I have a 2007 Prius with 323,000 miles on it for the past 3 years I have had problems with the aux battery dying. The battery I have was purchased in October of 2015 from a Toyota dealer with a 7 year warranty. From Jan 2017 until April 2017 I was placing a trickle charge on the aux battery and it would last for a week. For the past month the battery would die after one day. I disconnected the battery and put a charge on it and reconnected and the following morning the battery was dead. I also disconnected the supply assembly brake control power. Now I am getting clicking noises from the brakes. If the condensers in the supply assembly brake control power is going bad could this be the reason that I have a dead battery?
Doubtful. Have you ever checked the charging voltage while the car is "running" ? It's possible that it isn't charging right. But it is more likely, I think, that your "trickle" charger voltage is too high and it fried the battery over a long period of time. Or the battery just failed. Things break, sometimes for no known reason.
I'm going to go with possibly, things break, sometimes for no known reason. Also consider if the car is drawing a higher current than it should and never getting to its fully quiesced state. A stuck on relay can do this, or having the keys close enough that the SKS (if you car has this) is always alert.
