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Life of eneloop batteries (before they stop holding as much charge)
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NY
Jan 17, 2023, 2:49:35 PM1/17/23
to
We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT phone
handsets. This is the same capacity and technology as the OEM batteries
which were supplied with handsets (BT 8500).
Until recently everything was fine, but now we've noticed that all the
handsets suddenly cut off after about 20-30 minutes (phone calls to parents
can last a while!) without any warning bleeps for "battery low" (*).
Afterwards the phone doesn't even have enough charge to turn on. However
often the battery-charge indicator will show full as soon as the handset is
placed on the charger, and will then have enough charge to run for at least
a few minutes.
It's as if the discharge characteristics of the battery are no longer what
the handset is expected, so the voltage is going straight from what the
phone regards as "charged" to what it regards as "dead" without gradually
decreasing until it reaches the warning level, with enough remaining charge
to keep going until we've had chance to get another handset to continue the
call.
Is that likely to be a handset problem or a battery problem. The batteries
are a year old (bought 5 Jan 2022) so they are not old. The packaging (I
kept it!) says "After 1 year, retains 90% capacity and after 10 years,
retains 70% capacity" and "Most suitable [for] DECT phone". Obviously DECT
phones spend most of their time on the charger so the batteries (and the
charging circuit in the handset) has to be tolerant of being permanently on
charge, rather than being disconnected from the charger when they are full,
as you'd do with most appliances.
It's interesting that all the handsets seem to have started doing this at
roughly the same time; maybe the one that is most often used for calls is a
bit more prone to it than the ones that are used less often so remain
charged rather than undergoing discharge-charge cycles.I would imagine that
even the frequently-used phone has undergone far fewer that the "recharge up
to 2100 times" limit.
OK, so the packaging may contain a certain amount of marketing bullshit, but
even allowing for that, these batteries seem to have failed very, very soon.
Any comments?
(*) That's for calls with speakerphone turned OFF: I know that speakerphone
eats battery charge very quickly.
handsets. This is the same capacity and technology as the OEM batteries
which were supplied with handsets (BT 8500).
Until recently everything was fine, but now we've noticed that all the
handsets suddenly cut off after about 20-30 minutes (phone calls to parents
can last a while!) without any warning bleeps for "battery low" (*).
Afterwards the phone doesn't even have enough charge to turn on. However
often the battery-charge indicator will show full as soon as the handset is
placed on the charger, and will then have enough charge to run for at least
a few minutes.
It's as if the discharge characteristics of the battery are no longer what
the handset is expected, so the voltage is going straight from what the
phone regards as "charged" to what it regards as "dead" without gradually
decreasing until it reaches the warning level, with enough remaining charge
to keep going until we've had chance to get another handset to continue the
call.
Is that likely to be a handset problem or a battery problem. The batteries
are a year old (bought 5 Jan 2022) so they are not old. The packaging (I
kept it!) says "After 1 year, retains 90% capacity and after 10 years,
retains 70% capacity" and "Most suitable [for] DECT phone". Obviously DECT
phones spend most of their time on the charger so the batteries (and the
charging circuit in the handset) has to be tolerant of being permanently on
charge, rather than being disconnected from the charger when they are full,
as you'd do with most appliances.
It's interesting that all the handsets seem to have started doing this at
roughly the same time; maybe the one that is most often used for calls is a
bit more prone to it than the ones that are used less often so remain
charged rather than undergoing discharge-charge cycles.I would imagine that
even the frequently-used phone has undergone far fewer that the "recharge up
to 2100 times" limit.
OK, so the packaging may contain a certain amount of marketing bullshit, but
even allowing for that, these batteries seem to have failed very, very soon.
Any comments?
(*) That's for calls with speakerphone turned OFF: I know that speakerphone
eats battery charge very quickly.
Theo
Jan 17, 2023, 3:54:26 PM1/17/23
to
NY <m...@privacy.invalid> wrote:
> It's interesting that all the handsets seem to have started doing this at
> roughly the same time; maybe the one that is most often used for calls is a
> bit more prone to it than the ones that are used less often so remain
> charged rather than undergoing discharge-charge cycles.I would imagine that
> even the frequently-used phone has undergone far fewer that the "recharge up
> to 2100 times" limit.
>
> OK, so the packaging may contain a certain amount of marketing bullshit, but
> even allowing for that, these batteries seem to have failed very, very soon.
