12 volt battery

[iainmangle]

Thanks but the car won't respond to either remote until I hook it up to charger. The alarm then sounds and the remote switches that off quite happily. The AA tech condemned the Battery on the second visit and I take his opinion over Lexus' who can't even be bothered to see it for four weeks, rendering me, effectively, car-less. Fro what I am reading the problem is not unique to my vehicle but Lexus have taken no action to rectify an obvious defect. 

[Herbie]

18 minutes ago, iainmangle said:

I very much doubt this particular LBX will even open in winter, in order to turn on the heated rear window 🙂 Woke up this morning, after jumping and running it twice yesterday, to my alarm going off (only just audible so not too impressive)). Tried to turn off with the remote but of course no response. Tried to get in the car and yet again could not! I now leave the tacky piece of trim from the door handle in the car as I always need to use the blade key to open the door. On trickle charge for the second time in a week, so that is 2 x AA call-outs; 2 x self jumpstarts; and 2 x trickle charge, all in the space of six weeks or so on a six months old £40k car. Not what I would have expected, but then neither is the disinterest of the dealer who couldn't look at the battery (big job obviously) for four weeks, two still to go. Buy a Lexus at your peril - first and last for me. 

Each time the Battery goes flat it sustains some damage and loses some capacity, so it reduces what is already a small Battery even further.

Just as an example so these figures won't be correct but we'll say that it's 100% charged. If/when it goes flat it'll be slightly damaged so it won't accept any more than 95%, even though the charger will think it's 100%. If it happens again, next time it may drop to 90% and so on until it finally dies.

It sounds very much like your AA man is correct and the Battery is fubar. If it was me, I'd put it on a proper Battery charger for an overnight charge, maybe even a full 24-hour charge. Then you need to have it load tested, preferrably with a proper drop tester something like this one. The modern electronic ones look at various parameters and show a reading that it thinks it should be. They're alright but there's no substitute for a proper drop test using a proper load.

[Lbeex]

Even if a dead Battery is replaced for a new one, the problem will probably reoccur, unless the old suffered due to improper treatment during shipment to and at the dealer site?

BTW: my LBX Battery failed on Friday, then I used a jump starter, then drove 1 hour, and  another 1 hour on Saturday, and today (Sunday) I measured voltage at this red terminal in the fuse box (not in ready mode). It showed 11.98V

[Lbeex]

Assuming that Lexus/Toyota engineers are smart anyway, I suspect that they sacrifice 12V Battery life at cost of running out traction Battery, since otherwise this would be really big issue in comparison to easy to recover 12V charge using a jump starter, particularly because this is users who pay for these boosters. Keeping your car at READY to charge 12V Battery result typically in starting piston engine and thus emitting fumes – not an ecological approach, and often not permitted in many countries  to run engine while car is stopped, due to pollution. I

I asked GPT chat why producers prefer not to use proven solutions like alternators. Here is the answer( Note below  the DC-DC converter issue mentioned due to high voltage configuration :  “…manage power transfer between the high-voltage and 12V batteries…):

You're right—while manufacturers design hybrid systems with efficiency and integration in mind, users often have different experiences and preferences. Many owners might find that traditional setups, like using an alternator, could seem more straightforward or reliable based on their familiarity with conventional vehicles.

Here are some reasons why users might prefer a system with an alternator:

•     Simplicity: An alternator system is familiar and straightforward. Many users understand how it works and can easily diagnose issues related to it.
  

•     Reliability: Alternators have a long track record of reliability in conventional vehicles, which can lead to user trust. If a hybrid's 12V Battery has issues, some may wish they could rely on a simple alternator instead.
  

•     Ease of Replacement: Alternators can be easier to replace or service in many cases, as they're a common part that most mechanics are familiar with.
  

•     Direct Charging: Users may prefer the idea of direct charging from the engine rather than relying on a secondary system to manage power transfer between the high-voltage and 12V batteries.
  

•     User Control: With an alternator, users often feel they have more control over Battery maintenance and care, compared to the more complex management systems in hybrids.
  

These perspectives highlight a gap between manufacturer designs aimed at efficiency and user preferences for simplicity and reliability. As hybrid technology evolves, manufacturers may consider incorporating more traditional elements that resonate better with users, while still maintaining efficiency.

[Herbie]

The only reason that hybrids don't have alternators is that an alternator is driven by a belt attached to the petrol engine.

