Might not be the battery, but probably is a voltage thing. I would do the simple thing first. Check all connections especially fuses. Sounds dumb, but just a little resistance can cause this. From time to time, I just pull the spaded fuses and put them back in, and just look around the engine compartment and modules for corrosion or loose connections

In fact, today, I am buying regular batteries for both cars today. I will keep the little batteries on life support for race days. I no longer trust them on long trips anymore. I don't drive the cars enough to keep charged properly. Even with that, I haven't had any real problems.