Originally posted by KjetilH and try to even out the voltages, either by charging in pairs,
depending on the type of charger (most only charge batteries in pairs, as far as I know).
I hope I am not reading you incorrectly -
but charging in pairs (in series) although works is generally not so good for the batteries - exactly for the reasons you gave - if they are unevenly charged then that leads to a possible over-charge of the higher battery and the lower battery does not achieve a full charge.
Over-charging is one of the two main reasons for shortening NiMH battery life - the other is over-heating - which normally accompanies over-charge.
Most good (read more expensive) chargers have individual and independent charging channels which means they can charge batteries one at a time - this is much, much better for NiMH batteries.
One need not buy the all-singing-dancing chargers like the wonderful (but expensive) Maha/PowerEX C-9000 - there are affordable chargers that do charge cells individually:
Sanyo eneloop MQH03 (if you can find it - available in Asia, esp Singapore - see
CPF thread)
Sony BCG-34HRMF4 - $27.46, with 4x Sony 2500mAh NiMH, but prices can often change within a few dollars
Soshine SC-C3 Intelligent Rapid Charger - $13.98 shipped - but ships from Hong Kong, and does not have UL listing, however it does have CE mark - this is often sold-out or back-ordered (mine was back-ordered, but I got it within a couple of weeks - it is in stock right now....). (
my review on CPF)
It's a real pity that the sticky thread that used to be at the top of this forum section:
Sticky: Battery for K-x (and other cameras that take AA's)
has been moved to
Camera and Studio Accessories section.
I may be wrong, but it seems to me that battery questions always come up in this
Pentax DSLR Discussion section - perhaps it could be sticky-ed in both sections? or at least have a sticky link from here to that sticky thread?