Wired Doorbell

[jaizan]

I have a WIRED doorbell that runs off 4 x AA batteries

The batteries need changing at least once a year. Yet all it's doing is running for a few seconds once or twice per day.

Since it's not WiFi, I'm assuming the current draw ought to be nothing until someone presses the switch and makes a circuit.

I've got AA batteries in other devices that last for years. For instance, electronic radiator thermostats & those adjust position several times per day.

1 Any ideas why this doorbell is so bad ?

2 Can anyone recommend a better doorbell that needs less frequent attention ? Preferably wired.

[tacpot12]

I can't recommend these as I don't have one myself, but this link will give you an idea of what is available: https://www.greenbrook.co.uk/mpattachme ... ad/id/302/

You may find that your existing chime has the terminals to accept power from a bell transformer, in which case you just need the transformer.

If you have space in your consumer unit you can add a transformer to the consumer unit and run low voltage cable to the chime. If you don't have the space, the transformer will need to be somewhere near the chimes, and have some mains power run to it from the closest socket.

[Dicky99]

4 rechargeable batteries and a charger are 14 quid at Argos. Probably cheaper at Amazon. Beats faffing about fitting another bell which just might eat batteries faster

[9873210]

I can think of several possibilities. If you want to track it down, it's time to get out a multimeter and measure some currents.

First it's possible that the bell draws quite a large current when it is operating. 10s a day is an hour a year, if the bell draws a few amps when operating that could be enough to drain a battery.

Second it's possible there is a high resistance short when not operating. Less than a milliamp continuously will drain a battery in a year. Low voltage wiring and devices are always not built to high standards. My first check would be the bell push which is likely to be out in the weather. There might also be a snubber across the solenoids.

Third is there by any chance a lamp in the bell push?

[Stompa]

Ours is around 30 years old, but it looks identical to this:

https://www.edwardes.co.uk/products/fri ... ell-in-one

It takes a pair of D Cell batteries, and my last set lasted almost 8 years. Sadly I'm the sort of old git who keeps a record of these things!

[jfgw]

1 Any ideas why this doorbell is so bad ?

Can you tell us what sort of bell it is?


Julian F. G. W.

[DrFfybes]

Third is there by any chance a lamp in the bell push?

That would be my first thought, especially with AA batteries. Think of it as a small torch switched on for a year.

Paul

[jaizan]

Thank you for the helpful suggestions.

1 It's a Friedland. Photo attached. This has 3 AA batteries, rather than the 4 that I thought.

2 The switch is not illuminated. Whilst I might be lazy enough to ask questions here before getting my multi-meter out, I'm not quite dumb enough to run an illuminated switch 24-7 off 3 x AA batteries.

3 The model recommended by Stompa with D-cell batteries that last 8 years is my kind of solution. As long as Friedland haven't changed the internal design & noting that mine is a Friedland. Buy something, spend 15 minutes fitting it and hopefully not touch it for 8 years. That is about the maintenance interval I have in mind for a doorbell.
Of course, if they have cheapened it by fitting the same internals as mine, that purchase would be a waste of money !

My second choice would be a mains powered solution. Second choice because I need to buy something AND spend a couple of hours routing some wiring.

Buying some "Energizer AA Ultimate Lithium" batteries would be the very lazy option. These last about 3 times as long as the normal AAs in my battery guzzling Philishave travel shaver. However, the price of those has increased from £3.60 to £8.45.

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[bungeejumper]

Hmmm, don't get me wrong but....

You said four AA batteries, right? But your pic shows three.

Two Varta AA units, which aren't the long life LR6. And something called Activ Energy, which is an Aldi own brand, and which is proper cheapo. And which has the reviews to match. "Great price if you don't expect too much" seems to be the general flavour of them.

I'd definitely check the resistance on my doorbell wire and bell push, but I'd also fit a set of three/four batteries that actually match. Cruel, I know, but those three look like the assortment of anybrand batteries that I keep in a drawer, and some of which may be of unknown vintage. (Yeah, we all do it..... )

FWIW, you can get the LR6 batteries : £2.79 for eight. https://www.batterystation.co.uk/varta- ... ies-8-pack. That would be my starting point.

BJ

[Dicky99]

. Buy something, spend 15 minutes fitting it and hopefully not touch it for 8 years.

A door knocker would satisfy this specification

[jfgw]

It looks like a Friedland Seattle D844 but I can't find much on it. Why so many terminals? Can it play a different tune for front and back?

If you take the batteries out, does it forget which tune you have it set to?


Julian F. G. W.

[jaizan]

I've already published a correction from 4 to 3 batteries, before anyone else pointed it out.

The Aldi own brand batteries got good test results by Which magazine, which is why I sometimes use them.
I've tried Duracell as well, which also don't last in the doorbell.

I was just looking at a bell transfomer on the Screwfix site. Someone pointed out the idle current was 45 mA. So 10.8W, or about 35 kWh per year !!
Do I not like that.
A 2amp phone charger would be far more efficient, if it worked.

My doorbell bell may be capable of playing tunes, but I just have it set up with a boring ring tone. It doesn't forget the setting after the batteries go flat.

[88V8]

Can anyone recommend a better doorbell that needs less frequent attention ?

This one works like clockwork and will never flatten the batteries.

V8

[jfgw]

I was just looking at a bell transfomer on the Screwfix site. Someone pointed out the idle current was 45 mA. So 10.8W, or about 35 kWh per year !!

