Rx400H Battery

[jap lover]

Hi just joined group in hope of help just spent week away and on return to airport the remote would not open car,also would not open via key even with pulling handle and turning key as suggested by lexus dealer.Called AA didnt have a clue coudnt be recoverd as in park and parked in tight spot(so i didnt get any muppets dinking the door,3hrs later AA man smashed window then lifted bonnet to jump it!!!!!(has this ever happend before)

[MartyCee]

This Battery issue is well known by the AA & the RAC. My own lexus agent has told me that there is a problem (that has been fixed on the new RX450h) the, basically speaking, allows the charging system on the car to fool itself as to the charging state/cycle of the RX400h.

I've had a new Battery & the rescue services have been out 3 times due to this issue.

So far I've been unable to find a larger capacity Battery to replace the Lexus original.

There isn't a fix available from Lexus, although there should be & in light of the number of stranded owners they really should be thinking about this as (from my limited feedback) it seems to be a software issue, rather than anything mechanical.

The Battery itself only initalises the car's systems, the actual starting is off the Hybrid Battery, hence it's small size.

I am looking into a solar charger as a stop gap, although you need to understand things like how to get a seperate feed through the car (the accessory sockets inside are both dead when the ignition is off, rulling out this way back) & the need for a blocking diode to prevent the panel itself discharging the Battery. It is also fair to point out that the need for light, even a street light at night can provide a limited amount of power, & that this option may not provide a "solution" as such, more a staving off of the power drain, because..........

........ the bottom line is that the Lexus Battery isn't of sufficient capacity for the car to be left parked for a couple of weeks without use to keep it charged.

If any other owners have had similar problems please add your experiences to this mail. If there are enough of us we MAY be able to persaude Lexus to develop a solution, rather than let the word spread through their dealers & the roadside services the the RX 400h has an issue that needs a fix, not a recovery truck.

A solution is, in light of the recent Toyota publicity, in everyone's mutual interest - after all, how do we know if this is an RX issue, or a general Toyota Hybrid issue that affects all but the latest generation cars?

[Linehill]

Hi just joined group in hope of help just spent week away and on return to airport the remote would not open car,also would not open via key even with pulling handle and turning key as suggested by lexus dealer.Called AA didnt have a clue coudnt be recoverd as in park and parked in tight spot(so i didnt get any muppets dinking the door,3hrs later AA man smashed window then lifted bonnet to jump it!!!!!(has this ever happend before)

Have a look at my forum entry headed "Do not leave your lights on" from January 2010. Extensive ideas and suggestions were made by many RX400h owners. We all know the auxillary Battery which primes the hybrid system is inadequate, Lexus know as well, but the Battery tray is too small to fit a larger capacity Battery in its place. No one has suggested that it might be worth actually disconnecting a Battery terminal if the car is going to be left for a few weeks unused. I don't know if it would stop a flat Battery, but downside is the alarm system would not function. But this is probably the cause of the Battery drain. Would the central locking work? This is a frustrating problem on what is otherwise an excellent car.

[LRX400hBF]

Hi just joined group in hope of help just spent week away and on return to airport the remote would not open car,also would not open via key even with pulling handle and turning key as suggested by lexus dealer.Called AA didnt have a clue coudnt be recoverd as in park and parked in tight spot(so i didnt get any muppets dinking the door,3hrs later AA man smashed window then lifted bonnet to jump it!!!!!(has this ever happend before)

I too had a problem with the RX400h Battery going flat after just a few days - and called out the Lexus/RAC service a few times.......each time having to wait several hours for someone to turn up!

The RAC chap said that Flat Batteries on Lexus Hybrids was his biggest call out (which made him happy at least!) - and that it was indeed due to Toyota/Lexus fitting a silly little Battery instead of a suitably sized one.

Your driver's door should have unlocked manually with the key - even with a flat Battery - to enable access to the bonnet release.

