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What happens if I keep leaving the radio on when the engine is off, and for how long can it stay before the battery dies?
 

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I believe we have what is called a "deep cycle" main battery. As such it may be recharged from a depleted state resultant of a component being left on for an extended period. Although not good for the battery's longevity to do repeatedly.

Regular batteries (usually found in less expensive vehicles) typically can not be recovered from such an incident.

As far as time I am not sure as I have never done same.
 

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Discussion Starter · #3 ·
So basically the GLA got a second battery (deep cycle) to recover the main battery?
 

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No. The main battery is, I believe, a "deep cycle" type. Only one main 12VDC battery.
The small "aux" battery appears not to hold a charge very well and has been problematic for many. But then basically all you lose when the "aux" is depleted is auto start/stop capability.
GLA Battery Locations.png
 

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When you open the driver's door the radio should shut off. Also, I have found if you turn the engine off and do not open the doors the radio will continue to play for a short time and will then shut off again. There are lights and a few other items that will shut down after a time with the switch off. Leaving a door open or rear hatch open with the switch off after a short time the inside lights will turn off. The car is designed so if the owner leaves something on it will shut it off to protect the battery.
 
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... unless of course in ACC mode when someone desires to have the radio play for an extended period, with the engine off. I assumed that was the OP's case. That's actually one of the secondary reasons for "deep cycle" battery development, primary being maritime use.
I alas haven't needed that capability since a teenager at the pond. "Ahh.. Summer nights" -Seinfeld :ROFLMAO:
But then Blako is French ;) [I'm genetically 70% French, as is my wife, so some experience.]

Note: first response vehicles typically have two deep cycle batteries in parallel given their frequent need to operate equipment with the engine off.
When you open the driver's door the radio should shut off. Also, I have found if you turn the engine off and do not open the doors the radio will continue to play for a short time and will then shut off again. There are lights and a few other items that will shut down after a time with the switch off. Leaving a door open or rear hatch open with the switch off after a short time the inside lights will turn off. The car is designed so if the owner leaves something on it will shut it off to protect the battery.
 

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With the switch in position 1 or ACC, there are several other things that will also be on that will draw current from the battery. The dash lights, daylight running lights are just a few of the things that will remain on. In doing something like detailing the car I have left the switch in position 1 for a long time and had to hook up the charger to start the car as the battery had drained down too much.
 
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The answer is "it depends".

First, the GLA is not like older cars that run till the battery dies. It runs until the car has decided it had enough and then turns the radio off to save the ability to crank the car.

Set ACC on, turn off all your climate control, and enjoy the radio. If your battery is dying (and I don't know which one because I ended up replacing both in short order), then the radio on time is short. If your battery needs imminent replacement (and I don't know which one) then the on time is less than a minute.

But after you put a fresh battery in, the radio lasts a long time in ACC. many minutes. I never timed it but was surprised how much longer it stayed on after battery replacement (I bought the car used with a dying battery)
 

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My wife and I have gone to the drive in movie in NY (yes there are still some around that survived) and listen to the movie over the car radio. We have not had any issues after listening with the engine off for an hour and a half to two hours. The drive in management claims listening is equal to one engine start, but I can't confirm that. Haven't seen anyone else's battery die at the drive in either.
 

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My radio turn off after 10-15 minutes without the engine running.. :(
 

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mine is similar, but I have an aftermarket stereo that pulls way more current than that "one engine start" worth in 2 hours. :)

Still, if you are OEM and get 10-15 minutes you are probably 9 months to 1.5 years off of a battery replacement. That's just a WAG on my part, but my guess. Replace if it's 1-2 min
 
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