This starts with the batteries that go into cordless phones.

BT insist that the batteries in their cordless phones are replace ones
that have identical chemistry, voltage and capacity.

I can see that chemistry and voltage should be identical and why.
However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
capacity battery would allow for longer use of the phone between
charges, on the base station.

Some capacities used in rechargeable devices are quite difficult to
source.

Then we come to solar lights. They seem to have quite low capacities,
300 or 400 mAH, and universally have a green plastic covering. They are
described as NiMH. The on-line stores that sell NiMH batteries have a
separate section for solar light batteries. Are they different again
from the more easily bought rechargeable NiMH batteries. Would a 2000
mAH battery not work in a solar light or even damage it.

Moving on to chargers, can the easily available chargers be used to
refresh the charge in these small capacity batteries. I could imagine
that these chargers may allow to high a charging current for these small
capacity batteries. In winter there is not enough daylight to adequately
recharge the batteries in these solar lights.

In summary:

- Is the capacity of the rechargeable battery important to
a device (other than the length of use between charges)?

- Is there a difference between solar light batteries and
rechargeable batteries?

- Can mains powered chargers be used for all rechargeable
batteries of the chemistry that the charger was designed for?
--
0sterc@tcher -

"Où sont les neiges d'antan?"

On Sun, 26 Feb 2023 10:29:35 +0000
"Nicholas D. Richards" <nicholas@salmiron.com> wrote:

> This starts with the batteries that go into cordless phones.
>
> BT insist that the batteries in their cordless phones are replace ones
> that have identical chemistry, voltage and capacity.

Bussy fuggers.

> I can see that chemistry and voltage should be identical and why.
> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
> capacity battery would allow for longer use of the phone between
> charges, on the base station.

No reason whatsoever.

> Then we come to solar lights. They seem to have quite low capacities,
> 300 or 400 mAH, and universally have a green plastic covering. They are
> described as NiMH. The on-line stores that sell NiMH batteries have a
> separate section for solar light batteries. Are they different again
> from the more easily bought rechargeable NiMH batteries. Would a 2000
> mAH battery not work in a solar light or even damage it.

They may be built for outdoor use and almost certainly aren't low
leakage, otherwise I can't think of any reason they should be different.

> Moving on to chargers, can the easily available chargers be used to
> refresh the charge in these small capacity batteries. I could imagine

Sure, very few easily available chargers run at a dangerously fast
rate for anything - at least by default.

> - Can mains powered chargers be used for all rechargeable
> batteries of the chemistry that the charger was designed for?

Really good mains chargers will charge almost anything and
autodetect. I have two that will do NiCd, NiMH (normal or low leakage) and
various lithium variants in any size that will fit between the terminals.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On 26/02/2023 10:29, Nicholas D. Richards wrote:
> This starts with the batteries that go into cordless phones.
>
> BT insist that the batteries in their cordless phones are replace ones
> that have identical chemistry, voltage and capacity.
>
> I can see that chemistry and voltage should be identical and why.
> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
> capacity battery would allow for longer use of the phone between
> charges, on the base station.
>
I suspect that Beattie's stipulation is nefr covering. When their phones
first came out, they didn't sell them, they rented them out, so they
were nervous about any changes to the way things were made and repaired.

> Moving on to chargers, can the easily available chargers be used to
> refresh the charge in these small capacity batteries. I could imagine
> that these chargers may allow to high a charging current for these small
> capacity batteries. In winter there is not enough daylight to adequately
> recharge the batteries in these solar lights.
>
The maximum safe current is normally 10% to 25% of the capacity. If your
charger is below this, then you will have no problems.

Be wary of smart, fast chargers for NiMH batteries, as they put a lot
more current in, and detect full charge by noting a drop in terminal
voltage. In some conditions and with cheap batteries, this may happen at
the wrong time.

--
Tciao for Now!

John.

