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Batteries ?

If you're looking at cars, whatever new whizbang high-energy density batteries you come up with had better be cheap too. An electric car running on modern lithium ion batteries would kick tail, and you would pay for it too. There's a reason most of the electric cars used lead-acid.
 
9 years after I opened this thread I remain totally underwhelmed by battery technology.
 
El Greco said:
9 years after I opened this thread I remain totally underwhelmed by battery technology.
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Their technology hasn't moved quite as fast as the development of power hungry new processors, displays and other stuff to put into phones.

My current phone (3 years old) has a battery that can last a week easily, and it's a much smarter device than the basic phone I had when you started this thread as it's also a camera, music player, (slow and clunky) email and web browsing device etc.

If I trade up to a modern smart phone then I'd have something which is essentially a miniature tablet computer which coincidentally also makes phone calls. That'll have a battery life of a day. Not because it has a lesser battery; just because it's using so damned much power.
 
El Greco said:
9 years after I opened this thread I remain totally underwhelmed by battery technology.
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Maybe something will come of this, maybe not.

Energy Department Launches ‘Battery Hub,’ For Battery Manhattan Project

They have a pretty ambitious goal:
Specifically, Argonne wants the Battery Hub to be able to make a battery with five times the energy storage capacity as the upper limit of current technologies, at one-fifth the cost, within five years, the so-called “5-5-5” plan.
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Jack by the hedge said:
Their technology hasn't moved quite as fast as the development of power hungry new processors, displays and other stuff to put into phones.

My current phone (3 years old) has a battery that can last a week easily, and it's a much smarter device than the basic phone I had when you started this thread as it's also a camera, music player, (slow and clunky) email and web browsing device etc.

If I trade up to a modern smart phone then I'd have something which is essentially a miniature tablet computer which coincidentally also makes phone calls. That'll have a battery life of a day. Not because it has a lesser battery; just because it's using so damned much power.
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I'd say the battery technology has hardly moved at all. Here's what Ove was writing 9 years ago:

Ove said:
Simple math: Ni-Ca. cell 4-5 years ago = 500-600 MAH (Milli Ampére Hours - tells something about how long the cell stays charged)
Latest cell i bought is 2000+ MAH, that is some improvement AND the latest cells i bought was cheap, very cheap. One 1,2V cell, back then costed more than 4 cells + a charger costs today.:D
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Ok, so where are we now ? Samsung Galaxy S3 comes with a 2100 Mah battery, and they also have an extended battery extra that goes to 2600 or 3000 Mah. Not very impressive, is it ?
 
Fundamental dilemma with all energy storage -- be it batteries, cans of gasoline, wound-up springs, or water sitting above turbines:

By definition the device is in high energy state, and as it goes into lower energy state (battery discharges, gasoline combusts, spring unwinds) people extract the energy being released.

Given the same total energy amount, the smaller is device the greater is energy content per gram. Which is a different way of saying: the greater is the gradient between starting high state and ending low state. And the greater is that gradient, the more device "wants" to release all its energy at once. High-capacity modern battery, like lithium-ion, is by its very nature an incendiary device. Which is why we occasionally get spontaneously combusting laptops, and recent fires aboard Boeing 787 planes. An even more high-capacity battery would be an explosive device. No way around it. So development must take safety into consideration. Making what is basically a grenade release its contents slowly is far from trivial.
 
El Greco said:
I'd say the battery technology has hardly moved at all. Here's what Ove was writing 9 years ago:



Ok, so where are we now ? Samsung Galaxy S3 comes with a 2100 Mah battery, and they also have an extended battery extra that goes to 2600 or 3000 Mah. Not very impressive, is it ?
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It is impressive if the size of the battery has been unsubstantialy reduced.

My original Widows mobile smart phone was considerable larger than my current android phone. The battery in the new phone is about one third the size of the old one. I do not have them together here so I don't know what the battery Mah ratings between them are right now.
 
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Starthinker said:
Much of what is on the internet seems to come from toilet rolls, it just eliminates the middle man.
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I thought that I was the only person who thought that. Most of the people I know think that what’s on it is gospel.

It doesn’t stop there. I had an entertaining “discussion” not so long ago about high definition television. It seems to me that all it does is to show the same rubbish in more detail.
 
Drooper said:
My guess is that you could have a phone that only needs charging once a month, but you would have to go without the snazzy LCD colour screen, sound capabilities, some of the transmission power, increase its size back to the luggable bricks we used to carry (you forgot about that didn't you?) etc
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Point of reference, e-ink based ereaders like the Amazon Kindle or Nook. They last weeks on a charge because they are using new modern batteries in extremely power efficient devices.

An iPhone or high end Android phone has the specs of a decent computer of 5 years ago. Is several hours of battery life really all that unimpressive?
 
Doubt said:
It is impressive if the size of the battery has been unsubstantialy reduced.
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I think part of that is the move away from the classic replaceable one size fit all batteries to device specific built in rechargables.

How long would a Nintendo 3DS last on 2 AAs? How long would an original Gameboy last on a modern lithium ion rechargable power pack?
 
There have been considerable improvements in cordless tool battery technology. Ten years ago I was using an 18volt nicad system that's batteries were seven c-cells in a plastic housing that weighed roughly two pounds and constant use would require rotating three batteries in chargers with the fourth battery in the tool. The lithium 18v cordless system I bought last year has six aa-cells in the housing that weighs less than a pound and I only need three batteries to rotate through two chargers.

I'm pretty happy with that, as long as it lasts ten years or so. :)
 
Can I derail this thread slightly, mainly because I can’t think of anywhere else to pose the question!

In the UK we keep getting mail order catalogues which contain advertisements for battery chargers which not only recharge NiCad and similar batteries, but also “recharge" zinc-carbon ones.

