called the Memory Effect, and yes it exist! No Myth.

      The reverse polarity problem is complete different from the memory effect problem, but both exist.
      • Yes, I did read the article, and the author draws the wrong conclusion from the facts that he presents in his own article.

        He points out that memory effect is hard to reproduce, and it's seen on spacecraft with fixed discharge cycles. He even points out that a bigger problem is reversing a cell during a deep discharge.

        Yes, the memory effect is real, but will the average person run into it frequently? No. The average user will kill the battery pack through deep discharge way before a memory effect can be noticed. Show me a dead battery pack, and I bet it was severely overcharged, charged when it was too hot, or had cells driven in reverse because of a deep discharge.

  • Not the most expensive phones on the market, but far from shoddy. We've been using the VT-2431 at home for over a year now. Speaker phone handsets, Caller ID, and CID w/Call waiting, speaker base. The base has a spot for an extra battery. Only had one problem with the base, exchanged it, reset the system, and voila.... And, yes, the speaker on the handsets works quite well, from both ends of the call.
    All four phones make it half a block to the mail box, all three levels of the town house. Each hand set has it's own charger base. Two people can use the phone at the same time, and no interference. Worth the money.

    There are two other bases available, plain jane, and one with a built in digital answering machine.
    • The high-end VTechs are nice from what I've heard, but avoid the 2468 at all costs. No call timer, limited volume range (at least when plugging in a headset), and very staticky reception. By "very" I mean "loud bursts of static every few seconds".

      Note that although it's advertised as "2.4GHz!!!!!!!" it, like most phones in that price range, is analog, not DSS. If you want a good analog 2.4GHz phone, though, get GE's $50 phone or a higher model in that series (the highest-end one has a speakerphone and answering machine). However, make sure to get the one with the Caller ID display and the volume controls on the side, even if you don't use Caller ID, because the phones in that series are a bit better designed. Among other things, it has much better volume range on the handset. You can get it at Office Depot, Target, or wherever; it's black and shiny blue.

  • Save your old phones. They have a great radio transmitter/receiver module along with other useful parts. Imagine the possiblities with webcams or wireless links.

  • Siemens Gigaset (Score:3, Informative)

    by maggard ( 5579 ) <michael@michaelmaggard.com> on Saturday May 11, 2002 @08:27PM (#3504036) Homepage Journal
    The older 2nnn series and the new 4nnn series of the Siemens Gigasets all come with 3 AA NiCad batteries. These can be switched out for other batteries if you prefer. This was a big sales feature to us after years of dealing with non-standard battery packs.

    I bought 3 4200 handsets and a 4215 basestation/answering machine a few months ago (first US shipment) and have loved them. We did replace the shipped batteries with Lithium ones but friends with the same phone didn't and they've never had problems either.

    We constantly leave our phones floating around the house and they last for a few days before running down. In conversation I've never had one run down except once when it really was on it's last mAmps - it beeped to warn & I just walked over to another extension and switched to it.

    Other nice features are a great shape for the hand (the older series was flat like old TV remotes and uncomfortable to hold after awhile), reasonable controls & menus, the ability synch phone books from handset to handset, can PA from room to room and also PA incoming messages being left on the answering machine.

    One big win in our case was individual handsets can be set to dial a specified extension or outside number if the sound volume exceeds some number. We use that if we have guests coming in to visit when we're out of town. Their voices trigger the call to us and we can welcome them, give them a rundown of the house.

    Oh, and the phones can be set to dial in response to a spoken name. Really it's the same as speed dial but is useful for the non-techie members of the household. It'll also announce out the name of a caller who is set up this way and recognized via Caller ID. We've 4 or 5 numbers set up for that and it's worked out well.

    Only thing I could still wish for would be a USB link for doing that first entry of phone numbers.

    • Just one thing :)

      Here in europe (Well, atleast in Norway, Sweden, Denmark, France) we have the Gigaset 4170 ISDN (Or the 3070 ISDN) which you can connect to your PC with a USB cable and edit the phonebook, set up ring allocation, surf, etc :)

      It's extremely handy, especially when you're too lazy to type in all the phone-numbers and names by hand on a tiny handset, and rather feel like synchronizing it with outlook instead!

  • Check out RAM Batteries (Score:3, Informative)

    by frank249 ( 100528 ) on Sunday May 12, 2002 @10:59AM (#3505807)
    A Canadian company called Battery Technologies produces Rechargeable Alkaline Manganese (RAM) batteries. [www.bti.ca] A technical description is here [www.bti.ca]. Compared with NiCad batteries, the advantages of using RAM batteries include the following:

    * Longer Operating Time
    * Environmentaly Friendly(contains no hazardous toxic substances)
    * Longer Shelf Life (minimal Self Discharge)
    * Ready For Use when purchased
    * No Memory Effect
    * Lower Cost
    * Better Cell Capacity

    These batteries are currently available in four brands- PURE ENERGY(Canada), RENEWAL (manufactured in the United States by Rayovac Corporation), ALCAVA (manufactured in Korea by Young Poong) and GRANDCELL (manufactured in Malaysia by Grand Battery Technologies).
  • One dies, Use the other while it charges, they don't cost that much, I've been using two 30 Dollar vtech phones for 2.5 years now, 1 base, two phones, works out really well.
  • When my phone ate it's last set of NiCd's, I went to Radio Shack, and bought a $1.50 4-AA battery holder - Then took the contacts out, and mounted them in the phone's battery bay with a few small self-tapping screws.(More work, but the compartment was too tight of a fit for the pack itself.), and popped three AA NiCd's cut out of a larger, burned out pack in it. It's a tight fit, but it definately works.
  • Do you need WAP? If not, make sure your phone doesn't have WAP features, because in my experience battery life of WAP phones is as poor as the service you get with it, even with WAP disabled.

    Back to the matter at hand though, a more elegant solution would be to carry a spare charged battery wouldn't it? There are several companies that make dedicated mobile battery chargers that use conventional batteries for "emergency use". Here's one [web-success.net] and several more [google.com]. The best solution I found for me though was a USB cable to phone power charger. I almost never go far without my laptop, and it's a snip to plug in a USB cable and power your phone up while you type/frag/whatever. Of course, it's a tradeoff against your laptop battery, but hey, you probably have the mains adapter for that in the carry case, right?

  • I had a weird experience the other day. I picked up my cordless phone (which my daughter uses way too much and never hangs up to recharge), dialed a number and, just as it was connecting, the battery went dead. I hung it up and went to my corded phone and the line was dead. Ditto for my other corded phones and for my cordless when then battery recharged. Eventually, I called the phone company on my celluar phone and the tech said to unplug all of the phones in my house, wait 15-20 minutes, then plug one corded phone in and see if it worked. At first I thought this was one of those "put your phone in a plastic bag because we are going to blow the dust out of the phone lines", so I just waited for the amount of time with the phones hung up. Didn't work. Unplugged them all but one (that I forgot about), didn't work. Finally unplugged them all, waited 15 minutes, plugged on in and, bingo, it worked now. This has made me paranoid about using the portable with weak batteries.

    Does anyone know the explaination for why this left my line hanging? It doesn't happen when the phone goes dead during a conversation, only when it is connecting.

  • After the stock batteries wore out on my phone I went to Office max and picked up a couple of AA rechargable batteries that are meant for digital cameras. The only hard part is making sure you get the right voltage. A lot of the these batteries have a higher voltage rating because the are meant for devices that draw a lot more juice at once.

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