I don't know, but the mobile, ie portable phone ones should not care which
capacity they are, however do not mix them up in one phone. I have
discovered that the batteries in those phone are charged in series, and
often they do not discharge equally, and the phone can still run if one
reaches its lowest voltage, thereby reverse charging the duffish one and
shortening its life even more. Quite why they do start do degrade ourt of
step is anyone's guess, but Nicads used to do exactly the same.
Most chargers say what they can charge. Most good chargers have circuits
that charge each cell separately and then turn to pulse and trickle when
charged. Most phones of the type you mention charge them in series and hence
cook the logt until the last one has charged, further messing them up. I
really do not understand why a simple test system is not built in that cuts
the call if one battery dips too low, or why some smart charger like you see
in Roberts radios cannot be used to charge them one at a time. I imagine its
cost and that they consider that a couple of years from your cells is good
enough.
Sorry I know nothing about garden lights.
The other day I bought a hand cranked charging radio with a solar cell and
the battery can charge up phones as well, it says. Nice little gadget, but
would not win any hi fi or ergonomic awards, since the tuning is too fast.
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Nicholas D. Richards" <nicholas@salmiron.com> wrote in message
news:VLk6KJAPSz+jFAFb@salmiron.com...
> This starts with the batteries that go into cordless phones.
>
> BT insist that the batteries in their cordless phones are replace ones
> that have identical chemistry, voltage and capacity.
>
> I can see that chemistry and voltage should be identical and why.
> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
> capacity battery would allow for longer use of the phone between
> charges, on the base station.
>
> Some capacities used in rechargeable devices are quite difficult to
> source.
>
> Then we come to solar lights. They seem to have quite low capacities,
> 300 or 400 mAH, and universally have a green plastic covering. They are
> described as NiMH. The on-line stores that sell NiMH batteries have a
> separate section for solar light batteries. Are they different again
> from the more easily bought rechargeable NiMH batteries. Would a 2000
> mAH battery not work in a solar light or even damage it.
>
> Moving on to chargers, can the easily available chargers be used to
> refresh the charge in these small capacity batteries. I could imagine
> that these chargers may allow to high a charging current for these small
> capacity batteries. In winter there is not enough daylight to adequately
> recharge the batteries in these solar lights.
>
> In summary:
>
> - Is the capacity of the rechargeable battery important to
> a device (other than the length of use between charges)?
>
> - Is there a difference between solar light batteries and
> rechargeable batteries?
>
> - Can mains powered chargers be used for all rechargeable
> batteries of the chemistry that the charger was designed for?
> --
> 0sterc@tcher -
>
> "O� sont les neiges d'antan?"

On 26-Feb-23 14:58, John Williamson wrote:
> On 26/02/2023 10:29, Nicholas D. Richards wrote:
>> This starts with the batteries that go into cordless phones.
>>
>> BT insist that the batteries in their cordless phones are replace ones
>> that have identical chemistry, voltage and capacity.
>>
>> I can see that chemistry and voltage should be identical and why.
>> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
>> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
>> capacity battery would allow for longer use of the phone between
>> charges, on the base station.
>>
> I suspect that Beattie's stipulation is nefr covering. When their phones
> first came out, they didn't sell them, they rented them out, so they
> were nervous about any changes to the way things were made and repaired.

_Just_ possible...
The BT base station usually recharges the batteries when you put the
phone back in place. The charger is only intended to trickle-charge the
phone as it sits there for hours/days/weeks/months, and not supply much
current.
Would a depleted battery with a (much) greater capacity draw a larger
current, over a longer time, than the base station is designed to supply?
>
>> Moving on to chargers, can the easily available chargers be used to
>> refresh the charge in these small capacity batteries.  I could imagine
>> that these chargers may allow to high a charging current for these small
>> capacity batteries. In winter there is not enough daylight to adequately
>> recharge the batteries in these solar lights.
>>
> The maximum safe current is normally 10% to 25% of the capacity. If your
> charger is below this, then you will have no problems.
>
> Be wary of smart, fast chargers for NiMH batteries, as they put a lot
> more current in, and detect full charge by noting a drop in terminal
> voltage. In some conditions and with cheap batteries, this may happen at
> the wrong time.

Smart chargers make 'decisions' based on some simple measurements of the
batteries characteristics. Sometimes they do their sums wrong and screw up.

