Originally posted by vilx Had the same problem, describet in initial post. As it turned out, problem was bad cell, a few days later my advanced charger Ansmann Powerline 5 showed "bad" for one of cells. Until that used the same cells in Canon A75 with no problems, and charged cells with cheap charder, wich charged cells in pairs. Now I use Sanyo NiMH AA (Mignon - HR 6) 2700 mAh, for about one week, made ~150 shots, mostly with flash on, still shows "full".
Canon compact digicams are very tolerant and frugal with batteries - which obviously is a very good thing - unfortunately as you've found out it is not good for a reliable indication of the condition/state of the batteries.
Sanyo has a very good reputation for NiMH rechargeable batteries.
However the main complaint of NiMH is their high self-discharge rate - often people return to thie cameras some months later to find the batteries flat.
Regular NiMH lose about 15% of their charge in the initial 24hours, then tapers down to about 15% every 30 days thereafter (ref: BatteryUniversity.com) - so they lose about 30% of their charge in a month (~45% at 2 months, and ~60% at 3 months).
The current trend seems to be to use LSD (see
5.1.1 Low Self Discharge Batteries at Wikipedia) batteries in the K100D - such as eneloops, RayOVac Hybrid, Kodak Pre-Charged (all 3 of these are reasonably easily obtainable - eg: WalMart has all 3). The LSD batteries have lower capacity (2000-2100mAh) but hold their charge a lot longer (to about 70-85% in a year)
Apparently the Sanyo eneloops are different from the others. Eneloops have very slightly lower capacity (although the rating seems very accurate) - but seem to hold their charge longer. Eneloops are the most popular because of name recognition - but reports on others are all favorable - but beware these are all relatively new on the market.
The cross-over point between 2000-2100mAh LSD batteries (like eneloop, Hybrid, or Kodak Pre-Charged) and higher capacity regular 2500-2700mAh NiMH is about 30 days - ie: on par at about 30 days.
My personal "strategy" is to use freshly charged high capacity NiMH ~2500mAh when I know I have to shoot a lot over a short period of time and keep a set of LSD batteries (I use the Kodak Pre-Charged mainly because they are cheap) as back-up/spare.
If I am not going to use the camera for a while - I then keep the LSD/Kodak Pre-charged in the K100D so it's always ready to use, without notice. Plan to do a top-up charge of LSD's about every 6 months
Some references on LSD -
Eneloop Self Discharge study - CandlePowerForums new Kodac "Pre Charged" NiMH batteries?
see posts
#13 ,
#14 for comparison graphs of capacity between the Kodaks and the standard Duracell 2650mAh NiMH, and against the Uniross Hybrio (LSD).
Kodak Pre-Charged at WalMart
Get a good charger for the batteries - the cheapo over-night/"value" chargers are too frustrating - but they do work - however be very aware and only do "top-up" charges very sparingly as these chargers are timer based so canNOT detect true end of charge - so are prone to OVERcharging which can kill NiMH early.
A reasonable charger is one that charges batteries in 2 to 1 hours and automatically detects end of charge, and shuts down or goes into lower "trickle mode". (15-30 minute chargers apparently are a bit harsh on batteries).