When capacitors are in series do they still charge to the supply voltage?

Together they do, each one has a portion of the voltage as the smaller one cuts current off.

The only thing wrong with the answer supplied by supastremph is that he thinks 4x4 = 12. If you put 4 identical capacitors in series with a 12V battery, the voltage drop on each capacitor is 3V, not 4V.

Nah. Think about it. Say you put 12V across 4 identical caps in series. Each one will have a voltage across it. But if the first one is 12V, and the next one is 12V, you're already at 24V, which exceeds your supply. But if the first one has 3, the second 3, and the third and fourth 3, the sum across the voltages will sum to give you the Vin of the supply.

Thanks, az_lender for the edit.