2650mAh batteries.

I have a torch which used 4 AA batteries in series. It draws approx 1.1 amps so should got for over 2 hours with 2650mAh batteries. However when I tested it was getting down at 1.25hrs and was pretty much completely flat at 1.5Hrs. Is the rating rubbish or am I missing something? These are Duracell batteries purchased from a large chain retail store so I presume they are genuine.

Cheers, Michael

Reply to
Mickel
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Check out the duracell website, IIRC there are curves there that will show you the rated capacity at various current ratings. You'll see that as the load current increases, the capacity of the cell decreases.

Reply to
Bruce Varley

"Mickel"

** No way is it that simple.

The mAh capacity of cells is a function of the discharge rate.

Duracell's 2650 mAh figure for AAs relates to discharge at 25mA where it will take just over 100 hours to get down to 0.8 volts.

** Normal.

The way to get better results is to use NiMH AA cells which can cope with continuous discharge rates up to 5 amps with little loss of capacity.

.... Phil

Reply to
Phil Allison

"Bruce Varley"

** Seem to have all disappeared.

The Energiser site still has them.

.... Phil

Reply to
Phil Allison

Thanks Phil and Bruce for the reply. As long as it's expected then that's good. I thought maybe I had a poor charger. The torch will actually take 8 batteries to produce 4.8 volts, so with only 0.5 amps maybe I'll get more than twice the time.

Reply to
Mickel

On Sun, 28 Feb 2010 23:57:03 +1100, Mickel wrote as:

snip

You might consider the new hybrio type NiMH which dont self discharge so quickly - this is a major fault especially with the high capacity cells I found. Hybrio type are more expensive tho. The normal high capacity ones (eg.AA - 2500+mAh) seem to self discharge a large chunk of their capacity in about two+ weeks! Energiser seem the worst of the ones I have, -had actually, I sent them to the recycler as useless in real life! Charlie+

Reply to
Charlie+

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