As we know, in a hybrid the petrol engine doesn't run all the time so an alternator would be as much use as a chocolate fireguard. Same with other things like the aircon compressor and the power steering pump. Imagine being halfway through a hard turn and the hybrid system decided to turn off the petrol engine, resulting in sudden and unexpected loss of steering assistance.

[iainmangle]

You are 100% correct. Lexus and everybody else needs to work out how to fill the void left by a competent 12v Battery and its means of remaining functional. They sp/out on about their advanced technologies whilst leaving basic engineering in their dust.

[ColinBarber]

18 hours ago, Lbeex said:

BTW: my LBX battery failed on Friday, then I used a jump starter, then drove 1 hour, and  another 1 hour on Saturday, and today (Sunday) I measured voltage at this red terminal in the fuse box (not in ready mode). It showed 11.98V

If your Battery was completely flat then a couple of hours isn't enough to fully charge it - you would want to put it on a Battery charger for 8 hours @ 5 amps.

[iainmangle]

I took the advice of two different AA techs who both stated that the hybrid Battery would charge the 12v in 20 minutes, simply by running. When I eventually tried mains charging it was left on trickle for 25 hours. It might just be a rogue Battery but it might equally be a design flaw - time will tell, as I'm pretty sure Lexus won't say it's design. 

[Lexusjim]

Iian 

From my experience with my own car I can say that the advice you received would not apply in my case. I have a Battery monitor fitted and it takes about half an hour with the car in park and in ready mode to charge from 50% to 100%

The monitor (other makes are available) takes all the guesswork of charging/ checking,  and are not expensive 

https://www.ancel.com/products/ancel-bm200

[Herbie]

1 hour ago, iainmangle said:

who both stated that the hybrid battery would charge the 12v in 20 minutes, simply by running. When I eventually tried mains charging it was left on trickle for 25 hours.

Unfortunately that was probably just wasted time and did nothing for the Battery, because that's not how you use a trickle charger.

If the Battery was as flat as it sounds then it needed to be put on a proper charger capable of supplying about 5A or more, for an overnight charge at the very least. Personally I'd probably give it a full 24-hour charge. When initially connected the charger will squirt out 5A but as the Battery gets more and more charged, the output of the charger will regulate itself down to about 1.0A or whatever. Big punch of power at the beginning of the process, dropping very low at the end.

The maximum output of a trickle charger is somewhere around 1.5A and the idea is that once the Battery is fully charged (using a proper charger) you then connect the trickle charger and leave it connected 24/7 until you need to use the car again. Although the output of a trickle charger is very low, it's higher than what would be leaving the Battery so the net result is that the Battery doesn't lose charge.

[iainmangle]

That's helpful, thank you. Shame that it took nearly 40 years of driving, with all the technological "advances" along the way to suddenly need something like this 😞 . Thanks for the link - cheaper than amazon! Cheers.

[Lbeex]

36 minutes ago, Herbie said:

Big punch of power at the beginning of the process, dropping very low at the end.

Right, and I noticed also that AGM bateries (LBX case) actually need a charger that is designed to charge at 14.7 V in AGM mode. Sometimes standard chargers have so called winter mode in which the output voltage is increased and can be used for AGM charging.

[Lbeex]

Today, my Lexus dealer replaced LBX 12V Battery. The charged it to 100% and got around 11.9 V which is far too low. So it was defective. It is the same voltage as I measured after 2 hour driving.

Anyway, I asked if except jump-starter connected to the fuse box red terminal as described in LBX manual I can alternatively use a charger in place as a preventive measure?

Surprisingly they said no, because this is dedicated only for jump starting (as LBX manual says), and a charger needs to be connected to 12V terminal directly. Noticed that the cars inside a dealer premises exposition are all connected to chargers and in case of LBX the cable runs under the rear seat to the Battery compartment.

OK but still I do not understand then why Lexus did not provide a socked on the 12V Battery cover under rear seat to connect to it easily? I think they suggest to use jump starter as a simplest way, but then why do not they give it for free to each buyer.

Also, the dealer service had no objection to install (not for free) a 12V Battery monitor. Again,  which also should be installed as a standard in out cars. There is not way to display actual voltage in LBX menu nor in Lexus Link+ application!

The manual states there could be low 12V Battery  warning displayed, but it does not always prevents from discharging and start problem.

