Flat battery

[Kevin F]

I've given myself a bit of a problem. On Saturday I was finishing installing some cables to a front and rear dash cam, while I was doing this I was entertaining myself by listening to some CD's so I had the car in AUX mode on the start button. I was working on the car for around 25 mins, then locked up and went inside the house, subsequently after a brew I came back out for another 20 mins, same again, AUX / CD on, then back inside and then I came out a third time for about 5-10 minutes, AUX / CD on again. The last time I was positioning an extender for the power outlet, I was looking to position on the tunnel on the passengers side, but was not happy with it so ended up leaving it by the cup holders in the centre console and going back inside for a rethink on positioning.

I was at the back of the house for probably about 1.5 hrs when Mrs F pipes up and says there is a car alarm sounding at the front, sure enough its the lexus so I rush out and open the car with the fob and manage to get the alarm to switch off. I'm not sure why the alarm came on, suspect it may have been the cables and box settling into the drinks holders on the centre console. At this stage I tried to start the car but the dash would not even boot up, it was clicking and whirring under the bonnet and I ended up having to lock it with the mechanical key and because it was dark by then I went inside with Battery removal planned in for Sunday morning.

The extender for the power has a voltage display on it, last Saturday I plugged it in and it displayed 12.2 V, it displayed the same reading when I plugged it in on Saturday as well.

I charged my golf trolley Battery and was going to try to jump it with that but could not find my jump leads so I ended up clambering into the back and removing the Battery to charge it.

I connected my Optimate charger which I use for my motorbike and it ran through its checks and started charging the Battery, it only completed the charge after nearly 48 hrs (which was the maximum time the instructions say the battery should be left charging for), it was showing OK on the display on the charger, it tells you if its in good, fair or poor condition and it came up good.

The voltage after charging was 12.6V. I connected the Battery this afternoon. I tried to start the car and it came up with 'Check the hybrid system' and the warning triangle was solid. I did a bit or research and tried the various options to force the system to start, tried it with the keyfob adjacent to the start button, but no bleep came although I could see the LED flashing on the fob.

I did connect my code reader to the socket under the steering wheel and its not showing any fault codes.

I checked the Battery voltage with the start button pressed once (AUX) and the voltage went down to 12.4 is (measuring directly on the Battery with my multimeter), I then pushed the button again and with the lights on as well, voltage went down to 12.2.

My thoughts are as follows ;-

I've flattened the Battery with my 3 trips out to the car and using the aux position to use the CD.

The Battery voltage seems low to me even though the optimate gave the battery a clean bill of health (My trolley battery which I have not used for 18 months is still showing 13.1 volts after charging it on Saturday night).

I can't imagine the hybrid system is faulty but I've seen comments that low Battery voltage gives spurious faults. The Battery is not OEM, its an Exide wet Battery so I think I will change to the correct one anyway. 

Anyone any experience of this or can shed any light?

best regards

Kev

 

[royoftherovers]

Just you wait until Professor Herbie read this Kev.

Do you write books for a hobby?

Where abouts in Chester are you ?

[Herbie]

36 minutes ago, royoftherovers said:

Just you wait until Professor Herbie read this Kev.

Just a quick reply because our tea is nearly ready 😊

The fact that it took so long to charge may be an indication that the 12V Battery has a faulty cell or two. It may show the voltage as being alright but when put under load it just collapses and can't supply the current as it should.

What happens if you monitor the voltage as you attempt to get the car into READY mode Kev? I would hazard a guess that it would drop quite noticably.

Having said that, a conventional starter motor will pull more than 300A from the Battery when cranking the engine, but our hybrids draw less than 20A so the volt drop may not be as dramatic.

You really need to get jump leads on or use a jump start Battery pack and see if it boots into READY mode then. If it does then it's new Battery time.

If you ever do anything like this again, make sure the car is in READY mode so that the petrol engine will fire up as and when necessary to keep that 12V Battery charged up.

EDIT: Just FYI:

[ColinBarber]

2 hours ago, Kevin F said:

I've flattened the battery with my 3 trips out to the car and using the aux position to use the CD.

Yes I'd say that is correct and the alarm went off because it detected the Battery voltage to have dropped below a certain threshold which it interprets as the Battery being disconnected in an attempt to disable the alarm.

What code reader did you use? Sounds like it isn't able to display non-engine or vendor specific codes.

[Guest]

Hello Kevin, I had similar problems to yourself a few weeks back and as Colin and Herbie suggest jump start it and it should go back to 'Ready'. When my Battery was flat it put up hybrid system fault etc.

Once mine was running again I attempted to use the car to keep the Battery topped up but it let me down again soon after, so I purchased a new Battery from Lexus and touch wood it's been fine since. It does seem that if the Battery is weak it will soon flatten - I spent an afternoon cleaning the car with doors open and keys in my pocket, so the car was 'awake' as it were and this was enough to flatten the old Battery.

Hope you got it sorted!

Neal

[Barry14UK]

Perhaps there is a difference in the way the 12v Battery is protected on my RX450h but if left in Aux mode for 20 minutes, while I listen to the radio, it cuts it off. I suppose it's good that it protects the Battery and surprised OP's car does not work in this way but a little annoying that you have to reset. to continuing listening.