I got sick of the Battery going flat - so obtained a replacement (new) Battery under warranty. As with all other Lexus/Toyota faults - Lexus/Toyota claimed that they'd never heard of the problems before!!!!

[rickj]

In Feb my Battery went flat on my 400H (although I was able to open the driver door with the key). The RAC came out, jump started it and then recommended I contact Lexus who asked me to bring the car in for a Battery check. They diagnosed the Battery as faulty and replaced it with a new one.

All was well until last Friday afternoon when I experienced the same issue again, flat Battery. This time the AA came out and jump started it and today my vehicle is back in at Lexus for I presume what will be another new Battery.

I'm using the vehicle everyday so can't understand how the Battery can fail like this in only 3 months of use?

I must say this isn't the Lexus experience I was hoping for when I bought the car. Overall I think the car is excellent but this Battery issue is starting to wear me down, okay I can just about live with this while I've got the extended warranty support and breakdown cover but beyond this I can see this becoming a costly exercise re batteries and will force my hand to change the vehicle and move away from the Lexus brand.

I find it frustrating that the dealer pleads ignorance on this issue, surely Lexus HQ must know about the number of reported Battery problems on the 400H? has anybody tried contacting them on this issue ???

[rickj]

I just got an update from the service manager at my local Lexus dealership who has been checking my Battery.

After talking to him at length about how the vehicle was used prior to the flat bettery, he diagnosed the drain on the Battery down to me leaving the doors and boot open for several hours whilst I was loading the car up when returning from holiday. I didn't have the keys in the ignition and he said the interior lights and doors illumators would be enough to drain the small auxillary Battery if left on for as little as 30 minutes !!!

He admitted his embarrasment on this issue and said that he has had this conversation many times before with 400H owners whom have used power without realising and not having the ignition key in the ready position. He said "Always, always leave the ignition key in the ready position" when using any of the vehicles systems radio/CD/DVD or even stationary with the doors and/or boot open - Lesson learned!

I even asked him about the Battery size on the new 450H and lo and behold Lexus now fit a bigger auxillary Battery to this model ! so I think that speaks for itself.

[MartyCee]

In light of this problem I am taking 2 (with a possible third later) route towards a solution.

1. A larger Battery must exist somewhere, if not in physical dimensions, surely in terms of a better amp/hr rating.

Now before everyone jumps up & down with joy there may be downsides to this. a) Warranty, always a b***er when you resort to non standard kit! For my part I'd argue this through to the High Court if penalised, the voltage remains the same & the extra capacity stays in the Battery & doesn't feed extra current into the system.

However it might weel extend airport park ups & similar by a measurable amount, because the voltage won't go critical so quickly.

2. If you only do short(ish) trips most of the time you won't achieve anything with the above in the long run because the Battery will take long to charge as you drive ...... eventually you could kill the Battery through lack of charge.

So ................... Solar charging to keep the power up no matter what. I;ve used these things with my motorhome to amazing affect, a 90amp/hr Battery dropped to 50% overnight through use can be restored to health through a 90watt panel. Now thats extreme, so a 5watt (ish) panel should do the job one most days. Bear in mind even a street light can give a small amount of power through a solar panel. The principal isn't a constant charge, more a varying charge dependant on light .... so a shaded parking spot might need a bigger panel to gather enough light to be effective.

These can be bought for about £30, less than a replacement Battery.

However it will require a seperate in car socket with a feed to the Battery, to modify one of the Lexus dash fitted ones would be unwise (& a warranty issue for those so affected) ..... unless the one on the boot is constantly powered............

IMPORTANT!!!!!! If you decide to follow this route independently make sure you fit or have inclded in the solar panel a blocking diode or a supply controller. If you don't you can lose power back to the panel .... not a good idea.

If anyone's interested I'll post my findings as & when I have them.

Of course the real answer might be both at the same time .............. as J. Clarkson would put it ......POWEEEEERRRRRRRRRRR!

