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Battery costs.

 
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adam2
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Joined: 02 Jul 2007
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Location: North Somerset

PostPosted: Fri Jan 26, 2018 4:02 pm    Post subject: Battery costs. Reply with quote

Whilst most people understand that power from disposable batteries is expensive, it is not generally realised just HOW expensive !

The cheapest readily available batteries in cost per watt hour are alkaline D cells.
These cost about £1 each in bulk and each cell contains about* 20 watt hours.
A box of fifty such cells therefore contains about 1KWH, at a cost of about £50 a KWH !

And that is about the cheapest you will get from disposables.

A higher priced but very popular alternative would be AA alkaline cells purchased for about £1 each in small numbers from the high street.
They contain about* 2 watt hours or cost about £500 a KWH.

Despite the high costs, batteries are most useful in emergencies or when mains power is not available, and I urge keeping a good supply.
Shelf lives vary a lot, a guide would be
Zinc carbon---------3 years from production
Alkaline-------------7 years for most brands but some offer 10 years.
Energiser L91 lithium, 20 years.
The less common air/alkaline batteries are available in huge capacities, but only keep for a few years and spoil more rapidly once started.

I would expect most batteries to keep good for at least twice the shelf life stated by the manufacturers, if kept in good conditions and if accepting some loss or reliability and capacity.

Rechargeables are much cheaper of course if used regularly, but still a lot more expensive than mains power.
I would recommend rechargeables for regular use, but they are not in general ideal for emergencies owing to the need for frequent charging.

*No accuracy can be claimed since the achieved watt hours vary according to quality of the cell used, ambient temperature, discharge rate, and at what voltage the load ceases to work correctly.
20WH is reasonable for D cells discharged slowly
2WH is reasonable for AA cells discharged more rapidly as is common.
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cubes



Joined: 10 Jun 2008
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Location: Norfolk

PostPosted: Fri Jan 26, 2018 7:59 pm    Post subject: Reply with quote

Modern Nimh batteries keep their charge really well though (low-self discharge type). I'm guessing a solar charger of some sort is implied too.
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emordnilap



Joined: 05 Sep 2007
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Location: Houǝsʇlʎ' ᴉʇ,s ɹǝɐllʎ uoʇ ʍoɹʇɥ ʇɥǝ ǝɟɟoɹʇ' pou,ʇ ǝʌǝu qoʇɥǝɹ˙

PostPosted: Tue Jan 30, 2018 12:36 pm    Post subject: Reply with quote

I've been using eneloop batteries for years now and find they're the best rechargeables I've ever used.

Something strange is afoot though: the AA batteries in coloured outers (HR-3UTGB 1.2V 1,900mAh) are not as good as the white ones (HR-3UTGA 1.2V 1,900mAh). Honestly. It seems very odd but it's true. Maybe their seconds are put in coloured jackets?
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woodburner



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PostPosted: Wed Jan 31, 2018 1:23 am    Post subject: Reply with quote

The battery world is a mire. Too much money to be made from selling sub-standard product. For example Sony do not make 18650 lithium cells, despite what some sellers offer. Sony wanted to have nothing to do with them because of the significant fire risk, and there were counterfitters selling rubbish with the Sony name on.
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Little John



Joined: 08 Mar 2008
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PostPosted: Wed Jan 31, 2018 1:41 am    Post subject: Reply with quote

Is there a lead acid battery on the market that is fully dismantleable/rebuildable?
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adam2
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PostPosted: Wed Jan 31, 2018 4:49 am    Post subject: Reply with quote

Little John wrote:
Is there a lead acid battery on the market that is fully dismantleable/rebuildable?


Not so far as I know. Some of the larger stationary batteries look fairly easy to dismantle, BUT I doubt that much would be gained thereby, since even if the makers could be persuaded to sell replacement plates, then these represent most of the cost. By replacing the plates, all that has been saved for re-use is a relatively cheap glass or plastic container.

A "one off order" for replacement battery plates, including shipping, special packing, and customs clearance, would almost certainly cost more than simply buying a new battery, complete and ready for use and with a warranty.

It is possible to make your own lead acid battery, basic ones are low technology, but the capacity will be very small relative to the weight, bulk, and the cost of materials.
I have made lead acid cells in one gallon glass pickle jars, they worked fine but the total energy content was only comparable to one or two modern AA rechargeables.
Such a cell though crude and exceedingly bulky should last 25 years or so of use, and the materials to make it should store forever.

Also be aware that battery acid is about to become very much harder to obtain.
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Potemkin Villager



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PostPosted: Wed Jan 31, 2018 11:25 am    Post subject: Reply with quote

adam2 wrote:


Also be aware that battery acid is about to become very much harder to obtain.


A2 could you enlarge upon this please.
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adam2
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PostPosted: Wed Jan 31, 2018 12:26 pm    Post subject: Reply with quote

There has recently been a great increase in acid attacks, whereby acid is thrown at persons in order to cause severe pain, injury, and often very serious disfigurement.

As a result there are calls for the sale of "acid" to be banned, restricted or controlled in various ways. It remains to be seen exactly what will happen, but it seems likely that battery acid will become a lot harder to obtain.

Battery acid should be handled with care, but is not in fact that dangerous, however I doubt that politicians understand this. Distressed relatives of victims certainly wont understand the difference between different types and concentrations.
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woodburner



Joined: 06 Apr 2009
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PostPosted: Wed Jan 31, 2018 6:39 pm    Post subject: Reply with quote

I wonder what they will do with brick cleaner then.
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