Battery Power

[Linehill]

Why has the RX400h such a tiny Battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the Battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent Battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

[robroy]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

[robroy]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

Hi Roy

And a Happy New Year to you :)

To initialise the windows just go to each window and if you look carefully you will see the little LED light flashing on the switch. So open an shut it by holding the switch up while it shuts and the light will stop flashing. Done! You may need to send it up and down a couple of times though. Then test them from the drivers door.

repeat performance for moon roof.

Re boot, just lock and unlock car doors by remote or by switch on drivers door.

I am afraid you will have to retune the radio manually!

I hope this helps.

Billy

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

Hi Roy

And a Happy New Year to you :)

To initialise the windows just go to each window and if you look carefully you will see the little LED light flashing on the switch. So open an shut it by holding the switch up while it shuts and the light will stop flashing. Done! You may need to send it up and down a couple of times though. Then test them from the drivers door.

repeat performance for moon roof.

Re boot, just lock and unlock car doors by remote or by switch on drivers door.

I am afraid you will have to retune the radio manually!

I hope this helps.

Billy

[The Editor]

.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

AGM Battery???? - You will easily find one that has bags more power than anything in the standard form factor. In fact one with the same rating as the RX (70ah) will only be around 2/3rds the size. The crank current will probably be around double that of anything you find in the high street and the discharge recovery is second to none.

The Ed

[robroy]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

Hi Roy

And a Happy New Year to you :)

To initialise the windows just go to each window and if you look carefully you will see the little LED light flashing on the switch. So open an shut it by holding the switch up while it shuts and the light will stop flashing. Done! You may need to send it up and down a couple of times though. Then test them from the drivers door.

repeat performance for moon roof.

Re boot, just lock and unlock car doors by remote or by switch on drivers door.

I am afraid you will have to retune the radio manually!

I hope this helps.

Billy

Hi Billy.

Thanks for the info.. Will certainly keep it in mind...

Now then , if we keep chipping away at this problem, we all may get some where... fingers crossed.

A couple of points if I am not boring everyone... namely.

1. The best 3 car batteries on plant earth at the moment are :-

OPTIMA bcI 34 ...

SONNENSCHEIN DEEP CYCLING 70AH LEISURE BATTEERY

ELECSOL 70AH, 300a CCA.

I have a Sonnenschein from the caravan and an Optima which I use for jump starting , blowing tyres up etc.

I will have a go at fitting them to my RX to see if I can 'shoe horn' one of them in..... At present I have a damaged hand so this may take some time.

I have also ordered (so I am told) the best Battery Charger/Conditioner availabe at present, the Accumate 6/12v Battery Conditioner/Charger.. This should arrive next week, now that the hols are almost over.

Watch this space and I'll pass on as much info as I can get.... In the meantime , keep those sun visors closed, remove the key, disconnect any Bluetooth phone equipment ... also let us all know if anyone cracks this one.. I do not think however we will get much technical help from the main Lexus Dealers... If I cannot improve the problem before Easter, I feel it will be Good Bye Lexus and hello to a BMW 4x4.

PS Google in the above products and let us know what you think?

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

Hi Roy

And a Happy New Year to you :)

To initialise the windows just go to each window and if you look carefully you will see the little LED light flashing on the switch. So open an shut it by holding the switch up while it shuts and the light will stop flashing. Done! You may need to send it up and down a couple of times though. Then test them from the drivers door.

repeat performance for moon roof.

Re boot, just lock and unlock car doors by remote or by switch on drivers door.

I am afraid you will have to retune the radio manually!

I hope this helps.

Billy

Hi Billy.

Thanks for the info.. Will certainly keep it in mind...

Now then , if we keep chipping away at this problem, we all may get some where... fingers crossed.

A couple of points if I am not boring everyone... namely.

1. The best 3 car batteries on plant earth at the moment are :-

OPTIMA bcI 34 ...

SONNENSCHEIN DEEP CYCLING 70AH LEISURE BATTEERY

ELECSOL 70AH, 300a CCA.

I have a Sonnenschein from the caravan and an Optima which I use for jump starting , blowing tyres up etc.