On the Q & A tab, there are a number of replies from the Luceco technical team which are just plain wrong.

Is it DC?
...you would need to feed it with a DC input to get a DC output...

Er, no. Transformers do not work on DC at all. If you supplied it with DC, the most you would get out of it is smoke!

...AC and thus switching direction of flow 50 times a second...

100 times actually (50 full cycles per second).

45mA idle current seems a lot but I don't have one to test. This would be mostly reactive (the current is not in phase with the voltage). That means that watts does not equal volts times amps but is actually a lot less.

This data sheet says that it consumes 1.15W, https://www.tlc-direct.co.uk/Technical/DataSheets/BG/BGCUB1_Datasheet.pdf.


Julian F. G. W.

[servodude]

If that transformer is typical for the use case it suggests the batteries are looking at something around an 8W load when the bell is ringing?

I'd be tempted in the first instance to try replacing the the cells with low-self-discharge NiMH rechargeables (eneloops or IKEA ones would be the ones in my charger). I suspect normal alkaline batteries will quickly struggle with the current required even if they have a decent amount of charge remaining. The NiMH will be much more consistent throughout their use - even if they start with a slightly lower nominal voltage.

[jaizan]

Again, thank you for the comments.

It's not very confidence inspiring when the Screwfix technical expert expects transformers to work on DC.

I agree 45mA idle current seems high for a transformer. 10W is in the right ballpark for consumption when operating the bell & the unit would be noticeably warm if consuming a constant 10W. However, Screwfix didn't provide a data sheet. Thank you for finding one.

Even at 1.15W idle consumption, this would consume 10 kWh per year.
I'm not entirely sure what the long term cost of electric will be, but that's likely to be more expensive than batteries. Perhaps £3 to £5 per year.
At least it should be maintenance free.

I may investigate the idea of using a 2A mobile phone charger, since some of these consume a lot less than 1.15W in standby. I believe 0.2W is common and Samsung actually developed one that's claimed to consume 20 mW.

[jaizan]

I'd be tempted in the first instance to try replacing the the cells with low-self-discharge NiMH rechargeables (eneloops or IKEA ones would be the ones in my charger). I suspect normal alkaline batteries will quickly struggle with the current required even if they have a decent amount of charge remaining. The NiMH will be much more consistent throughout their use - even if they start with a slightly lower nominal voltage.

Thank you.
I think 2A current was mentioned on one of the Friedland downloads, although that might have been the required capacity for the external power supply.

Quantifying the potential improvement that you mention, this website has some data showing how much better NiMH performance is at 2 Amps. With the slight caveat that they are testing their own brand NiMH v other brands of Alkaline.

https://www.powerstream.com/AA-tests.htm

[My last purchase of Eneloop AAs was in 2011 @ £6.79 for 4. They now want £15.95 ]

[servodude]

I'd be tempted in the first instance to try replacing the the cells with low-self-discharge NiMH rechargeables (eneloops or IKEA ones would be the ones in my charger). I suspect normal alkaline batteries will quickly struggle with the current required even if they have a decent amount of charge remaining. The NiMH will be much more consistent throughout their use - even if they start with a slightly lower nominal voltage.

Thank you.
I think 2A current was mentioned on one of the Friedland downloads, although that might have been the required capacity for the external power supply.

Quantifying the potential improvement that you mention, this website has some data showing how much better NiMH performance is at 2 Amps. With the slight caveat that they are testing their own brand NiMH v other brands of Alkaline.

https://www.powerstream.com/AA-tests.htm

[My last purchase of Eneloop AAs was in 2011 @ £6.79 for 4. They now want £15.95 ]

The difference in the delivery profile of the two tech is very well understood - and a good reason a lot of consumer devices (like cameras) moved away from using AA cells.
Eneloops do go on special every so often (we use them in a lot of things and have a variety of fancy finishes) and the IKEA ones (LADDA I think they can them) are as far as folk can tell pretty much identical in performance

[9873210]

Quantifying the potential improvement that you mention, this website has some data showing how much better NiMH performance is at 2 Amps. With the slight caveat that they are testing their own brand NiMH v other brands of Alkaline.

https://www.powerstream.com/AA-tests.htm

Those curves are for continuous current. Intermittent discharge such as pulse of 2A for a second every hour may (and probably will) be quite different. I haven't worked on this for a decade or two, but when I did a few datasheets would include the results for intermittent pulses as used in a camera flash. The results were unpredictable from the continuous discharge data. There are lots of strange effects, for some batteries high current pulses caused high self-discharge. For a really low average power use such as a doorbell the self-discharge would dominate. In that case even the published pulse test might not reflect performance in a doorbell, which is fairly rare use case.

OTOH for a few quids worth of batteries per year it's not economic to try to optimize this. It might be worth it for the doorbell and battery manufacturers, who are selling tens of thousands of units, but you'd have to believe them and there is far too much snake oil out there.

[genou]

Again, thank you for the comments.


I'm not entirely sure what the long term cost of electric will be, but that's likely to be more expensive than batteries. Perhaps £3 to £5 per year.
At least it should be maintenance free.

Is there some religious objection to a wireless piezoelectric bell with plugged in receivers? I confess I have no idea what the power consumption of my receivers is, but the whole show is utterly maintenance free. The one at MiL is not - every time she has a power cut the ringers default to an utterly appalling notification, which I have to reset. And for reasons know only to Scottish Power, her DNO, they happen amazingly often ( well, for a lifelong townie like me ).