Battery problem

[kevinc23]

Is there a way we could all sign a group email or letter and pressure Lexus into changing the batteries asap?

[ColinBarber]

1 hour ago, kevinc23 said:

Is there a way we could all sign a group email or letter and pressure Lexus into changing the batteries asap?

I'm not sure there is physical space for anything meaningfully larger in capacity that could fit.

[Expatma]

I test drove an LBX in June, one short and one long (2hr) drive. Loved the car but my wife found the passenger seat uncomfortable so in the end decided not to buy. Eventually bought a new Mini Countryman instead for less than the price of the LBX but comfortable seats and a more comfortable drive. Often thought about the LBX but reading the problems people are having with the 12V batteries of many small hybrids I am glad I passed on the LBX. This was brought home to me by a neighbour who bought an LBX in the summer complaining that he has to keep trickle charging the Battery or else he can’t start the car. He freely admits he only uses the car for short journeys and not every day but thought a hybrid would be ideal for that use with minimal running costs. Advice he got from Lexus dealer and AA was to make sure he did a longish drive weekly to keep the Battery in good condition OR use a trickle charger. He is a bit upset because inn his late 70’s he could do without this hassle and thought he was buying a car suitable for his needs. I got the impression he would be swapping his LBX for something else as soon as his wife lets him!

[Briar]

The 12v Battery can be maintained by leaving the car in Ready Mode for an hour each week.  It doesn't have to be driven.  The hybrid Battery will then charge the  12v Battery.  If this causes the hybrid Battery to get low the ICE will start in order to charge the hybrid Battery.  In one hour of Ready Mode the engine will start two or three times and run for about three minutes each time.  I usually leave my car in Ready Mode when I am giving it a wash.  On other occasions when I leave it in Ready Mode I lock the drivers door mechanically with the key for security.  I have a Corolla so I don't know if the LBX has a mechanical lock.

[NemesisUK]

Turning the climate control off when leaving the car in Ready mode will reduce the number of times the ICE kicks in as it won't need to heat the cabin

[Briar]

Further to my previous post; I should have said turn off the climate control and radio when in Ready Mode.  In addition I have permanently turned off the interior lights to reduce the drain on the Battery.

[Pauly C]

As others have alluded to...what's with this thing about making current/future motoring much more complicated that it needs to be?  It's ridiculous, reading through all these little tips /hints/tricks people have kindly provided, just to try and ensure we can all drive our cars without thinking too hard, or worrying about it.  It shouldn't be like this....manufacturers take note....people just want to get in their cars and drive...so sort it out🤔

[Iain24]

Tel comments that testing a VW Battery for comparison (in the video above) is odd as it is not for a hybrid car, but I think the point is that all three batteries are similar in format so each could fit in an LBX - so the test suggests Lexus could fit a better Battery despite the design limitations on Battery size.

Shufman reports that Lexus are indeed now providing better batteries but not clear if it refers to all LBX, only new buys, or only ones where the Battery fails. I haven’t seen any official info on this - anyone aware?

[Tel]

I hope we all get better Batteries before Winter sets-in & Issues rocket.

Tel

[Emjay2]

I’m new to this forum and posting in general so bear with me if I get anything wrong. I’ve recently bought a LBX and suffered the same issues as many posters here. I’m still carrying out monitoring activities on my LBX Battery and will report my observations in due course. Going back to this video, I watched this a number of times and this is my take on it. The guy is using the Battery analyser to carry out a test on the Cold Cranking performance of the batteries and as some people have pointed out is not relevant to its use in a hybrid vehicle. What is interesting though is the other information displayed on the meter namely the Battery voltage. 
The VW Varta Battery shows a voltage at the start of the test of 12.83v which on the SOC vs Batt volts curve I’m using equates to about 95% charged. He then puts a on a load of about 30A for 10 mins, lets it settle for ten mins then carries out the test again. The batt volts read 12.55v equivalent to about 73% charged, a loss of 23%.