I will have a go at fitting them to my RX to see if I can 'shoe horn' one of them in..... At present I have a damaged hand so this may take some time.

I have also ordered (so I am told) the best Battery Charger/Conditioner availabe at present, the Accumate 6/12v Battery Conditioner/Charger.. This should arrive next week, now that the hols are almost over.

Watch this space and I'll pass on as much info as I can get.... In the meantime , keep those sun visors closed, remove the key, disconnect any Bluetooth phone equipment ... also let us all know if anyone cracks this one.. I do not think however we will get much technical help from the main Lexus Dealers... If I cannot improve the problem before Easter, I feel it will be Good Bye Lexus and hello to a BMW 4x4.

PS Google in the above products and let us know what you think?

Thank you Ed for your suggestion re AGM Battery. Perhaps Roy could look into that option?

Roy, I do have a powerful 6v/12v charger / booster so I never have a problem if I flatten the Battery at home.

However your conditioner could be good if the car is in storage for extended periods. It looks good on the web anyway and not very expensive!

Actually I am working on a completely different option which I don't want to publicise until I have it working. Suffice it to say there will be a built in jumpstart facility available at all times! Watch this space (phev) but please don't ask me any more about it for now!!

BTW, I think my Bluetooth does turn off as when I switch off the ignition as my phione tells me BT is disconnected.

Billy

[Linehill]

Hello to Billy and Roy and Editor. Very interested to hear about your opinions on this problem, although there does not seem to be a simple solution like fitting a more powerful Battery, I have now got a rechargable jump Battery device which I have connected to the 12 volt socket in the luggage area. I now should not be left stranded at 1.a.m. as before! However I hope Lexus feel ashamed that such a superb vehicle has to carry a £25 product to keep it running! By the way have Lexus got the same problem on the RX450h?

[billygarrett]

Hello to Billy and Roy and Editor. Very interested to hear about your opinions on this problem, although there does not seem to be a simple solution like fitting a more powerful battery, I have now got a rechargable jump battery device which I have connected to the 12 volt socket in the luggage area. I now should not be left stranded at 1.a.m. as before! However I hope Lexus feel ashamed that such a superb vehicle has to carry a £25 product to keep it running! By the way have Lexus got the same problem on the RX450h?

Hi Linehill!#

Yes, that is exactly what I have done! It has got me out of trouble many times :)

I don't know about the 450. Perhaps someone else does?

Happy New Decade Everyone.

Billy

[robroy]

Hello to Billy and Roy and Editor. Very interested to hear about your opinions on this problem, although there does not seem to be a simple solution like fitting a more powerful battery, I have now got a rechargable jump battery device which I have connected to the 12 volt socket in the luggage area. I now should not be left stranded at 1.a.m. as before! However I hope Lexus feel ashamed that such a superb vehicle has to carry a £25 product to keep it running! By the way have Lexus got the same problem on the RX450h?

Hi Linehill!#

Yes, that is exactly what I have done! It has got me out of trouble many times :)

I don't know about the 450. Perhaps someone else does?

Happy New Decade Everyone.

Billy

[The Editor]

I have also ordered (so I am told) the best Battery Charger/Conditioner availabe at present, the Accumate 6/12v Battery Conditioner/Charger..

You could also look at one of these - I have one and can thoroughly recommend them.

They actually take the Battery through 7 levels of charge automatically whilst constantly monitoring the internal resistance of the Battery and adjusts the charge current accordingly.

The charge stages are:

1. Desulphation

2. Soft start

3. Bulk

4. Absorbtion

5. Test

6. Recondition

7. Float

Cheers

The Ed

[robroy]

I have also ordered (so I am told) the best Battery Charger/Conditioner availabe at present, the Accumate 6/12v Battery Conditioner/Charger..

You could also look at one of these - I have one and can thoroughly recommend them.

They actually take the Battery through 7 levels of charge automatically whilst constantly monitoring the internal resistance of the Battery and adjusts the charge current accordingly.