>
> Any comments?
This seems to be a common problem, and one I've had with various different
> It's interesting that all the handsets seem to have started doing this at
> roughly the same time; maybe the one that is most often used for calls is a
> bit more prone to it than the ones that are used less often so remain
> charged rather than undergoing discharge-charge cycles.I would imagine that
> even the frequently-used phone has undergone far fewer that the "recharge up
> to 2100 times" limit.
>
> OK, so the packaging may contain a certain amount of marketing bullshit, but
> even allowing for that, these batteries seem to have failed very, very soon.
>
> Any comments?
brands of batteries - this points to the phone being the problem.
One thought was that the batteries which are designed for capacity are not
ideal for the never-running-flat mode of operation of a DECT phone, which is
more about frequent cycling. I tend to buy Eneloop Lite, which have a
better cycle life and a lower capacity, than regular Eneloop (the ones you
have). I would rate 750mAh as 'high capacity' and I'd expect a regular DECT
cell to be 500-550mAh.
Another thought is that certain brands of phone overcharge their batteries -
I have Gigaset as prime suspect here, but yours isn't one of those (unless
it's a rebrand?). The handset charging doesn't seem very smart.
At the end of the day, they would be much better using lithium cells and a
proper BMS. But they don't do that. So we're left with batteries being a
regular consumable.
Theo
Rod Speed
Jan 17, 2023, 4:14:32 PM1/17/23
to
NY <m...@privacy.invalid> wrote
> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
> phone handsets.
I had Eneloops, 2x AA, in my Panasonic KX-TCD735ALM cordless phones.
> This is the same capacity and technology as the OEM batteries which were
> supplied with handsets (BT 8500).
Mine were quite different in capacity to those supplied.
> Until recently everything was fine, but now we've noticed that all the
> handsets suddenly cut off after about 20-30 minutes (phone calls to
> parents can last a while!) without any warning bleeps for "battery low"
> (*).
I got a similar result eventually, not even being able to answer an
incoming call without the handset turning off when answering the call.
> Afterwards the phone doesn't even have enough charge to turn on. However
> often the battery-charge indicator will show full as soon as the handset
> is placed on the charger, and will then have enough charge to run for at
> least a few minutes.
> It's as if the discharge characteristics of the battery are no longer
> what the handset is expected, so the voltage is going straight from what
> the phone regards as "charged" to what it regards as "dead" without
> gradually decreasing until it reaches the warning level, with enough
> remaining charge to keep going until we've had chance to get another
> handset to continue the call.
> Is that likely to be a handset problem or a battery problem.
I found that replacing the batterys with Active Energy rechargeables
from Aldi fixed the problem.
> The batteries are a year old (bought 5 Jan 2022) so they are not old.
My Eneloops lasted much long than that.
> The packaging (I kept it!) says "After 1 year, retains 90% capacity and
> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
> phone". Obviously DECT phones spend most of their time on the charger so
> the batteries (and the charging circuit in the handset) has to be
> tolerant of being permanently on charge,
Not clear that they are actually permanently on charge.
The Panasonic KX-TCD735ALM does have a very smart
charger and for a while I did use it to charge rechargables
that the not very good charger would fail to charge.
> rather than being disconnected from the charger when they are full, as
> you'd do with most appliances.
> It's interesting that all the handsets seem to have started doing this
> at roughly the same time;
Yeah, I got that result too, tho I only have two handsets.
> maybe the one that is most often used for calls is a bit more prone to
> it than the ones that are used less often so remain charged rather than
> undergoing discharge-charge cycles.I would imagine that even the
> frequently-used phone has undergone far fewer that the "recharge up to
> 2100 times" limit.
> OK, so the packaging may contain a certain amount of marketing bullshit,
> but even allowing for that, these batteries seem to have failed very,
> very soon.
> Any comments?
Eneloops are notorious for not lasting as long as they should.
I'd just replace the Eneloops and see how that goes. You don't
need the very slow self discharge in a cordless phone handset if
you always put the handset back on the base when the call is over.
> (*) That's for calls with speakerphone turned OFF: I know that
> speakerphone eats battery charge very quickly.
I almost never use the phone in other than speakerphone mode
unless the other end says that the call breaks up, normally with
the other end in a noisy environment.
> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
> phone handsets.
