Multiple on and off per day - security light - which type of bulb?

[Dave Plowman (News)]

I'd say any filament lamp will have a shorter life with higher voltage. But also a higher output.

[dennis]

8<

They would be as dim as hell if you wanted them to last forever.

[Andrew]

That's what I always thought.

Bit surprised at the Woolies 240V bulb in my bathroom lasting so long. People always said Woolies paint was good too.

In the same period, I have replaced the 4 foot fluorescent tube in the kitchen twice, and the starter once.

The bathroom is the end of the spur. I might measure the voltage at the socket out of interest.

[Andrew]

It makes an annoying humming. Sometimes more obvious than others, and I can hear it upstairs in bed.

I only used it because I have an illuminated friedland push button - except that the 'bulb' has failed :-(.

[ChrisK]

This is pretty much the worst use case for CFL. There are all sorts of nasty start up conditions in the inverter with extra strain in cold weather when the internal mercury vapour pressure is low - plus they never have time to get up to working temperature.

LED should be OK though - preferably the cheap and cheerful ones with capacitative droppers (poundland is your friend) unless the PIR switch objects. They sometimes don't like the non resistive loads.

Chris K

[ChrisK]

Every year :-)

I have the same set of batteries in the door chimes that were installed in 1987. Sainsbury's own brand C cell alkalines, expiry date 1995. They show no sign of leakage and still show a short circuit test current of about 3A.

Unlike many of the alkalines I seem to get today which leak within months - if not before they have been removed from their packaging.

Chris K

[Dave Plowman (News)]

The cost of a tungsten lamp is a small proportion of the cost of the energy it uses in its life. If you are happy to have a very inefficient one, it will certainly last longer. But you'd save a lot of money overall by using efficient ones and changing them when they fail.

[Harry Bloomfield]

All filament lamps are a tradeoff between design life and light output/ efficiency. I would not buy any lamp marked 220-240v, they will work on our 240v, but not for long.

You may notice car tail bulbs produce a yellower light than car stop light bulbs. Tail bulbs are slightly under run for a longer working life. Top lamp filaments are slightly over run, for extra brightness, but their on time is (should be) much less. Notice those who wait at the lights and don't make use of their handbrake, often have blown stop lamp bulbs.

[Harry Bloomfield]

Andrew has brought this to us :

Well, nearly. It is a simple tradeoff between life and light output and efficiency. Put two lamps in series, halve the voltage and you get your lamps which would last for ever. They would not be very efficient, or very useful, but last they would.

[Harry Bloomfield]

Andrew used his keyboard to write :

I have a lamp in the understairs cupboard, put there in the 1960's and that still works.

[Terry Casey]

Buy your batteries from Poundland like I do. Kodak alkalines, six AA for a pound and long dated (about 2025 at the moment, I think), so the cheapest of anywhere I've found and, although I've been using them for ages, I've never had one leak.

Any other brand I've ever used always leak at some point in their life cycle

[Max Demian]

Oddly torch bulbs for 3V torches were always rated at 2.5V, for 4.5V torches 3.5V - I assume for a brighter light.

[Harry Bloomfield]

Max Demian presented the following explanation :

Yes, brighter light at the cost of lamp life, but battery voltages would dive somewhat under load anyway.

[ChrisK]

Agree, haven't had those leak. Maplin batteries have also been completely trustworthy. By far the worst have been B&Q own brand that have leaked before and during use.

Problem is, they are only slapping a label on whatever supplier is cheapest at the moment so things could change unpredictably.

Hopefully, Maplin *might* take a bit more care as they probably have a higher proportion of informed customers than Poundland - who knows?

Chris K

[Martin Brown]

On time won't make any difference. LED stabilise after

I suspect that could well be a problem.

I have put a battery powered one on the village hall to make life easier locking up after dark. It is still on its first set of C cells.

[Huge]

Lightweight.

[Max Demian]

I've rarely had any problem with pound shop batteries, except a few years ago when I had a batch of dodgy Hyundais. They're a lot cheaper than from most shops. Except that they don't sell LR44s - I get Duracells through Amazon for £3.84 for 10, post free.

[Andy Burns]

My transformer is DIN-rail mounted within the CU, I can only hear it when in the cupboard under the stairs.

I replaced the lamp in my bell-push with a pair of white LEDs in inverse parallel plus a series resistor, it was a little tight soldering them in there and yes it has 100Hz flicker, but it's not too bad.

[Dave Plowman (News)]

Is it on some form of sounding board? Like ply or whatever?

If not, you could (carefully) try putting a G-clamp on the laminations (if they are exposed with the cover off) If that helps, perhaps some hot melt glue might stop it.

Prime case for a LED. ;-)

I've been looking at bell pushes - and can't seem to find one I like the look of - with a LED, obviously. Needs to be architrave sized, flush fitting, and either satin chrome or brushed SS. Plain plate but nice looking button. Most of the illuminated ones look like part of a cheap set.

[Terry Casey]

Not in my experience!

I bought a box of 100 AAs on special offer about 3 or 4 years ago and had terrible trouble with them.

I slung out what was almost certainly a perfectly good doorbell because it suddenly started gobbling up batteries, then it was a small radio, so I got somewhat suspicious!

I put a meter across the 4 AAs and got 3V!

On further investigation, 3 of them still read around 1.5V but the fourth one read -1.5V!

It had obviously discharged fully in a short period of time and become reverse charged!

I then looked at the others remaining in the box and noted that several were just starting to leak, so I took the rest back, as well as the four from the radio.

One of the staff checked what I'd said about the cells from the radio and suggested it had been built 'with the cartridge reversed!'

At least the manager saw sense - eventually - and I got a full refund.

Maplin? Never again!

But then, why would I? My Poundland cells cost 16.66P each wheras Maplin's own brand cells - checked just now - cost

87.25P each!

I note they have a special offer on 100s right now - half price at 15P each instead of 30P each - but I fell into that trap before ...