The charge stages are:

1. Desulphation

2. Soft start

3. Bulk

4. Absorbtion

5. Test

6. Recondition

7. Float

Cheers

The Ed

Hi, Ed, Billy and Linehill.

Thanks to this excellent web site and the exchange of ideas, We will crack this Problem.

Ed. The AGM batteries you mentioned are first class Varta products and the 90 ah product is JUST WHAT WE ARE LOOKING FOR... Unfortunately it will not fit the existing tray on the RX300/350 . It is to long. I also believe the terminal posts are wrong handed for the older RX300's.. I have fired E Mails off asking more info on the layout....

Obviously, I will make postings as more info comes in... For interest, Varta are now part of Johnson Controls. The same Company that owns Optima... From what I can make out the product line up of these SUPERB batteries is very similar...Also we are getting prices around the £175 each level.. Probably get a better price if we can find what fits ?

Billy and Linehill.... PLEASE can you forward me details of the 'Jump Start' gadget you have both purchased ... ie Where from ? How much? Do you fit a smaller starter Battery in the boot ? etc...

I know I am going on about this problem... My wife has just returned from Hospital following a replacement Hip operation.

The Lexus RX is a superb vehicle for an older person getting in and out of with the hospital supplied metal supports..

The 3 series BMW we have is definitely not advised.. Far to low down like a sports car.....

The beast would not start today (without a jump start in these very low temperatures). If I cannot crack this problem, I have no alternative to get rid of it for a more reliable car (starting issues only) .Dont want to do this as like Linehill I think it is a superb vehicle.... with a) to low a Battery Capacity on ther Ampere Hour side ie low drain and B) To high a quiescent drain from all the live relays supporting all the toys (mainly the alarm system), sun visor lights etc. etc etc. Like Billy I agree that a first class deep cycling Battery around 90 ampere hour would crack this problem. Alternatively Lexus should fit 2 batteries like the Mercedes E and S series ... One Battery for starting and one completely independent to sop up all the drainage from the toys... regards Roy

[Linehill]

Roy,

The gadget is called an "Engine Starter with air compressor" No branded name. It is a yellow plastic case which has a built in 12 volt Battery with a live and negative heavy duty jump leads attached. It is charged either by a mains transformer supplied, or via the 12 v socket through a type of cigarette connection, also supplied. It has an air compressor built in and a good lamp. Mine cast about £25 from The Range in Kidderminster, and I think Halfords, HomeBase etc also stock these.

On the 400h it kicked the "Ready" system in, and I have also used to jump start my SL320 and garden tractor. Happy new year and trust this will give you peace of mind! Linehill

[robroy]

Roy,

The gadget is called an "Engine Starter with air compressor" No branded name. It is a yellow plastic case which has a built in 12 volt battery with a live and negative heavy duty jump leads attached. It is charged either by a mains transformer supplied, or via the 12 v socket through a type of cigarette connection, also supplied. It has an air compressor built in and a good lamp. Mine cast about £25 from The Range in Kidderminster, and I think Halfords, HomeBase etc also stock these.

On the 400h it kicked the "Ready" system in, and I have also used to jump start my SL320 and garden tractor. Happy new year and trust this will give you peace of mind! Linehill

Thanks Linehill, I am on the search... Will keep up with postings as more info is received . We will crack this problem.Roy

[kt1]

I think I'll have to pick up one of these, Thanks, never know when you will need it.

[Linehill]

Roy, The starter device is called a Blackspur. Go to eBay or Google search "engine starters with air compressor" and you will find pages of offers! Linehill

[malcolmn5143]

This is a recurring thread. I too have had problems with my Battery. It seems if you do a reasonable journey everyday then there is no porblem. However, if you do a short commute, such as myself (3M) then the Battery discharges and does't recover. I have however done some longer journey's and then come left it overnight and come to a flat Battery in the morning. It is also affecting my stereo i.e. sometimes it doesn't work, but after a little run it will burst into life. This is an alternative to just a heavy 'hotel load' and I believe that there is a constant drain which may be coming from a small short somewhere. My guess is the fuse box (dry joint). Its going back to the dealer in Feb as its still under warranty and hopefully then I will get an owners manual and try and figure this out.

