Expatriate working overseas, with mailing address in CA, but not Resident of CA. Do I have to file CA State taxes?

You are not a CA resident so you don't need to file a return. You don't have CA source income. You don't have a home, license, vote, act like a resident then CA is not a place of residence, just where you get mail.

 

Reference: CA Do You Need to File?

Thanks a lot for your help.

Yes, I don't have any CA source income, neither a home nor a vote.  However, 3 years ago (summer 2021), I visited my brother in CA for 3 weeks vacation, and since I wanted to rent a car, I applied for CA driver license and got it.  Is this an issue?  My vacation in CA was for only 3 weeks during the last 20 years.

Thanks and appreciate your help again

Your mailing address should be the address you want the IRS to use if they have to send you a letter or check.  But in the Personal Info section of TurboTax, be sure to enter "Foreign or U.S. Possession" as your State of Residence.  (It's the last choice in the State of Residence drop-down window.)

Going forward you should be aware that some states are aggressively looking for additional revenue. Some states are now going over federal returns looking for people with mailing addresses in their state who didn't file as a resident. With no other supporting data they are then sending out demand letters saying "we think you are a resident so refile your taxes and pay us $X plus interest and fees." I would highly avoid using any mailing address that isn't in the same state or country as your residence as it could send up a red flag.

For all the "it's just your mailing address" help you may see online, I can personally tell you it took me $3500 in lawyer fees and 6 months to fight off an aggressive state where I bought a second home and had hoped to retire one day. Starting to rethink that now.

If I receive Medicare benefits in California, but live abroad for most of the year with visits to see family, do I still have to pay California state taxes on foreign earned income? I kept my CA drivers license for the same reason and am registered to vote there. My foreign earned income is $20,000 a year, not including social security but I always get socked with state and federal taxes.

It depends.  Since you were a resident of CA prior to moving abroad,  you would fall under the "Leaving California" rules.  Some of the things CA uses to determine if you are still a resident as per Publication 1031are as follows

1. Amount of time you spend in CA vs outside of CA- When you visit how long do you stay?
2. Do you still have a home you maintain in CA?
3. Did you establish a home in another state or country?
4. Where you are registered to vote
5. Where you have a driver's license
6. Where you have any professional  licenses 
7. If you intend to return
8. If your connections to CA are greater than or less than your connections to the other place you are staying.  Ex. your doctors, personal belongings, bank accounts, etc. 

Since you do maintain a drivers license, voters registration and mail there, you would need to compare the time spent in CA and outside of CA as well as your intention to returning to CA to decide if you are a CA resident, Part Year Resident or Non-Resident for tax purposes. 

I own homes in Mexico and Turkey. I own no property or license in California. However I have a bank account in California as well as one in Mexico.

I spend approximately 6 weeks a year visiting family in California. The rest of the year I am in Mexico in my home.

 

what is minimum time spent in US to qualify as an expatriate?

It depends. There is no minimum of spent in US to qualify as an ex-pat.  If you are still a US citizen, you will still need to report all your world wide income if you earned above the minimum income threshold. 

 

Please read the link i provided below for Tax Tips for expatriates.

 

Tax Tip for Ex-Patriates