The car hasn't always had a low voltage problem. It worked just fine when it was new. Voltage drop occurs at aged weakened connections, bulkhead, amp gauge, etc...
Throwing a higher voltage at the system will hide the actual issue.
Yes, I would be in remiss not to preach my favorite sermon...connections, connections, connections!!! Clean every connection in your electrical, it's free and will give you the best chance at running at your peak!!