Battery life of wireless doorbell

[Gizmo.]

Though I now work for a different industrial battery manufacturer...I used
to work for Exide...
but never worked with cells larger than 1700 AH. I think the largest cell
I
could carry into my basement
would be about 300AH

Had to remove 192 flooded cells from a Nortel site once, each one with 56
litres of acid.
Wasnt exactly the nicest job we've ever done ... but sure did pay well !
Replaced them with good old VH57s

 

[philo]

Had to remove 192 flooded cells from a Nortel site once, each one with 56
litres of acid.
Wasnt exactly the nicest job we've ever done ... but sure did pay well !
Replaced them with good old VH57s

Well I'm 57 years old and my heavy lifting days are over.
they hired a 300# (135kg) "kid" to help me out on the heavy jobs.

The first week on the job he laughed at me because I could no
longer lift all those "very light" cells.

After I had him carry a dozen cells up a flight of stairs
(and the old ones back down) he started laughing a bit less

I really rubbed it in a bit and told him that I was the one who installed
them originally
about 5 years before!

Heck my heavy lifting ended about 6 years ago when I had knee surgery

 

[Gizmo.]

Well I'm 57 years old and my heavy lifting days are over.
they hired a 300# (135kg) "kid" to help me out on the heavy jobs.

The first week on the job he laughed at me because I could no
longer lift all those "very light" cells.

Ahh but once you get to a certain age you've learnt that using an electric /
hydraulic battery lifter may not be so fast, but is way easier - and kinder
on the back ! ;o)
Although we still get the youngsters come in lifting VH57s at 127Kg each by
hand.

After I had him carry a dozen cells up a flight of stairs
(and the old ones back down) he started laughing a bit less

I really rubbed it in a bit and told him that I was the one who installed
them originally
about 5 years before!

I realised I was getting on when I started ripping out equipment that was
state of the art 8-10 years ago when I first installed it, and replacing it
with kit that was a fraction of the size (

Heck my heavy lifting ended about 6 years ago when I had knee surgery

I just get contractors to do it )

 

[philo]

I realised I was getting on when I started ripping out equipment that was
state of the art 8-10 years ago when I first installed it, and replacing it
with kit that was a fraction of the size (


I just get contractors to do it )

Though the electronics has changed quite a bit in the 32 years I've been in
the battery business...
and there have even been some changes in the batteries too...
Lead is lead...and it's heavy!

 

[Charlie Mitchell]

The wired one I put in is just an old fashioned ding dong one,
it's not one that's wired into the mains, that really does
sound dangerous, epseically where my wiring skills are
concerned!!

I've got a mains fire-bell[1] wired up to the phone line.

Owain


[1] Security bell actually, fire-bells don't run on mains

Good god, it must be the equivalent of being woken up by being
kicked in the head!

 

[Owain]

I've got a mains fire-bell[1] wired up to the phone line.
[1] Security bell actually, fire-bells don't run on mains

Good god, it must be the equivalent of being woken up by being
kicked in the head!

No, the klaxon on the alarm clock has that effect. I'm out of bed and
standing before I wake up!

I guess I just like my neighbours in the tenement to share in my
lifestyle...

Owain

 

[kony]

get a set of batteries like this:

http://www.plazaearth.com/philo/batt.jpg

they can ring your bell continuously for 25 years or so

Unless those are of exotic construction, won't they have
self-discharged within a couple years' time?

 

[Terry]

No, the klaxon on the alarm clock has that effect. I'm out of bed and
standing before I wake up!

Reminds me of my (very much) younger days (I was still at school) and
listening to AFN after Radio Luxembourg closed down - yes! I am going
back a very long time!

(For the benefit of younger listeners: AFN was the American Forces
Network, Europe.)

