Do I have to file a TM 47 after staying in a hotel for a night if the hotel filed a TM 30?

Nope. Only leaving and re-entering the country does that.

Always fun when people use the number that Immigration gave the applications.

TM30 : a from used for notification where the foreigner has stayed.

TM47 : a form used to notify that the foreigner stayed longer than 90 days inside the Kingdom

Yes, you do need an address to register that you lived on an address while being inside Thailand.

So first step is to make sure your CURRENT address is registered at the local Immigration Office, by using the TM30 form or on-line (make a print) AND IF you are 90 days consecutive inside Thailand, day of arrival is day number 1, you report this at the same local Immigration Office using the TM47 form.

IF you want to do the 90 day report (TM47) on-line you have to be sure that you use the same address as the last address which is registered at the Immigration Office.

for example: you visit another town, the hotel make a new address registration and you use the hotels address NOT the address you normally reside and call home.

No. 90 days report is to report that you are staying in THAILAND continuously for 90 days, not at the exact same address.

You have to do a 90-day report every 90 days as long as you are in Thailand, not leaving Thailand, regardless of address, such as hotel, or guest house.