For the Turkish Mutly the results are start volts 12.85v equivalent to 97% charged, finish volts 12.54v equivalent to 73% charged, a loss of 24%.

For the Yuasa LBX Battery the results are start volts 12.65 equivalent to 80% charged finish volts 12.32v equivalent to 56% charged, a loss of 24%.

I think there are a number of issues associated with this guy’s test :

The CCA test is not a relevant test for hybrid owners.

Despite his meter saying the LBX Battery is 100% charged I believe that unlike the other2 batteries, it’s only at 80% charge, he should have ensured all batteries were  fully charged before starting the test.

It would have been more helpful if he had waited a lot longer than the 10 mins after applying the load before carrying out the final test to allow the batteries to settle to their stable voltage.

My conclusion therefore is that all 3 batteries showed a similar loss in capacity after the test and so were performing in a similar manner. The 24% ish loss of capacity is probably less than that had the batteries been allow to settle back to a higher finishing voltage as the theoretical loss of 30A for 10mins is only about 5Ah.

I believe the real issue with the LBX Battery is it’s just not got the capacity to do the task it’s being asked to do, for any length of time, with all the electrical load being placed on it.

[ColinBarber]

28 minutes ago, Emjay2 said:

The VW Varta battery shows a voltage at the start of the test of 12.83v which on the SOC vs Batt volts curve I’m using equates to about 95% charged. He then puts a on a load of about 30A for 10 mins, lets it settle for ten mins then carries out the test again. The batt volts read 12.55v equivalent to about 73% charged, a loss of 23%.

For the Turkish Mutly the results are start volts 12.85v equivalent to 97% charged, finish volts 12.54v equivalent to 73% charged, a loss of 24%.

For the Yuasa LBX battery the results are start volts 12.65 equivalent to 80% charged finish volts 12.32v equivalent to 56% charged, a loss of 24%.

The Toyota and Lexus batteries are flooded, so 12.6 v is fully charged. Ideally he should have put the load on for 20 seconds on all three just to remove any plate surface charge before measuring the voltage to get a more accurate reading.

 

As you conclude, all three show a similar loss and differences are minimal (and your own Battery may perform slightly better or worse just because of manufacturing tolerances). Anyone thinking of 'upgrading' to the Varta Battery is going to be disappointed - there isn't a big enough difference to make any meaningful difference to how long your vehicle will last unattended.

[Heuer]

Having recently fitted the BM200 Battery monitor I took the car for a good run and then left it for 5 days. These are the reported results:

later:

I am not sure the State of Charge measure is correct for a hybrid, the voltage appears to be key. At no time has the voltage dipped below 12V and the LBX starts without problem. Car first registered March 2024 and now has 4,014 miles on the clock.

[Expatma]

The question I keep asking myself is why do hybrids like the LBX need a 12V Battery at all? Why not run everything off the hybrid-battery with step down transformers if necessary? That way no problems with ‘small’ 12V batteries running out of charge and ICE could cut in as necessary to keep hybrid Battery sufficiently charged for all ancillaries. Protective software would prevent hybrid-battery being depleted by ancillaries/long time storage etc. to the point it wouldn’t have sufficient power to start engine. Can’t think of a good reason why this wouldn’t work for both hybrids and pure EV’s - anyone any thoughts?

[ColinBarber]

1 hour ago, Expatma said:

The question I keep asking myself is why do hybrids like the LBX need a 12V battery at all? Why not run everything off the hybrid-battery with step down transformers if necessary?

The high voltage Battery is isolated when the vehicle is switched off for safety as the voltage is dangerous.

Having the DC/DC converter (a simple transformer cannot be used as that only works for AC supplies) capable of generating 120+ Amps needed when the car is being driven and efficiently being able to just supply 50 mA when the vehicle is asleep is difficult.

You really don't want the hybrid Battery to go flat - there is a whole industry around getting you going again if your 12 v Battery goes flat. If your traction Battery goes flat then it is a flatbed to Lexus to charge it up again.

