Capacity of Duracell AA cell versus NiMH

In my sony digital camera, a P100, crap..! A set of duracell lasted about three hours last work night out. I wasn't counting flashes and pics etc, just general use but the sony supplied batteries last at least twice as long, probably alot more.

Basically, unless the drain is very small, not well.

It depends on current drain. Alkalines are vastly superior in low drain appliances, such as clocks or smoke alarms, to the point where NiMH would be useless. In high drain appliances, such as DVD players with integral screens, the alkaline would be in chocolate teapot territory.

The changeover point where one is better than the other is very much in the direction of low drain. Any appliance that uses remotely much electricity will much prefer NiMH, even with the lower nominal voltage. In fact, the alkaline will produce a lower voltage for most of its discharge cycle in any medium to high usage application. 1.5V is only available when the battery is totally fresh and not being discharged to any extent. Any depletion in the cell, or any current drain will result in rapid voltage drop, often even to

0.8V or so. This doesn't happen with NiMH. They can produce almost full voltage until very nearly depleted, even at high current levels.

Christian.

It really depends on the current being drawn. With high current devices which would flatten the NiMH in say an hour of continuous use, the Duracell might just die earlier. Go to say 6 hours of continuous use, and the Duracell will last about 1/3rd longer.

They're roughly comparable, under conditions of moderate load (e.g.

100 mA or so). The Duracell performance spec indicates that a MN1500 AA alkaline cell has a service life of around 20-22 hours at 100 mA... and this assumes that the battery can be drawn down all the way to 0.8 volts per cell. This work out to around 2000-2200 mAh, and this figure seems to be good for discharge rates from trickle-load up to around 400 mA.

The service life of an alkaline decreases significantly under conditions of rapid discharge. At a 1-ampere rate, the MN1500 reaches the 0.8-volt level after only 1 hour, resulting in a useful capacity of only 1000 mAh. I assume that losses from the cell's internal resistance (stated to be "usually less than 1 ohm") are responsible for the reduction in capacity.

If they don't, they'd have problems with alkalines in the latter portion of the discharge curve, too.

All good info.

I have an AA NiMH with a specified capacity of 1700 mAh. Some NiMHs go up to 2400 mAh. Alkaline AA cells can go up to 3000 mAh or more.

One thing to keep in mind is that the capacity vs voltage characteristics of alkaline and NiMH cells differ significantly. Alkaline cells' voltage ramps down slowly whereas NiMH cells hold a stable voltage until they reach a few percent charge, then their voltage drops rapidly. The load equipment's tolerance for low voltage will affect the amount of power it can use from each battery type.

This effect also leads to the annoying behavior that some equipment has where the battery appears to go dead very rapidly following the 'low battery' indication or the battery level bar graph begins to show a low level.

A quick google returned this page:

stating 2850mAh.

NiMH and LiON reghargables do better in digital items though (digital cameras, MP3 players, mobile phones) because the current drain is not a constant drain, but a high drain pulsed on and off (think memory clock cycles). A 1800mAh battery would probably outperform Duracells in a digital camera.

ISTR my camera manual saying not to use ordinary alkaline batteries because they overheat with the large current drain, so you have to use photo alkaline batteries.

Bob

| They're roughly comparable, under conditions of moderate load (e.g. | 100 mA or so). The Duracell performance spec indicates that a MN1500 | AA alkaline cell has a service life of around 20-22 hours at 100 mA... | and this assumes that the battery can be drawn down all the way to 0.8 | volts per cell. This work out to around 2000-2200 mAh, and this | figure seems to be good for discharge rates from trickle-load up to | around 400 mA.

My noice-canelling headphones run from a single AAA battery. I bought an 8-pack of Duracell MN2400B8 (AAA) in late June and have put about

80 to 90 hours on the first cell (still have 7 in the pack), and it's still running fine. So this must be drawing a lot less than 100 mA.

Complete rubbish.

Any variation in current drain at the clock rate is smoothed by the decoupling capacitors scattered throughout the circuit. otherwise you get unnacceptable voltage drop in the PCB, let alone the batteries internal resistance.

MBQ

That's the first time I've heard of that, so I had to google it.

