Dead 12v battery Incident
03-27-24, 02:52 AM
#16
I strongly suspect there are multiple factors at play (I used to get paid to do reliable system design 
, so speaking based on that experience)...
One is there is definitely defective batteries in brand new cars - such as in the experience by RBach below. And in my car, there wasn't evidently a defective battery. This is a problem that only Lexus/user can fix, by replacing the battery for those that have it. From Stefanos' experience, I suspect even he might have a defective one. Also "defective"/non-defective isn't exactly a binary categorization here, since we are talking about an analog signal coming of the battery (voltage) that leads to the problem. WellB's measurements showing the degradation, BUT him never actually having a dead battery, proves this point.
The other is parasitic drain, which is something we/users can try to mitigate - assuming the defective, shipping battery is not present in the car. While I'll not claim that stopping the Drive Pulse made a difference in my case, the not-so-cold temperature (say, relative to Canada or Northeast US) did surely make a difference, from the perspective of battery physics.
Another detail: When I had tried and failed to remote start after 12 days, I had also tried "Refreshing" the "Status" screen in the App - the "Tire Pressure" and The "Vehicle Information" one-line status dates didn't update from the day I had stopped using the car to begin with (the beginning of the 26 day period). In other words, this probably suggests it got into a deep-sleep state and did not transmit data in that state to the Lexus servers - probably reducing the parasitic drain. In normal usage, that status updates fine. Also, I don't have any after-market devices attached to the car.
I'll also add that the previous ICE car I owned (an Audi from 2014), I used to have a 4 mile commute to my work in that car for the most part - very short hops. The battery had died and had to be replaced by the dealer in 2-3 years for that too. So usage model of the battery definitely matters, as does temperature etc. - despite being a pure ICE and not having parasitic drains like a heavily computerized cars as the modern ones.
, so speaking based on that experience)...One is there is definitely defective batteries in brand new cars - such as in the experience by RBach below. And in my car, there wasn't evidently a defective battery. This is a problem that only Lexus/user can fix, by replacing the battery for those that have it. From Stefanos' experience, I suspect even he might have a defective one. Also "defective"/non-defective isn't exactly a binary categorization here, since we are talking about an analog signal coming of the battery (voltage) that leads to the problem. WellB's measurements showing the degradation, BUT him never actually having a dead battery, proves this point.
The other is parasitic drain, which is something we/users can try to mitigate - assuming the defective, shipping battery is not present in the car. While I'll not claim that stopping the Drive Pulse made a difference in my case, the not-so-cold temperature (say, relative to Canada or Northeast US) did surely make a difference, from the perspective of battery physics.
Another detail: When I had tried and failed to remote start after 12 days, I had also tried "Refreshing" the "Status" screen in the App - the "Tire Pressure" and The "Vehicle Information" one-line status dates didn't update from the day I had stopped using the car to begin with (the beginning of the 26 day period). In other words, this probably suggests it got into a deep-sleep state and did not transmit data in that state to the Lexus servers - probably reducing the parasitic drain. In normal usage, that status updates fine. Also, I don't have any after-market devices attached to the car.
I'll also add that the previous ICE car I owned (an Audi from 2014), I used to have a 4 mile commute to my work in that car for the most part - very short hops. The battery had died and had to be replaced by the dealer in 2-3 years for that too. So usage model of the battery definitely matters, as does temperature etc. - despite being a pure ICE and not having parasitic drains like a heavily computerized cars as the modern ones.
Last edited by asj2024; 03-27-24 at 02:56 AM.
03-28-24, 12:26 AM
#17
Driver School Candidate
Add my SO to the list of “dead battery syndrome” sufferers. After 5 days of non-use in our garage, she found the battery so dead that we shoulda dug a hole and buried it. When I returned from work, I put the booster charger to work and got the rear hatch to open. Found the battery and my meter showed 3.9 volts😱😱. Serious WTF moment. Attached my SO’s 45+ year old dumb charger directly to the battery for a good 5 hours. Once the 9a output dropped to less than 2a, I removed the charger and plugged the level 2 for the night. Next day the battery was 12.3 and within 2 days of non-use it was 11.8 Scheduled for service to check it out as the car is going in to body shop for 7-10 day repair. I gotta bad feeling that this battery won’t survive the body shop stay and some minimum wage worker is gonna jump start it and crispy critter something expensive.