I will let you know how I get on.

[robroy]

This is a recurring thread. I too have had problems with my battery. It seems if you do a reasonable journey everyday then there is no porblem. However, if you do a short commute, such as myself (3M) then the battery discharges and does't recover. I have however done some longer journey's and then come left it overnight and come to a flat battery in the morning. It is also affecting my stereo i.e. sometimes it doesn't work, but after a little run it will burst into life. This is an alternative to just a heavy 'hotel load' and I believe that there is a constant drain which may be coming from a small short somewhere. My guess is the fuse box (dry joint). Its going back to the dealer in Feb as its still under warranty and hopefully then I will get an owners manual and try and figure this out.

I will let you know how I get on.

Hi Malcolm

If you read through all the postings on this problem, you will fall asleep

In a few words.

Check your starter Battery capacity on the Battery label ? Is it 40ah or 70ah ? Mine was a 40 ah and I got it changed to a new 70ah as a warranty.foc. Also check your sun visors .. On the RX300 if the mirror is not closed securely, the light stays on. The car requires a deep cycling/starter Battery around 90 ah ... I have discovered that a Elecsol 70 will fit the tight space with a little bit of persuasion. This is a deep cycling/starter Battery (albeit 70 ah) I have ordered one and I'll post back on here how I get on (If it arrives soon through the snow.) In a nutshell all the poxy batteries fitted by Lexus are to small in the ampere hour capacity department to handle all the toys on these excellent cars if the car is stored for longer than a couple of weeks. Regards Roy

[malcolmn5143]

Hey Rob,

Well I said I'd let you know how I got on. It turned out to be the pre-amp thatwas cutting out, but the head unit was still taking power. pre-amp has been replaced as has the aux Battery (45ah). Not having any problems at all, but will let you know if it satrts to reocurr.

This is a recurring thread. I too have had problems with my battery. It seems if you do a reasonable journey everyday then there is no porblem. However, if you do a short commute, such as myself (3M) then the battery discharges and does't recover. I have however done some longer journey's and then come left it overnight and come to a flat battery in the morning. It is also affecting my stereo i.e. sometimes it doesn't work, but after a little run it will burst into life. This is an alternative to just a heavy 'hotel load' and I believe that there is a constant drain which may be coming from a small short somewhere. My guess is the fuse box (dry joint). Its going back to the dealer in Feb as its still under warranty and hopefully then I will get an owners manual and try and figure this out.

I will let you know how I get on.

Hi Malcolm

If you read through all the postings on this problem, you will fall asleep

In a few words.

Check your starter Battery capacity on the Battery label ? Is it 40ah or 70ah ? Mine was a 40 ah and I got it changed to a new 70ah as a warranty.foc. Also check your sun visors .. On the RX300 if the mirror is not closed securely, the light stays on. The car requires a deep cycling/starter Battery around 90 ah ... I have discovered that a Elecsol 70 will fit the tight space with a little bit of persuasion. This is a deep cycling/starter Battery (albeit 70 ah) I have ordered one and I'll post back on here how I get on (If it arrives soon through the snow.) In a nutshell all the poxy batteries fitted by Lexus are to small in the ampere hour capacity department to handle all the toys on these excellent cars if the car is stored for longer than a couple of weeks. Regards Roy

[malcolmn5143]

It's been a while now since I posted, but I have just come back from two week sin Canada and the Battery was fine when I came back.

Hey Rob,

Well I said I'd let you know how I got on. It turned out to be the pre-amp thatwas cutting out, but the head unit was still taking power. pre-amp has been replaced as has the aux battery (45ah). Not having any problems at all, but will let you know if it satrts to reocurr.

This is a recurring thread. I too have had problems with my battery. It seems if you do a reasonable journey everyday then there is no porblem. However, if you do a short commute, such as myself (3M) then the battery discharges and does't recover. I have however done some longer journey's and then come left it overnight and come to a flat battery in the morning. It is also affecting my stereo i.e. sometimes it doesn't work, but after a little run it will burst into life. This is an alternative to just a heavy 'hotel load' and I believe that there is a constant drain which may be coming from a small short somewhere. My guess is the fuse box (dry joint). Its going back to the dealer in Feb as its still under warranty and hopefully then I will get an owners manual and try and figure this out.

