The Sony clock radio also has a power supply, the only way to even the time can be read at a distance of 3-4 meters in daylight without any problems. So a purely battery-operated clock radio came not questioned.
The setting of the brightness can be selected by three stages, I am using the brightest level for daylight use. If the room is flooded with sunlight, I wished indeed an even higher level, thanks to the very large luminous numbers, the time is still easy to read.
The manual can be seen that Sony a preset clock (date / time) with mains voltage bridging battery installed extradite (button cell # 2023), ie, plug in, ready clock runs immediately with clock display.
That was not the case with me, the display showed 12:00, the battery discharge indicator lit up, ie, the battery was empty (should probably be normal when pulled in the work of the power plug after adjustment, and the clock for a few weeks is stored on the shelves). Battery was discharged, which one reads with other reviewers.
Since the setting of the date and time is done after a few seconds, the radio and alarm settings are not needed, I have the battery removed completely. After any power failure, the clock is adjusted so quickly.
By pressing a button (DST), the clock 'told' that it currently is set to automatic daylight saving time (NOT is a radio clock). We'll see if the time change in the fall is automatic.
In operation you can see now, in addition to displaying the time left up a green indicator dot (DST) for automatic daylight saving time, lower right shows a green indicator point that the battery is low, or no battery is inserted, ok., As described above , I have completely removed.
Sony clock with big green digital display for less than 30, - Euro, it serves its purpose .. :-).