While I have a Accord hybrid, the 12v battery in mine was questionable. I took it to the local AutoZone to be checked and it was tested as weak. I charged it over night and it still retested as weak. I knew something was up with the battery because the charger had gotten pretty darn warm while attempting to recharge it.

Anyways, I bought a battery from the same place with an 8 yr warranty and the car really came to life. The assist was like I had never seen it before ever, the mpg increased a couple too.

My suggestion is to take it to a local autoparts store that tests batteries for free. The battery is nothing special and I see no reason to buy it from a dealer.

Best of luck

Tony