I will let you know how I get on.

Hi Malcolm

If you read through all the postings on this problem, you will fall asleep

In a few words.

Check your starter Battery capacity on the Battery label ? Is it 40ah or 70ah ? Mine was a 40 ah and I got it changed to a new 70ah as a warranty.foc. Also check your sun visors .. On the RX300 if the mirror is not closed securely, the light stays on. The car requires a deep cycling/starter Battery around 90 ah ... I have discovered that a Elecsol 70 will fit the tight space with a little bit of persuasion. This is a deep cycling/starter Battery (albeit 70 ah) I have ordered one and I'll post back on here how I get on (If it arrives soon through the snow.) In a nutshell all the poxy batteries fitted by Lexus are to small in the ampere hour capacity department to handle all the toys on these excellent cars if the car is stored for longer than a couple of weeks. Regards Roy

[billygarrett]

Why has the RX400h such a tiny battery? I learned the hard way over Christmas not to be a good citizen and put the parking lights on. The owners hand book does not tell you it will flatten the battery in less than 1 hour and you will not be able to start the car! Brilliant!! My Lexus dealer in Cheltenham told me I should have been warned about this when I purchased the car. Also don't run the Air Con, Sat Nav, Radio/CD etc for long if the engine is not running. Why on earth did Lexus not fit a decent battery with adequate back up power? Otherwise the RX400h is a fantastic car and in over 50 years of driving the best car I have ever had.

Hi Linehill in Worcestershie. Roy here in Warwickshire, next door...

The flat batterryproblem on the RX series is as old as the hills... I have had mine just over 4 years and have been plagued with this problem from the start. If you check on the forums you will pick up many pointers from myself and other users. Alas we have not solved this problem... Maybe this will be helpful...

My RX300 was purchased for summer use only. ie pulling our caravan throughout the UK and Europe.. Cannot fault it. It is a superb tow car and apart from the battey problem , has been trouble free. Shortly after buying it ( and storing it in a well heated garage over the winter,) I realised it would not start... In this case Lexus were very good. I bought the car from Lexus Oxford with the first initial equipment Battery fitted ( a poxy 40 ampere hour Lucas). Lexus arranged for me to take the car to Lexus Coventry as we live in Stratford... Lexus Coventry changed the Battery to a NEW LEXUS 70amp hour Battery which was the largest and only Battery one could fit in the RX frame... Problem solved (nearly) now the car is able to stand for between 3 and 4 weeks .. After that no start on the button is possible.....

As I was employed in a tech position with Chloride for around 26 years, I think I know a little bit about batteries..... This is not really a Battery quality problem.

In a nut shell the 70 amp Battery on an RX 300 or 400 series is just not up to the job of coping with the very high ' Hotel Loads' which discharge the Battery when it is stood... There is virtually no problem with starting in the summer months when the car is used every couple of days or so.. I have today ordered the latest state of the art ACCUMATE charger/conditioner.. Google Accumate Charger and Conditioner and let us all know what you think ! I will put some postings upon the site if I can find any improvements. Money won't solve this one if you find a 90 ampere hour Battery like ambulances fit ( and our 3 series BMW) you still will not be able to shoe horn it into the tight Battery tray.... If anyoner out there has found any improvements with this problem I would love to know how to improve this dreadful design problem

Hi, As mentioned in several previous threads, I also have been plagued by flat batteries in my RX400h

But my problem is that I sometimes leave the key in the ignition switch for too long, maybe 3 hours, and when I go back the Battery is flat. The reason I think is that the solenoid which tilts the steering wheel is drawing power all the time.

My solution is twofold:

1. I always carry a small jumpstart box in the boot which is on permanent charge through the "lighter" socket. This has saved my bacon numerous times!!! ( I am starting to remember to remove the key!!)

2. I have a small security Battery connector, which disconnects the Battery completely when I loosen or remove the nut on the top of it. I can use this if I am leaving the car for more than 2 weeks while on holiday etc.

