Bassat, for lack of ability to include a cheap smart charger in a kit (because of inherenty higher cost of circuitry and logic for temperature sensors), Panasonic had to come up with a design that was
- suitable for the charging profile needs of NiMH
- suitable for the average no-thinking no-understanding layman
- least likely to induce harm to the batteries inserted for charge and then forgotten for days/weeks/months
so they provide a slow charge rate that induces less temperature rise, that (maybe) drops to a trickle charge rate, and (just maybe) there is some timer mechanism for added safety.
But the NiMH batteries do not thrive, they 'get by'. And that probably explains which about 25-50% of my NiMH AA purchased and used lightly during the past decade have died -- not merely lost capacity, just plain died! -- in spite of not being subjected to heavy use and rapid charge cycles. For a very long time I used a LaCrosse charger/conditioner that defaulted to a slow 200ma...you had to choose a faster rate if you wanted to use it and I thought that 700ma was a 'quick charge' that I did not want to use unless I was pressed for time. That 200ma rate did me no favors for battery longevity. In the past 3 years, I started to use (along with replacement batteries puchased to replace the failed AA batteries) in order of preference...
- a Tenergy TN190 charger/conditioner with neg-DeltaV sensing and 1300ma rate (AA) that can handle all battery configurations AAA/AA/C/D/9v
- a Maha MHC401 with neg-DeltaV sensing and 1000ma fast rate (0.5C)/300ma slow rate (0.25C)/50ma trickle for AA/AAA individual charge (not forcing pairs)
- a Powerex MHC204W charger/conditioner with neg-DeltaV sensing and 2000ma fast rate (1C) or 1000ma quick rate (0.5C)/50ma trickle for AA/AAA (which forces AA paired charge)
Even better chargers would sense temperature, but since I do not ever 'rush' charge I do not feel as compelled about that.
I now know better, I wish I did 10 years ago.
The Fujitsu charger included in the newegg.com Fujitsu Smart Cut-Off Advance Individual AA/AAA Ni-MH Battery 4-hour Quick Charger Kit is the FCT344AUFX, and claims no smart charge capability for having neg-DeltaV sensing!
if you get the cheaper newegg.com Fujitsu kit (8 hour) the charger is FCT343-AUFX and it merely shuts off at 8 hours.