OT - 9V battery purchase

[Lobster]

On 30 May 2015, Lobster grunted:

Sorry, Babs = Babz, innit; as I found out 10 secs later. Wish you could reliably unpost stuff on usenet :(

[alan_m]

BABZ Duracell CR2032

2 off for £1.25 incl postage (dated 2019) 10 off for £5.50 incl postage (dated 2024 or better)

[PeterC]

OK, I didn't look far enough. It was a matter of interest for the future as I have some CR2032s from 7dayshop that are undated - OK for minor uses but not for a MoBo. Site bookmarked for future ref.

[Huge]

Keep them in the frig - they should last more-or-less forever.

[Adam Aglionby]

bit dated but interesting

[PeterC]

It was after reading that that I started using Ikea's cells.

At one time the £ish shops were good value, but now they're big enough to get badged crap so that they can stay within their self-imposed confine of a pound.

I saw LSD NiMH cells in one of those shops. The AA was less than a Sanyo AAA and the AAA was about 200mAh!

[Andrew Gabriel]

I used them for a while, but found they were very likely to leak, even before use and before the date mark (although this was about 15 years ago - not bought them since).

I switched to GP Ultra which CPC used to sell in bulk very cheaply.

When CPC switched to supplying GP Super and GP "not for resale" as the bulk packaged products, I switched to Costco Kirkland.

Extra low capacity batteries (sometimes marked "not for resale") are made for bundling with an appliance, but often make their way into cheap shops and market stalls.

[Robert]

[Chris French]

As well as Babz, I also use MDS Batteries - they were cheaper for some D cells I bought recently.

[Johnny B Good]

I bought a pack of assorted CR lithium cells from Poundland a few weeks back, it didn't bother me that the BB date was 2015 since that just means they've still got 90% of their original capacity left in them at the end of their 10 year shelf life (assuming they'd been properly stored and not subjected to high temperature conditions for any protracted periods).

[Johnny B Good]

Poundland (or maybe it was PounWorld) were still selling the zinc/carbon PP3s in packs of three a couple of weeks ago. I bought two packs and stored them in the freezer (triple poly bagged and placed in a small tupperware like container - apparently this cell type can be deep frozen without detriment).

The packs themselves make for a convenient source of 27 volt for the door bell once I've soldered a couple of straps to series the batteries and attached flying leads. The pack even has a convenient hole by which to hang it from a screw head in the door frame below the ex-GPO trembler bell that's been doing duty as the front door bell these past 30 odd years or so.

The one and only time I used such a pack was a good two or three years back and it's still going strong (it replaced a monster 16 x AA cell battery pack that finally started showing its age after quarter of a century, rendering the pair of back to back 8 cell holders unservicable due to contact corrosion from cell leakage - even 'leakproof' steel clad alkalines have their limits!).

Using battery power in this case works out a lot cheaper than satisfying the vampiric appetite of a typical door bell transformer even when the cost per KWH's worth of primary cell battery power works out to something like 500 quid or so!

[Johnny B Good]

Get a few whilst you still can. They make an excellent 27v doorbell battery when coupled with a 12 to 24v GPO trembler bell. :-)

You can safely store them in a freezer (sealed against moisture - I triple poly bagged mine before putting the two packs I purchased a few weeks ago into a small tupperware like box)

My first 27 volt doorbell battery must have seen at least two years service by now with no signs of flagging so have more than sufficient life to justify their use over a bell transformer.

I know what you mean! I take a gander at their battery prices every so often just to keep my lip curling muscle tone in good shape.

[PeterC]

OK for some instruments but not for a MoBo. 8years from the original one; OK, so it won't need another 8 years, but I don't want to have to replace it in a year or two. I'd rather pay a quid extra for a known make than risk leakage/flattage.

[Johnny B Good]

I see your point. The 'battery' location on most MoBos leaves a lot to be desired in regard of accessibility since the designers' priorities on component placement puts this at the bottom of the list meaning the battery holder lands up being squeezed in with minimal disruption to the ideal placement of everything else. In a lot of cases, this can mean having to pull an adapter card or three out of its (their) expansion slot (s) or unplug cables from headers.

Even if the battery is readily accessible, this still leaves you with having to extract the PC from its normal location in order to remove the cover, often requiring the typical tower case to be laid on its side in order to facilitate access. This can be enough disruption in itself even if the PC is free standing alongside the monitor on a decent sized office desk let alone when it may have been tucked away 'out of sight' in an alcove attached to the underside of said office desk or just simply free standing on the floor.

Considering the potential hassle involve in replacing the CR2032, shelling out a pound or two extra on a long date coin cell is a small price to pay for the privilege of never having to repeat this exercise ever again.

The point I was trying to make is that the BB date on these coin cells is not as important as you might suppose. I can't recall seeing leaking CR2032 cells even when they've been totally exhausted (down to open circuit readings of a few millivolts) so the risk of corroded battery holder contacts is virtually zero leaving you with just the issue of having to replace it a year or two sooner than would have been the case with a long BB dated cell.

In your case, having had 8 years use out of the original coin cell, I'd have expected the Poundland BB expired cells to be good for another 5 or

6 years of service life, probably exceeding your requirements by a good couple of years due to age related failure of other components on the MoBo (typically the electrolytic capacitors) or just simply from obsolescence.