Q: Car won't start after cleaning battery

The battery terminal connections should be inspected since they were serviced recently. These are often left loose, or even applied too tightly. Allow me to explain:

Some people tend to turn the securing fasteners on batteries until they cannot turn any further. Since the terminals are made of a thin metal, the first time on will make for a very secure connection, but it stretches the wire terminal. Once removed again, the stretched wire terminal will never be as tight, causing a loose connection which may drain the battery - even with a working alternator.

My suggestion is to have an experienced mechanic, like the ones at YourMechanic, run a full diagnostic on your battery and cables to pinpoint the problem and suggest the most appropriate repair.