We own a 2010 rx450h and were having to replace the battery every year for the last 5 years. The batteries cost over $300 each. Our mechanic and the Lexus dealer told us we weren't driving it enough. I decided to replace the battery myself the last time instead of paying our mechanic $200 over the cost of the battery. I discovered most battery dealers don't list a battery for the car. The one in the car was a panasonic sold only by Toyota. After several hours of research I found an Optima 8040-218 D35 that fits. My solution is to leave a smart charger like a Genius hooked up to the battery all the time and plug the charger in every time the car sits for more than a day. The more often the battery goes completely dead the weaker the battery gets until replacement is the only option.
