educate me on NiMH AA batteries, and mah

M

MATTRESS

Gawd
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Sep 26, 2003
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I'm looking for the best/most powerful/longest lasting rechargable double A (AA) batteries.

I see that they have a rating on the packages measured in mah. The higher the better, i assume. the local electronics store's batteries max out at 2100mah.

browsing ebay, i see there are 2700mah batteries in some generic brand name. would these truely be better than say, sony 2500mah batteries?

thanks for the lesson!
-Matt
 
To answer the easy part, the higher the mah rating, the longer the battery will last under load.

As for whether it would be better to go with the 2700 'no-name' as opposed to 2500 Sony (or other 'brand' named) ones is a whole different kettle of fish. If you only get X number of re-charge cycles out of the 'no-name' and X+500 cycles out of the Brand named ones, then in the long run you are better off with the latter, even tho each cycle is shorter. The difference in 2500 and 2700 really isn't that much anyway.

Personally, I'd go with the 'Brand Named' ones, unless there was a MAJOR $$ difference.
 
Well it depends on the brand. I doubt Sony actually make their own batteries, they just slap their logo on them. I've never seen their batteries outside of being supplied with a remote control or whatever.
 
spine said:
Well it depends on the brand. I doubt Sony actually make their own batteries, they just slap their logo on them. I've never seen their batteries outside of being supplied with a remote control or whatever.
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True, I saw a test of AA, C, & D batteries amongst a lot of different brands. Some no name & some name brand.

I think a GE (thats right a General Electric battery) beat out all of them (I'm not sure, it was a few years ago), I know Duracell did good as well.
 
To be more specific about mAh, it stands for milli-Amp hour. If your device used 1Amp, a 2200 mAh battery would last 2.2 hours, a 2Amp draining device would last 1.1 hours.
 
tom61 said:
To be more specific about mAh, it stands for milli-Amp hour. If your device used 1Amp, a 2200 mAh battery would last 2.2 hours, a 2Amp draining device would last 1.1 hours.
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it's a bit more complicated than that... mAh is measured at a certain discharge current and voltage depression point, and almost no manufacturer will reveal that information.

Buy name-brand batteries (GP, duracell, sony, etc) with a decent name, and you'll be fine. I wouldn't trust generic 2700mAh batteries...

Oh, and Sony makes their own batteries.
 
gee said:
it's a bit more complicated than that... mAh is measured at a certain discharge current and voltage depression point, and almost no manufacturer will reveal that information.
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I think mAh is still a useful guide in choosing a battery for a particular design. Have you found the manufacturer's supplied information for this parameter to be substantially incorrect? Like, more than 20% or so?

.B ekiM
 
how do i find out how much power my canon powershot a85 takes to calculate the time ?
 
Cameras don't pull steady current so it's hard to reliably calculate how long it will last in terms of time. Instead you could count how many photos it is able to take at a given setting before the battery died, among other measurements.

MATTRESS said:
how do i find out how much power my canon powershot a85 takes to calculate the time ?
Click to expand...
 
I don't think brand makes much (if any difference) to chemistry. They all operate on the same reaction. There are some differences in vent design, etc, but I think the only big concern between brands is that their method of obtaining the mAh rating may differ, and so a direct comparison is not always accurate (but at worst is a good ballpark figure)

Sony batteries, last I checked, were a waste of money. When you can get three sets of identical batteries for the one Sony branded one, there is no debate. You'd be lucky if the Sony batteries were 20% better, there is no way in hell they are 300% better - they're the same chemistry. Sony has a bad habit of over-pricing consumables, across the board, going hand in hand with their attempts to tie you in to their consumables using proprietary instead of standard connecters, etc.
 
Harlequin said:
I don't think brand makes much (if any difference) to chemistry. They all operate on the same reaction. There are some differences in vent design, etc, but I think the only big concern between brands is that their method of obtaining the mAh rating may differ, and so a direct comparison is not always accurate (but at worst is a good ballpark figure)
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there's many other factors involved too, different formulas, different materials, different manufacturing techniques, etc... which can all make a difference.
 
One important factor, that may not be easy to find, is ESR (Equivalent Series Resistance). The lower the better.

Batteries are not ideal, they do have some internal resistance.
 
Harlequin said:
I don't think brand makes much (if any difference) to chemistry. They all operate on the same reaction. There are some differences in vent design, etc, but I think the only big concern between brands is that their method of obtaining the mAh rating may differ, and so a direct comparison is not always accurate (but at worst is a good ballpark figure).
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You obviously have never taken a chemistry lab before. If chemistry is chemistry, then why were my intro chem labs graded on yield? If every reaction yields the same results, then everyone in the class would get the same grade...wrong. There a multitude of variables, hinted at by plot and H8 above, that contribute to the "efficiency" of a reaction. One such factor not already mentioned is the actual purity of the starting materials. You can be certain that cheaper batteries use cheaper metals and solutions. Not to mention the fact that cheaper batteries can contain lots of environmentally unfriendly things in them...aka Lead.

In answer to the OP, you're best bet is to find datasheets on those batteries. You wanna see if the manufacturer actually specs the number of recharges they can take. That is the best inidication as to the quality of the cell(s).
 
joecool234 said:
You obviously have never taken a chemistry lab before.
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Sure I have, and if you think you've found Sony batteries that somehow offer 300% better performance than equivalent spec non-big-name batteries, more power to you. But I have never found such batteries, and so have stopped wasting my money on Sony accessories.

I guess I should have been clearer that I was talking about batteries where you've already looked into the specs, have already found some similar spec options, and are considering deciding between them based on branding. In my experience, once you've found similar spec batteries, it's much better to decide between them based on price, not brand, with the proviso that when you're looking at the specs, you have to keep an eye out for differences in method (eg the loading, or rest periods, or recharging methods, etc used to establish the info may differ between brands and may vary in the extent to which they're more in line with what the battery works best at than with what is likely real-world use).
 
As a side note, the mAh rating is typically done by finding a load that, when attached to a fully-charged battery, will drain the battery in 20 hours. In the process, they measure how much total charge is provided by the battery, giving a total in mAh.
 
With less reputable brands (or nonbranded), they may measure under conditions to give the highest mah possible, even if it doesn't represent typical conditions. Or they may massage the advertised value a bit.
 
Harlequin said:
Sure I have, and if you think you've found Sony batteries that somehow offer 300% better performance than equivalent spec non-big-name batteries, more power to you.
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Hah hah hah haha ha, that's funny.
 
You can also get the spec values from the manufacturer's sites; just go to energizer.com or duracell.com, for example.

The ZBattery.com cuttoff voltages seem quite low.
 
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