Battery disconnect - saving presents/mileage info?

So Ive read on the forums that one of those gadgets you plug into the 12v cigarette lighter socket with a 9v battery wont save your radio presets, etc, like other vehicles because our 12v outlets are switched off after the ignition is off - Gotchya.

I need to disconnect my battery tomorrow but I dont want to lose all of my presets again, Prius settings and mileage info.

I do still have the old (albeit only holding 10.5v) bad OEM battery. Can I hook that up somehow under the hood so that when I disconnect the 12v battery in the trunk, it wont make me start over from scratch again?

 

Thanks. Im good on the reverse polarity. Ive been working with cars for years and electricity scares the heck out of me - Im always the triple checker of anything to do with the battery (watching my idiot brother weld a wrench to my dads fender while removing the pos+ battery cable when I was real young helped reinforce that electricity fear) LOL.

So I do have a jump box. Can I hook the jump box up under the hood, turn it on, then remove the 12v battery, install the new one? Would that save all my info BUT not damage anything?

 

haha.... Im not scared at all of the actual battery swap. Ive done many many in my day. Just seeing what happens when you touch a wrench to the POS+ and then to fender by your Brother at age ~10 will change the way you respect automotive 12v systems.

Thanks for all the tips. I have to call AAP to see if the replacement Optima battery is in. If it is, Ill swap it in their parking lot (Ive removed the battery 2x already and brought the tools to work with me today).

 

I used the VISA code to get $50 off over the weekend. But AAP gave me a defective Optima - it was the only one they had. They had to special order me a new one and Im doing the warranty swap today.

 

Oops! duplicate. How the heck did that happen?!