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[aesmith]

Hi,

Our third and last Gigaset handset has just dropped dead.  They seem to last a few years then fail, once safely out of warranty.  The fault symptoms are always the same, the handset charges up correctly and the batteries measure as fully charged. Once the handset is lifted from the cradle it drops dead after sometime between a few seconds and a few minutes later. It stays dead until replaced in the charging cradle, when it wakes back up. Two different models, the older ones were S79H and the last one is a C430HX which started dying earlier this year, at about two and a half years old.

Firstly, for those using the N300, what handsets do you use and what sort of life do you get from them?

Secondly and this is really a long shot, any ideas for how to fix my faulty handsets?

Thanks, Tony S

[craigski]

That sound like batteries to me. I have several S68H handsets, no longer used with N300, as I ditched my landline when moving to FTTP.

I used Enloop batteries in the Siemens handsets, as they seemed to perform best.

[aesmith]

Initially that's what I thought, but the batteries always measure OK.  The C430HX has standard (white) Eneloops replacing the originals, but that hasn't helped.  The two batteries both measure over 1.4V when I tested just now, but the handset is as dead as a dodo.  If I remove and re-seat either battery the handset powers up long enough to show the Gigaset logo before dropping dead again.

However I noticed something I hadn't noticed before. I stuck the two Eneloops in the charged to check that it agreed they were fully charged, which it did. But once the handset was back in the charger and alive again, it showed a battery low indication.  I don't remember seeing that before.

[craigski]

Do you have any other batteries? I have seen 1 of my Enloops fail, and saw same symptoms as you.
One battery was fine, the other would not provide any power under load, using an old battery tester. I replace the faulty battery with another and all was fine.

[aesmith]

I'm a bit short of AAA batteries at the moment, but that's on my list of things to try.  Different batteries in the handset, and test the Eneloops in something else to confirm under load.

[Alex Atkin UK]

Our kitchen handset which pretty much never gets used had the same problem.   I charged the batteries in a proper battery charger and last I checked it seemed to bring them back to life.

From what I understand the handset chargers kinda suck and cause issues.

[craigski]

Different batteries in the handset, and test the Eneloops in something else to confirm under load.

You obviously have something to measure voltage, do you have a 100 ohm or similar resistor?


https://youtu.be/JjElWj0fFX4

My money is on just one of the batteries has failed, will show correct voltage on a multimeter with no load, but underload this will drop.

I charged the batteries in a proper battery charger and last I checked it seemed to bring them back to life.

From what I understand the handset chargers kinda suck and cause issues.

I tried the proper battery charger trick, was not successful in my case, but certainly worth a try if you have a charger.

[Alex Atkin UK]

I tried the proper battery charger trick, was not successful in my case, but certainly worth a try if you have a charger.

It was under 2 years, trickle-charging a battery for 2 years its not all that surprising it would trash the batteries, especially if the batteries aren't the best quality.

I'd actually be more wary of Eneloops for this, as a battery designed for low self discharge I'd expect to suffer even worse as the trickle charge will be much higher than their discharge rate.

[parkdale]

Gigaset recommend changing the batteries about 18mths!! Handset chargers seem to be more susceptible to "Memory" effect on batteries than my Panasonic phone. I currently use GP ReCyko+ in mine.
Did put used GP one's in my Panasonic and seem to be ok now! Like every thing these days... there's trade off's, but still prefer the Gigaset phones.

[Alex Atkin UK]

Yeah my Panasonic ran for years on the same batteries.

[tiffy]

My experience has been very similar, I very much like my Gigaset DECT handsets but have found that the 2 X AAA NiMh batteries have a limited life wheras an old Panasonic DECT phone I also used with 2 X AA NiMh batteries lasted for ever, never been replaced.
I think it's very much down to the charging method adopted (cost) by the respective manufactures, if they spend a few quid more and incorporate some form of "smart" charging rather than basic trickle charging then longer battery life can be expected.
Of course it will help battery life if the battery is periodically cycled, regularly left off the charger overnight for example, however, how many of us remember to do this?

A few years ago I bought one of these smart chargers:
https://www.amazon.co.uk/Youshiko-YC4000-Intelligent-Professional-Standard/dp/B00N7GHUH0/ref=dp_prsubs_1?pd_rd_i=B00N7GHUH0&psc=1
Have managed to extend the battery life of quite a few cells which initially failed in use, has paid for itself.

7 day shop, here, advertise quite a range of smart chargers and battery testers with integrated dummy loads:
https://www.7dayshop.com/categories/batteries-power-chargers/battery-chargers-and-testers/aa-aaa-battery-chargers

 

[aesmith]

Thanks for the comments.  I have a couple of proper smart NiMH battery chargers.  Using these I can confirm that the batteries taken out of the handset were pretty much fully charged, only a few minutes in the charger before it stopped with the "Full" indication.  I have also tested with some different NiMH batteries, charging them fully first before installing in the handset. These show the same symptoms.

I tested the two AAAs in my torch and both were happy to run for several minutes.

Testing yesterday I found the handset worked OK with some disposable AAAs, or at least it stayed alive for several minutes while I went in and out of menus and listened to a voicemail.  These disposables have a slightly higher open circuit voltage than rechargeables, but there is very little in it. Open circuit the pair of disposables measured 3.12V, on load in the handset it varied between 2.90 and 3.00.

The rechargeables measure 2.95 open circuit, I can't measure them on load as the handset doesn't stay alive long enough. 

Based on all this I can't see that there is anything wrong with the rechargeable batteries themselves. One theory is the handset has become unduly sensitive and needs a higher voltage than can be delivered by NiMH cells.

I suppose it's also possible that it's drawing too much current and pulling the voltage of the NiMH down. I had a go at measuring this with not much success. Using the disposables and with my Fluke in series to measure the current, it behaves the same as with the NiMHs - powers up for just a second or so then drops dead.  Take the Fluke out of the picture and it works normally. For what it's worth it looks like a draw of around 50mA for those couple of seconds.