To avoid a dead battery I was told to disconect the terminal on the battery. They showed me how to do it. I did so and reconnected it on return. The car started up fine. However, the windows wouldn't go up (fortunately the roof closed) and you couldn't activate the phone button on the steering wheel! Apparently, it needs to be reinitialized afterwards. Even though it was very busy in the service department they did it right away.

 

A while back I had a house in NY and house in TX. I kept the Jeep in NY and the Lexus in TX but there were times when the car was kept in the garage for over a month. The first time I left the Lexus in TX I only planned on being away for 10 days but it was a lot longer than that and I wound up with a dead battery. Every time after that I kept it on a battery tender and haven't had a single problem. WARNING do not use a cheap charger it will over charge the battery and destroy it

http://batterytender.com/faqs.php

 

They advised me to disconnect the battery to avoid it going dead. That worked. Just remember to have the doors and other items reinitiated.

 

I don't know who "they" is but I think they gave you bad advice. Every time you disconnect the battery the shop (it will cost you $$) will have to redo the settings. And some cars adjust to your driving habits (I don't know if the Lexus does) and it will have to relearn how you drive all over again. Also even if the battery is disconnected it will still lose it's charge, it will just do it more slowly. It will cost you less in the long run if you buy a tender an you won't spend your valuable time at the dealer getting the setting fixed.

 

The dealer suggested it. They are only 10 minutes away. Even though they had 30 people waiting they did it right away for free. It took 5 minutes to reinitialize the settings. As for forgetting how I drive that could be another issue. The battery did hold it's charge over the 3 weeks.

 

I'm a bit dense here so please bear with me - are you folks talking about the hybrid battery itself?
i wasn't aware that you could manually disconnect and reconnect the hybrid cells and want to confirm that a battery tender can keep them from going zero.
My international trips can easily last 4weeks or more and I've been wondering what to do during such times..

 

I don't know the answer, but my best guess is that the hybrid batteries can hold a charge longer than the regular battery with out the need for a tender. I left my Lexus alone without a tender for about two months and the hybrid seemed fine, but the regular battery didn't have enough juice to start the car. If I remember correctly it was kind of frustrating to see the hybrid had plenty of bars showing but the battery to start the engine was almost dead and would not turn over the engine. I can't say if this is proof that the hybrid battery will hold a charge without any attention but based on my experience and observations I think my assumptions are correct for all other hybrids.

 

Bottom line, I think Lexus short changed us on the capacity of the "starter" battery.

Yes it's designed to turn the engine over and then the rest of the electrical system is handled by the hybrid cells, but come on... did they do it to save weight? No. The RX is a porker right from the get go.

Was the engine bay tight? Ya ok (sarcasm), if they could install an oil filter in the location they did, I'm sure they could of moved around the oil pan and installed it right side up so as to make room for the battery (additional sarcasm and sour grapes... hey! Has anyone other than me and a moderator ever changed they own oil AND filter?).

When the day comes to replace the factory battery, I'm sure there must be something available in the same size and dimensions with alot more CCA and reserve. This battery reminds me too much of a Honda Civic battery, and what with all the craze in the past 15 years into modding Japanese products there MUST be an "Optima" like battery available.

Cheers,

MadloR