Dealer replaced the battery and we have our RX back. Loaner was NX350h. Will work on the settings. I’m getting a better handle on understanding how the charging system works. One of them boosters is probably necessary to keep in the car, just not in the trunk. An external manual rear hatch release would have been nice, Lexus.
03-28-24, 04:15 AM
#18
Updating progress on diagnosing the parasitic draw on this new RX450h+ w/ the new deeper-discharge Lexus battery replacement:
Continuing to try to find things to turn "off" and "on". Latest is indeed the 'Connected Services' that Lexus offers - the ones you interact with on the Lexus app. Turned off yesterday, will let rest for 24h and test resting state of 12v battery.
Sitting still with car in "Ready" mode to talk with Lexus support and disconnect the services, the traction battery charges up the 12v to 12.61.
Also, for more info, answering these diagnositic questions from before:
What did they say the ma parasitic draw was?
[ sorry, I didn't think to ask to get that from the service technician; what I was told is after two hours of testing 'at rest', they couldn't find a parasitic draw with their volt meter connected to the 12v battery in series w/ the negative post ]
A full charged battery after 20 minute rest should read 12.7v. How many nights to attain that 11.76v reading?
[ two days essentially; from 12.6 usually down to 11.96 in first 24h cycle, then from 11.96 down to either 11.76v or even 11.43v sometimes next day ]
What kind of driving each day?
[ car is typically used every two to three days, full EV mode for about 20 ~ 30 miles, garage kept, insulated garage in Virginia, mild weather; not cold by any means; typical ambient temp 60 F ]
[[ note on full EV mode: when we drove back from dealer servicing (12v battery change), we drove 100 miles obviously using the ICE only. Running on ICE vs EV has no effect on what the 12v parasitic drain does. ]]
Are both keys far away from car at night
[ ahhh, great joke there my friend, assuming Lexus would provide two key fobs at delivery; only have one right now; have the key 100' + away from vehicle, inside a Faraday RF blocking pouch for anti-theft measure ]
and try disable the digital key in Lexus app as in background may try to communicate continuously
[ yes, working on that avenue now, to try something new/ different ]
Now my experience with my 2020 ES300h UL. Software updates fixed a lot of draw but still acts just like yours.
[ assuming nothing we are trying works, we will hand vehicle over to the Lexus dealer for a full week to have them go through everything, and hopefully update any software ]
Most people will not test battery voltage so don't really see the drainage each day. My car driving around 15 miles per day will see battery depleted more each morning down to as low as 11.76v but will still go in ready mode. Drive it and goes back to 12.2 after rest. Even long trips the charging system will never fully charge the battery like an alternator does probably to preserve the HV battery as that is what charges the Aux battery. Once /mth I put a trickle charger on to fully charge the battery but the way this system is designed probably don't have to. No one I have talked to fully understands the aux charging systems in the hybrid just it charges from the HV battery. So long as the parasitic draw is not too high and will give a 2 week ready mode it should be ok but that is also from a fully charged battery and not starting the 2 week point at 12.1v. There should be a switch to completely cut off the DCM module that is causing this excessive drain. A test here for you is to fully charge your battery and test voltage each morning.
[ yes agreed, some days we will let the traction battery with car in 'Ready' mode get up to 12.6v +, and then every day now we test the 12v battery four times a day; yes, fun . . . ]
[[ a switch to turn off the DCM module ? does anyone know where that would be ? ]]
[ Hoping not to have to go the trickle charger route, as I do with my 21 year old pickup truck; seems wrong on multiple levels, but if it has to be . . . ]
Continuing to try to find things to turn "off" and "on". Latest is indeed the 'Connected Services' that Lexus offers - the ones you interact with on the Lexus app. Turned off yesterday, will let rest for 24h and test resting state of 12v battery.
Sitting still with car in "Ready" mode to talk with Lexus support and disconnect the services, the traction battery charges up the 12v to 12.61.
Also, for more info, answering these diagnositic questions from before:
What did they say the ma parasitic draw was?
[ sorry, I didn't think to ask to get that from the service technician; what I was told is after two hours of testing 'at rest', they couldn't find a parasitic draw with their volt meter connected to the 12v battery in series w/ the negative post ]
A full charged battery after 20 minute rest should read 12.7v. How many nights to attain that 11.76v reading?
