|
Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
|
Thread Tools |
17th Jun 2020, 9:16 am | #1 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,736
|
Dry battery longevity
I have just re-stuffed the large combined HT & LT battery that I use in my Ever Ready Sky King. I originally re-stuffed this battery what seemed like three or four years ago, but when I opened it up I was amazed to discover that the cells had ‘best before’ dates of 2013 and 2014 on them. I used all brand new cells at the time, so I must have done the original re-stuffing around ten years ago!
There were 54 pound-shop ‘Panasonic’ branded zinc chloride AA cells. Only one was showing significant leakage and the terminal voltage was down to roughly 1.1 volts per cell. Three ‘Maplin’ C-size alkaline cells in parallel supply the LT, and annoyingly one of these had leaked quite badly, necessitating a clean-up of its holder. All in all though, I was quite impressed with the longevity of these cells. Of course, if I had made more regular inspections I might have spotted the deterioration sooner. I have been less impressed by a batch of ‘Maxell’ CR2025 Lithium button cells, bought from Amazon and bearing a date code of 12-2024. From my stock of ten, two were OK and eight were virtually flat. Looking at other purchasers’ feedback proves my experience is far from unique. Avoid! Phil
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
17th Jun 2020, 10:54 am | #2 |
Octode
Join Date: May 2011
Location: Lancashire, UK.
Posts: 1,349
|
Re: Dry battery longevity
I wonder, do batteries get 'faked' in the same way other electronic parts seem to do?
|
17th Jun 2020, 1:07 pm | #3 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
|
Re: Dry battery longevity
Was the radio used often, for short periods? I wonder if that helps with battery life and health?
|
17th Jun 2020, 2:38 pm | #4 | |
Guest
Posts: n/a
|
Re: Dry battery longevity
Quote:
*in the sense of "it does what it says on the tin" rather than a beautiful finish and superlative (superfluous!) packaging. |
|
17th Jun 2020, 2:59 pm | #5 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,736
|
Re: Dry battery longevity
Yes, Bill, it’s my workshop radio, so it’s used once or twice a week, sometimes less, for maybe half an hour at a time. Zinc chloride cells are indeed reputed to last a long time in intermittent low-current, light duty applications. Thinking about it, half an hour a week over ten years is not far off 240 hours, which this type of battery was originally designed to achieve in later sets using the Dx96 range of low consumption miniature valves.
Regarding the faking of Maxell batteries, it’s hard to know for sure, but quite possible. In future I’ll buy all my batteries from CPC. Merlin, you make a good point about pound shop batteries and I’ve always used them when making replica HT/LT batteries with very few problems.
__________________
Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 17th Jun 2020 at 3:14 pm. Reason: Clarity |
17th Jun 2020, 4:09 pm | #6 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
|
Re: Dry battery longevity
...It's possible for Lithium coin cells to appear dead after a period of storage- i forget the exact chemistry but it's something like an oxide layer that needs to be broken through by asking the cell to supply a zap of greater current than it would normally be asked for in use. The cell is reanimated by this action.
(This is anecdotal, based on someone else's experience- can't remember who.) Dave |
17th Jun 2020, 4:23 pm | #7 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,736
|
Re: Dry battery longevity
This is exactly what happened with a couple of these cells, Dave. I have a tester that draws 200mA from the cell under test. Most of the dud ones tested at virtually zero current permanently, but one or two did start off showing ‘flat’ but recovered after a second to read well into the ‘good’ category.
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
17th Jun 2020, 4:50 pm | #8 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
|
Re: Dry battery longevity
The 4.5V Panasonic Zinc Cloride flat battery in our kitchen torch with a use by date of Oct 2010 still gives a bright light. It only gets intermittent use, but always works when it is needed.
Last edited by emeritus; 17th Jun 2020 at 4:52 pm. Reason: Typo |
17th Jun 2020, 7:54 pm | #9 | |||
Octode
Join Date: May 2011
Location: Lancashire, UK.
Posts: 1,349
|
Re: Dry battery longevity
Quote:
Quote:
I blamed the contacts in the past but then found if I hold the lock/unlock button down for several seconds it starts to come back to life. So I alternate them now and don't have the problem. The oxide layer thing is something I read about somewhere in the distant past and I also have a recollection of reading that some coin cells are more suited to usage such as key fobs than others in that they don't suffer this issue so much. |
|||
29th Jun 2020, 3:38 pm | #10 |
Heptode
Join Date: Sep 2009
Location: Tonbridge, Kent, UK.