> This is the same capacity and technology as the OEM batteries which were
> supplied with handsets (BT 8500).
> Until recently everything was fine, but now we've noticed that all the
> handsets suddenly cut off after about 20-30 minutes (phone calls to
> parents can last a while!) without any warning bleeps for "battery low"
> (*).
incoming call without the handset turning off when answering the call.
> Afterwards the phone doesn't even have enough charge to turn on. However
> often the battery-charge indicator will show full as soon as the handset
> is placed on the charger, and will then have enough charge to run for at
> least a few minutes.
> It's as if the discharge characteristics of the battery are no longer
> what the handset is expected, so the voltage is going straight from what
> the phone regards as "charged" to what it regards as "dead" without
> gradually decreasing until it reaches the warning level, with enough
> remaining charge to keep going until we've had chance to get another
> handset to continue the call.
> Is that likely to be a handset problem or a battery problem.
from Aldi fixed the problem.
> The batteries are a year old (bought 5 Jan 2022) so they are not old.
> The packaging (I kept it!) says "After 1 year, retains 90% capacity and
> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
> phone". Obviously DECT phones spend most of their time on the charger so
> the batteries (and the charging circuit in the handset) has to be
> tolerant of being permanently on charge,
The Panasonic KX-TCD735ALM does have a very smart
charger and for a while I did use it to charge rechargables
that the not very good charger would fail to charge.
> rather than being disconnected from the charger when they are full, as
> you'd do with most appliances.
> It's interesting that all the handsets seem to have started doing this
> at roughly the same time;
> maybe the one that is most often used for calls is a bit more prone to
> it than the ones that are used less often so remain charged rather than
> undergoing discharge-charge cycles.I would imagine that even the
> frequently-used phone has undergone far fewer that the "recharge up to
> 2100 times" limit.
> OK, so the packaging may contain a certain amount of marketing bullshit,
> but even allowing for that, these batteries seem to have failed very,
> very soon.
> Any comments?
I'd just replace the Eneloops and see how that goes. You don't
need the very slow self discharge in a cordless phone handset if
you always put the handset back on the base when the call is over.
> (*) That's for calls with speakerphone turned OFF: I know that
> speakerphone eats battery charge very quickly.
unless the other end says that the call breaks up, normally with
the other end in a noisy environment.
Peeler
Jan 17, 2023, 4:35:19 PM1/17/23
to
On Wed, 18 Jan 2023 08:14:15 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
MrTu...@down.the.farm about senile Rodent Speed:
"This is like having a conversation with someone with brain damage."
MID: <ps10v9$uo2$1...@gioia.aioe.org>
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
MrTu...@down.the.farm about senile Rodent Speed:
"This is like having a conversation with someone with brain damage."
MID: <ps10v9$uo2$1...@gioia.aioe.org>
Michael Chare
Jan 17, 2023, 6:39:02 PM1/17/23
to
using eneloop batteries so an recommendations forn the best batteries to
use would be appreciated.
I recently wanted to call HMRC regarding a tax return. There was a
warning about wait time so I thought the battery in the DECT phone might
go flat. I used a wired phone which fortunately has a loud speaker
instead. After about 30 minutes I was able to speak to a human who told
me how I could make a formal complaint about a problem with their website.
--
Michael Chare
Martin Brown
Jan 18, 2023, 4:38:27 AM1/18/23
to
On 17/01/2023 19:49, NY wrote:
> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
> phone handsets. This is the same capacity and technology as the OEM
> batteries which were supplied with handsets (BT 8500).
The handset chargers are complete crap and destroy batteries by
> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
> phone handsets. This is the same capacity and technology as the OEM
> batteries which were supplied with handsets (BT 8500).
continuing to trickle charge them at far too high a rate. The result is
that the battery loses its ability to supply current when asked to.
>
> Until recently everything was fine, but now we've noticed that all the
> handsets suddenly cut off after about 20-30 minutes (phone calls to
> parents can last a while!) without any warning bleeps for "battery low"
> (*). Afterwards the phone doesn't even have enough charge to turn on.
> However often the battery-charge indicator will show full as soon as the
> handset is placed on the charger, and will then have enough charge to
> run for at least a few minutes.
You describe the symptoms perfectly. Terminal voltage falls from
> Until recently everything was fine, but now we've noticed that all the
> handsets suddenly cut off after about 20-30 minutes (phone calls to
> parents can last a while!) without any warning bleeps for "battery low"
> (*). Afterwards the phone doesn't even have enough charge to turn on.
> However often the battery-charge indicator will show full as soon as the
> handset is placed on the charger, and will then have enough charge to
> run for at least a few minutes.
nominally fully charged to too low to work shortly after the battery is
asked to do any work. The very act of ringing can sometimes be enough.
>
> It's as if the discharge characteristics of the battery are no longer
> what the handset is expected, so the voltage is going straight from what
> the phone regards as "charged" to what it regards as "dead" without
> gradually decreasing until it reaches the warning level, with enough
> remaining charge to keep going until we've had chance to get another
> handset to continue the call.
>
> Is that likely to be a handset problem or a battery problem. The
> batteries are a year old (bought 5 Jan 2022) so they are not old. The
> packaging (I kept it!) says "After 1 year, retains 90% capacity and
> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
> phone". Obviously DECT phones spend most of their time on the charger so
> the batteries (and the charging circuit in the handset) has to be
> tolerant of being permanently on charge, rather than being disconnected
> from the charger when they are full, as you'd do with most appliances.
It is a cheap and nasty charger problem. There is always a tension
> It's as if the discharge characteristics of the battery are no longer
> what the handset is expected, so the voltage is going straight from what
> the phone regards as "charged" to what it regards as "dead" without
> gradually decreasing until it reaches the warning level, with enough
> remaining charge to keep going until we've had chance to get another
> handset to continue the call.
>
> Is that likely to be a handset problem or a battery problem. The
> batteries are a year old (bought 5 Jan 2022) so they are not old. The
> packaging (I kept it!) says "After 1 year, retains 90% capacity and
> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
> phone". Obviously DECT phones spend most of their time on the charger so
> the batteries (and the charging circuit in the handset) has to be
> tolerant of being permanently on charge, rather than being disconnected
> from the charger when they are full, as you'd do with most appliances.
between keeping a battery ready to do the maximum amount of work and its
longevity. Most DECT mobile phone chargers make a questionable choice.
They typically destroy a set of batteries completely every 3-4 years -
although some are worse than others. One of my "identical" set of
charges is less damaging to batteries than the others.
> It's interesting that all the handsets seem to have started doing this
> at roughly the same time; maybe the one that is most often used for
> calls is a bit more prone to it than the ones that are used less often
> so remain charged rather than undergoing discharge-charge cycles.I would
> imagine that even the frequently-used phone has undergone far fewer that
> the "recharge up to 2100 times" limit.
>
> OK, so the packaging may contain a certain amount of marketing bullshit,
> but even allowing for that, these batteries seem to have failed very,
> very soon.
>
> Any comments?
dumb charger that does the damage. You can't blame the batteries for
this they are being wilfully abused by the equipment.
--
Regards,
Martin Brown
NY
Jan 18, 2023, 5:30:28 AM1/18/23
to
On 17/01/2023 23:38, Michael Chare wrote:
> I recently wanted to call HMRC regarding a tax return. There was a
> warning about wait time so I thought the battery in the DECT phone might
> go flat. I used a wired phone which fortunately has a loud speaker
> instead. After about 30 minutes I was able to speak to a human who told
> me how I could make a formal complaint about a problem with their website.
Same here: I got out a wired phone for use when I was stuck in a long
> I recently wanted to call HMRC regarding a tax return. There was a
> warning about wait time so I thought the battery in the DECT phone might
> go flat. I used a wired phone which fortunately has a loud speaker
> instead. After about 30 minutes I was able to speak to a human who told
> me how I could make a formal complaint about a problem with their website.
queue waiting to talk to the self-assessment tax officer to sort out why
the amount of tax that I owed was *less* than expected.
When I'd filled in the tax return, I'd ticked the box saying that
although my self-employment earnings were below a threshold, I wanted to
pay voluntary National Insurance (so I maximise the amount of state
pension I will get). And it turned out that there was a bug in their
system: I know I ticked the box and it showed up on the PDF tax return
that the online system sends you: I could see it in front of me as I was
on the phone to HMRC. But the tax officer said it was not entered on
their system, and she couldn't do anything about it, even after checking
with her supervisor. She referred me to the NI people, which would have
meant another long queue and then probably back to the self-employment
people after that, because HMRC departments haven't got the hang of
talking to each other, and everything must go through the punter. HMRC's
level of customer service really is pathetic.
