How soon should I deposit 800,000 THB into my account after entering Thailand on a Non-O visa?

I would try and get it in within 2 weeks to allow a little bit of leeway in case you have any paperwork issues with renewal

Apply visa From your country by e-visa from Thai embassy website,enter Thailand with non-O 90 days,and open bank account after arrive here , deposit 800K on bank account, wait 2 months, continue 1 year visa 🙂👍🏻

when you enter on a 90-days Non-Imm-O Visa, you will get stamped in for 90 days. For the application to the 1-year extension, your 800,000 THB in your Thai bank account need to have "seasoned" for 2 months. This means you have one thru two weeks to get your ducks in a row - THE MINIMUM REQUIREMENTS to get a bank account opened: get a mobile SIM card registered to your name and passport, get TM30 registered in your accomodation and visit Immigration to apply for the "certificate of residence" where Immigration asks a bank to open an account for you. If banks make you run around or invent random requirements, use an agent to get an account opened for you, in Pattaya you pay only 5000 Baht for this service . . . . and a direct SWIFT transfer from your home bank to your new Thai bank acocunt should not take much longer than 1-2 days

It has to be "seasoned" in your Thai bank account for two months prior to applying for a one year extension of stay in the Kingdom.