Hi to readers,
viewing and loccking thru the comments made by each one of you, seems like its a common problem of our Lexus RX400h cars. We have the same problem in Europe. ( Germany, Austria, Swiss) most of the folks decided to use a Black&Decker Emergency Starter (Black&Decker BDV040) . I hope this message might help you to solve your Battery Problem.
Greeting s to all of you and enjoy drive safely with yourLexus.
Burkhard