need advise to avoid f500bt from lockup

[absense9]

i seem to get the f500bt to lockup every other week. And i must unplug the f500bt battery to de-freeze it. The f500bt got its power thru the ND-G500, and the yellow+12v wire is already connected directly to the car battery. Here is what i think the problem is. When the car cranking duration become longer, (not start up instantly) i think the it confuse the f500bt and cause a lockup. So i just want to brain storm an idea. what if i put an automotive grade capacitor inline with the red+12v wire, would it help? My thinking is that the yellow+12v has already connected to car battery directly, so i suspect the only problem is the red+12v wire. But here is problem, first i don't know what kind of capacitor to use to provide several seconds of uninterrupted power to the red+12v wire. And in addition, would the capacitor keep my engine running for additional few seconds, after i switch off ignition? (such as a turbo timer). If you have any insight, would appreciate your input.