Beep, beep .......beep, beep

For the past three years, I have been treated to a regular, but very weak beep, beep - several minutes gap and then a another, but not even constant, it came and went.

I have a linked fire alarm system, I seemed to have traced it to somewhere up stairs, but it alluded any attempt to be sure where it was coming from. Yesterday, I needed something from the loft space, where I have an electronics workshop, accessed by a loft ladder. Just as I dropped the ladder down, there was a loud beep, beep. Found it at last. I installed a smoke monitor up there, not connected to the main system.

Harry Bloomfield said:

For the past three years, I have been treated to a regular, but very weak beep, beep - several minutes gap and then a another, but not even constant, it came and went. ... Found it at last. I installed a smoke monitor up there, not connected to the main system.

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I had a similar experience a few weeks ago - intermittent beep-beep-beep in my (very large) cellar/workshop. It was surprisingly difficult to even localise where it was coming from. However, having eventually decided which corner of the cellar it was probably coming from, I started hunting through very dusty boxes on my shelves in that area, and eventually found a pretty old battery-operated portable PIR 'intruder alarm' - the battery had been left in and, after a good few years in the box on the shelves, was now trying to tell me that the (now very 'messy'!) battery needed to be replaced!

Kind Regards, John

At least it did not cost you anything, a friend had at one time a shop, he had closed the shop and sold off most of the stock, and one of the items not sold was a smoke alarm which was in a cupboard next to central heating boiler, he called out the heating guy for a fault, and was old smoke alarm so had to pay call out fee.

I note my smoke and heat alarms although main powered still have PP3 batteries in them which last longer than the non mains connected but still cause the alarms to peep when they go flat.

ericmark said:

I note my smoke and heat alarms although main powered still have PP3 batteries in them which last longer than the non mains connected but still cause the alarms to peep when they go flat.

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Last year, having tracked the noise down to somewhere upstairs, I tried taking down both of the upstairs linked alarms. Batteries on both seemed fine, so I refitted them. The noise seemed only to occur when it was cooler. My loft is well insulated, but normally has no heating and it is also insulated from the floor below, so it never gets really cold up there, just a bit cooler than the rest of the house.

My workshop/junk store is a granny annex built on the side of the house, being a 'chalet style' the back bedroom has less noise insulation from the annex than the rest of the house. My grandsons have often had sleepovers form an early age and when the eldest was about 6 he kept complaining about the noise in the room, this was traced to a flat battery in a digital thermometer in the annex which did a double beep every hour or so for at least 6 weeks. and all that time we kept telling him off for not going to bed on time... My wife couldn't hear it at all due to hearing loss even when it was right beside her, I couldn't hear it in the bedroom but had no problem when i was in the right part of the annex.

Around this time of year I would do a battery change, the wall thermostat batteries should last two years, but going flat resulted in getting cold and the battery indicator showed all well even when not enough in them to work relay, so I would do all at the same time, clocks, TRV heads, smoke alarms, etc. However now use Nest 3rd Gen and batteries are rechargeable so not needing to change them, tend not to do the rest, so guess I will have loads to do through the year now.

I can see need for battery back up in smoke alarms, but why not rechargeable? Although seen battery chargers in intruder alarms, and they just trickle charge all the time so a battery which should have around a 10 to 15 year life, is dead in 2 years, so suppose if such poor engineering may as well have a battery that is not rechargeable?

ericmark said:

Around this time of year I would do a battery change, the wall thermostat batteries should last two years, but going flat resulted in getting cold and the battery indicator showed all well even when not enough in them to work relay, so I would do all at the same time, clocks, TRV heads, smoke alarms, etc. However now use Nest 3rd Gen and batteries are rechargeable so not needing to change them, tend not to do the rest, so guess I will have loads to do through the year now.

I can see need for battery back up in smoke alarms, but why not rechargeable? Although seen battery chargers in intruder alarms, and they just trickle charge all the time so a battery which should have around a 10 to 15 year life, is dead in 2 years, so suppose if such poor engineering may as well have a battery that is not rechargeable?

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I agree it is a conundrum whether to change on a regular basis or not, currently we only have batteries in clocks and non mains smoke alarms. Clocks can be a problem when they start losing time and we don't realise (that reminds me I need to do my watch!!) but changing them every year when some seem to last many years seems a bit silly and certainly not good on the environment. I'll make the claim I check the smoke alarms every month but realistically i suspect it's more like 4 times a year when I think about it - like now.

Batteries on trickle charge if done correctly should have a long lifespan. I replaced one in a UPS last week so it's still standing here.
Tha annual test of the 170VA UPS is with an ACT battery tester to ensure the capacity is above 80% of original then load with 160W of lamp bulbs (4x40W) and ensure it lasts for 10minutes. This battery still passes that test.
I pulled it from service because there is now a significant white deposit on the +ve terminal, the remains of which shows less in this pic than I expected.I felt quite sad that I pulled it just 6 weeks short of 18/11/19 or 21 years so it didn't come of age

The mobility scooter with VRLA did around 25 years, and father-in-laws chair lift around 10 years, but my mothers stair lift would need new batteries every 2 years, measure the voltage with mothers it was around 30 to 32 volt, but I would have expected no more than 28 volt, more like 27 volt, I think the idea was a average of 27 volt when lift used 6 times a day, but it was only used around once a week I would put all the bins on it to take them down stairs.