--
Sam Plusnet

On 26/02/2023 19:22, Sam Plusnet wrote:
> On 26-Feb-23 14:58, John Williamson wrote:
>> On 26/02/2023 10:29, Nicholas D. Richards wrote:
>>> This starts with the batteries that go into cordless phones.
>>>
>>> BT insist that the batteries in their cordless phones are replace ones
>>> that have identical chemistry, voltage and capacity.
>>>
>>> I can see that chemistry and voltage should be identical and why.
>>> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
>>> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
>>> capacity battery would allow for longer use of the phone between
>>> charges, on the base station.
>>>
>> I suspect that Beattie's stipulation is nefr covering. When their
>> phones first came out, they didn't sell them, they rented them out, so
>> they were nervous about any changes to the way things were made and
>> repaired.
>
> _Just_ possible...
> The BT base station usually recharges the batteries when you put the
> phone back in place. The charger is only intended to trickle-charge the
> phone as it sits there for hours/days/weeks/months, and not supply much
> current.
> Would a depleted battery with a (much) greater capacity draw a larger
> current, over a longer time, than the base station is designed to supply?

"It was tested to work with this type of battery. We will not approve it
for use with your battery unless you pay for the test"

It will work happily, and the warranty has expired by now anyway.

--
Tciao for Now!

John.

Nicholas D. Richards <nicholas@salmiron.com> wrote:
> This starts with the batteries that go into cordless phones.
>
> BT insist that the batteries in their cordless phones are replace ones
> that have identical chemistry, voltage and capacity.

....because they have a penc charging circuit.

> Some capacities used in rechargeable devices are quite difficult to
> source.
>
> Then we come to solar lights. They seem to have quite low capacities,
> 300 or 400 mAH, and universally have a green plastic covering. They are
> described as NiMH. The on-line stores that sell NiMH batteries have a
> separate section for solar light batteries. Are they different again
> from the more easily bought rechargeable NiMH batteries. Would a 2000
> mAH battery not work in a solar light or even damage it.

The problem with solar lights and maybe cordless phones is charging
*cycles*. Larger capacity batteries are rated for fewer charging cycles.
Frex, a battery could have 300 or 3000 cycles. A solar light with a 300
cycle battery would last less than a year. A 3000 cycle would
(theoretically) last 8 years. For a solar light there's no point having a
bigger battery because there's not enough sun to get close to filling it
with the tiny solar panel.

Panasonic has three Eneloop ranges. For the AAA size the ratings are:

Eneloop Lite: 550mAh, 3000 cycles to 70% of capacity
Eneloop: 800mAh, 2100 cycles to 70% of capacity
Eneloop Pro: 900mAh, 500 cycles to 85% of capacity

so a larger capacity battery will wear out faster. They're more tightly
wound with less tolerance for degradation.
(batteries in garden lights are cooked and frozen on a daily basis, so I
wouldn't expect a long life from them anyway)

> Moving on to chargers, can the easily available chargers be used to
> refresh the charge in these small capacity batteries. I could imagine
> that these chargers may allow to high a charging current for these small
> capacity batteries. In winter there is not enough daylight to adequately
> recharge the batteries in these solar lights.

For consumer chargers, as long as the charging current isn't too high than
the maximum charge current specced for the cell, you should be ok, as long
as you don't leave them on charge forever.

For integrated chargers like in cordless phones I think the conclusion is
that they are trickle charged all day every day and that kills the battery
after a year or so. The vendors don't put in decent battery management, and
it may be the lower capacity / less tightly wound cells take this abuse
better than fancier cells.

> In summary:
>
> - Is the capacity of the rechargeable battery important to
> a device (other than the length of use between charges)?

Yes, I think so.

> - Is there a difference between solar light batteries and
> rechargeable batteries?

No and yes. There is a technical reason why smaller cells might be better,
but I think mostly it's just cost-engineered down to the actual requirement
for solar lights.

> - Can mains powered chargers be used for all rechargeable
> batteries of the chemistry that the charger was designed for?

Apart from overcharging, both in current and time, mostly. Although it may
be the end-of-charge detection is missed on different cells and they get
overcharged.

TBH I wouldn't think too hard about it, just fit cheap batteries and maybe
be prepared to change them more frequently.

Theo
(putting Eneloop Lite in cordless phones as an experiment, not enough data
as yet)

On Sun, 26 Feb 2023 10:29:35 +0000, "Nicholas D. Richards"
<nicholas@salmiron.com> wrote:

>BT insist that the batteries in their cordless phones are replace ones
>that have identical chemistry, voltage and capacity.
>
>I can see that chemistry and voltage should be identical and why.
>However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
>2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
>capacity battery would allow for longer use of the phone between
>charges, on the base station.