Closedown procedure varied from station to station and I can't remember
now if it was Frankfurt, Munich or Stuttgart, (I think Frankfurt) but
it went something like this:

"At the sound of the last tone, Central European Time will be One Hour
..... AFN Frankfurt broadcasts on an assigned frequency of Eight
Hundred, Seventy Two kilocycles per second, Three Hunded, Fourty-Four
meters in the Medium Waveband with a power of One Hundred, Fifty
Thousand Watts! ... AFN is now closing down and will return to the air
at six hours this morning ... Ladies and Gentlemen: Our National
Anthem!..."

.... at which point, as a 14 year old listening under the bedcovers (as
we all did, didn't we?) I had this mental picture of all these yanks
jumping out of bed just after 1am, snapping smartly to attention and
saluting (possibly to the flag propped up in the corner of the
bedroom!)

Terry

 

[philo]

Unless those are of exotic construction, won't they have
self-discharged within a couple years' time?

You bet they will discharge...
that's why I keep them on a hysteresis-loop charger
(it's built into the UPS)

 

[John]

Irrespective of usage, the receiver must be active all the time waiting for
a call - like leaving a radio switched on - with the volume turned down - it
will eat the batteries. Plug in ones are better.


--

 

[kony]

Irrespective of usage, the receiver must be active all the time waiting for
a call - like leaving a radio switched on - with the volume turned down - it
will eat the batteries. Plug in ones are better.

I would suspect the receiver battery lasts at least as long
as the transmitter battery. Supposing one with a separate
transformer plug in supply costs $10 more, it may come close
to erasing any cost difference too over the life of the
unit, though the plug in type would reduce # of batteries
going into a landfill.

 

[GB]

I would suspect the receiver battery lasts at least as long
as the transmitter battery. Supposing one with a separate
transformer plug in supply costs $10 more, it may come close
to erasing any cost difference too over the life of the
unit, though the plug in type would reduce # of batteries
going into a landfill.

The transmitter is only consuming power for a few seconds at a time, when
somebody presses the button. The receiver is on 24/7, and it has to power
the bell/buzzer.

 

[kony]

The transmitter is only consuming power for a few seconds at a time, when
somebody presses the button. The receiver is on 24/7, and it has to power
the bell/buzzer.

While that is true, that doesn't mean it necessarily
consumes a lot of current. Take an LCD watch for example,
it runs years from a tiny battery. How long do you think it
would run from 2 x C cells? It is an irrelevant question
because the cells will have self discharged faster than the
watch would have drained them.

As a % of time the buzzer isn't running very often and the
rest of the receiver may be using on a few uA. Since I have
one that uses 2 x C cells and they have lasted a little over
a year already, it is already clear it uses significantly
less than 1mA on average.

 

[John]

While that is true, that doesn't mean it necessarily
consumes a lot of current. Take an LCD watch for example,
it runs years from a tiny battery. How long do you think it
would run from 2 x C cells? It is an irrelevant question
because the cells will have self discharged faster than the
watch would have drained them.

As a % of time the buzzer isn't running very often and the
rest of the receiver may be using on a few uA. Since I have
one that uses 2 x C cells and they have lasted a little over
a year already, it is already clear it uses significantly
less than 1mA on average.

I stand by my point - the bell unit is acting as a radio receiver all the
time - ready to ring if it receives the correct input. It is bound to use a
significant amount of power. I would only consider having a mains powered
one - as many have a 13 amp plug through facility you are not even losing a
socket.
Battery quality is also an obvious factor.

 

[kony]

I stand by my point - the bell unit is acting as a radio receiver all the
time - ready to ring if it receives the correct input. It is bound to use a
significant amount of power. I would only consider having a mains powered
one - as many have a 13 amp plug through facility you are not even losing a
socket.
Battery quality is also an obvious factor.

Define "significant amount of power". Since the batteries
in mine are plain old Duracell alkalines rated for 7800mAh,
http://www.duracell.com/oem/Pdf/others/ATB-full.pdf
and since it's already ran for over a year (but let's round
down to 1 year for simplicities' sake), 24/7 constantly,
that's already an absolute maximum possible avg. current of

7800 / [24 * 365] = 0.9mA

.... and it only goes lower every day it continues to run off
same pair of cells. It may be that those Duracells can
produce more than 7800mAh at such a slow drain rate, but not
enough to make much of a difference in the calculations,
we're still looking at a sub-1mA range considering those
cells aren't dead yet and may not be any day soon.

