[PenguinQX]

I'm not too knowledgeable about car batteries, so bear with me here. I noticed that my car has become kinda hesitant starting, and figured it was probably time to change the battery since I'm fairly certain it's the original. I had it tested at an autoparts store, and they told confirmed the battery was "bad". I also noticed that when starting my car with the radar detector on already (Bel RX65), my radar would flash "VOLT" on the display. This only started happening recently, previously the display would just remain on without any change on the display.

I went to AutoZone, and based on some reading I had done on the forum, I went with the Duralast battery for the Mini Cooper to save some $ and weight. Install went just fine, car started up properly etc. Out of curiosity, I tried starting the car with the radar detector on and noticed it no longer flashed "VOLT" across the screen. However, I tested this again yesterday when leaving work, and noticed that the radar flashed "VOLT" this time. I tested it again this morning, and it did the same thing. Is this something to be worried about?

FYI, my radar detector manual states that "VOLT" will appear if vehicle voltage drops below 10.5V.

Any advice would be appreciated, maybe you guys can save me a trip back to AutoZone if this isn't something to be concerned about.