12V Backup Battery

[ATPMSD]

Here is one for the 12V battery gurus out there.

What if a lead is run from the battery to the frunk storage area, like for those who connect a battery tender for long term storage. But in this case in the event of a 12V battery problem, could we connect a second 12V battery to the lead and have a drivable car? This might be a good idea for those taking road trips far from the beaten path. Also, it could be easy to make a run to a battery store to buy a small 12V battery to make do until a proper replacement can be made.

Workable or a really bad idea?

 

[tga]

Old nosecone cars (pre front end refresh) had a jumper terminal behind the nosecone for this very purpose. You could connect a 12V jumper pack to the terminal which would provide enough power for the computers to boot up and activate the HV relay in the pack and energize the DC-DC converter. After that, the DC-DC converter takes over powering the 12V system and the jumper battery is no longer needed. Everything will work fine until the car turns off turning off the DC-DC converter.

 

[DB13S60]

Newbie here go easy. So I have the jump pack and it powers up the car well in a test from behind the nose cone. But I question if I'll be able to get into either the frunk or the car if 12v battery is dead. I've read about having a dead key and the tricks to get in but this isn't that. Has anyone here actually had a dead 12v and been able to open the frunk or the car?

 

[Snerruc]

Newbie here go easy. So I have the jump pack and it powers up the car well in a test from behind the nose cone. But I question if I'll be able to get into either the frunk or the car if 12v battery is dead. I've read about having a dead key and the tricks to get in but this isn't that. Has anyone here actually had a dead 12v and been able to open the frunk or the car?

The cars have a manual opening system. It varies by year and model. Google for your year and model if you can’t find it in the manual.

 

[Cobe]

Reviewing the MY manual, is this what you are referencing?

 

[Rice&Curry]

MX has 2 pull cords labelled A and B and you need to pull them one after the another and it will open the trunk and you will be able to access the 12V battery. The car doors will still be locked till you address the 12V battery problem.