How to make COMAND not turn off?
Thread Starter
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Joined: Mar 2011
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2011 E63, 2013 CLS63
How to make COMAND not turn off?
Hey guys,
I love watching movies in the back seat of the car. I have a tablet which I connect the AUX to and mount between the headrests. The problem is, the COMAND turns off every now and then and so I have to pause, get up, open the door, close the door and turn it back on.
Obviously the car battery will go down and so the car wants to conserve it for starting and not to mention they aren't deep cycle batteries made for this use.
My question is, can I wire a second deep cycle battery to the system or maybe even use a Li-on battery with alot more capacity. In that case would the message automatically stop coming on if the car doesn't detect a drop in voltage past a certain number or will it turn off regardless as it's just programmed to do that and how can it be modified to not do that. I'm only using the COMAND for the AUX access to the car's speakers.
I love watching movies in the back seat of the car. I have a tablet which I connect the AUX to and mount between the headrests. The problem is, the COMAND turns off every now and then and so I have to pause, get up, open the door, close the door and turn it back on.
Obviously the car battery will go down and so the car wants to conserve it for starting and not to mention they aren't deep cycle batteries made for this use.
My question is, can I wire a second deep cycle battery to the system or maybe even use a Li-on battery with alot more capacity. In that case would the message automatically stop coming on if the car doesn't detect a drop in voltage past a certain number or will it turn off regardless as it's just programmed to do that and how can it be modified to not do that. I'm only using the COMAND for the AUX access to the car's speakers.
Super Member
Joined: Feb 2005
Posts: 614
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From: MD
S 63 Coupe, GLS 63
Do not attempt to let anyone wire an additional battery into your vehicle, it will not work and I guarantee it will mess up many other systems and cost a ton to fix. The car is programmed to kill power to anything drawing the battery down after a certain time frame so the battery won't die. Leave the car running or get a trickle charger to plug in while watching and keep the key on.
Out Of Control!!
Joined: Jun 2004
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
You could just keep a spare car battery in trunk and connect it in parallel with car in ON position, engine off, on beach night ... then when you're home trickle charge it for next use
the solution youre looking for is likely buried in the can bus programming and you can call mid city engineering to see if they can a usb module that'll accomplish this
the solution youre looking for is likely buried in the can bus programming and you can call mid city engineering to see if they can a usb module that'll accomplish this
Last edited by PeterUbers; Oct 27, 2019 at 03:55 PM.
Super Member
Joined: Apr 2018
Posts: 609
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From: Boston area
2016 E63 Wagon
By FAR the best and easiest solution is to buy a power bank, have it connected to your 12V (or 110V if you have it) so it's always fully charged and then connect your tablet to it.
Thread Starter
MBWorld Fanatic!
Joined: Mar 2011
Posts: 2,214
Likes: 29
2011 E63, 2013 CLS63
You could just keep a spare car battery in trunk and connect it in parallel with car in ON position, engine off, on beach night ... then when you're home trickle charge it for next use
the solution youre looking for is likely buried in the can bus programming and you can call mid city engineering to see if they can a usb module that'll accomplish this
the solution youre looking for is likely buried in the can bus programming and you can call mid city engineering to see if they can a usb module that'll accomplish this
No it's not the tablet that's using the battery it's the car speakers and COMAND for the AUX, the tablet is fully charged and runs on battery. It's just to use the cars sound system because it's decent and it's like a cinema.
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2016 E63 Wagon
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Out Of Control!!
Joined: Jun 2004
Posts: 13,799
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
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Joined: Sep 2018
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From: New Orleans Area
2015 E400 Sedan
Guess I am.
He wants to sit in car and watch movies on I pad but listen thru cars speakers while engine is off.
yeah I do not get that... or am I missing something....
Cars are not made to really do that for fear of BAttery dieing and then car nto starting so to do what he wants.
Pop the hood and hook up battery charger... will keep batery on but Command will still turn off to save battery...
So to keep command on you need engine on.
He wants to sit in car and watch movies on I pad but listen thru cars speakers while engine is off.
yeah I do not get that... or am I missing something....
Cars are not made to really do that for fear of BAttery dieing and then car nto starting so to do what he wants.
Pop the hood and hook up battery charger... will keep batery on but Command will still turn off to save battery...
So to keep command on you need engine on.
