Alkaline battery capacity

[donn_]

Does anyone have a link to information on the mAH capacities of commercial alkaline batteries like Duracell and Energizer?

I'm trying to calculate the payback on using rechargeable AA batteries in holders to replace D cell alkalines.

 

[VidPro]

try here
http://www.candlepowerforums.com/vb/showthread.php?t=171887&highlight=capacity
first, might get a lot of it covered?

 

[donn_]

Interesting thread, but it doesn't get me closer to being able to calculate the pay back in using rechargeable AA cells to replace alkaline D cells.

 

[VidPro]

ahh, cause there was no D size data sheet
like say this one http://data.energizer.com/PDFs/E95.pdf

and here is durasells
http://www.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf

 

[donn_]

AHA! That appears to be what I was looking for. It looks like a standard alkaline D cell has approximately 19-20,000mAh of capacity.

9 NiMH AA cells would range from 18,000 to 24,000 (LSD to hi-cap) mAh.

All else being equal, the AA's would power the light as long, or a little longer than the D's.

9 Eneloop or ROV Hybrid AA's will run about $20, and can be cycled at least a few hundred times.

3 Duracell D's will run about $2.50, and go the the landfill after 1 cycle.

Seems like a no-brainer.

Thanx, VidPro.

 

[VidPro]

but if you were going to ADD up the 9 AA cells capacity numbers?
It shoulda been like 6000ma for each 3, vrses the ONE alledged 12000ma of the alkaline Dcell.
so if you were going to add up all the capacites at the single cell voltage to get 18,000 to 24,000 , then you should have included 3 of the D cells TOO, at what 36000.

if your going to draw a FULL amp from the series set of Dcells, then a single LSD 10,000 nimhy would give you the same relative power as a alkaline. and if you were drawing more like 3amps, or more, the ni-mhy will work better. Discluding the fact that the Alkaine would prefer to be rested, and when rested it would work a bit better.

so relativly speaking a Ni-mhy would indeed be very good, a nice fat D cell being best for the application vrses having so many connections of the multiple parellel AA cells, which can cause more problems.

check out the latest thread on LSD D cells, they were sure to come, and HAVE, the answer to the D cell problem, and trying to wedge 50 enloops into something
already any of the ni-mhy Dcells worked great, with 9000ma and up, they didnt have as much issue with self discharge to begin with, compared to high cap AAs.

if you parellel series a bunch of high capacity self discharging AAs together, then let it SIT and discharge , you will end up with a mess, they will stay "balanced" in the parellel sets, assuming they are connected well, but the self discharge will still cause each series set to be offset. sooo less parts and pieces, less self discharge, and less stuff to have problems would be big fat Dcell LSDs that just came out.

 

[donn_]

but if you were going to ADD up the 9 AA cells capacity numbers?
It shoulda been like 6000ma for each 3, vrses the ONE alledged 12000ma of the alkaline Dcell.
so if you were going to add up all the capacites at the single cell voltage to get 18,000 to 24,000 , then you should have included 3 of the D cells TOO, at what 36000.

That's why I ask these silly questions. I can't even do arithmetic, much less math.:sigh:

I saw the LSD D's on Thomas, but was trying to avoid buying yet another charger. I have plently of charging capacity for AA cells, but none for D's. Maha's got a nice unit which will handle the D's, but it's nearly a C-note.

I'll be drawing 1A, with a Malkoff LED drop-in in a Mag 3D.

 

[VidPro]

ohh yes the charger problem :-(
and trying to sneak off the connections from a AA charger to a Dcell , can be a real kludge, any added resistance and stuff and the terminations, and testing will fail, so its not easy to jump off them things to faux up a D charge from a AA only charger. plus most of them cutoff the charge max capacity.

i use a few cheapo methods, an old slow energyser charger from the 1900's , that takes a few DAYS (not hours) to charge, or series dumb charging them at 1/10th either IN the light or in the pack things that hold them. which takes overnight.

 

[donn_]

I probably should use a spreadsheet, and quit trying to calculate this stuff in my head.

Maha C808M charger = $88
3 D LSD cells = $36
Total = $124

At the manufacturer's claimed 10,000mAh and 1,000 cycles, that buys me 30 million mAh.

The same money buys me 150 alkaline cells, or 50 loads. So I'd be ahead after 50 cycles on the LSD cells. I can reduce that number somewhat by buying more than 3 LSD cells, and I have 1x6D, 2x3D lights and 2x2D lights.

Oy!

 

[VidPro]

well that is a LOT, ya gotta need the charger for more than one item.
because while you might get 1000 charges in a perfect world in a lab somewhere, its more like 100-250 depending on the load, and your ability to keep reverse charge out from series discharge.
after the 100-150 cycles IN an item, they are lots lower in capacity, still useable but lots lower.
you might get a full 500+ short cycles though, where you leave with a FULL battery

so if that would buy 50 loads, then unless you apply the charger in many other situations your payback wont be till sometime in the year 2012
by 2012 , they should have some even newer junk that obsoletes the battery AND the charger

on the other hand, you have 2 huge advantages from the rechargables, you Leave with a FULL battery, so you dont need to carry spares, i never carry spares, and walk at night for Hours each night.
and the cells are really powerfull compared to alkalines, they dont sag, they dont NEED to be rested, they just work everytime untill thier time is up.
how much is saved when you dont have to have 1/2 dead unreliable weak cells in your light? depends on if it "instaflashes"

 

[monkeyboy]

Has everyone forgotten about the tests by Silverfox?

http://www.candlepowerforums.com/vb/showthread.php?t=64660


Most brands tested here at various discharge rates.

 

[GaryF]

Exactly, the Energizer alkaline D cells produced about 11Ah at a 500mA rate, very close to Energizers data sheet number for that rate. Energizer didn't provide numbers for a 1A rate, but Silverfox's tests showed from 5 to 8Ah at this rate for all cells tested.

So the rechargeable payback will come even quicker.