[MartyCee]

Forgot to add the third possible option .....!!!! Ooooppss!

When (IF!) I find the above works I'll approach Lexus with a clear line of how to fix it..... after all they probably only go for the batteries Toyota stock & even the new Prius has a solar roof option (for entirely differnet reasons .... maybe they missed a trick? Maybe I need to contact the Patents Office in short order!).

In the ned they will find it harder to reject claims if someone has proved a solution works ......

"Fit for purpose" as in the Sale of Goods Act comes to mind ....... any car that fails on something as basic as a repeatedly flat Battery could weel be failing under that criteria.

[Brusberg]

It happened to me as well - but on a RX450h (I guess it is not fixed). Ten days at the airport - flat "as a pancake".

The service guy at Lexus told me straight up that I couldn't expect to have the car standing tat long without removing the fuses. He politely showed me how to remove cover, open fusebox and locate/remove the white fuse. Then coming home, just open the car manually with the key, dig in under the bonnet, reverse the procedure, put everything in place and drive off.

I thought that we has joking.

Grrr...

[lexington013]

L9XSS private plate available. First £520 secures. Great plate. On retention certificate for 11 months. New 318d m sport forces sale. Contact me on paul.mussett@tiscali.co.uk

[Surfbum]

In light of this problem I am taking 2 (with a possible third later) route towards a solution.

1. A larger battery must exist somewhere, if not in physical dimensions, surely in terms of a better amp/hr rating.

Now before everyone jumps up & down with joy there may be downsides to this. a) Warranty, always a b***er when you resort to non standard kit! For my part I'd argue this through to the High Court if penalised, the voltage remains the same & the extra capacity stays in the battery & doesn't feed extra current into the system.

However it might weel extend airport park ups & similar by a measurable amount, because the voltage won't go critical so quickly.

2. If you only do short(ish) trips most of the time you won't achieve anything with the above in the long run because the battery will take long to charge as you drive ...... eventually you could kill the battery through lack of charge.

So ................... Solar charging to keep the power up no matter what. I;ve used these things with my motorhome to amazing affect, a 90amp/hr battery dropped to 50% overnight through use can be restored to health through a 90watt panel. Now thats extreme, so a 5watt (ish) panel should do the job one most days. Bear in mind even a street light can give a small amount of power through a solar panel. The principal isn't a constant charge, more a varying charge dependant on light .... so a shaded parking spot might need a bigger panel to gather enough light to be effective.

These can be bought for about £30, less than a replacement battery.

However it will require a seperate in car socket with a feed to the battery, to modify one of the Lexus dash fitted ones would be unwise (& a warranty issue for those so affected) ..... unless the one on the boot is constantly powered............

IMPORTANT!!!!!! If you decide to follow this route independently make sure you fit or have inclded in the solar panel a blocking diode or a supply controller. If you don't you can lose power back to the panel .... not a good idea.

If anyone's interested I'll post my findings as & when I have them.

Of course the real answer might be both at the same time .............. as J. Clarkson would put it ......POWEEEEERRRRRRRRRRR!

[Surfbum]

I am a new member to the LOC so I thought I would share my info on the dead Battery issue.

I work away a lot so my '57 400h is left standing for weeks on end and as other members have noted the Battery is dead after a few days of not being driven.Lexus are aware of this but there is no 'fix' unless you get the new 450h.

However,I have got the 'fix' sorted.

I got my local lexus agency to put permanent power to the lower power socket at floor level,purchased a solar power panel and leave that on the dash when I leave the car;the Battery gets a trickle charge while I'm away,the panel also has a diode fitted which stops reverse drain from the Battery.

I have not had any trouble with Battery drain since having this done.

Surfbum

[rhosneigr]

The power socket in the boot only works when the auxiliary is switched on.

[Linehill]

The power socket in the boot only works when the auxiliary is switched on.

