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I joined this forum today because I was literally preparing to withdraw the cash to buy an off-lease 2023 Lexus RZ 450e Premium this afternoon. I am glad I stumbled upon this fantastic thread, which may have saved me from doing something stupid, because the Carfax service history looked strange (lacking service mileage and detail) or very frequent compared to how boring my Lexus ownership has been service wise.
I work from home now (maybe not forever) and wanted something to be there for local trips, and if we need to road trip we can take my wife's NX, but I also do not want a massive dead paperweight in there if I don't drive it for 2 weeks or more, which has me rethinking this Lexus EV thing entirely when I thought it was an obvious fit due to reliability and reputation.
The lack of detail in some of the service records almost looks like avoidance of a lemon law claim, or it at least shows me that my experience of visiting a Lexus dealer only twice on my wife's newest NX is not what I can expect with this RZ and that is a dealbreaker for me.
I am not married to the idea of owning this car, no emotion either way here, so tell me if you would avoid this vehicle or go ahead with it and try all suggestions here including the Ionic device on the battery...which, I don't know how I feel about all of it.
Very smart solution. Do we think anyone from Lexus is seeing these threads ?
This could potentially eliminate the need for Lexus Roadside Assistance to dispatch a tow truck for our RX-hybrid dead-battery events.
I could bring up the Lexus app on my phone, select the link for emergency start option. This brings up the IONIC app (maybe rebranded as Lexus via licensing agreements) so I can get the door open and pres the start button.
Or create a Lexus based device ?
Very smart solution. Do we think anyone from Lexus is seeing these threads ?
This could potentially eliminate the need for Lexus Roadside Assistance to dispatch a tow truck for our RX-hybrid dead-battery events.
I could bring up the Lexus app on my phone, select the link for emergency start option. This brings up the IONIC app (maybe rebranded as Lexus via licensing agreements) so I can get the door open and pres the start button.
Or create a Lexus based device ?
Yes happened to me 2 weeks ago, I was detailing the RX for about 40 minutes and had the doors open, really did not think that the interior lights would draw that much power. To my surprise the battery was dead and I had to call Lexus service (that worked well)
There is a TSB about some modules that fail to go to sleep after the car is shut off in the older models. There is Youtube video on this. The software update is free and should reduce battery drain substantially. You have to ask for it specifically.
There is a TSB about some modules that fail to go to sleep after the car is shut off in the older models. There is Youtube video on this. The software update is free and should reduce battery drain substantially. You have to ask for it specifically.
Anyone recall the number or title for the TSB ?
Anyone know the url for the YouTube video reference ?
The Incident My 2024 Lexus RX 500h suffered a complete electrical failure due to the well-documented 12V parasitic drain. To make matters worse, the tow truck operator lifted the rear and dragged the locked front tires approximately two feet, risking damage to the AWD transaxle. The vehicle is currently being inspected at Lexus of Tampa Bay, but the root cause of the entire ordeal is the inadequate OEM 12V battery.
The Root Cause Standard flooded lead-acid batteries cannot handle the continuous discharge and recharge cycle caused by the hybrid system's parasitic draw. They rapidly sulfatize and fail prematurely, a process accelerated by high Florida temperatures.
The Solution: Odyssey ODP-AGM48 (Group 48 / H6) Instead of another OEM replacement, I evaluated the market for a structural fix and upgraded to the Odyssey ODP-AGM48 for roughly $280.
Pure Lead Architecture: It uses 99.99% pure virgin lead rather than recycled alloys. This drastically lowers internal resistance and provides extreme deep-cycle resilience. It treats the constant parasitic draw as a standard operating condition rather than a crisis.
The Critical Metric: It delivers 130 minutes of Reserve Capacity (RC). RC is the true metric that dictates how long the battery can sustain the draw before the voltage drops below the hybrid computers' boot threshold.
Installation Pro-Tip If you do this swap, plug a 12V memory saver into the OBD-II port before pulling the terminals. This keeps the modules powered and saves you from recalibrating the power back door, steering angle sensor, and interior electronics.
The Incident My 2024 Lexus RX 500h suffered a complete electrical failure due to the well-documented 12V parasitic drain. To make matters worse, the tow truck operator lifted the rear and dragged the locked front tires approximately two feet, risking damage to the AWD transaxle. The vehicle is currently being inspected at Lexus of Tampa Bay, but the root cause of the entire ordeal is the inadequate OEM 12V battery.
The Root Cause Standard flooded lead-acid batteries cannot handle the continuous discharge and recharge cycle caused by the hybrid system's parasitic draw. They rapidly sulfatize and fail prematurely, a process accelerated by high Florida temperatures.
The Solution: Odyssey ODP-AGM48 (Group 48 / H6) Instead of another OEM replacement, I evaluated the market for a structural fix and upgraded to the Odyssey ODP-AGM48 for roughly $280.
