Do 220V battery chargers also work on 110V?

Anyone ever tried to see if 220V battery-chargers for e.g. a cordless drill still work on 110V (probably takes twice as long to charge)?

Yup, I had to get one for my phone when I was in America, plugged it in and I thought it wasn't working, but it was just taking so long to get to the point where it had enough power to tell me that it was charging. I left it for a day and it was grand, fully charged. But that was for a phone, not a drill.
I presume this has to do with you moving to America?