You can retain settings with a device like this -

which uses a 9V battery plugged into a power port or lighter port.

 

That looks like a really good idea. I read the reviews and they were split between really worked great and worthless. To be fair, the worthless reviews were over a year old and the better ones were in the last 6 months so maybe it's a re-design or maybe doesn't worth with all systems. I have no way of telling.

 

It only works if it is in a power port that's on all the time - if it is in a port which shuts off with the key off, then no power gets where you want it.
I don't know which, if any, of our power ports stay on.

 

My 2011 RX 450H with 42k miles still has the original Panasonic12 volt battery. It is just over 5 years old. My SA at the dealership says that it test good. However he also says that he would replace it before winter if I wanted to be on the safe side. What is the average life of the battery?
What brand would be the best and what should the cost be? I never use the accessory mode.
Thanks in advance.

 

Stanford, I'm on the original battery at almost six years with 40.5K on the odometer. It's been checked every six months for the past two years. Still going strong. Generally the average life span is about 3-5 years but obviously there are exceptions. I don't use accessory mode either except when filling up the tires. Now the 450h is going in next month for service. I'm considering having the battery replaced, especially if we have another prolonged cold winter again. I'll see what my SA says. She can be tough when it comes to spending my money, LOL! I'll probably have it replaced there since I can use Lexus points and for the convenience. I know other members get replacement batteries from places like Costco.

 

Over 6 years and 75,000 miles on the original battery and still going. The 12V in my Sienna lasted 11 years. Only other car I kept long enough to need a battery change, that one was 9 years old. All other cars I had were kept between 3 and 6 years and never needed new batteries. I'm expecting to get at least 8 out of the current one in my RX. Two things kill batteries, extreme heat (95F+ regularly), or lying around unused (especially in winter). That kind of heat is rare here, so battery life is usually pretty good for me.

 

Great thing about our hybrid is the 12v battery is not used to crank the engine. It doesn't get stressed out like a battery in a conventional car so it's likely to last longer than 5-6 years.

 

Thanks for all the information. If the 12 volt battery doesn't start the engine, what does it do? Before the battery becomes inoperative will there be an indication on the instrument panel, so that I don't get stranded? How do you jump start the car without damaging anything? It is now becoming a test of how long it will last? However if it does go dead after a late night Steelers game and I get stuck downtown. It will now become a test of my patience and the balance of my check book.

 

Everything you ever wanted to know about Toyota/Lexus hybrid.

https://en.m.wikipedia.org/wiki/Hybrid_Synergy_Drive

I can tell you from experience with our Prius, if the 12 volt battery gets bad or is depleted by sitting for a month, the car will not start. You then have to follow the jump start process in the owners manual to get it to start even though the High Voltage Traction battery is what turns the MG1 to crank the engine. With a failed 12 volt battery the car is dead. No lights, no horn no main relay engagement to bring the electronics alive.

Interestingly, we traded in our CT200h a few months ago and when they certified it for resale the 12 volt battery did not pass and had to be replaced. We never had a problem with it.

 

Thanks for the education. That is some interesting information.

 

The RX450h 12V battery, being an AGM (Absorbent Glass Mat) is a lot more expensive than the more common floaded lead acid batteries. Hence, I intend to extend its life as much as possible (10 years looks to me a decent enough period). My receipt, in order to achieve this result, is to "cure" it with a smart charger like this one: every three months I left the battery connected to the charger a whole night. I have been doing it with my 2010 Prius for 3 years now, after the sudden depletion of the 12 V battery , and started to do the same with the RX that I bought recently... no bad surprises so far.

 

My original 2010 year Panasonic battery shows 12.5 volts after being in charger over night, so it's not good anymore, it has failed turn the car in ready mode couple of times now.

Is it Agm battery as it has breather tube going outside under the car?
I have though Agm batteries are completely sealed, including charging vapours?

Any suggestions for replacement batteries, what you have installed?
I have Optima in Rx400 but they don't have direct fit for Rx450

 

To answer myself, finding right size Agm battery is tricky.
Optima, Varta Agm, Exide Agm won't fit. Also some online battery search tools gives battery for Rx350 although Rx450 is chosen. And some tools don't give any answer.

I measured maximum size of battery without altering the battery holder:
length 225mm/8.85inch, width 175mm/6.88inch, height 195mm/7.67inch

Yuasa has 50Ah Agm battery YBX9012 (012AGM) that fits. I'll try to get one.
---updated--
Local importer does not have Yuasa 50Ah Agm in stock, if I order now, they promised I could have it next winter. Sellers in Uk/Germany have it but won't post it to my country as they have contract not to sell country where is own dealer.. .nice
Only Agm battery available that would fit and what I could get is 50 Ah Thunderbatteries AGM50520 battery. Technical details are identical with Yuasa, maybe a copy one.

Currently prolonging Oem battery life with battery tender
Easy way would be just take what Lexus dealer offers... or cut off the battery holder's edge towards spare wheel

 

My 2009 RX450h also has the original Panasonic 12V battery. A month or two ago the battery also failed to switch the vehicle on to a READY state with all the relay clicking and display flickering and dimming that accompanies such an event. I removed the battery from the vehicle and then peeled off the sticker covering the top of the battery only to find the filler caps for the individual battery cells covered by a semi-transparent piece of plastic that was glued or melted in place. I proceeded to break out the plastic covering the filler caps and opened the caps. All of the cells were dried out to the point where the top of the plates inside the cells were not covered by water. I filled the cells with distilled water to cover the plates, closed the filler caps and fitted the battery back in the vehicle. I connected an intelligent Black & Decker Battery Maintainer (BDV090) overnight and the following morning everything was back to normal. I proceeded to connect the battery maintainer for a week when I was not driving the vehicle and so far it looks as if the battery may be good for some time to come. One thing that I did notice was that the standby current used by the vehicle while it is unlocked is large enough to prevent the maintainer from fully charging the battery while fitted in the vehicle. When the vehicle is locked the maintainer slowly gives the battery an absorption charge and when the battery is fully charged the maintainer switch to a float charge. I will update this post if anything out of the ordinary happens.

 

Yes the battery load depends on many factors.
✿ When locked with all windows shut the current drops to about 60 mA after about 10 minutes.
✿ When unlocked with all the windows shut the current drops to about 120 mA after about 10 minutes
✿ When the windows are open the current stays at about 1.1 Ampere irrespective of whether the doors are locked or not!

When the doors are closed or locked the current is at about 3 Ampere and decrease gradually in steps as time pass. The last decrease in battery current happens around 10 minutes after closing or locking the doors.

How much current is drawn by the tracking device I would not be able to say, and if these values are the same for vehicles sold outside of South Africa I also won't be able to say.