I've written a formal complaint and asked them to sort it (I enclosed
the printout of the page in the tax return). But the Royal Mail tracking
hasn't recorded that the letter has been delivered yet, after a week.
The UK really is going to hell in a handbasket at the moment.
NY
Jan 18, 2023, 5:36:25 AM1/18/23
to
On 18/01/2023 09:38, Martin Brown wrote:
> On 17/01/2023 19:49, NY wrote:
>> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
>> phone handsets. This is the same capacity and technology as the OEM
>> batteries which were supplied with handsets (BT 8500).
> On 17/01/2023 19:49, NY wrote:
>> We have eneloop 750 mAhr BK-4MCCE NIMH batteries (2x AAA) in our DECT
>> phone handsets. This is the same capacity and technology as the OEM
>> batteries which were supplied with handsets (BT 8500).
>> Is that likely to be a handset problem or a battery problem. The
>> batteries are a year old (bought 5 Jan 2022) so they are not old. The
>> packaging (I kept it!) says "After 1 year, retains 90% capacity and
>> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
>> phone". Obviously DECT phones spend most of their time on the charger
>> so the batteries (and the charging circuit in the handset) has to be
>> tolerant of being permanently on charge, rather than being
>> disconnected from the charger when they are full, as you'd do with
>> most appliances.
>
> It is a cheap and nasty charger problem. There is always a tension
> between keeping a battery ready to do the maximum amount of work and its
> longevity. Most DECT mobile phone chargers make a questionable choice.
>
> They typically destroy a set of batteries completely every 3-4 years -
> although some are worse than others. One of my "identical" set of
> charges is less damaging to batteries than the others.
>
>> batteries are a year old (bought 5 Jan 2022) so they are not old. The
>> packaging (I kept it!) says "After 1 year, retains 90% capacity and
>> after 10 years, retains 70% capacity" and "Most suitable [for] DECT
>> phone". Obviously DECT phones spend most of their time on the charger
>> so the batteries (and the charging circuit in the handset) has to be
>> tolerant of being permanently on charge, rather than being
>> disconnected from the charger when they are full, as you'd do with
>> most appliances.
>
> It is a cheap and nasty charger problem. There is always a tension
> between keeping a battery ready to do the maximum amount of work and its
> longevity. Most DECT mobile phone chargers make a questionable choice.
>
> They typically destroy a set of batteries completely every 3-4 years -
> although some are worse than others. One of my "identical" set of
> charges is less damaging to batteries than the others.
>
> It is all the time that they spend on the charging stands and a very
> dumb charger that does the damage. You can't blame the batteries for
> this they are being wilfully abused by the equipment.
And you can't take the handset off the charger when you notice the
> dumb charger that does the damage. You can't blame the batteries for
> this they are being wilfully abused by the equipment.
battery is charged, because then it will gradually get used up as the
phone listens to the base station for a call, so it will be low/flat by
the time that happens.
The chargers really need to handle trickle charging and voltage
monitoring properly, so they stop charging the batteries when their
terminal voltage says "full" and then periodically re-check the voltage
in case the batteries have started to discharge through normal usage
(listening to base station). But keeping permanent charging current
flowing through full batteries does not sound good for them :-(
Clive Arthur
Jan 18, 2023, 6:00:16 AM1/18/23
to
On 17/01/2023 20:54, Theo wrote:
<snip>
> Another thought is that certain brands of phone overcharge their batteries -
> I have Gigaset as prime suspect here, but yours isn't one of those (unless
> it's a rebrand?). The handset charging doesn't seem very smart.
while but have now gone back to NiCd from eBay. They last a couple of
years, and certainly longer that the NiMH.
--
Cheers
Clive
Brian Gaff
Jan 18, 2023, 8:09:00 AM1/18/23
to
What is happening is that the battery in effect has a smaller area of its
electrodes working. Draw some current. the voltage drops away since its
impedance is high. They are usually like this due to a poorly designed
charger that cooks the cells once they are fully charged and this gradually
means that the working parts get poisoned by overcharging. I've watched good
chargers that simply test the voltage under load and pulse the charger.
These seem not to cook the batteries. It is a bit of a bodge though, as to
my mind there needs to be some kind of sensor system or a third connection
that monitors things.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"NY" <m...@privacy.invalid> wrote in message
news:tq6u4b$3ca8u$1...@dont-email.me...
electrodes working. Draw some current. the voltage drops away since its
impedance is high. They are usually like this due to a poorly designed
charger that cooks the cells once they are fully charged and this gradually
means that the working parts get poisoned by overcharging. I've watched good
chargers that simply test the voltage under load and pulse the charger.
These seem not to cook the batteries. It is a bit of a bodge though, as to
my mind there needs to be some kind of sensor system or a third connection
that monitors things.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"NY" <m...@privacy.invalid> wrote in message
news:tq6u4b$3ca8u$1...@dont-email.me...
Dave W
Jan 19, 2023, 6:05:06 PM1/19/23
to
I never leave it on the charger because it's bad karma, as you
describe. I put it on the charger when the bars go down to one.
--
Dave W
NY
Jan 20, 2023, 4:33:59 AM1/20/23
to
"Dave W" <dave...@yahoo.co.uk> wrote in message
news:mkijsht914bhl3b8o...@4ax.com...
> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
> I never leave it on the charger because it's bad karma, as you
> describe. I put it on the charger when the bars go down to one.
How do you cope with the fact that sometimes when the phone rings or you
come to make a phone call, the battery has discharged (due to the normal
"listening to the base station" circuitry), so you need to charge it before
you can make/receive a call, depending on when you need to use the phone in
relation to your charge/discharge cycle throughout the day?
Why is it that DECT phones only last about an hour (less if "squawkerphone"
is turned on) on a battery charge, but a mobile phone will last a lot longer
on a call? Is it partly that mobile phone batteries have a third terminal
for monitoring the terminal voltage, so can determine better when the
battery is full so as to stop charging, whereas normal two-terminal AA
batteries don't have that? Or is it that mobiles normally use Li-Ion
batteries which perhaps are more tolerant of over-charging?
news:mkijsht914bhl3b8o...@4ax.com...
> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
> I never leave it on the charger because it's bad karma, as you
> describe. I put it on the charger when the bars go down to one.
come to make a phone call, the battery has discharged (due to the normal
"listening to the base station" circuitry), so you need to charge it before
you can make/receive a call, depending on when you need to use the phone in
relation to your charge/discharge cycle throughout the day?
Why is it that DECT phones only last about an hour (less if "squawkerphone"
is turned on) on a battery charge, but a mobile phone will last a lot longer
on a call? Is it partly that mobile phone batteries have a third terminal
for monitoring the terminal voltage, so can determine better when the
battery is full so as to stop charging, whereas normal two-terminal AA
batteries don't have that? Or is it that mobiles normally use Li-Ion
batteries which perhaps are more tolerant of over-charging?
Rod Speed
Jan 20, 2023, 4:49:14 AM1/20/23
to
On Fri, 20 Jan 2023 20:33:49 +1100, NY <m...@privacy.invalid> wrote:
> "Dave W" <dave...@yahoo.co.uk> wrote in message
> news:mkijsht914bhl3b8o...@4ax.com...
>
>> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
>> I never leave it on the charger because it's bad karma, as you
>> describe. I put it on the charger when the bars go down to one.
>
> How do you cope with the fact that sometimes when the phone rings or you
> come to make a phone call, the battery has discharged (due to the normal
> "listening to the base station" circuitry), so you need to charge it
> before you can make/receive a call, depending on when you need to use
> the phone in relation to your charge/discharge cycle throughout the day?
> Why is it that DECT phones only last about an hour (less if
> "squawkerphone" is turned on) on a battery charge,
Never seen that with my Panasonic KX-TCD735ALMs
> "Dave W" <dave...@yahoo.co.uk> wrote in message
> news:mkijsht914bhl3b8o...@4ax.com...
>
>> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
>> I never leave it on the charger because it's bad karma, as you
>> describe. I put it on the charger when the bars go down to one.
>
> How do you cope with the fact that sometimes when the phone rings or you
> come to make a phone call, the battery has discharged (due to the normal
> "listening to the base station" circuitry), so you need to charge it
> before you can make/receive a call, depending on when you need to use
> the phone in relation to your charge/discharge cycle throughout the day?
> Why is it that DECT phones only last about an hour (less if
> "squawkerphone" is turned on) on a battery charge,
and I almost always use them in speakerphone mode.