Interesting. What exactly do you mean when the auxiliary is switched on? I carry a Blackspur Battery starter/tyre air pump/torch unit which is connected to the 12 volt contact in the boot to keep it fully charged in case of an emergency. The charging light on the unit does not light up even when the car is running. Do you know if this connection is fused? I do not think it is recharging the blackspur and once a month I boost it on the mains adapter, which does show the charging light!

[rhosneigr]

The ignition key has to be turned to the auxilliary position where the radio, sat nav etc become active or the start position.

[rhosneigr]

The power socket in the boot only works when the auxiliary is switched on.

Interesting. What exactly do you mean when the auxiliary is switched on? I carry a Blackspur Battery starter/tyre air pump/torch unit which is connected to the 12 volt contact in the boot to keep it fully charged in case of an emergency. The charging light on the unit does not light up even when the car is running. Do you know if this connection is fused? I do not think it is recharging the blackspur and once a month I boost it on the mains adapter, which does show the charging light!

I would think that these connections are fused but it does not give any information in the handbook about individual fuses only where the fuse boxes are located.

[Fredza]

Mine 05'400h, 130000km on clock (owner sience feb10-in my hand 13000km) standed in airport 8 days in march, -10 C(estonia), no problems. In summer I have 12V 32litre cooler in back, tomtom in cigarette 12V and 12V-220V inverter in floor for laptop and photocamcharger (2*220V socets). No problem. I don't leave key in ignition and stuff won't work at standing.

Battery Dimensions:

230*130*h200mm

Hankook calcium+(made in korea)

45 Ah(20hr)/71min(rc)

220A din, 360A en, 430A sae

[wrcharlesworth]

Looks like I'm the latest to suffer from this fault. I have a 2 year old RX400H. Did a thousand miles or so over the summer. It was parked up for a week last week while I was away on work. On my return the Battery was almost completely dead - just enough to open the doors thank goodness but otherwise nothing. AA man (Lexus Roadside assistance) jump started it and said the Battery looked faulty. I've had it replaced under warranty.

When I was younger and poorer I had old bangers that needed to be jump started from time to time. I don't expect a £40,000 plus two-year old car to need jump starting in 2010. I've been a loyal Lexus customer for ages now but I am starting to wonder about reliability. (The power steering on my previous RX400H had to be replaced after two years. It's no joke trying to manoeuvre one without power steering as you can imagine.) I have seen lots of helpful ideas on here about how to prevent a Battery discharge occurring again but I return to the £40,000 point. I don't think it should be up to me to devise clever tricks involving the cigarette lighter. Have they acknowledged that this is a problem or are they keeping their heads down?

[daveyboo]

This battery issue is well known by the AA & the RAC. My own lexus agent has told me that there is a problem (that has been fixed on the new RX450h) the, basically speaking, allows the charging system on the car to fool itself as to the charging state/cycle of the RX400h.

I've had a new battery & the rescue services have been out 3 times due to this issue.

So far I've been unable to find a larger capacity battery to replace the Lexus original.

There isn't a fix available from Lexus, although there should be & in light of the number of stranded owners they really should be thinking about this as (from my limited feedback) it seems to be a software issue, rather than anything mechanical.

The battery itself only initalises the car's systems, the actual starting is off the Hybrid battery, hence it's small size.

I am looking into a solar charger as a stop gap, although you need to understand things like how to get a seperate feed through the car (the accessory sockets inside are both dead when the ignition is off, rulling out this way back) & the need for a blocking diode to prevent the panel itself discharging the battery. It is also fair to point out that the need for light, even a street light at night can provide a limited amount of power, & that this option may not provide a "solution" as such, more a staving off of the power drain, because..........

........ the bottom line is that the Lexus battery isn't of sufficient capacity for the car to be left parked for a couple of weeks without use to keep it charged.

If any other owners have had similar problems please add your experiences to this mail. If there are enough of us we MAY be able to persaude Lexus to develop a solution, rather than let the word spread through their dealers & the roadside services the the RX 400h has an issue that needs a fix, not a recovery truck.