In theory: yes.

In practice, some cordless phones have sub-optimal charging circuits -- Gigaset
are one brand known for this. And a 600 (or 800) mAh designated "DECT" cell is
more robust and withstands this abuse better than a 2200 mAh cell...

Sticking any old cell in will work, but the 2200 one will not last as long.
Might still make economic sense to use the latter.

Thomas Prufer

On 26-Feb-23 20:26, John Williamson wrote:
> On 26/02/2023 19:22, Sam Plusnet wrote:
>> On 26-Feb-23 14:58, John Williamson wrote:
>>> On 26/02/2023 10:29, Nicholas D. Richards wrote:
>>>> This starts with the batteries that go into cordless phones.
>>>>
>>>> BT insist that the batteries in their cordless phones are replace ones
>>>> that have identical chemistry, voltage and capacity.
>>>>
>>>> I can see that chemistry and voltage should be identical and why.
>>>> However why should a AA NiMH 750mAH battery not be replaced by a AA
>>>> NiMH
>>>> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
>>>> capacity battery would allow for longer use of the phone between
>>>> charges, on the base station.
>>>>
>>> I suspect that Beattie's stipulation is nefr covering. When their
>>> phones first came out, they didn't sell them, they rented them out, so
>>> they were nervous about any changes to the way things were made and
>>> repaired.
>>
>> _Just_ possible...
>> The BT base station usually recharges the batteries when you put the
>> phone back in place.  The charger is only intended to trickle-charge the
>> phone as it sits there for hours/days/weeks/months, and not supply much
>> current.
>> Would a depleted battery with a (much) greater capacity draw a larger
>> current, over a longer time, than the base station is designed to supply?
>
> "It was tested to work with this type of battery. We will not approve it
> for use with your battery unless you pay for the test"
>
> It will work happily, and the warranty has expired by now anyway.

I think you've nailed it.

(Don't try nailing your phone at home Kids)

--
Sam Plusnet

In article <k61tkgF58pkU1@mid.individual.net>, John Williamson
<johnwilliamson@btinternet.com> on Sun, 26 Feb 2023 at 20:26:54 awoke
Nicholas from his slumbers and wrote
>On 26/02/2023 19:22, Sam Plusnet wrote:
>> On 26-Feb-23 14:58, John Williamson wrote:
>>> On 26/02/2023 10:29, Nicholas D. Richards wrote:
>>>> This starts with the batteries that go into cordless phones.
>>>>
>>>> BT insist that the batteries in their cordless phones are replace ones
>>>> that have identical chemistry, voltage and capacity.
>>>>
>>>> I can see that chemistry and voltage should be identical and why.
>>>> However why should a AA NiMH 750mAH battery not be replaced by a AA NiMH
>>>> 2000mAH (say) battery? The voltage would be the same, 1.2V. A larger
>>>> capacity battery would allow for longer use of the phone between
>>>> charges, on the base station.
>>>>
>>> I suspect that Beattie's stipulation is nefr covering. When their
>>> phones first came out, they didn't sell them, they rented them out, so
>>> they were nervous about any changes to the way things were made and
>>> repaired.
>>
>> _Just_ possible...
>> The BT base station usually recharges the batteries when you put the
>> phone back in place. The charger is only intended to trickle-charge the
>> phone as it sits there for hours/days/weeks/months, and not supply much
>> current.
>> Would a depleted battery with a (much) greater capacity draw a larger
>> current, over a longer time, than the base station is designed to supply?
>
>"It was tested to work with this type of battery. We will not approve it
>for use with your battery unless you pay for the test"
>
>It will work happily, and the warranty has expired by now anyway.
>
Its not the warranty that often worries me, as you say it has long
expired. It is the expiry of a lot of my kit which is irreplaceable.

Irreplaceable because the functionality is no longer available.

As an example I have a portable radio which is programmable to record
programmes off air. They are recorded onto SD card. It can hold a list
of up to 20 programmes to be recorded, once, daily or weekly. Nothing
like that is now available.

--
0sterc@tcher -

"Où sont les neiges d'antan?"