> but a mobile phone will last a lot longer on a call? Is it partly that
> mobile phone batteries have a third terminal for monitoring the terminal
> voltage, so can determine better when the battery is full so as to stop
> charging, whereas normal two-terminal AA batteries don't have that?
> Or is it that mobiles normally use Li-Ion batteries which perhaps are
> more tolerant of over-charging?
Peeler
Jan 20, 2023, 5:11:46 AM1/20/23
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On Fri, 20 Jan 2023 20:48:44 +1100, cantankerous trolling geezer Rodent
"You're a sad old man Rod, truly sad."
MID: <id04c3...@mid.individual.net>
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
Xeno to senile Rodent:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
"You're a sad old man Rod, truly sad."
MID: <id04c3...@mid.individual.net>
Paul
Jan 20, 2023, 5:20:51 AM1/20/23
to
https://batteryuniversity.com/article/bu-408-charging-nickel-metal-hydride
When chemistries like that, the manufacturer says the cells can be charged
at the 1.0 C rate, that makes it a lot easier to design a precision charger.
The negative slope endpoint can be detected (negative dV/dT), compared to other noise
sources in the circuit.
That article says, if your NiMh device is unwilling to charge the cells
properly, you should switch to NiCd which is more tolerant of abuse.
They are not infinitely tolerant, but more tolerant than NiMh. If you
choose to use NiCd, check the battery compartment frequently for
signs of electrolyte venting and corrosion.
Paul
NY
Jan 20, 2023, 5:26:48 AM1/20/23
to
"Paul" <nos...@needed.invalid> wrote in message
news:tqdptu$19c0$1...@gioia.aioe.org...
end-of-charge logic, won't it be designed for the charge-amount versus
voltage characteristics of one battery technology, so there is a risk of
making things worse if the end-of-charge state never gets reached or else
the charging stops too soon when the batteries are only partly charged.
news:tqdptu$19c0$1...@gioia.aioe.org...
> That article says, if your NiMh device is unwilling to charge the cells
> properly, you should switch to NiCd which is more tolerant of abuse.
> They are not infinitely tolerant, but more tolerant than NiMh. If you
> choose to use NiCd, check the battery compartment frequently for
> signs of electrolyte venting and corrosion.
Can a device which is designed for NiMH use NiCad instead? If there is any
> properly, you should switch to NiCd which is more tolerant of abuse.
> They are not infinitely tolerant, but more tolerant than NiMh. If you
> choose to use NiCd, check the battery compartment frequently for
> signs of electrolyte venting and corrosion.
end-of-charge logic, won't it be designed for the charge-amount versus
voltage characteristics of one battery technology, so there is a risk of
making things worse if the end-of-charge state never gets reached or else
the charging stops too soon when the batteries are only partly charged.
Martin Brown
Jan 20, 2023, 5:27:26 AM1/20/23
to
On 20/01/2023 09:33, NY wrote:
> "Dave W" <dave...@yahoo.co.uk> wrote in message
> news:mkijsht914bhl3b8o...@4ax.com...
>
>> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
>> I never leave it on the charger because it's bad karma, as you
>> describe. I put it on the charger when the bars go down to one.
>
> How do you cope with the fact that sometimes when the phone rings or you
> come to make a phone call, the battery has discharged (due to the normal
> "listening to the base station" circuitry), so you need to charge it
> before you can make/receive a call, depending on when you need to use
> the phone in relation to your charge/discharge cycle throughout the day?
I think you can get away with leaving them off the base station for a
> "Dave W" <dave...@yahoo.co.uk> wrote in message
> news:mkijsht914bhl3b8o...@4ax.com...
>
>> My Gigaset A120 handset has two Duracell NiMH AAA rechargeables in it.
>> I never leave it on the charger because it's bad karma, as you
>> describe. I put it on the charger when the bars go down to one.
>
> How do you cope with the fact that sometimes when the phone rings or you
> come to make a phone call, the battery has discharged (due to the normal
> "listening to the base station" circuitry), so you need to charge it
> before you can make/receive a call, depending on when you need to use
> the phone in relation to your charge/discharge cycle throughout the day?
few hours every now and then and it will help a bit but it would be nice
if the charging regime of DECT bases was more battery friendly.