[Heuer]

All hybrids and EV's use a 12V battery:

"It’s worth noting that the 12-volt batteries used for EVs have a lower output than those used to start combustion engines. When cranking a combustion engine, the Battery needs to provide a burst of power quickly—between 200 and 600 amps—while in an EV, the requirement is many times lower.

EVs use their DC-to-DC converter to step down the voltage to 12 volts to power all auxiliary systems without passing the current through the 12-volt Battery. The most important function served by the 12-volt Battery in these vehicles is to wake them up and keep some systems online while the vehicle is off. What the 12-volt Battery is used for and when it’s used varies from EV to EV.

When an electric vehicle is turned off, its traction Battery is disconnected from its electrical system using special contactors, which are electronically controlled switches. The 12-volt system also powers these in an EV, and the Battery needs to be disconnected to prevent power leakage through the system as well as to make EVs safer when parked by having its high-voltage system de-energized.

It therefore needs an additional power source for the electrical contactors that connect the traction Battery and turn on the EV. That’s where the 12-volt Battery comes in, and in this role, it performs a task similar to providing power for an ICE car’s electrical starter."

[Emjay2]

power all auxiliary systems without passing the current through the 12-volt Battery. 
 

Does this apply to the LBX  ie when in ready/ drive mode 12v systems are powered directly by the DC-DC converter without passing through the 12v Battery ?
 

 

[ColinBarber]

3 minutes ago, Emjay2 said:

Does this apply to the LBX  ie when in ready/ drive mode 12v systems are powered directly by the DC-DC converter without passing through the 12v battery ?

Yes. The DC-DC converter is supplying 14.4 v to power all low voltage systems and charging the 12 v Battery.

[Heuer]

The 12V Battery is a 100 year+ legacy from ICE cars and manufacturers are now adopting 48V systems for ancillaries as it means the cables can be thinner and lighter so big cost and weight savings. They will still need a 'starter' Battery though.

[Heuer]

Another measurement from the BM200. Put the LBX in the garage on Monday in anticipation of a cold and snowy few days. This morning I saw the lowest voltage reading so far:

Car started without problem so these batteries must be pretty resilient!

[Emjay2]

1 hour ago, ColinBarber said:

Yes. The DC-DC converter is supplying 14.4 v to power all low voltage systems and charging the 12 v battery.

Thanks for that Colin. (Looks like I might have managed to do a proper quote this time! 😂 )

[Lexusjim]

36 minutes ago, Heuer said:

Car started without problem so these batteries must be pretty resilient!

It shows that when a 12v fails to start a car, the SoC must be extremely low, and why when owners subsequently say they then 'drove for an hour to recharge the battery' it doesn't come close to doing so

[Heuer]

Not sure about that. I have left the LBX on the drive in 'ready' mode for an hour and it has taken the SoC from 21% to 98%.

[Lexusjim]

I'm glad you said that......using the data from my monitor,  I have concluded that my 12v charges twice as fast in ready mode/park as it would if I was driving....thought it was just a quirk of my car or perhaps my advancing age.....😱

[ColinBarber]

2 hours ago, Heuer said:

Car started without problem so these batteries must be pretty resilient!

Your voltages look a little suspect (the first one where it wasn't as high as 14.4 v when presumably it was in Ready mode) - possibly reading lower than reality so would be good to double check with a volt meter if you have one.

 

The fact that the vehicle started isn't really the problem in question. If 11.4 v is accurate then your Battery went down to 20% state of charge - that level of discharge has damaged it slightly (lead acid batteries don't like going below 50% SoC), so you now have less capacity. Keep repeating that and it will take a shorter and shorter time to drop to a voltage level where the vehicle won't be able to start.

[Heuer]

All measurements taken from outside the locked car. The SoC on the BM200 is a calculation based on voltage and Battery temp (the device is stuck to the top of the Battery with doubled sided tape) so not convinced it is accurate. I checked the voltage with a Fluke test meter and it corresponds with the BM200. 

Only downside to the device is it makes you slightly paranoid as I never worried before 😱