When I first got into NiMH batteries, I bought a Maha C9000 charger, and I've always charged at .5C (except during a break-in of course), because the standard advice on here and in the manual is to charge at .5C. I've got all Eneloops.
I've been in the market for a less expensive, more compact travel charger. I'm not finding too many chargers that charge at .5C/1000ma... for example, the Sony Cycle BCG34HRE charges at about 1000ma if you have two AAs on it, but only 640ma if you have four. The Eneloop charger MQN06 has a 7-hour charge cycle for four AAs, which I assume means it's .14C! Even their two position "quick charger" MDR02 has a 4-hour charge cycle, which means it's only .25C.
From what I've read here, the issue with charging at a slow rate is that the charger may not detect the delta-V - or the battery may not produce it, so the charger could fail to terminate and overcharge the cell. I know that my C9000 has other safety precautions, such as a thermal cutoff and I think a timer cutoff, but I doubt that a lot of these less expensive ones do.
So what's the deal here? Is charging at a slower rate really all that bad? Why the inconsistency with these lower-end chargers? Is there a safety issue? Or am I just confused?