It is one of those situations where if you use your phone a lot and move
them around so that each gets equal wear you can probably extend the
battery service life. OTOH if they spend almost all their time on charge
and are seldom used then the batteries will gradually be destroyed by
overcharging. It is hard to damage a rechargeable battery at C/100
charge rate but eventually it will result in failure.
Next time I have chance I will measure what my DECT base stations do.
It is a bit like with UPS's - maximum runtime is a selling point but it
comes at a cost (to the user) of frying the batteries more quickly. Then
they make a profit selling over priced extra batteries every few years.
> Why is it that DECT phones only last about an hour (less if
> "squawkerphone" is turned on) on a battery charge, but a mobile phone
> will last a lot longer on a call? Is it partly that mobile phone
> batteries have a third terminal for monitoring the terminal voltage, so
> can determine better when the battery is full so as to stop charging,
> whereas normal two-terminal AA batteries don't have that? Or is it that
> mobiles normally use Li-Ion batteries which perhaps are more tolerant of
> over-charging?
a minimal ping to stay in touch with their base station. In an area with
very low or no mobile signal the battery life of mobiles is compromised
as in drops like a stone. Spending all its time pinging at maximum power
"ET phone home".
--
Regards,
Martin Brown
Martin Brown
Jan 20, 2023, 5:38:26 AM1/20/23
to
either it isn't or that the NiCad is better able to handle the abuse.
I recall an amusing historic MFU when NiFe cells were withdrawn from
service use and the new improved NiCads were charged using the same SOP.
The result was most of them used as emergency standby power were ruined
within a year by the wrong charging procedure (big expensive batteries).
NiFe could stand any amount of abuse and still be OK, NiCad were a bit
more tetchy.
--
Regards,
Martin Brown
Andy Burns
Jan 20, 2023, 6:19:48 AM1/20/23
to
Theo wrote:
> Another thought is that certain brands of phone overcharge their batteries -
> I have Gigaset as prime suspect here, but yours isn't one of those (unless
> it's a rebrand?). The handset charging doesn't seem very smart.
I have previously had early battery death from Philips DECT handsets, my
> Another thought is that certain brands of phone overcharge their batteries -
> I have Gigaset as prime suspect here, but yours isn't one of those (unless
> it's a rebrand?). The handset charging doesn't seem very smart.
current Gigaset is pushing 7 years old and still has original GP Battery
NiMH 750mAh in both handsets and they live in their charging cradles 24x7
Chris Green
Jan 20, 2023, 7:33:06 AM1/20/23
to
DECT handsets. We have a mix of different Gigaset ones and there
seems little rhyme or reason to battery life. I do think that lower
capacity (i.e. around 700mAh) NiMh seem to last longer. Our oldest
ones are now 13 years old and I'm pretty sure I've only changed the
batteries once in any of them.
--
Chris Green
·
The Natural Philosopher
Jan 20, 2023, 1:26:47 PM1/20/23
to
On 20/01/2023 10:26, NY wrote:
> "Paul" <nos...@needed.invalid> wrote in message
> news:tqdptu$19c0$1...@gioia.aioe.org...
>> That article says, if your NiMh device is unwilling to charge the cells
>> properly, you should switch to NiCd which is more tolerant of abuse.
>> They are not infinitely tolerant, but more tolerant than NiMh. If you
>> choose to use NiCd, check the battery compartment frequently for
>> signs of electrolyte venting and corrosion.
>
> Can a device which is designed for NiMH use NiCad instead?
yes.
> news:tqdptu$19c0$1...@gioia.aioe.org...
>> That article says, if your NiMh device is unwilling to charge the cells
>> properly, you should switch to NiCd which is more tolerant of abuse.
>> They are not infinitely tolerant, but more tolerant than NiMh. If you
>> choose to use NiCd, check the battery compartment frequently for
>> signs of electrolyte venting and corrosion.
>
> Can a device which is designed for NiMH use NiCad instead?
If there is
> any end-of-charge logic, won't it be designed for the charge-amount
> versus voltage characteristics of one battery technology, so there is a
> risk of making things worse if the end-of-charge state never gets
> reached or else the charging stops too soon when the batteries are only
> partly charged.
it is rather small.
Nicads work in NiMh chargers, not always the other way around.
--
“Ideas are inherently conservative. They yield not to the attack of
other ideas but to the massive onslaught of circumstance"
- John K Galbraith
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