Alkaline Battery Capacity

[Bill Bowden]

Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

Thanks,

-Bill

 

[Bob Monsen]

Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

Thanks,

-Bill

http://www.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf

 

[neon]

asume 15ah you got 300 hours. that rating at 15amps is into a dead short. i allways claim "D" that can kill you if you can get to the blood supply. 300ma trough your clicker and you are gone interesting. 300 hours is an extimate not a rule depends on battery condition temperature and then some more.

 

[Jonathan Kirwan]

Take a look at the so-called "hybrid" NiMH batteries. They claim MUCH longer
shelf life, and as a side benefit of this, they come pre-charged.

There are a few manufacturers of this new technology. Sanyo (Eneloop brand)
is one of them:

http://www.eneloopusa.com/eneloop.html

http://www.eneloop.info/fileadmin/redakteur/Articles/Teraoka_Article_EN.pdf

Bob

To name a few I've read about:
Uniross Hybrio
Sanyo Eneloop
Nexcell EnergyOn
Accupower Acculoop

I think they are typically a little less in terms of mAh capacity
(2000 to 2100 versus 2600+ elsewhere, for example.) Also, I remember
reading this:

http://www.amazon.com/review/R1HMYU4BKE0VY7/ref=cm_cr_rdp_perm

Not sure if the poster did their work well, or not. But it is a
cautionary word on the topic of taking the manufacturers' specs on
their face.

If the OP is close on the 12-16 Ah capacity of an alkaline D cell and
that is the range the OP is looking for (or better), then with 500uA
draw we are talking about 3-4 year operation. NiMH seems wrong on
that point.

Jon

 

[bw]

Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

AAA = 1 AH
AA = 2
C = 5
D = 10

Note that each capacity is max. Max capacity for each size occurs at a
different current.
Your application may be limited by operating temperature and shelf life.

 

[Eeyore]

Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

Off the top of my head it was between 2 and 3 Ah.

You'll get better out of other brands than Duracell though.

Graham

 

[David L. Jones]

Can't seem to locate any battery specs for Alkaline "D" cells. Tried
the Duracell and Raovac sites, but couldn't find much data for
standard cells. Read a few notes indicating the capacity of a standard
"D cell" is somewhere between 12 and 16 amp hours.

Anybody know what capacity to expect from a standard Alkaline "D cell"
at a continuous 0.5mA discharge rate until the voltage falls to 1.1
volts?

http://data.energizer.com/PDFs/E95.pdf

Note that the capacity vs discharge curves don't go down that low for D
cells. You could try and extrapolate the curves, but that's only guessing.
When you get to figures this low you are talking 40000 hours+, the shelf
life of the battery.

If you want to use the full capacity of the battery then you need to have a
0.9V cutoff or slightly lower. 1.1V will be wasting a fair bit of the
capacity.

What is your application?

Dave.

 

[Don Klipstein]

This post was a poor choice to proselytize given the life requirements,
I just have a 'thing' for folks who design battery-powered systems
assuming 1.2V per cell (or 1.5V per cell) because that's what it says on
the package.

0.9V per cell is about right for moderate discharge rates with NiCd and
NiMH batteries, and you can't exactly harm a primary cell by sucking a
bit more juice out of it.

I _do_ suspect that for many dry cells, you'll get killed by shelf life
(or rust) before the actual circuit drain causes a problem.

My experience with NiMH is that 1.2 volts per cell is conservative at
C/5 discharge rate and 80% of the way discharged. My experience is that
NiMH mostly achieves at least 1.25 volts/cell at that discharge rate.

- Don Klipstein ([email protected])

 

[Bill Bowden]

My experience with NiMH is that 1.2 volts per cell is conservative at
C/5 discharge rate and 80% of the way discharged. My experience is that
NiMH mostly achieves at least 1.25 volts/cell at that discharge rate.

- Don Klipstein ([email protected])

In what time frame? I need 2 to 3 year continuous operating time and
not sure that's doable with a NiMH battery due to the high self
discharge rate.

-Bill

 

[Don Klipstein]

In what time frame? I need 2 to 3 year continuous operating time and
not sure that's doable with a NiMH battery due to the high self
discharge rate.

NiMH ain't gonna do that. Use alkaline. I was only commenting on what
voltage NiMH delivers.

- Don Klipstein ([email protected])

 

[Jonathan Kirwan]

In <[email protected]>,
Bill Bowden wrote:

NiMH ain't gonna do that. Use alkaline. I was only commenting on what
voltage NiMH delivers.

- Don Klipstein ([email protected])

I just checked the Energizer curve for their alkaline D cell (E-95)
and they include a chart that shows a service life at a 2mA discharge
(4X the OP's spec) that is 4000 hours down to 1.2V or something around
6500 hours down to 1.0V. The curve is roughly linear in the 2mA to
1mA span, and shows about 8000 hours down to 1.2V at 1mA, so
extrapolating backwards it works out to 16k hours to 1.2V and 26k
hours down to 1.0V. This is squarely in the 2-3 year range. If the
op can accept operation down to 1.2V, then almost 2 years. If down to
1.0V, then almost 3 years.

Assuming the environmental characteristics required are consistent
with the specs, anyway, and that extrapolation backwards into 500uA
territory isn't too optimistic. I gather from cursory reading that
shelf lives are in the 5-7 year category, with an 80% of rated
capacity remaining, and assuming a constant 70F temp. If that
represents a rough guide for consideration, then D cell self-discharge
is somewhere in the neighborhood of 40-50uA. (The mid-span within a
larger span given from a rated capacity at 1.0V or 1.2V and 5 years or
7 years as the shelf life to 80%.) That is enough below 500uA to
suggest that extrapolation isn't unreasonable.

I may be missing something important, though.

Jon