Does a battery with a too-large capacity for the vehicle cause damage?
MVS Forum member tjai had the battery in an S60 replaced with an 800CCA three years ago and has been experiencing electrical issues ever since including power seat operation and a/c flow. A mechanic explained that a battery with a larger capacity than is recommended is what is causing the issues as the higher
voltage causes the computer to have these “brain fades.”
However, this was erroneous advice. The voltage of a larger battery is not different than that of a smaller one. A larger CCA battery rating can only help your car’s performance, not hinder it.