[ two days essentially; from 12.6 usually down to 11.96 in first 24h cycle, then from 11.96 down to either 11.76v or even 11.43v sometimes next day ]
What kind of driving each day?
[ car is typically used every two to three days, full EV mode for about 20 ~ 30 miles, garage kept, insulated garage in Virginia, mild weather; not cold by any means; typical ambient temp 60 F ]
[[ note on full EV mode: when we drove back from dealer servicing (12v battery change), we drove 100 miles obviously using the ICE only. Running on ICE vs EV has no effect on what the 12v parasitic drain does. ]]
Are both keys far away from car at night
[ ahhh, great joke there my friend, assuming Lexus would provide two key fobs at delivery; only have one right now; have the key 100' + away from vehicle, inside a Faraday RF blocking pouch for anti-theft measure ]
and try disable the digital key in Lexus app as in background may try to communicate continuously
[ yes, working on that avenue now, to try something new/ different ]
Now my experience with my 2020 ES300h UL. Software updates fixed a lot of draw but still acts just like yours.
[ assuming nothing we are trying works, we will hand vehicle over to the Lexus dealer for a full week to have them go through everything, and hopefully update any software ]
Most people will not test battery voltage so don't really see the drainage each day. My car driving around 15 miles per day will see battery depleted more each morning down to as low as 11.76v but will still go in ready mode. Drive it and goes back to 12.2 after rest. Even long trips the charging system will never fully charge the battery like an alternator does probably to preserve the HV battery as that is what charges the Aux battery. Once /mth I put a trickle charger on to fully charge the battery but the way this system is designed probably don't have to. No one I have talked to fully understands the aux charging systems in the hybrid just it charges from the HV battery. So long as the parasitic draw is not too high and will give a 2 week ready mode it should be ok but that is also from a fully charged battery and not starting the 2 week point at 12.1v. There should be a switch to completely cut off the DCM module that is causing this excessive drain. A test here for you is to fully charge your battery and test voltage each morning.
[ yes agreed, some days we will let the traction battery with car in 'Ready' mode get up to 12.6v +, and then every day now we test the 12v battery four times a day; yes, fun . . . ]
[[ a switch to turn off the DCM module ? does anyone know where that would be ? ]]
[ Hoping not to have to go the trickle charger route, as I do with my 21 year old pickup truck; seems wrong on multiple levels, but if it has to be . . . ]
04-07-24, 05:54 PM
#19
Intermediate
Now having posted about my dead-battery club membership in the general 5th RX forum (as it doesn't have to do with the hybrid drive-train, just the 12 battery) - I figured checking about the 12 V charging here specific to the 450H+ :
Is it now confirmed that the PHEV charging hours don't actually charge the 12 V battery ?
Is the 12 V battery then at least not discharged by parasitic drain with the traction battery charging ?
The parasitic drain causes is still quite a mystery under investigation - but I have now started to switch off my lone keyfob until the night temperatures are higher. I now have 2 consecutive nights of dead battery which I have tried to fix by driving around for more than an hour today.
Additionally, these are some of the reports from the NX450H+ members about members exploring AGM/Odyssey batteries. The Youtube video posted that the computer needs to be updated to "register" a new battery for its charging algorithms. I'm therefore wondering, for the PHEV, with even more complex electronics - is it best to get a dealer make the switch to an AGM battery - so that they take care of all these intricacies ? Being new to Lexus, I myself don't know an independent mechanic that I can trust with a 450H+ with regards to full knowledgebase of how to switch to an AGM.
Is it now confirmed that the PHEV charging hours don't actually charge the 12 V battery ?
Is the 12 V battery then at least not discharged by parasitic drain with the traction battery charging ?
The parasitic drain causes is still quite a mystery under investigation - but I have now started to switch off my lone keyfob until the night temperatures are higher. I now have 2 consecutive nights of dead battery which I have tried to fix by driving around for more than an hour today.
Additionally, these are some of the reports from the NX450H+ members about members exploring AGM/Odyssey batteries. The Youtube video posted that the computer needs to be updated to "register" a new battery for its charging algorithms. I'm therefore wondering, for the PHEV, with even more complex electronics - is it best to get a dealer make the switch to an AGM battery - so that they take care of all these intricacies ? Being new to Lexus, I myself don't know an independent mechanic that I can trust with a 450H+ with regards to full knowledgebase of how to switch to an AGM.