[Poundy]

1 hour ago, Barry14UK said:

Perhaps there is a difference in the way the 12v battery is protected on my RX450h but if left in Aux mode for 20 minutes, while I listen to the radio, it cuts it off. I suppose it's good that it protects the battery and surprised OP's car does not work in this way but a little annoying that you have to reset. to continuing listening.

My Ct200h has the same feature shuts down after a time if parked up.

The problem with the small auxiliary Battery is it only  powers up the initial screen to get the hybrid system working.  The Battery supplied is therefore rather lacking in any decent power reserves. I changed mine soon after purchasing the car because regular checks showed voltage in the low 12's even though it never failed me.

The new Lexus Battery fitted, still performs much the same as the old one, if the car is unused for a couple of weeks I just hook up my C-Tek via  a comfort lead in the boot area for the day.

[Kevin F]

On 11/17/2020 at 7:24 PM, royoftherovers said:

Just you wait until Professor Herbie read this Kev.

Do you write books for a hobby?

Where abouts in Chester are you ?

Haha!! No I don't but thought I would give as much info as possible 🙂 I'm in Hoole 

[royoftherovers]

14 minutes ago, Kevin F said:

Haha!! No I don't but thought I would give as much info as possible 🙂 I'm in Hoole 

Herbie has pronounced. 

I can`t ask you to sign a first edition then.

I`m on Wirral and use Lexus Cheshire Oaks.

[Kevin F]

On 11/17/2020 at 10:11 PM, ColinBarber said:

Yes I'd say that is correct and the alarm went off because it detected the battery voltage to have dropped below a certain threshold which it interprets as the battery being disconnected in an attempt to disable the alarm.

What code reader did you use? Sounds like it isn't able to display non-engine or vendor specific codes.

It's an Autophix OM123, bought it for my previous car, a Honda accord. I seem to remember it brought a menu up for me to select the vehicle when I connected to the Honda. I don't get that menu but it does let me in and I get 2 options '$7EA' and '$7E8  Engine', I don't get any 'stored codes' or 'pending codes' for either.  Having a look through the forum it seems the techsteam is the route to go to cover any hybrid system issues as a generic reader won't read any vendor specific codes so I will explore purchase of a mini VCI etc. 

[Kevin F]

23 hours ago, Poundy said:

My Ct200h has the same feature shuts down after a time if parked up.

The problem with the small auxiliary battery is it only  powers up the initial screen to get the hybrid system working.  The battery supplied is therefore rather lacking in any decent power reserves. I changed mine soon after purchasing the car because regular checks showed voltage in the low 12's even though it never failed me.

The new Lexus battery fitted, still performs much the same as the old one, if the car is unused for a couple of weeks I just hook up my C-Tek via  a comfort lead in the boot area for the day.

Barry / Poundy, yes there is a fail safe shutdown on my car also, sadly my 2 coffee breaks managed to fool it 🙂

[Kevin F]

On 11/17/2020 at 7:09 PM, Kevin F said:

I can't imagine the hybrid system is faulty but I've seen comments that low battery voltage gives spurious faults. The battery is not OEM, its an Exide wet battery so I think I will change to the correct one anyway. 

OK Folks, bit of an update. I ordered a replacement OEM Battery which I fitted Saturday. Tried the start up sequence per page 499 when reconnecting a Battery. The 'ready' light did not come on and the message Check Hybrid System and the yellow triangle. The immobiliser light is clear, it's displaying 'P' mode. I've tried the emergency hybrid start function but that did not work, I found a couple of other methods mentioned on forums(eg unlock car with fob, operate mechanical lock 3 times then press start, all to no avail. I've tried my OBD2 reader, it does let me in and I get 2 options '$7EA' and '$7E8  Engine', I don't get any 'stored codes' or 'pending codes' for either but as mentioned in the forums I won't get any data bespoke to Lexus ie Hybrid system and it seems Techstream is the route for further analysis. I've ordered a cable and software from an outfit in Manchester and its due to be delivered tomorrow so I will hopefully load on my laptop and have a look on Tuesday.

Save giving it a 'Basil Fawlty' I will wait until I've got the cable and software an see what I find. I suspect my flailing about shutting the alarm off and trying to start it numerous times may have left a fault code. Oh, thankfully the drive Battery is still fully charged. Will update you next week, cheers Kev

 

[Kevin F]

On 11/22/2020 at 3:02 PM, Kevin F said:

Save giving it a 'Basil Fawlty' I will wait until I've got the cable and software an see what I find. I suspect my flailing about shutting the alarm off and trying to start it numerous times may have left a fault code. Oh, thankfully the drive battery is still fully charged. Will update you next week, cheers Kev

 

Problem solved.

I connected the laptop with the techstream software and found code P0A0D in the hybrid ECU, googled and found the code relates to a safety device being operated. When I found one of those devices was the emergency Battery pack disconnect in the 'boot' well I went out to take a look and found that it was not locked, it only moved about 3-4 mm but obviously that was enough for the pins on the interlock not to make. Connected the laptop and cleared the code, hey presto all OK.

What I think I did was catch the switch with the tray that sits in the boot,I had to lift it up to get my hand down into the well to pick up the screwed bar for the Battery strap and the back lip of the tray must have just caught it.

Cheers Kev

[Herbie]

Well done Kev, good result.