SUNRAY said:

... Batteries on trickle charge if done correctly should have a long lifespan. I replaced one in a UPS last week so it's still standing here. ... Tha annual test of the 170VA UPS is with an ACT battery tester to ensure the capacity is above 80% of original then load with 160W of lamp bulbs (4x40W) and ensure it lasts for 10minutes. This battery still passes that test.

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One thing which never occurred to me until I started playing with 'energy meters' was that, quite apart from the need for a UPS battery to remain in good enough condition to 'suipply power for long enough' when used in anger, as the battery gets older, it is being charged an increasing amount - such as the energy consumption of the UPS (over and above that of the load) when powered 24/7 can rise very appreciably - something I've seen with older batteries, even when they still have enough capacity to do what the UPS says on the tin!

Kind Regards, John

JohnW2 said:

One thing which never occurred to me until I started playing with 'energy meters' was that, quite apart from the need for a UPS battery to remain in good enough condition to 'suipply power for long enough' when used in anger, as the battery gets older, it is being charged an increasing amount - such as the energy consumption of the UPS (over and above that of the load) when powered 24/7 can rise very appreciably - something I've seen with older batteries, even when they still have enough capacity to do what the UPS says on the tin!

Kind Regards, John

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That particular battery was taking 7mA of trickle and 4.7A after discharge

ericmark said:

The mobility scooter with VRLA did around 25 years, and father-in-laws chair lift around 10 years, but my mothers stair lift would need new batteries every 2 years, measure the voltage with mothers it was around 30 to 32 volt, but I would have expected no more than 28 volt, more like 27 volt, I think the idea was a average of 27 volt when lift used 6 times a day, but it was only used around once a week I would put all the bins on it to take them down stairs.

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28V is too much for this type of battery on constant trickle, I think the spec sheets say something like 14.2 but in my experience that will make them fail in about 2 years. At college some 35-40 years ago we learnt 2.27V per cell or 13.62, the battery in the pic was set to 13.64 (2.273V) and at the end of the 10 minute test it was at 11.82V having been discharging at >15A (by cheap clamp meter and known to be inaccurate).

A long time ago I had some brand new 38AH and some 100AH 6V VRLA's. I made the big mistake of using a standard 6A battery charger (around 15-16V off load) and I think the only thing that kept the 100AH's going for as long as they did was the fact that they probably never had enough time to fully charge, which kept the battery voltage down to below a damaging level. But the 38's suffered from the start when I put them on charge for 3 days straight.

My first check with VRLA's is feel the sides, the size of the bulges is a fairly good indication of the charge voltage and capacity. (The one above has one cell with a detectable shape change and 5 which show no signs of a bulge.
This one from the same company but a different division where they don't do annual testing to avoid interuptions automatically change the batteries after 5 years.
The charge current was 4mA at 13.63V and the ACT tester indicates >6.5AH capacity:

I think I have proved the above voltages to myself far too often to be to be wrong (without being big headed).

Sorry the stair lifts and mobility scooters use two batteries in series, so 13.63V each = 27.26 which lines up with what I say 27 to 28 volt. But at over 30 volt no wonder batteries did not last long.

In the main off the appliance I use a Lidi 3.8A battery charger this does not have a fixed volt and variable current, but 5 fixed current outputs which are selected by battery voltage, so 3.8, 3, 0.8, 0.1, zero for small batteries top currents not used and for large batteries zero not used. It seems to work very well, new version starts at 5 amp.

The mobility scooter I think a more standard type of stage charger.

What has surprised me is time before final stage is reached, often a week or more, it shows fully charged with the bar graph, but the energy meter shows it is still charging well after all four bars are shown, then finally switches off completely, it then cycles as the battery hits 12.8 volt it re-starts the charge sequence.

Harry Bloomfield said:

Last year, having tracked the noise down to somewhere upstairs, I tried taking down both of the upstairs linked alarms. Batteries on both seemed fine, so I refitted them. The noise seemed only to occur when it was cooler. My loft is well insulated, but normally has no heating and it is also insulated from the floor below, so it never gets really cold up there, just a bit cooler than the rest of the house.

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To continue this tale...

I removed the fire alarm unit and abandoned it on the hall window ledge, where it resided for a while until it began beeping again. Intending to open it up and have a closer look inside and for the sake of peace and quiet, I transferred it to the downstairs toilet, then still annoying - out to my garage.

One of our two border collies was behaving rather strangely, throughout all of this, but I didn't tie the strange behaviour to the bleep, until I had moved it out to the garage - where upon she was terrified to go for a wonder in the back garden on her own. She was desperate to go out at 2am this morning and the only way to get her out, was on a lead, then came the bleep from the garage and she panicked. At 2am, the only thing I could think of to do with it, to quickly silence it, was to drop it in a bowl of water which silenced it completely. She is now all back to normal.