04-07-24, 07:43 PM
#20
The parasitic drain causes is still quite a mystery under investigation - but I have now started to switch off my lone keyfob until the night temperatures are higher. I now have 2 consecutive nights of dead battery which I have tried to fix by driving around for more than an hour today.
Granted, the car is in the garage so it might not actually hit that low inside there.
I have my Drive Pulse turned off, but have switched on the digital key again.
Also, I remember in my HEV Prius, there is no need to actually drive the car around to charge the 12V. I used to charge it by simply letting the Prius run in the driveway, as the hybrid battery will power up the 12V. I assume the PHEV will do the same.
04-07-24, 08:10 PM
#21
Intermediate
I am in FL right now and outside temps can hit all the way down to upper 50s F (13-15 C), and I have yet to see a dead 12V in my RX450h+
Also, I remember in my HEV Prius, there is no need to actually drive the car around to charge the 12V. I used to charge it by simply letting the Prius run in the driveway, as the hybrid battery will power up the 12V. I assume the PHEV will do the same.
Also, I remember in my HEV Prius, there is no need to actually drive the car around to charge the 12V. I used to charge it by simply letting the Prius run in the driveway, as the hybrid battery will power up the 12V. I assume the PHEV will do the same.
I did some measurements with my multimeter connected to the jumpstart-connection points of the battery in the hood today, and found that while keeping the car in "Ready" mode does provide charging voltages (13.5 V and above, I think I noticed) to the 12 V battery - I can confirm that charging the PHEV with a Level 2 charger does NOT actually charge the 12 V battery. In fact, switching on the Level 2 charging switched the car off from Ready mode that I kept it in, and thereby essentially force-switched off the 12 V charging - and the 12 V battery voltage dropped to 12.4-12.5 volts. This 12.4 - 12.5 V was still higher than the fully switched off car's voltage (i.e. powered off, locked and non-level2-charging state) of the 12 V battery that was at about 12.1-12.2 volts at 15 C when I checked today. This last fact suggests that the 12 V battery is "floated" and may not be susceptible to parasitic drain with the Level 2 charger connected - so I plan to Level 2 charge at 6 Amps tonight to prevent encountering another successive night of 12 V battery death.
The other annoying thing I noticed when dead battery happens and after I jump start is: The "panic" mode sets with flashers and horn until I hit the panic button of the keyfob. And the settings of the PHEV charger, such as my set max current setting of 16 A and off state of Auto lock/unlock of the charger are lost - although the seat settings are retained and many other settings are also retained.
04-07-24, 08:56 PM
#22
My experience suggests that it needs single digit temperatures (4 C in my case) for the problem to show up. So definitely a problem even in California winters.
I did some measurements with my multimeter connected to the jumpstart-connection points of the battery in the hood today, and found that while keeping the car in "Ready" mode does provide charging voltages (13.5 V and above, I think I noticed) to the 12 V battery - I can confirm that charging the PHEV with a Level 2 charger does NOT actually charge the 12 V battery..
I did some measurements with my multimeter connected to the jumpstart-connection points of the battery in the hood today, and found that while keeping the car in "Ready" mode does provide charging voltages (13.5 V and above, I think I noticed) to the 12 V battery - I can confirm that charging the PHEV with a Level 2 charger does NOT actually charge the 12 V battery..
As to charging with the hybrid battery...yes, my point was that you don't need to take the trouble of actually driving around to charge the 12V, just let your car run in the garage (with open door) and the traction battery will charge it. Have done it at times with the Prius when the wife forgot to close a light.
Toyota probably has to give us a way to shut down the various tech (that run even when the car is stopped) when needed so as not to drain the 12V when it gets really cold.
04-07-24, 09:20 PM
#23
Intermediate
As to charging with the hybrid battery...yes, my point was that you don't need to take the trouble of actually driving around to charge the 12V, just let your car run in the garage (with open door) and the traction battery will charge it. Have done it at times with the Prius when the wife forgot to close a light.
Toyota probably has to give us a way to shut down the various tech (that run even when the car is stopped) when needed so as not to drain the 12V when it gets really cold.
