Alternator/generator/regulator problems of the 2012 Toyota Sienna

In Nov 2013, the battery light on the dashboard turned on. Within a few minutes of that happening, the vehicle stalled while driving and would not move again. The vehicle was towed to the dealer, where the dealer discovered that the car’s alternator needed to be replaced. In Jan 2014, the battery light turned on again, so I drove the vehicle back to the dealer, where they claimed that the problem was once again with the alternator. They replaced the Sienna’s alternator again. In Mar 2014, the battery light came on yet again. I brought it into the dealer for a third time, but this time the dealer claimed to be unable to find any problems with the car’s electrical system. He returned it to me with advice to bring it back in if the problem continued. After the third dealer visit for the battery light issue, we still saw that the battery light would light up on several occasions. The dealer made it clear that I should only bring in the car if the battery light was on so that they could diagnose the problem. However, the intermittent times that it was on would not line up well with the dealer’s repair shop’s schedule. I have recorded video evidence that the car exhibits the battery light issue outside of dealer hours and sent it back to Toyota. I have tried to contact Toyota through both the dealer and directly. I have even filed a claim through California's lemon law. Toyota denied my claim, saying that they conformed my vehicle to the terms of the warranty within a reasonable number of opportunities. Despite this, the problem persists. It has been over half a year since the problem started, and I still do not know if my vehicle is safe to drive in. I fear that one day it may stall again without warning while driving on the road and put my loved ones and myself in danger. Toyota's handling of the situation has been slow and puts my family's safety in danger.