've heard the teats on a boarhog one and fish needs a bicycle, but not a chocolate anything. Seems like most of the younger folk haven't even seen a fireplace so that one's kind of nonsensical to the average joe. And then there's the average American, who drinks more coffee than tea, however that depends a lot nowadays, since there seems to be a kick in tea consumption now that they are promoting its health benefits - antioxidants, etc. But then most tea is bought in teabags, so teapots seem to be getting rare...

But I'd _love_ to have a chocolate teapot, it'd be very useful to me, to nosh on!

electricity

devices

It used to be that with all C, D, and probably AA cells, the battery useage measurements were made with the assumption that the load was going to be a prefocus incandescent lamp, i.e. the load was going to be a flashlight. Seems like times have changed and portable electronics gizmos are as common as the flashlights.

BTW, today I was reading in Popular Mechanics that in 2008 they will be using LEDs for auto headlights, something about the Audi might have them. However for the last five years, red LEDs have been used in tail lights.

They also had an article on how well the gizmos worked for increasing the gas mileage on your vehicle. They tried several different gizmos, the magnets on the fuel lines, and the vortex turbine gizmo in the air intake, etc., and *none* of them increased the gas mileage. Some even made it worse! P.T. Barnum was right.

Must not be very noisy. ;-) What brand and model are they?

You can still use tea bags in a teapot. The idea of putting one in a cup is much newer than tea bags themselves, and a disgusting way of making proper tea.

|> | They're roughly comparable, under conditions of moderate load (e.g. |> | 100 mA or so). The Duracell performance spec indicates that a | MN1500 |> | AA alkaline cell has a service life of around 20-22 hours at 100 | mA... |> | and this assumes that the battery can be drawn down all the way to | 0.8 |> | volts per cell. This work out to around 2000-2200 mAh, and this |> | figure seems to be good for discharge rates from trickle-load up to |> | around 400 mA. |>

|> My noice-canelling headphones run from a single AAA battery. I bought |> an 8-pack of Duracell MN2400B8 (AAA) in late June and have put about |> 80 to 90 hours on the first cell (still have 7 in the pack), and it's |> still running fine. So this must be drawing a lot less than 100 mA. | | Must not be very noisy. ;-) What brand and model are they?

EarHugger[tm] EH1420-NC

Well, I get the feeling that anything having to do with tea here in the 'states' hasn't agreed with Brits since we dumped it overboard into the Boston harbor. ;-)

Now the big kick here is to promote green tea as having healing capabilities because of the antioxidants in it. As far as I can see, it'd take at least a gallon of it a day to do any good.

I don't drink either, but I also get the feeling that most 'Merkins drink coffee and think that tea is for sissies.

Well, there's some of us Americans that appreciate good tea. Do note that Portland (OR) has at least two tea companies creating their own blends of tea (Tazo, The Tao of Tea), and several teahouses. (note that Starbucks now owns and sells Tazo).

Personally, loose tea is better than tea bag tea - though there are some very good bagged teas (like from Tazo). Twinnings tea is utter crap - on a scale of 1 to 10, Twinnings Oolong is a -2.

Lipton loose black tea is ok for every-day use, but I can get just as good black tea at a local Asian market for less than a quarter of the price of Lipton.

On Thu, 18 Aug 2005 06:02:45 -0700, "Watson A.Name - \"Watt Sun, the Dark Remover\"" Gave us:

There are more antioxidants in chocolate. Red wine is a good one as well.

ALSO... HEMP SEEDS! Quite a bit actually. Let's see...

Omega 3, fairly high content, protein, second only in amount to soy...

Feed the world's hungry masses, I say!

Probably a subconscious reaction not too dissimilar to that which you describe in the first sentence of your response.

Tea is for intelligent folk. More than a cup of coffee a day can do your body quite a bit of harm. One can drink tea practically incessantly and see no ill effect... well teeth, maybe.

I should be dead, then, given I drink about 8 per day. And mugs, not cups.

On Thu, 18 Aug 2005 18:45:54 +0100, "Dave Plowman (News)" Gave us:

My mom thought so too. The doc told her 6 a day was too much, and she cut down to about two a day.

You won't be dead, but you probably stink pretty bad, and will lean toward things like hiatal hernias and the like.