My copy loads silently and reliably 4 Eneloop AA since more than 1 year. Excessive heat was never determine. Not even the occasional quick charging 2 AA.
With weak cells he denied like to the charge because he apparently checks the internal resistance of the inserted cells on and off at too high a value. With Eneloops and similar high-quality batteries from other manufacturers, there are no problems.
After Panasonic now be extinct, the Sanyo brand, the Sanyo MQR06 is now running as a Panasonic BQ-CC16.