Pure Lead Architecture: It uses 99.99% pure virgin lead rather than recycled alloys. This drastically lowers internal resistance and provides extreme deep-cycle resilience. It treats the constant parasitic draw as a standard operating condition rather than a crisis.
The Critical Metric: It delivers 130 minutes of Reserve Capacity (RC). RC is the true metric that dictates how long the battery can sustain the draw before the voltage drops below the hybrid computers' boot threshold.
Installation Pro-Tip If you do this swap, plug a 12V memory saver into the OBD-II port before pulling the terminals. This keeps the modules powered and saves you from recalibrating the power back door, steering angle sensor, and interior electronics.
I knew someone had an answer!! Thanks for your post!! The battery you are referring to has 130 reserve capacity vs the OEM of 100. The battery you referred to has 69-amp\hr as opposed to the OEM of 60-amp\hr.
Now, that may not seem a lot.....but more is always better....unless the subject is bikini's.
The Root Cause Standard flooded lead-acid batteries cannot handle the continuous discharge and recharge cycle caused by the hybrid system's parasitic draw. They rapidly sulfatize and fail prematurely, a process accelerated by high Florida temperatures.
The Solution: Odyssey ODP-AGM48 (Group 48 / H6) Instead of another OEM replacement, I evaluated the market for a structural fix and upgraded to the Odyssey ODP-AGM48 for roughly $280.
You have misidentified the root cause.
The root cause is a battery charging algorithm that does not fully charge the battery. When the root cause is eliminated, the OE battery thrives.
I had looked into the Odyssey, and it is a great battery, but it does not appear to be any more resistant to sulfation than a flooded lead-acid battery when kept in a perpetually undercharged state. It also requires a specialized charger and procedure to rejuvenate it.
The root cause is a battery charging algorithm that does not fully charge the battery. When the root cause is eliminated, the OE battery thrives.
I had looked into the Odyssey, and it is a great battery, but it does not appear to be any more resistant to sulfation than a flooded lead-acid battery when kept in a perpetually undercharged state. It also requires a specialized charger and procedure to rejuvenate it.
With all due respect, I think he did ID the root cause. He just stated it in a different manner.
However, no one but Lexus can change the algorithm of the charge cycle.....so consumers are left with a daily threat of a dead battery, or left to "have" to charge the battery with aftermarket Do-Dad's, or a simple battery charger. Neither of these are acceptable to the end use consumer. Some are tolerant of the need for aftermarket diapers, others....not so much.
The sulfating is going to occur no matter what battery is used. However, a battery that "holds more juice" when compared to the OEM is better. Both the OEM and the better aftermarket battery are going to die within the same time frame. Say 3 years.
But the OEM must be "fiddled with" via aftermarket boosters, aftermarket chargers, aftermarket jump start units. Or, the "better battery" can just be used. I has much less of a chance at leaving you stranded, and it won't need the aftermarket diapers. It may sulfate and die in that 3 year time period. But in that time frame it won't leave you stranded or with the necessity of needing to be fiddled with.
Crying won't help you, praying won't do you no good. A bigger battery might help however.
In my extreme service the Odyssey battery will last 4 years.
I don't care about sulfation because I will replace it by then. https://www.clublexus.com/forums/rx-...ter-audit.html
Crying won't help you, praying won't do you no good. A bigger battery might help however.
In my extreme service the Odyssey battery will last 4 years.
I don't care about sulfation because I will replace it by then. https://www.clublexus.com/forums/rx-...ter-audit.html
With all due respect, I think he did ID the root cause. He just stated it in a different manner.
However, no one but Lexus can change the algorithm of the charge cycle.....so consumers are left with a daily threat of a dead battery, or left to "have" to charge the battery with aftermarket Do-Dad's, or a simple battery charger. Neither of these are acceptable to the end use consumer. Some are tolerant of the need for aftermarket diapers, others....not so much.
The sulfating is going to occur no matter what battery is used. However, a battery that "holds more juice" when compared to the OEM is better. Both the OEM and the better aftermarket battery are going to die within the same time frame. Say 3 years.
But the OEM must be "fiddled with" via aftermarket boosters, aftermarket chargers, aftermarket jump start units. Or, the "better battery" can just be used. I has much less of a chance at leaving you stranded, and it won't need the aftermarket diapers. It may sulfate and die in that 3 year time period. But in that time frame it won't leave you stranded or with the necessity of needing to be fiddled with.
I'll take that option every day of the week.
The "better battery" is just another bandaid and it remains to be seen if it will help avoid stranding you. At least an Ionic Emergency Start is known to prevent stranding in a safe and convenient manner.
Unplugging the 12v battery voltage sensor literally addresses the root cause, though it may introduce other issues.
I changed to AGM on day one of ownership. The performance of the Odyssey battery for me was not great at the end of year 4 so I would have replaced but incidentally bought a new car the last 2 times.
Last edited by nx450plus; May 20, 2026 at 10:16 AM.