 

 

 

Now, except that I am aware of ways to prevent discharging, and also ordered the Battery monitor mentioned above, which draws 2.5mA which is ok. I am going to verify the current consumption and let you know.

[iainmangle]

That is interesting, especially tat Lexus conceded and changed your Battery. I would expect them to do the same with mine but I suspect they will simply charge, as I have already, and say it is fine. I have never received anything via the info system or dash to say that charge is low - it just drops to the point where the doors won't open etc. Difficult to comprehend how this discussion is even necessary in 2024 with all the supposed technology available to Lexus and they cannot even supply a Battery which is fit for purpose. 

[Don C]

On 10/16/2024 at 3:28 PM, iainmangle said:

With respect, those manufacturing and selling the vehicles suggest they will suit ALL users, whether short commutes or long distance. An owner's "ignorance" (your dismissive term) is not an excuse for poor design and specification. I certainly don't recall being quizzed by the Lexus salesman on my driving habits when discussing the merits of an LBX. And in the last 30 minutes an AA technician has tested my battery, concluding it failed! 

To be fair, the Lexus sales people are new to LBX and it’s only that model that is turning out to be vulnerable.  The Toyota guys know all about it because the Yaris/Yaris Cross are known for it.   The calculations show the Battery should be correct but in practice it’s borderline.  You can change the Battery for a larger capacity one which I’ve done successfully, several times on the Yaris equivalent but it’ll usually be at your own expense.   I know that won’t sit well on a new car but by the time you’ve been back and to the dealer, you’ll wish you’d done it in the first place.  

[Don C]

20 hours ago, Lbeex said:

Right, and I noticed also that AGM bateries (LBX case) actually need a charger that is designed to charge at 14.7 V in AGM mode. Sometimes standard chargers have so called winter mode in which the output voltage is increased and can be used for AGM charging.

It isn’t an AGM Battery, it’s a conventional lead acid.  

10 hours ago, Lbeex said:

Today, my Lexus dealer replaced LBX 12V battery. The charged it to 100% and got around 11.9 V which is far too low. So it was defective. It is the same voltage as I measured after 2 hour driving.

Anyway, I asked if except jump-starter connected to the fuse box red terminal as described in LBX manual I can alternatively use a charger in place as a preventive measure?

Surprisingly they said no, because this is dedicated only for jump starting (as LBX manual says), and a charger needs to be connected to 12V terminal directly. Noticed that the cars inside a dealer premises exposition are all connected to chargers and in case of LBX the cable runs under the rear seat to the battery compartment.

OK but still I do not understand then why Lexus did not provide a socked on the 12V battery cover under rear seat to connect to it easily? I think they suggest to use jump starter as a simplest way, but then why do not they give it for free to each buyer.

Also, the dealer service had no objection to install (not for free) a 12V battery monitor. Again,  which also should be installed as a standard in out cars. There is not way to display actual voltage in LBX menu nor in Lexus Link+ application!

The manual states there could be low 12V battery  warning displayed, but it does not always prevents from discharging and start problem.

 

 

 

Now, except that I am aware of ways to prevent discharging, and also ordered the battery monitor mentioned above, which draws 2.5mA which is ok. I am going to verify the current consumption and let you know.

I can assure you that you can charge the Battery from the jump start terminal.  I don’t know why they would say otherwise other than a lack of understanding on their part.  It’s just an extension wire from the Battery.  I leave mine on a smart charger while I’m away and I can monitor the charge rate via the smart plug from another country.  

[stepppy]

26 minutes ago, Don C said:

It isn’t an AGM battery, it’s a conventional lead acid.  

I can assure you that you can charge the battery from the jump start terminal.  I don’t know why they would say otherwise other than a lack of understanding on their part.  It’s just an extension wire from the battery.  I leave mine on a smart charger while I’m away and I can monitor the charge rate via the smart plug from another country.  

Same here, I use the jump terminal on my NX to connect my smart charger when I go away on holiday and have had no issues. 

[iainmangle]

1 hour ago, Don C said:

To be fair, the Lexus sales people are new to LBX and it’s only that model that is turning out to be vulnerable.  The Toyota guys know all about it because the Yaris/Yaris Cross are known for it.   The calculations show the battery should be correct but in practice it’s borderline.  You can change the battery for a larger capacity one which I’ve done successfully, several times on the Yaris equivalent but it’ll usually be at your own expense.   I know that won’t sit well on a new car but by the time you’ve been back and to the dealer, you’ll wish you’d done it in the first place.  

