4 Storage technologies

[Skvez]

I can't think of more than 4 ways to store (Electric) Power:

1] Capacitor.
Stores electrical energy (DC) directly
Very small quantities compared to other storage options
High efficiency
Suffers from Leakage proportional to size (small caps have small leakage, big caps have big leakage)
Life expectancy of decades

2] Battery
Stores electrical energy by converting it to chemical
Moderate storage capability compared to other storage options
Moderate efficiency
Suffers from self discharge
Life expectance of years

3] Spinning Mass (flywheel)
Stores electrical energy by spinning a flywheel (often in a vacuum to reduce frictional losses)
Moderate storage capability compared to other storage options
Moderate efficiency
Suffers from frictional losses in bearings
Life expectance of years (in particular bearings wear away)

4] Potential energy (pumped storage)
Stores electrical energy by moving a mass (often water) 'up' and using this potential energy at a later date to drive a generator
Large storage capability compared to other storage options
Very Poor initial inefficient
Once the mass us 'up' ongoing losses are minimal.
Life expectancy of years (generators require replaced).

For us '3' and '4' are uncommon. '1' doesn't provide the quantity of energy we need except perhaps for small solar->light applicatons so most of us are stuck with '2' batteries.
I worry about what we will do in a TEOTWAWKI scenario after 10 or 20 years when the batteries all fail.

[Skean Dhude]

You are not including growing fruit here. A lemon stores some juice.

Looks to me like we need to include the components of batteries and the resources to rebuild them if we want to progress. The typical wet type battery, ignoring efficiencies, is not that difficult to build. I don't want to have to popout for 1000 lemons when I can make a car battery with some metal plates and some acid in a container.

[grumpy old man]

many brains are better than one for showing us the things we miss
thank you skean

[Skean Dhude]

(1 September 2011, 00:56)grumpy old man Wrote: many brains are better than one for showing us the things we miss

That is the whole point of these sites. To share our information and thoughts, discuss and find something that suits us.

[Skvez]

Skean wrote
> The typical wet type battery, ignoring efficiencies, is not that difficult to build.

I have to disagree there.
You need Sulphuric Acid, very pure sulphuric acid, this is difficult to "make" from raw materials.
You need a container that won't get eaten by said acid.
Although we talk about the 'plates' of a battery they are not simple plates. If you use (smooth) plates the surface area is very small and the battery is very weak. The plates are actually a complex shape to maximise the surface area.
Pure lead plates are weak and break easily due to vibration (and age), this might be OK for fixed storage but mobile applications need a complex reinforcement strategy using something that doesn't either pollute the acid or get dissolved by it.

A modern battery has a number of other enhancements to promote the lead to dissolve and re-crystallise, we could probably skip these if we were willing to accept the reduction in performance.

I won't be building a PbH+ battery any time soon!

Yes you can get current from fruit (enough to power an LCD clock) but it's miniscule, remember you can power the same clock from a tiny watch battery for years.

[Skean Dhude]

We make acid and have for thousands of years

The plates may be more difficult but we have two options, Store plenty of new usused ones or make very inefficient ones.

I agree about how portable they will be but I remember the old brick mobile phones with the attached battery packs. They worked but were heavy. We will live with it.

The fruit is not an option for most things I agree but was showing that other options are available for storage.

[grumpy old man]

what about buying the acid now and storing it. then just pour the old acid out the old battery and pouring the new acid in.
would that work ?

[Skean Dhude]

Grumpy,

It is possible. We used to do that before we got the sealed units.

In addition the plates get furred and need to be cleaned which is not easy. We should be buying plenty of new plates and acid now and replacing when required.

Eventually though we will need to make our own and the efficiency will drop dramatically as we will be unable to get the quality of the plates or the acid to what we can buy now.

[Skvez]

(5 September 2011, 02:25)grumpy old man Wrote: what about buying the acid now and storing it. then just pour the old acid out the old battery and pouring the new acid in.
would that work ?

unfortunately not, the plates degrade too.

Probably the best action is to buy 'wet' batteries (VRLA) dry, needing the addition of distilled water to activate them. Store these as air tight and dry as possible and store distilled water to activate them when the times comes.
Still that's only storing batteries not making new ones and so they'll run out eventually.

[grumpy old man]

dynamo and a pedal bike and have loads of kids pedaling
or a water wheel in you live near water
guess i'am cluching at staws now?