I believe that Lexus should fit Leisure batteries for Hybrids which don't need high current to start. but allow a longer slow drainage time, but nobody wants to listen to me!!!

Cheers

Billy

I forgot to mention that the downside of disconnecting completely is that all windows and bootlock and radio have to be re-initialised again, but now that I know about it is no problem (but a bit annoying!!)

Hi Billy, Happy New Year. Nice to hear from you again... Like me you have tried almost everything with the flat Battery problem.... As we live (hopefully) in a secure area and we have another car parked behind the Lexus, not only do I never lock the car. I NEVER leave the key in ever.... RESULT still a flat Battery after around 3 weeks parking... Over the last few weeks of freezing weather, this period has gone down to 2 weeks..... In a nutshell the RX does require a deep cycling leisure Battery to increase the time frame down to discharge condition when the car is stood... There has never been an issue (unless someone pops up on here and tells us otherwise) with engine starting... when the Battery is well up to charge my car always start at the first time. When I bought mine (2nd hand) it had a Bluetooth car phone hands free phone system fitted... As the kit married up easily with my Nokia phone I have left it in... Testing the car the other day it appears as though the Bluetooth is live all the time and not through the ignition... Dont want to remove it but I am considering it.

If you get a minute can you briefly go through the procedure of resetting the radio, windows, locks , alarm etc when you shut off all the power with a cut off switch on the Battery.... Cheers Roy

Hi Roy

And a Happy New Year to you :)

To initialise the windows just go to each window and if you look carefully you will see the little LED light flashing on the switch. So open an shut it by holding the switch up while it shuts and the light will stop flashing. Done! You may need to send it up and down a couple of times though. Then test them from the drivers door.

repeat performance for moon roof.

Re boot, just lock and unlock car doors by remote or by switch on drivers door.

I am afraid you will have to retune the radio manually!

I hope this helps.

Billy

Hi Billy.

Thanks for the info.. Will certainly keep it in mind...

Now then , if we keep chipping away at this problem, we all may get some where... fingers crossed.

A couple of points if I am not boring everyone... namely.

1. The best 3 car batteries on plant earth at the moment are :-

OPTIMA bcI 34 ...

SONNENSCHEIN DEEP CYCLING 70AH LEISURE BATTEERY

ELECSOL 70AH, 300a CCA.

I have a Sonnenschein from the caravan and an Optima which I use for jump starting , blowing tyres up etc.

I will have a go at fitting them to my RX to see if I can 'shoe horn' one of them in..... At present I have a damaged hand so this may take some time.

I have also ordered (so I am told) the best Battery Charger/Conditioner availabe at present, the Accumate 6/12v Battery Conditioner/Charger.. This should arrive next week, now that the hols are almost over.

Watch this space and I'll pass on as much info as I can get.... In the meantime , keep those sun visors closed, remove the key, disconnect any Bluetooth phone equipment ... also let us all know if anyone cracks this one.. I do not think however we will get much technical help from the main Lexus Dealers... If I cannot improve the problem before Easter, I feel it will be Good Bye Lexus and hello to a BMW 4x4.

PS Google in the above products and let us know what you think?

Hi Roy

I am back to revisit this problem!!!

I just wondered how you got on with trying to fit one of your deep cycle leisure type batteries?

I think mine is on the way out, so I need to start looking for a replacement!

Cheers

Billy in N. Yorks.

[rynd2it]

Hi,

Just to add that the Battery problem exists here in the US as well in a warm & sunny climate. I have an RX400h (2008) and my brother has the (mechanically identical) Toyota Highlander. Unattended Battery life is 3 weeks maxiumum - leave the key in the ignition and its one hour, leave a door cracked open and overnight a dead Battery. Part of the problem is that many electrical components are "live" and actually functioning when the vehicle is switched off ) only a Battery disconnect solves it and then you have to reprogra, everything: It's a royal pain.

However looks like you guys may have come up with a couple of partial solutions (70ah deep cycle and/or portable jump start)which is an option when I ,ove to France

Cheers

David