My chemistry and physics ended at A level, but I thought that zinc-carbon batteries depended on a chemical reaction in which the reactants were steadily depleted. In this case, recharging is not an option.

OK, if the battery was not used for a short while it tended to recover: is this what happens? And advertisers mistake or misinterpret this as “recharging”?

Any comments would be appreciated!
 
All batteries depend on a chemical reaction where the rectants are steadily depleted. The trick is whether it ends up in a state where it's practical to force current back into the cell and drive the reaction in reverse. You can in fact recharge zinc carbon and alkaline batteries, though not very efficiently; you're only going to get back a moderate proportion of the original capacity.

Back in the early '80s I built a circuit from an electronics magazine for recharging alkaline AA cells. It used a transformer to produce about 3 volts AC at mains frequency and then applied that to the battery through a current limiting resistor. The trick was that in parallel with the resistor was a second resistor and a diode. So when the current flowed one way it could only flow through one resistor but flowing the other way the diode conducted so current could pass through both resistors.

So it gradually charged the battery using alternating current biased to flow a little more in one direction than in the other. I found it could recharge Duracells to maybe half of their original capacity on the first attempt and got progressively worse on repeated charges. But it seemed pretty cool that it worked at all.
 
Paul W said:
In the UK we keep getting mail order catalogues which contain advertisements for battery chargers which not only recharge NiCad and similar batteries, but also “recharge" zinc-carbon ones.
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False advertizing. Zinc-carbon dry cells cannot be recharged to anywhere near full capacity, and will probably leak due to erosion of the zinc casing.

I thought that zinc-carbon batteries depended on a chemical reaction in which the reactants were steadily depleted. In this case, recharging is not an option.
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Correct. The chemical reactions that occur are not easily reversed, and even if they could be reversed the cell does not have any suitable structures (eg. porous plates) to store the result.

OK, if the battery was not used for a short while it tended to recover: is this what happens? And advertisers mistake or misinterpret this as “recharging”?
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Mistake, or deliberate 'misinterpretation'?

A zinc-carbon battery produces hydrogen gas during discharge, which must be absorbed (by reacting with manganese oxide to form water) to maintain the primary chemical reaction. At high discharge rates the hydrogen cannot be absorbed fast enough, so the battery may prematurely 'die', only to 'revive' itself later as the gas eventually gets absorbed. Heating also helps because the absorption reaction is more energetic at higher temperatures.
 
Jack by the hedge said:
I found it could recharge Duracells to maybe half of their original capacity on the first attempt and got progressively worse on repeated charges. But it seemed pretty cool that it worked at all.
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Others have had similar results with alkalines. This may seem like a useful extension of the cell's lifespan and a way to save money on batteries, but results are highly variable and the cells may develop leaks.

ceptimus said:
I fly battery-powered model planes. Battery technology has come on a lot in the last ten years. The latest Lithium Polymer cells have a pretty amazing energy density, compared to the Nickel Cadmium cells of a few years ago.
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It's now 9 years later, and Lipo batteries have continued to improve dramatically.

While cleaning out my workshop last weekend I found an old spec sheet for a (then) state-of-the-art Lipo made by Kokam in 2003. It had a 'blistering' 10C discharge rating (maximum current equal to 10 times the Ampere/hr capacity) and 1 hour minimum charge time. The Lipos I am currently using in my model planes are rated for 45C continuous discharge, and can be recharged in as little as 12 minutes.

Recent developments in electrode technology promise up to 10 times the capacity and energy density of current Lipos. No doubt it will take a while for these gains to be realized in a practice, but cells with at least doubled capacity are expected to come onto the market within the next 2 years.

Meanwhile, my 2.5GHz Windoze PC takes twice as long to boot and is slower responding than the 50MHz Amiga 3000 I was using in 1998. Moore's Law states that transistor density doubles every two years, but developers always find ways to make the software slower and more resource-hungry, negating any hardware gains.
 
El Greco said:
Ok, so where are we now ? Samsung Galaxy S3 comes with a 2100 Mah battery, and they also have an extended battery extra that goes to 2600 or 3000 Mah. Not very impressive, is it ?
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Unless the batteries you're comparing are the same size (volume), storage capacity alone tells you nothing. What you need to look at is energy density.

Here's an energy density chart I found showing how batteries have improved since 1900...

http://www.akbars.net/images/battery energy density.png
 
Thanks Jack and Roger.

From your replies, it does seem to me that at best the advertising is deliberately misleading, if not downright lies. The implication in the ads is that the batteries can be recharged indefinitely, although it is never explicitly stated.

Thanks, incidentally, for the explanation of why zinc carbon batteries seem to recover after heavy use.

I’ll not be buying a “recharger” yet!
 
a_unique_person said:
I am disappointed in these high capacity NiMh. When you go to pick up the camera every month of so for a couple of snaps, they are just about dead because they drain away internally. And there's no point having a couple of spares in the case, they'll be flat too.
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Regular NiMH cells discharge on the shelf at a fairly high rate, about 1/3 every month or so. There are cell designs that discharge more slowly. The Hybrio and Eneloop for instance. The tradoff is slightly lower capacity in exchange for longer shelf life. Eneloops retain the majority of their charge after 1 year which is far beyond where most NiMHs completely discharge. Also, Eneloop makes an "X" version which offers 2500MAH instead of the 2000MAH of the standard Eneloop. It has a very slightly reduced shelf discharge rate but still retains well over half of it's charge after 1 year.

I use the "X" versions for my Canon flash which can sit around a while and they have been quite dependable.

All cells deteriorate over charge.discharge cycles so one also needs a decent charger that you can use to determine the quality of older cells. The MAHA Powerx charger does a good job of that and lets me easily cull the marginal cells.
 
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