Last edited by wrinkle; 04-07-24 at 09:28 PM.
04-08-24, 08:19 AM
#24
An update on the 2024 RX 450h+ dead-battery/ parasitic draw issue.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
The following users liked this post:
wrinkle (04-08-24)
04-08-24, 08:36 AM
#25
04-08-24, 10:01 AM
#26
Instructor
As for changing the battery type the charging system itself comes into play. I have not talked with anyone that fully understands what parameters it uses in charging the aux battery. It is totally different than the alternator system that will actually fully charge the battery on a trip. I have read on ES forum where mpg was lost by not putting in the right battery. Internal resistance, etc come into play in how this charges. Even the dealer putting in a deep discharging battery probably affects how it charges. The original type should have been put back in unless Lexus high up advised to change.
The following users liked this post:
wrinkle (04-08-24)
04-08-24, 12:48 PM
#27
Intermediate
An update on the 2024 RX 450h+ dead-battery/ parasitic draw issue.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
04-08-24, 08:27 PM
#28
Locked up RX450h+ with dead battery
An update on the 2024 RX 450h+ dead-battery/ parasitic draw issue.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
Found w/ extensive experimentation at home that there is no apparent input a driver can change to avoid the dead battery or parasitic draw from occurring on this vehicle. Over twenty days tried turning various things off, leaving off, then turning back on. No difference. That includes the Lexus connected services/ Pulse, etc etc. Day by day the unattended vehicle will deplete the 12v battery from 12.6 to 12.1 to 11.7 to 11.4 to dead. Over a matter of a few days, not weeks. Previous RAV4 Prime XSE with every factory bell/ whistle could be left for weeks unattended w/ no discernable impairment.
Just to clarify - temperature should be a non-factor. Kept in an enclosed, insulated garage that during this test period didn't drop below 60F or rise above 70F.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
If it can be found - will share that info here for everyone's benefit.
If it can't be found - will share process of establishing a lemon.
----------------------
As a side note, considered an AGM battery replacement, but am staying w/ the Lexus dealer installed one for lemon paper-trail. AGM certainly seems logical, given it's strengths, and would seem best-suited to what a vehicle like the RX 450h+ requires. But if the mfg chose the battery (lead-acid), and it was designed to run with that battery, the system(s) should work as designed. Previous RAV4 Prime did. Might still install an AGM in the end, just to test the weekly results. Simple-enough solution, but doubt it could prevent the parasitic draw that is occurring. If the draw issue isn't resolved - the AGM would become a more-expensive paper weight.
04-08-24, 11:39 PM
#29
I have not had that problem, but a quick search finds that it is fairly common in quite a few late model cars.
In one post from 2019 from here, the dealership said this:
I took the car to Lexus who apparently never thought of putting an amp meter to each fuse terminal. Apparently the Car amplifier draws .25 amp when car is shut down which apparently is 5 times the normal for the entire car. They recommend to change the amplifier for about Cdn $750. This is after 4 years of checking and 3 batteries later
Someone with better voltage monitoring equipment might want to check that.
Great! A permanent solution to this potential problem would be better than trickle chargers and larger aux batteries.
I hope you mentioned it is happening to quite a few people, so they don't dismiss it later as being an isolated problem.
In one post from 2019 from here, the dealership said this:
I took the car to Lexus who apparently never thought of putting an amp meter to each fuse terminal. Apparently the Car amplifier draws .25 amp when car is shut down which apparently is 5 times the normal for the entire car. They recommend to change the amplifier for about Cdn $750. This is after 4 years of checking and 3 batteries later
Someone with better voltage monitoring equipment might want to check that.
An update on the 2024 RX 450h+ dead-battery/ parasitic draw issue.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
I've left the vehicle at the Lexus dealership for them to monitor and test/ experiment with for a week+ . They have begun talking with "Lexus Engineering" about the issue, and I'm assuming will try various logical tests to track down what the draw is.
I hope you mentioned it is happening to quite a few people, so they don't dismiss it later as being an isolated problem.
Last edited by asj2024; 04-08-24 at 11:46 PM.
04-09-24, 07:48 AM
#30
Intermediate
What is meant my the amplifier there ? Music system ? Does that mean disabling audio when parking might be the solution ?
If you have the original link of the post from 2019, please do share that
If you have the original link of the post from 2019, please do share that