I need to swap out my original Moll battery with an Interstate in the morning. There's not enough juice to start the motor but just enough to keep the aux power going. Is there a way I can swap batteries without losing codes, etc? I don't want to have to pull the head unit to get the codes. I have a battery maintainer on the way but it will not arrive for another week. Can I use a battery charger, jumper cables or ??? to keep a power source?