You may be right about upgrading but that shouldn't be necessary on a six months old car. The LBX is basically a Yaris in a posh frock so I wouldn't be too inclined to assume the Lexus people are innocent 🙂

[GMB]

I remember the old motorbikes with just a Magneto. No Battery needed therefore no problems.

I find it ridiculous all this complexity with batteries and the like when there is really no need for it. Just put a decent Battery in the damn thing Lexus. Surely that is not too difficult for them?

[iainmangle]

It's called technological innovation, apparently 🙂

[RONNIE W HODGEKINSON]

On 8/16/2024 at 8:33 PM, Alan Salisbury said:

Hi, I collect my new LBX on 2 Sept but am getting concerned at all the negative comments about the problems with 12v batteries especially on the Toyota Yaris Cross.  Owners are saying that they ‘hope’ their new Yaris will have a 45 a/h battery rather than the 35 fitted to earlier models.  So far I have been unable to find a detailed-enough spec to show the battery size that my new car will come with.

I know this sounds ‘nerdy’ but I am a low mileage user on top of which I will soon be ‘hors de combat’ for a while after an op and will have to put the battery on a trickle charger.

I would be grateful if any LBX owners out there know the capacity of their 12v battery and if there have been any problems. I am swapping my Audi Q3 for this LBX - I just hope I’ve made the right decision!

Many thanks for your patience in reading this. 

Alan.. The Great Majority of LBX Car Owners I'm Sure don't Experience any issues With The Battery...Settle Down, Keep Calm And Enjoy Your Amazing car...!!!! It did'nt get What Car Of The Year Award For Nothing....Stop Worrying..!!!

[Don C]

47 minutes ago, iainmangle said:

You may be right about upgrading but that shouldn't be necessary on a six months old car. The LBX is basically a Yaris in a posh frock so I wouldn't be too inclined to assume the Lexus people are innocent 🙂

Well you can err towards caution and shoot first if you want to and that might be the case if it’s a joint dealership.  The point is, you can cure the problem “mostly” by changing to a higher capacity Battery.  Keep in mind, we are not on conventional systems with any full hybrid car these days so forget what used to happen.  The 12v Battery on a conventional vehicle is capable of cranking an engine for several minutes and therefore has acres of capacity to power ancillary circuits.  A hybrid Battery has had all the cranking capacity omitted and has only the reserve by design.  It doesn’t have a starter, it starts the engine with a traction motor.  You can go on about how it should be and how Lexus should handle it but it isn’t going to change things.  If you go down the official route, they’ll want it in to test and, and….   It makes no odds to me, I have a smart charger and carry a jump pack but that doesn’t suite everybody especially if they’re not mechanically minded.  It’s not a Toyota/Lexus thing, it’s a hybrid thing and the shape of things to come.  

[Fredcl]

11 minutes ago, RONNIE W HODGEKINSON said:

Alan.. The Great Majority of LBX Car Owners I'm Sure don't Experience any issues With The battery...Settle Down, Keep Calm And Enjoy Your Amazing car...!!!! It did'nt get What Car Of The Year Award For Nothing....Stop Worrying..!!!

I agree it's an amazing car. And hope the majority of the LBX owners has no problem with the battery-setup. So indeed, no worries if you do not experience problems and no need to take any specific precautions. 

Nevertheless do I consider myself as an average customer with normal expectation from my LBX. We did nothing special and still encountered that the Battery was flat. The Battery was checked by the dealer and passed their testing. I do think it's a weak spot in the design of the LBX Battery setup.

(Btw I learned from a local Toyota dealer that the Toyota Yaris Cross (which has a similar/equal hybrid setup) had similar problems untill Toyota released a software fix and used a new Battery type. I don't know if this is different form the current LBX Battery setup.)

[Heuer]

[Lbeex]

I can tolerate vulnerability of the system due to 12V Battery, and I think that could be counterbalanced by a users' know how, but Lexus is not supporting us at all. Why there is no way to check remotely the 12V Battery actual voltage. If it is available, it could help us to anticipate no start/ locked door situation when it is required to use manual key and jump starting.

I bought simple monitor (mentioned earlier) for that purpose. Today I measured its current draw and it is as stated - 0.0025 A. Chinese one, ok but …I would prefer Lexus one.

Apart from that it's a great car.

Winter time will tell more...and I hope no dismal news.