How many times total can you shock someone with an AED in San Diego County?

As many as it takes. There is no limit to how many times you can shock them, usually it is up to the paramedics to decide how many times is necessary. They shock up until the point where it doesn't make a difference.

I'm in Sacramento, and in the training I had, there was nothing said about any kind of limitation on the number of times you can shock. The machine basically tells you what to do, and you should continue with the AED and CPR until such time as paramedics arrive to take over the care of the patient.

when the heart goes from ventricular fibrillation to asystole is when you stop. the machine will tell you when "shock is advised" and when to continue with cpr cycles. the paramedics are in radio contact with a physician who determines when to stop the code.