I would agree that battery quality is an obvious factor but
why would someone put low quality batteries in (anything?)
except perhaps for those generic NiMH if the device didn't
need run any longer than those can provide before another
recharge cycle is acceptible - definitely not the case in
this context with a door buzzer.

 

[John]

I stand by my point - the bell unit is acting as a radio receiver all the
time - ready to ring if it receives the correct input. It is bound to use
a
significant amount of power. I would only consider having a mains powered
one - as many have a 13 amp plug through facility you are not even losing
a
socket.
Battery quality is also an obvious factor.

Define "significant amount of power". Since the batteries
in mine are plain old Duracell alkalines rated for 7800mAh,
http://www.duracell.com/oem/Pdf/others/ATB-full.pdf
and since it's already ran for over a year (but let's round
down to 1 year for simplicities' sake), 24/7 constantly,
that's already an absolute maximum possible avg. current of

7800 / [24 * 365] = 0.9mA

... and it only goes lower every day it continues to run off
same pair of cells. It may be that those Duracells can
produce more than 7800mAh at such a slow drain rate, but not
enough to make much of a difference in the calculations,
we're still looking at a sub-1mA range considering those
cells aren't dead yet and may not be any day soon.

I would agree that battery quality is an obvious factor but
why would someone put low quality batteries in (anything?)
except perhaps for those generic NiMH if the device didn't
need run any longer than those can provide before another
recharge cycle is acceptible - definitely not the case in
this context with a door buzzer.

You must be fortunate with your choice of unit and batteries. People I know
seem to often have theirs dead (Please knock sticker) and complain about
battery consumption.

Good for you.

 

[Derek Geldard]

Not having such a device, why would the *receiver* be battery powered
unless you live somewhere without mains electricity?

You can move them about the house with you if, say you were working in
an upstairs room when expecting a parcel / take them into the
conservatory / out to the barbecue. Also you can site them on top of
tall cupboards where they are out of the way and inconspicuous without
trailing wires.

Oddly the transmitter unit in my 4 year old Friedland unit has never
had a new battery (presumably a button cell of some kind), whereas the
sounder has had 3 sets of 2 "C" cells.

DG

 

[Dave Plowman (News)]

You can move them about the house with you if, say you were working in
an upstairs room when expecting a parcel / take them into the
conservatory / out to the barbecue.

But I'd expect a mains bell system to be heard throughout the house. The
fact that you have to take a wireless one with you is just one more thing
against it.

Also you can site them on top of
tall cupboards where they are out of the way and inconspicuous without
trailing wires.

FFS, this is a DIY group. You don't need to put up with trailing cables.
;-)

Oddly the transmitter unit in my 4 year old Friedland unit has never
had a new battery (presumably a button cell of some kind), whereas the
sounder has had 3 sets of 2 "C" cells.

So not cheap to run, then.

 

[Owain]

But I'd expect a mains bell system to be heard throughout the house.

.... down the garden and into the next street if you choose the right
sort

Owain

 

[kony]

But I'd expect a mains bell system to be heard throughout the house. The
fact that you have to take a wireless one with you is just one more thing
against it.

.... or for it, not everyone has either a tiny house or wants
a bell system that loud, which tends to be that much louder
in areas adjacent to it. If you have plaster walls or
teenagers/others with loud stereos you may also find there's
no one bell system that can be heard everywhere without
waking the dead in the next zip code.

In short the ideal bell system is not as loud as possible,
it's only loud enough to be heard reliably. One could wire
up secondary chimes but considering the addt'l time and/or
expense it may not not suit all needs either.

You don't "have" to take anything with you, that's like
claiming it's a negative thing that a notebook is portable.