Usually if the 12V voltage drops you get several system errors, not just the IMA one.
If you live in a hot climate (you might add your general location to your profile) the IMA battery is likely to suffer more as batteries do not like excessive heat.
If the auxiliary fuse blows the IMA system throws an unclearable error and you get the battery symbol just like you have, but also the car won't lock and unlock remotely. If it does not respond to the key fob it is that fuse.
In all cases get a voltage readout for the 12V battery, even if it is just one of those digital volt meters you can plug in the cigarette lighter socket. If you ever see the voltage drop below 11 Volt you know enough.
Anyway, best of luck! I hope it all turns out fine.