NiMH battery ratings?

[Roy Smith]

I've got so many gizmos that take AA batteries, I'm thinking of
investing in a bunch of rechargeables. In the past I've had horrible
luck with NiCD, so I'm thinking NiMH.

I'm looking at the specs for a bunch of them
(http://www.onlybatteries.com/items.asp?db=62) and see AA's rated for
anything from 1400 mAH to 2300 mAH. How is this possible? Same
chemistry, same size. I can see some small variation in capacity, but a
factor of 1.6? Do brands really differ that much in capacity, or are
the ratings just a crock?

 

[Tim Wescott]

Roy Smith wrote:

I've got so many gizmos that take AA batteries, I'm thinking of
investing in a bunch of rechargeables. In the past I've had horrible
luck with NiCD, so I'm thinking NiMH.

I'm looking at the specs for a bunch of them
(http://www.onlybatteries.com/items.asp?db=62) and see AA's rated for
anything from 1400 mAH to 2300 mAH. How is this possible? Same
chemistry, same size. I can see some small variation in capacity, but a
factor of 1.6? Do brands really differ that much in capacity, or are
the ratings just a crock?

Battery construction can significantly affect the capacity. In general
making the battery cheaper will decrease capacity, as will making it
capable of high discharge current.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Spehro Pefhany]

On Sun, 15 Aug 2004 17:27:15 -0500, the renowned "Dave VanHorn"
<dvanhorn@cedar.net> wrote:

The knockoffs have good
capacity, but may lack proper vents, or excess plate capacity, or the
expensive catalyst for hydrogen/oxygen recombination.

Don't bet on anything when it comes to some of these guys.. I know a
US specialty consumer products company that had to throw away tens of
thousands of custom battery packs because they were something like
20%-25% lower mAh capacity than rated.

Best regards,
Spehro Pefhany
--
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