I have a 2008 RX 400h (bought new in 2008). Two years ago, we vacationed for a week at the beach. When we got in the car to leave, it wouldn't start. Had the car jumped, drove home (straight to the dealer) who said the battery tested fine, charged it, and said we were good, not to worry about it. No problems starting the car for the next year so I figured we probably left an interior light on or something.

Last year we went to the beach again, parked the car for a week, and had a repeat scenario. This time, after the recharge, we were told we needed to buy a trickle charger and plug the car in during our vacation so the battery would stay charged (right--there's one outlet in the parking garage). This sounds a little fishy to me. If we left it one month, even three weeks, maybe. But one week?

We are planning to go back to the beach again this year--and I would really like to avoid a repeat performance (and park the car for a week). So what's the deal? Is there something wrong with the car or is this typical for an RX 400h?

Thanks much for any insights/advice!

 

I bought my wife a 2007 Rx400h a month ago so I'm no expert on this topic, but maybe something I say will be of some help.

1) Apparently the Lexus/Toyota dealership battery is junk. The owners manual states that the 12V battery can deplete if not driven in a month. Most members here suggest to not purchase a battery from the dealership. Lastly, when I was shopping for the Rx400h and read through several different Carfax records, I noticed that many Rx400hs and Rav4s repeatedly had their batteries replaced after only 2 years!

2) If your car is parked outside, I would try a solar-panel trickle charger that rests on your dash (or underneath your moonroof) and plugs into the 12V cigarette power plug. VW/Audi uses these on their cars before they are sold. Oddly my VW TDI battery drains faster if the alarm isn't set. When the alarm is set, less current is drawn from the battery. I suspect the Rx400h to drain the battery when rested for awhile.

3) If you garage your car, buy yourself a trickle-charger that maintains the battery. It might be a fire hazard, but I wonder if you could plug in a timer so that you can set the charger to charge 3 days into your vacation.

I hope someone with more knowledge than me can help you. I'd hate for you to go on vacation with this nagging in the back of your mind.

 

Yup go with an aftermarket battery from Sams, Costco, etc and you should be fine...The OE batteries have had problems in that size.

 

The reason it is recommended to not let long periods go w/o driving the car is it 'can' discharge enough to cause you problems. It is computers that will do a slow drain. Normal periods of a few days or a week should not be a problem, but if you're gonna leave it longer you should have a friend drive it three or four miles each week.

 

Thanks very much for your insights. I do love this car--it's been great except for what's turned out to be an annual nuisance. I'll think about using a new battery source next time I need one.

We do park in a hotel garage so the solar route won't work. Other than that, I guess I could drive it around mid-week, but I drive so much when I'm not on vacation I'd prefer not to have to move the car at all. Thanks again and I hope your wife is enjoying her RX400h!

 

I say get a good aftermarket battery and you should have no issues.

 

The 12 volt battery in the RX400h has a history of failures. Do NOT trust it. If your wife drives the car alone, don't even think twice about getting a new battery from someplace other than the dealer. After 2 "lexus" battery failures on my 2007 RX400h I went to Autozone.

 

Anyone have the specs for the original OEM battery? CCA?

 

Since the 12 volt battery does not drive the starter, CCA (Cold Cranking Amps) isn't particularly relevant. The rating most important for us would be Reserve Capacity. Unfortunately, the relatively little group 51R battery Lexus put in the rx400h won't have as much as larger batteries. For reference, the Autozone Gold battery I bought recently has cca 500 and reserve capacity 85.

The problem with the lexus oem batteries seems to be intermittent dead cells. Fine one time, bad the next, and then fine again for a while. With non-hybrids, you can often hear the starter struggle when a battery is going bad. With ours, it's just "ready" or "no ready".

 

Secret: the dealer replacement batteries are simply black Interstate batteries. Do what this guy says and go get a battery from wherever if you want to save money.

On the flip side, the dealer will prorate any battery replacement in the next 80 months if you buy theirs, whereas you'll have a hard time getting many places to do that. I find that convenience worth the extra $30.

 

Thanks, all, for the additional information. Since this has only happened twice (June 2010 and June 2011) both times after the car sat for 8 days) I thought there might be something more complex going on. But other than those two weeks, I drive my car every single day (well, except for the blizzard we had last year--I think it sat 3-4 days then) and have had no issues.

I'm going to do some research on batteries and go with one that has a better reputation than the Lexus battery!

 

We let our 06 RX400h sit in the garage for little over 2 months since we were out of county. When we got back car didn't start, jumped it and took it the dealer and replaced the battery $180 out the door. I could've saved labor which was $69 but didn't wanna hear any of bull crap later if I ever have problem with hybrid system. Plus I got a loaner, free wash and has free 2yr replacement and prorated warranty til 84months. Plus it could've been something other than battery so I just didn't wanna bother with it since it was still under warranty. That's just my .02, hope it helps. Good Luck

 

man you could have bought three batteries for that price at Sams club, and probably not have any future problems.

 

Figured if I had some details, regardless of what, for the OEM battery I might be able to figure out how it compared to third-party batteries such as a Duralast Gold.

 

hmm, I can let my LS400 go for a month, and vroom first try.

Sounds fishy to me. maybe there is a drain somewhere there shouldn't be, a week is wayyyyyy to short.