Posts: 685
|
Re: Dry battery longevity
I'm just about to change the C cells in our doorbell as the present ones have finally died. They have only just started to show some whiskers around the negative end. They are, or were, Sainsburys Long Life Alkaline and dated coded 05-91. Not a bad life, maybe we just don't have enough visitors.
Gordon |
29th Jun 2020, 3:52 pm | #11 |
Triode
Join Date: Apr 2019
Location: Cheltenham, Gloucestershire, UK.
Posts: 26
|
Re: Dry battery longevity
Another vote here for Sainsbury's own brand alkaline. The 4 C cells in our doorbell were installed in 1987 & still working with no sign of leakage. On my crude test of short into the 10A range of a multimeter, they still deliver 3-4A so should be good for a few years yet.
Chris K |
29th Jun 2020, 4:00 pm | #12 |
Octode
Join Date: May 2011
Location: Lancashire, UK.
Posts: 1,349
|
Re: Dry battery longevity
Doorbells are an interesting study...
I don't know the exact numbers but I would guess a mains transformer for a bell consumes about 1 watt which is nearly 10kW over a year. We've one, powered up in 1953 and still running a bell. Do the sums, the batteries work out much cheaper overall, even if replaced quite frequently. |
29th Jun 2020, 4:25 pm | #13 |
Octode
Join Date: Nov 2004
Location: Hebden Bridge, West Yorkshire, UK.
Posts: 1,885
|
Re: Dry battery longevity
I make that 8.76 kWh which works out about £1.25...but does it really consume 1W when not energising the bell, assuming an older AC type (i.e. no DC rectification, bleed or switch mode stuff) - I'm genuinely interested in this.
|
29th Jun 2020, 5:58 pm | #14 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,736
|
Re: Dry battery longevity
I’m guessing that the bell transformer is probably pulling rather more current but at a very low power factor. Based on my observation that such transformers run slightly warm, one watt is not a bad estimate. The old rule of thumb, that “one watt, running continuously, equates to one pound per year” is a bit outdated now, but it’s a fair starting point.
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
29th Jun 2020, 6:30 pm | #15 |
Octode
Join Date: May 2011
Location: Lancashire, UK.
Posts: 1,349
|
Re: Dry battery longevity
Like Phil, I figured 1 watt a reasonable estimate. It runs 'not cold' rather than warm. It's also pretty large so I figure any core losses are quite low.
2020 back to 1953 is 67 years. 67 * 8.8kW is 590kW which would take you a couple of thousand miles in a Nissan Leaf (back of packet guestimations...) Actual energy used at say five 1.5 second bell pushes a week is 7.5 seconds a week or (rounding up) 400 seconds a year. Seven minutes use. 67 years of that would be 469 minutes or 7.8 hours. Lets say the transformer was 100% efficient and the bell drew 1 amp at 12 volt (no idea what the voltage is tbh but the current bell can use 4 C cells). That's 12 watts for 7.8 hours which is 93 watts over 67 years vs 590kW for the transformer. From memory it looks a bit like this: |
29th Jun 2020, 6:51 pm | #16 |
Hexode
Join Date: Oct 2012
Location: London, UK.
Posts: 497
|
Re: Dry battery longevity
In a porch with a decent push switch you could put it in the transformers primary side and save that £1.25 a year.
But transformer run bells ofter have an illuminated bell push which would prevent that and increase that £1.25 a year anyway. |
29th Jun 2020, 7:28 pm | #17 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
|
Re: Dry battery longevity
You would also be running the mains through your bell push and associated wiring, which isn't really a good idea - even if it's safe when you first install it, doorbell installations stay in place for many decades and multiple occupants. My (battery) doorbell was installed by a previous house owner sometime in the 70s, and is untouched apart from battery replacement and contact cleaning.
|
29th Jun 2020, 8:56 pm | #18 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,173
|
Re: Dry battery longevity
Hi Folks, if the bell push is not illuminated then there will be no sec load on the transformer and it will only be drawing primarily reactive current (low power factor).
The domestic electricity meter is generally only responsive to "real" power, so the low PF consumption will not be recorded Ed |
29th Jun 2020, 9:11 pm | #19 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,684
|
Re: Dry battery longevity
The 'Eveready' AD28 6V battery in my Bardic handlamp is still going strong and it is dated 'Best Before 01 2010'.
I only really use the handlamp in winter, and not for prolonged periods. And I have fitted an LED replacement bulb in it, but still...
__________________
Regds, Russell W. B. G4YLI. |
29th Jun 2020, 9:32 pm | #20 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,528
|
Re: Dry battery longevity
Can I put in a plea for kWh or Wh in those calculations for actual energy used, kW or just W is the rate at which the energy is consumed.
__________________
....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |