New RX 400h bought november 2006 milage is at present 3500. went on holiday for three week when I returned the battery was flat, I had to jump start it from another battery, very difficult when you are on your own ? as soon as you start the car get out to disconnect the engine stops and swtches to the drive battery than the car battery goes flat again. the only way to move the car is to have somebody remove the jump leads and drive away.

I have returned the car to Lexus at Hedge End Hampshire and they have assured me there is nothing wrong, and have informed me by letter that "Lexus advise if storing the vehical for more than 10 days disconnect negitive terminal of the 12v battery, this prevents discharge due to current to ECU's. Also advised by Lexus for battery maintenance (including the hv Battery) charged every two weeks for 30 minutes by starting the hybrid system (Ready) with all electrical components off"

This of course means you can't park up for a two week holiday without disconnecting the battery, not something I fancy doing at 3am at an airport carpark in the rain.

Has anyone got a solution.

http://cgi.ebay.co.uk/Battery-Isolator-Swi...VQQcmdZViewItem is what u will need then

I have to say I'm quite surprised at the problem. I have a Lexus GS450h obviously also hybrid. I have owned the car since October 2007 and covered only about 1,500 miles. So off course the car is left for several weeks at a time fully locked, and never had any problems starting. In fact the longest I have left it for is close on THREE Months, and apart from having to use the remote control button (the keyless entry shuts down after two weeks according to the handbook) it started without any problem. The handbook for the car states that in order to mainain the life of the Traction Battery, to drive the car for about 10 miles at least every three months.
Finaly since May I have driven the car about 1 mile. I am plannig on driving it in about 10 days time and fully anticipate it start without problem.
My advise is to speak once again to Lexus. Maybe you should try a Lexus dealer in the U.S. Its by far their biggest market and they may have a better idea.

Regards
Keith

[quote name='Rod' date='Jul 3 2007, 02:24 PM' post='450275']
New RX 400h bought november 2007 milage is at present 3500. went on holiday for three week when I returned the battery was flat, I had to jump start it from another battery, very difficult when you are on your own ? as soon as you start the car get out to disconnect the engine stops and swtches to the drive battery than the car battery goes flat again. the only way to move the car is to have somebody remove the jump leads and drive away.

I have returned the car to Lexus at Hedge End Hampshire and they have assured me there is nothing wrong, and have informed me by letter that "Lexus advise if storing the vehical for more than 10 days disconnect negitive terminal of the 12v battery, this prevents discharge due to current to ECU's. Also advised by Lexus for battery maintenance (including the hv Battery) charged every two weeks for 30 minutes by starting the hybrid system (Ready) with all electrical components off"

This of course means you can't park up for a two week holiday without disconnecting the battery, not something I fancy doing at 3am at an airport carpark in the rain.

Has anyone got a solution.

Another example of poor customer service from Lexus, I am beginning to wonder where they got their good reputation from. A new car that cannot hold its charge for more than 10 days is a joke, no not a joke a disgrace to any company who advertise their exceptional customer care standards. Truth is they do not give a damn or so it seems.

As for a solution, I would start looking at other makes.

The battery on my RX400h was flat on my return from a 2-week holiday. Lexus tells me it is quite usual for the Hybrid to do this after standing for 10 days. I am devastated by this. Most of my holidays are longer than 10 days. The suggestion to use a battery isolator is rejected by Lexus as dangerous. They say the main battery can explode!! They have no really good suggestions other than asking someone to take the car for a ride every few days. One of the technicians suggested using a solar tricke charger to start the car by plugging in to the cigarette lighter, but this means the car could not be lept in a garrage. I don't know what the answer is - but Lexus Service Department are looking into it. I can't believe that they have not come up with an answer, nor did they warn one about this problem.

Hi Rod, I posted a similar problem with my 400h. I too took this up with Lexus and got no joy. They say they are "working on a fix". What should we do meanwhile?? Have you thought about using a solar trickle charger (which sits on the dash-board in the sun) which is supposed to work via the cigarette lighter? One of the Lexus technicians suggested this. Should we try it?? Ruth

Hi Guys,

Very interested in the results of this one, if Lexus do come up with a "fix" can you let us all know, as I'll want to get mine fixed too.

I know how annoying duff batteries can be, I've been jump starting my mower all summer

Cheers

Jon

did they say how the battery can explode? if they say it is because of a spark when you open/close the contact then ask them will it explode when the battery is changed or the leads removed also?

Hi Fluff, I am an old lady so am not supposed to understand much about the inside of car engines, but was a scientist so do - a bit! They told me that becuase the two batterieds are connected and there is a flow of high voltage power between them even when the car is switched off, I should not even think of inserting the battery switch (mentioned by someone else on this page) as the main battery could explode. When I have a chance I will ask them for more details. They also said it would invalidate the guarantee of the main battery (which is for 5 years). I did notice that when the RAC man came to jump-start the car, he did not hesitate to disconnect the terminal, and nothing happened!!. I am not convinced by their story, but am too chicken to try that suggestion. Will just have to call the RAC every time, and not park it at the airport next holicay. I am thinking of investigating the solar trickle charger via the cigarette lighter socket.

Hi Friends!
Looks like we all face the same kind of problems!
I had to jump start my car 4 times in the last half year. My car is 2 years old; Lexus tells me “there is no technical problem”.

Fact is that the 12V battery is too small. Interestingly the first RX400 prototypes had an 80Ah 12V battery.
We did some investigations and sorry but there is not enough space to install a larger (say 70 to 80Ah) battery instead of the original 45Ah battery.
Next is the solar trickle charger. At least in my car it would be useless because the cigarette lighter and the 12V plugs are not connected to the 12V system if you take out the ignition key.

The only possibility we found so far is to carry a second small (25- 25 Ah) 12V battery in the trunk of your car to be able to jump start the car by yourself if it is needed.

This is a shame for a car of this price range and a company like Lexus.

Would be great if somebody (hopefully Lexus), will find a better and more elegant solution.

Trevor Bayliss might help - wind up crank handle in the boot -

or get a WEZA

http://www.ordertree.com/cms/Freecharge+We...Source/170.html

mmm so if there is a flow when the ignition switch is off that means that something is drawing a load all the time - no load = no power flow. it is true that the hybrid batteries are high voltage approx 280V but there is still a normal 12V battery.

As mentioned before and it has been something that i had my doubts about is the trickle charger via the cigar lighter - the plug is only active when the ignition is in the ACC position so a trickle charger is useless unless its connected directly to the battery.

a quick look on the lexus.com site says if the vehicle is parked for longer than 30 days then battery charging may be required.

so its obvois something in the system is drawing a constant current.

The clock etc.

Going back to my youth as a TVR owner, the deal was always to "plug" the car in to a 12V charger when leaving for a while - remember TVR's only come out in the summer.

Has anyone asked Lexus to provide an authorised plug in solution.

My TVR Tuscan had a purpose built socket just behind the passenger side front wheel, and you bought a lead with the correct plug on one end and crock clips on the other. Then when the battery was flat, you just plug the lead into the Tiv and the AA handled the other end. This was mainly because you could not even get in the car unless it had a 12V supply.

Obviously you don't need such a solution for the 400h, as you can easily open the bonnet and jump as normal, but a smaller socket for trickle charge would solve a lot of the problems reported here, not airport carparks obviously.

Just a few ideas

Cheers

Jon

I have written to Lexus UK as I wasn't happy with their verbal response. I particularly asked about using the battery isolator switch (told on the phone that it was dangerous), and the solar charger. I will let you all know when / if they deign to reply. Lets see their response, Ruth

This is for Fluff: I searched and have now been searching again on the lexus.com site but can't find the reference to 30 days that the battery should stay viable. If you have a moment could you tell me where to find it. I need all the ammunition I can get hold of in my battle with Lexus. Ruth

http://www.lexus.com/pdf/models/rxh_drivin...mance_guide.pdf

its on page 2

Thanks very much, fluff!
Ruth

What I don't understand if all his is true, why is it not a problem while the cars are some weeks on the high seas from Japan and then in storage for a few more days...
I can't imagine them going round starting up all the cars on the ship

i asked lexus the same question and was told that for transport and storage the 12V battery gets disconnected.

When reading this tread, I wonder whether we have got the same car. Our RX400h is parked in our garage in the Algarve (without any attention), it has started up every time we come down, even when as this last time it had been left for just under four months.
We must have been lucky and got a good model, as far as battery discharge is concerned. I take it you leave the car in "parked" mode, and have no additional electrical extras connected up? Wish you luck in getting the problem solved.

looks like we really have different cars!

during an upgrade to xenon high beams i disconnected the 12V battery of my car. when i reconnected the battery i used an amper meter to measure the the current the car is drawing when everything is off (no internal light on, ignition key is off).

the car draws 0,177 ampere. this means that the 45Ah battery will be empty after 10 days and this is what the user manual tells you i think.

Sorry guys, so if you do need to jump start your engine, how do you do it?

It is a shame you can not jump off the Hybrid battery or something until the car battery is up and running.

Just to keep everyone interested up to date: Lexus eventually contacted me. Even though the battery had been checked already, they want to re-test it ober a prolonged period. So - on my next holiday coming up soon, I will leave the car with them for testing. At least I won't have to call the RAC to start me up on return, but will have to take a cab home.

i will be with my RX400 next week at my lexus dealer to measure the current which is drawn from the 12V battery in parking mode and we will compare this to other RX400 in order to find out if my car does have a problem.
will keep you informed on the findings
willi

so my lexus service checkt my car and it is acording to specs and they also compared the mesurements to a new one and the two cars are drawing the same current from the 12V batterie.

so the RX400 is drawing around 0,177 Amps from the batterie. all lexus sources i asked are telling that the car should not stay for longer than 10 days without charging the 12V batt to make shure that you can start the car again. the 10 days multiplied by the 0,177 amps resulting in 42Amp/hours, the 12V batt of the RX400 has a capacity (fully charged) of 45Amps/hours so we have a perfect match here.

i was also told that the problem is very well known at lexus but nobody at lexus is taking aktion or at least there is no official statment from lexus to there dealers.

OK, sounds like a real mess regarding the 12V battery and large current drain.

I was thinking about this, am I correct if I say the 12V battery does turn the engine over when starting - this is done by the traction batteries driving the front electric motor ?????

If this is so, then in order to "jump" the car, you don't need too much current? Only enough to get the electronics going etc. Therefore could you carry a small 12V battery like I have in my mower or a 12V motorbike battery as backup? I had to replace my mower battery the other day - £34 and it would fit in the glove box! On occasions when you know you will be leaving the car for a while, you just take this along - no need for RAC/AA. A bit crap, but we are where we are, as they say.

If my theory is correct, you might get away with 8 'D cell' Duracells in series - I'd like to see someone do that!!!!

Jon

I would like to share with you the problem of restarting the car when the battery is flat. The RAC started the car with their jump leads. and advised me that I had to keep the engine ticking over. This is easier said than done. If the engine is not ticking over, the car once again "dies". The RAC instruction was to keep the engine ticking over by keeping the accelerator fully depressed for 20 minutes before releasing the accelerator. Releasing the accelerator earlier resulted in the engine cutting out, and the hybrid needing re-jumping. Of course I was nervous going for a ride to charge the battery in case it cut out at the traffic lights or in heavy traffic!!

Hi everyone,
Hope the following will be of interest.. Before I retired I worked in the Battery Industry for over 30 years. I do know a little about this subject.. but first :-
I run a 2002 RX300. Purchased second hand from Lexus Oxford last year. After only a few months I encountered the same problem with the battery.. Leave the car for a couple of weeks and no way would I get a start. Out came the jump leads.

I was APPALLED to see the car had only a 40 amp hour Lucas battery fitted which I assumed would have been the first original fit ( Lucas batteries were taken over by Japanese Yuasa).

As the car was purchased second hand, I had no idea what the guarantee would be . However I complained to Lexus and Lexus Coventry (nearer to where I live) came to the rescue. The fitted a new battery free of charge for me ... HOWEVER.. the replacement battery fitted was a 70 amp hour.TOYOTA GENUINE PARTS. 'OPTIFIT' QUALITY PRODUCT. MADE IN FRANCE. SEALED FOR LIFE WITH THE MAGIC EYE STATE OF CHARGE AID. From my past experience I am fairly sure this is an AC Delco product. made from LEAD CALCIUM plates, probably one of the best products ( in my opinion second to VARTA)
made. So far I have no had a starting problem.

With the present installation, the comments made about 'space to fit a bigger battery' not available are correct. the 70ah Toyota battery however is the same size...

Plese consider however the 'parasitic load' problem .. ie all the drain taking place all the time the car is stored from the pre-set radio, the relays, the alternator etc... My car does not have a Lexus Sat Nav. Their is proably a constant small drain from the sat nav.. I am not sure on this point however.

If any members get their battery replaced by Lexus on either the 300 series or the hybrid models INSIST Lexus replace the battery with the OPTIFIT (pt. no. 28800-YZZ ) 70 ah.
Hope this has been of interest.
Their is no doubt the starter battery spec on these cars is UNACCEPTABLE. My other car a 330D BMW has a 90 amp hour battery to 'sop' up all the quiescent drain.
Roy

sorry to say this, but your RCA guy does not have the slightest idea how your RX400 is working.
the 12V battery is getting charged from your 288V battery (the one below the back seats) as soon as the computers are in ready state! your cars engine is ONLY charging the 288V battery.

yes, a RX400 owner in swizerland is exactly doing this. he is carrying a 20A/h batterie in the trunk and connects it to the 12V connector in the trunk if he need to jumpstart the cars 12V batt.

yes this is of high interest! could you provide me with the dimensions (L/W/H) of this battery?

Interesting thread for two reasons to me:

1. My business partner has a 400h like me and his battery went flat after he spent an evening listening to his stereo whilst having a barbecue at a campsite. RAC confirmed that the 400h is "well known for having an undersized battery"
2. Having been duly warned, I parked my 400h in my garage leaving good access to the engine compartment when I went away for three weeks. Yup, it was as flat as a pancake when I got back. AA started it for me and I took it for a 10 mile fast drive. No further problems, although having to reprogram my driving position was annoying, and it still doesn't feel quite right....!

Lexus, we need more POWER!

Bladgb

Hi guys,

Yes, the RX-400h has a small battery but:

As any motorcycle owner knows (usually the hard way) if you leave your moto with the alarm on for more than 15 days you get a dead battery.

and because the beginning is the half of everything:

Has yor dealer delivered your car with the battery checked and fully charged?

Did you parked your car, leaving for holidays, with the battery fully charged or you placed it in the airport parking after many small stops here and there?

Did you park the car with the immobilizer and alarm ON for more than 15 days? ANY alarm circuit (including radar) can drain the battery if stayed on for more than 10-15 days.

By having a bigger battery you earn:

a. More stored current.
b. Or more parked days

you loose by having:

a. More carrying weight
b. More hood space
c. More replacement cost.

That's why cars made in Japan have starters needing smaller batteries. Try to start an Alfa Romeo with your Japan car battery and you will understand me.

a. More carrying weight - possibly depending on the materials used but a modern battery is usually lighter
b. More hood space - highter capacity battery doesnt always mean a larger battery - it still has to fit in the same battery tray
c. More replacement cost. i found prices to be all about the same at worst there was a few £ difference but this shouldnt be a deciding factor

Hi Robroy,
I'm sorry I didn't read your comments before collecting my 400h today. I have written on this Forum many times in the past few months about my battery problem. My car has been at Lexus for the past 4 weeks "being checked-out" while I was abroad for a month, because of my problems prior to leaving with a repeated flat 12V battery. They told me this morning that during the month they checked it after 2 weeks and it started; almost didn't start after 3 weeks, and was flat 2 days later. They charged it up, and they said that it had held its charge. They were due to deliver it to me this morning as being "perfectly fine", but when they tried to drive it here it was again flat and their "testing showed a battery fault"!!! ??What testing?? They replaced the battery. I think they are just trying to fob me off, being an old lady. But I will need to check the battery details as you describe.
I have found your comments the most useful so far. I will challenge Lexus tomorrow with this information.
Rufels

Hi Rob,
The battery I was given yesterday has the part number 28800-YZZ, so I presume this is what you recommend. They tell me that my previous 'bad" battery was the same!!! Will now have to wait for my next holiday abroad in December.
Ruth (Rufels)

In my experience it's vital to turn off the auto headlight switch when parking up for long periods. My old IS300 and RX300 both suffered from flat batteries after being left for 5-6 weeks with the auto h/l switched on, but when left for similar periods with it switched off they were fine. I recently left my RX400h for 3 weeks with the auto h/l switched off and it too was fine.

I've had mine (RX400h) for a year now and still hate the torque steer and am not fond of the constantly variable transmission. It's OK in normal use, but when calling for brisk acceleration when, say joing a motorway it all sounds a bit frenzied.

Les

During a commercial break one night the Black & Decker battery booster "popped" up.
Wonder whether that would be suitable to carry in the boot?
What do you think?

http://www.blackanddecker.co.uk/automotive...hierarchy/1744/

I saw that thing advertised, and in my experience things like that wouldn't jump start a fiat Uno if the battery was dead.

That said, as all you have to do is give the 12V system on the 400h a couple of amps to start the ECU's (the traction batteries actually start the V6), then this product is probably exactly what is required. I'm still on for trying 8 D Cell Duracells though!

just been reading these posts with interest (I have an IS200, not RX400h). Shame Lexus aren't bending over backwards to help out!!

As a suggestion to help "jbanfie" out, why doesn't someone measure the current draw from the 12V battery during starting, then you will know if the 8 D cell idea would work or not!! :-)

.............you never know!

I agree, trying it would be the thing to do, trouble is, I don't really want to start messing about with my 40 grand motor, in case it stops working!!!!!!!!

current measurement would be ok though. Plus its still under warrenty so if you do bust it, just deny all knowledge!!! :-)

Hi Guys and Gals

The battery saga rolls on..... I am so cheesed of with it I am in the throws of jumping ship and going back to Merc... A pity really as I do like the car and it is a super tow car...

To our friends who read my last screed and how I managed a new 70 ah battery foc out of Lexus Coventry, I thought my problems were at an end.... WRONG after 8 or 9 days untouched and with a voltage of only 11.7v the car would not start.. A jump start soon had it running. This seemed to happen after a couple of frosty nights.

On Monday I 'mothballed ' the car by moving the caravan from in front of the car and putting the Lexus in the garage... Hang on. I noticed something strange..... When I removed the ignition key... and closed all doors BUT DID NOT LOCK THEM... The red security diode still FLASHED.. Put the key back in the lock. Leave everything switched off. Leave the doors unloked... NO DIODE FLASHInG
Everything on the security side inactive.... Goodie goodie from this area NO PARASITIC LOAD from the ignition.

Obviously I am not going to recommend we all leave our cars unlocked and leave the key in the dashboard....... In my case for the time being this is what I am doing... OK the garage is locked, there is a caravan and another car in front of the garage door... I will take regulary voltage readings and dates to see how the battery discharges... If I come up with something I will report it on the forum immediately.Is it the drain from the security side that is flatening our batteries ?

Could anyone out there help me on a lttle puzzle in this area please.... My worry is... If we disconnect the battery on the RX and say leave the car overnight, question 1 Do we loose all our memory stored in the radio pre set stations,? 2. Do all other things work OK
things like electric windows etc... 3. Is the Lexus radio coded ? I did this with my previous car (Merc E series E300D 210 model..) I had a devil of a job to reset the windows.

Sorry to ramble on. Like you all I think the way Lexus are trying to put this matter right is a complete disgrace. I would be very nervous of changing my RX300 to a RX400/450 where jump starting becomes a real problem if you are on your own.

Roy

Roy,

Have you taken the headlights out of automatic mode as described by someone above in this thread? I can kind of see a way this would help, my lights stay on until the drivers door is opened, so there is still power to some of the circuits without the key in the ignition!!!!!!

Worth a test

Cheers

Jon

Regarding the dash LED flashing, this does it for 2 reasons. When you take key out of ignition and don;t lock the car, it indicates imobiliser as this is controlled via the inductive loop on the ignition barrell. Once you lock the car, it then shows alarm is active (detected by loop by door lock, or key fob receiver. Thats my understanding, though I have not looked at the LED on my IS for a bit, so would have to confirm.

I am guessing that when the key is out of the ignition and in the door, the system senses the key and turns the LED off?

Is the alarm in the RX the same as in IS200 - i.e. radar based? The drain from this is usually lower than normal sensors - so I read somewhere.

I am guessing that the alarm load on the RX is higher than normal/other cars and this is why the battery drains so quickly.

It is interesting though that someone mentioned they has a GSxxxh which had no issues after leaving for months! Why is the RX so bad - do people have battery drain issues on non hybrid models - RX300 etc?

I have no problem starting an IS with a 100% flat battery using a booster pack. think it supplies 900A for 5 secs - more than enough to start the car.

Thanks for replies guys... As you've gathered I intend cracking this nut or creating one hell of a stink..

NOW THEN..So far GOOD news and BAD news.
The good news. Following Kev and Jons replies, I have just come out of the garage where the car (2002 Lexus RX300 with 26k miles whas been stood for over 24 hours with the Ignition key in the lock and a battery OCV of 12.46v.
The voltage still reads 12.46v.... NO NOTICEABLE current drain whatsoever. I am convinced here that the problem lies in the high
current drain when the car is parked up and locked in the normal way with the keyfob which automatically sends in the deadlock and alarms the car as it should do... I also have a BMW 3 series diesel with a similar system... 3 weeks in Teneriife have been enjoyed with the car stored and secured near B'Ham Airpot .... Started first time.

NOW THEN The BAD news , first the quiescent loads flattening the battery (40 ah ot 70ah) whilst the veicle is in storage ar FAR to HIGH. None of us can fix this... It requires a complete re-design of the security ignition system and a system introduced with a far lower storage discharge. This should also be coupled with a higher Ah battery. The smaller BMW 3 series diesel as a 90 ah battery (the same size as an ambulance battery.

The comments from Jon have been noted... No, I have never used the automatic Headlight on and off thing. For my motoring this is a feature I can do without.

I will continue to monitor Battery voltage and report back from time to time... From my end I think I have cracked quite wrongly, this problem by storing the car in the locked garage and leaving the dam key in the dashboard all the time the car is off the road.. ie all winter.

WILLIZ over there in Vienna , where are you ? You are the man on these things and with your RX400 have suffered... There are many people over here would love to hear your views on the above.. kind regards Roy.

Before I go... VERY INTERESTED in the 900 booster pack.... However are you happy that the cable with this kit can handle 900A?

If I get the RX nicked the laughs on me !