A solution is, in light of the recent Toyota publicity, in everyone's mutual interest - after all, how do we know if this is an RX issue, or a general Toyota Hybrid issue that affects all but the latest generation cars?

Been on holliday a couple of times and left the car parked, no problem. This morning took it to the carwash, left it with them for an hour came back to a dead car. Dont make a lot of sense!

[JBPRX400h]

Been on holliday a couple of times and left the car parked, no problem. This morning took it to the carwash, left it with them for an hour came back to a dead car. Dont make a lot of sense!

They probably had the doors open all the time (with the interior lights on) and were listening to the wonderful sound system in your car. This alone would cause the auxilliary Battery volts to drop low enough for the car electronics not to operate after less than an hour. The audio draws a lot of current. It must to produce that amount of sound. You don't get something for nothing!

Often, if this happens, leave the car with everything switched off for about 15-20 minutes then try starting it again. The Battery might recover enough for it to boot up the statring computers again.

JBP

[Surfbum]

Looks like I'm the latest to suffer from this fault. I have a 2 year old RX400H. Did a thousand miles or so over the summer. It was parked up for a week last week while I was away on work. On my return the battery was almost completely dead - just enough to open the doors thank goodness but otherwise nothing. AA man (Lexus Roadside assistance) jump started it and said the battery looked faulty. I've had it replaced under warranty.

When I was younger and poorer I had old bangers that needed to be jump started from time to time. I don't expect a £40,000 plus two-year old car to need jump starting in 2010. I've been a loyal Lexus customer for ages now but I am starting to wonder about reliability. (The power steering on my previous RX400H had to be replaced after two years. It's no joke trying to manoeuvre one without power steering as you can imagine.) I have seen lots of helpful ideas on here about how to prevent a battery discharge occurring again but I return to the £40,000 point. I don't think it should be up to me to devise clever tricks involving the cigarette lighter. Have they acknowledged that this is a problem or are they keeping their heads down?

My local Lexus agency(Plymouth) changed my Battery 3 times before eventually installing permanent power to the front power socket at floor level..its connected to the Battery with an inline fuse.My '57 400H is left unused for upto 4 weeks at a time due to overseas work and since using the solar charger plugged into the floor socket and laying on the dashboard I have had no problems with starting the car after being away.

[Herkyboy]

This Battery problem needs to be sorted by Lexus. My Dec 2008 RX 400h was recently left for nine days and the Battery went completely flat in that time. I took it to Lexus Brighton and was told that this was normal by the same chap who told me when I bought the car in June that the Battery problem was "largely confined to the IS series". They may think this is normal but I don't. The employees read these posts so I'm sure that they can work out my identity. The car is still under warranty and I await a phone call or email offering a free and permanent solution. Failing that I shall sell the car and go back to Mercedes. It will be Lexus's loss.

[ihpj]

This Battery issue with the 400h is (sadly) another example of Lexus failing to take into account everyday occurrences when designing and engineering their vehicles. It beggars belief that a company dedicated to 'the pursuit of perfection' seems dominated by the over-engineering aspect and forgetting the basics, like the reversing camera not functioning in low light conditions...I mean WTF?

Hope you guys get this sorted...

[F.A.]

This battery issue with the 400h is (sadly) another example of Lexus failing to take into account everyday occurrences when designing and engineering their vehicles. It beggars belief that a company dedicated to 'the pursuit of perfection' seems dominated by the over-engineering aspect and forgetting the basics, like the reversing camera not functioning in low light conditions...I mean WTF?

Hope you guys get this sorted...

I find that the reversing camera works fine on my IS in low light conditions

[Arjuna]

Hello all

I read these treads and felt shocked. My Lexus rx400h is a keyless system that works on proximity. Can anyone tell me what I can do if the Battery drains and the door does not open - even for a jump start I need to open the door and reach the bonnet latch!!!

Regards

Arjuna