AlanW

How long can you guys listen to your sound system (radio, cd, etc) with the engine off and key in #2 position (accessory) before draining your battery to the point of needing a jump start?
( nothing else on )

Both our MDX and RDX will only go like 10 minutes or so before the battery won't start the vehicle. And yes, the batteries are sort of old, but jump starting and just driving the vehicle, the batteries will read 12.8 volts in the morning without any additional charging. It's hard to blame the batteries when they read that high after sitting all night. And they are never dead in the morning, so I don't think any drain like from a bad HFL is occurring.

These 2 vehicles drain the batteries quicker than any other vehicles I've ever had, including my 02 TLS & 06 TL. Is this normal sounding for these vehicles?
Could there be a problem with the batteries other than the voltage? Like a capacity problem, not big enough for the vehicle? What are the battery requirements for these, the owner's manual only gives some A/H figure, not CCA

Altair

very likely normal.

Did you consider what you cant see from drivers seat: partial lighted front lights, 7-10 speakers and most important the amplifier for the sound maybe 400 max rating?
For tech trim add the navigation dvd power to spin, load, standby, more power for more speakers...

consider an older cousin, a civic 2002 in similar conditions would be lucky to make it to 20' of radio only listening.

if you JUST reached the no start point, take key out for about 5', battery chemistry will be sufficient to provide a clean start, ask me how I know 😁

having said that, check the grounding loops for any corrosion or breakage, find at least 3 around the engine bay, let us know what you find.

Tomtwtwtw

I've listened to my radio in the car for over an hour while cleaning the inside without issue. I think 10 minutes is pointing to a weak battery.

CSmoney28

You need one of these then...