Replacement 12v battery for RX450h

[PCM]

10 hours ago, BartLexusFan said:

Do we know if 12V batteries are covered by extended warranty? (Not lexus relax)

I didn't think so... unless the Battery was faulty when fitted?

[UR2]

I was having trouble finding a place to replace my 12 volt Battery in my 2017 RX450H.  I went to Auto Zone and bought the correct Battery.  I used jumper cabels from my truck to the Lexus to keep power to the system so I did loose any settings.  I changed the Battery making sure the hot cable didn't touch anything by rapping it in a rag. I started the Lexus and disconected the jumper cables. As showen in the manuel the Lexus is jumped from under the hood and not the Battery. Make sure the jumper cables are making good contact.  Sorry no spell check.

[Herbie]

4 hours ago, UR2 said:

As showen in the manuel the Lexus is jumped from under the hood and not the battery.

It doesn't matter which one, 12V from the front is exactly the same as 12V from the back.

[kotofeus]

Hello everyone,

Just wanted to share my Lexus Rx450h Battery replacement. After a lot of reading on different forums I've decided to go for a simple standard Bosch s4 024  12V 60Ah Type 005L battery (see photos). 

Cost was GBP 67.95 delivered 

Size wise it fits perfectly. 

There are two vent plugs on both sides of the Battery. One was removed to fit the vent tube....but the vent tube was slightly larger than the vent hole. 

I just carefully extended the hole with a drill to fit the size of the standard Lexus vent tube. 

 

After that, Battery was fitted without any issues.

The debate about AGM batteries feels a bit strange, bearing in mind that the standard Panasonic D23 Battery is not AGM (mine was fitted 12 years ago and was never changed). 

 

Hope that helps someone. 

Any questions, let me know 

[Illogan]

Anton,

What an excellent first post on the Forum.    That's a well constructed and beautifully illustrated article.  Come the day when I need to install a new Battery, I will make a point of reading this article again.   

Thank you.

[Barry14UK]

You say Standard Pan D23 Battery fitted to your car is not AGM anyway but think this is incorrect.  It does not say AGM on it but says VRLA (Valve Regulated Lead Acid) which means the acid is absorbed within the glass mat which makes it AGM rather than free flow lead acid.  The main advantage is that with AGM batteries in a serious accident there is not the potential for the acid to affect anybody within the cabin as with full flow batteries of the type you have now fitted.  However, it has to be said that the risk is quite small and I understand that even Lexus are  now fitting free flow  lead acid 12v batteries to some cars. These are more readily available and less expensive and generally size for size contain less lead than AGM batteries.

Rather than enlarge the vent hole on your new Battery by drilling, with the possibility of any claim on it being rejected on it due to modification, you could have bought a smaller adapter off eBay for under £3 as others like me have done and fitted this to the Lexus tube. Incidentally, this vent only comes into effect with the AGM batteries where the regulating valve releases over gassing usually due to overcharging.

[Grey RX]

My RX completely failed to start on Friday as the cold weather hit.  It was more or less ok after a recharge but I ordered a new one from Lexus parts direct for £200 including shipping and it should be with me today.  Can't take the risk of being stranded and when charging it took hours to go from 40% to 60% charged, and then quickly hit 100%.  I think the Battery was seriously harmed during the pandemic lockdown in 2020 when it went completely flat and I didn't start the car for several months.  Although it has limped on since, I think this weather was the last straw.  13 years old so I can't complain.  

[Brad Ched]

Hi All,

With everything that was said in this thread for the last 3 years, I'm getting more and more confused, especially with regards to the Start / Stop functionality of the 2009 RX 450h.

I certainly don't want to sponsor the millionaires' owners of Lexus dealerships in their quest for one more house in Portsmouth harbour, by paying for a needlessly expensive 12V Battery.

I understand that:

- it is Not compulsory for the Battery to be gel, the VRLA one does the trick just as well.

- it seems that an even cheaper 12v Battery Panasonic, Varta or even the Bosch one (in Anton's post above) also might work. (Risks of acid leak on body if involved in an accident accepted at owners risk).

- pay particular attention to the Battery size as the space in the boot is rahter small and the batteries vary in size.

- connect another power source to the underhood terminals to keep all sorts of dahsboard settings.

In light of all this, I wonder shall I not go for this allegedly genuine part:
https://lexuspartsdirect.co.uk/product/lexus-rx-phase-3-auxiliary-12v-starter-battery/

I went on amazon, but only these two show as compatible... And the Bosch one says in the description - not compatible with Start / Stop vehicles. In my mind, the 2009 RX 450h is a start/stop vehicle, or is it not?

[Barry14UK]

Hi Brad,

You are under a misapprehension in a couple of respects.

Lexus did not fit Gel type batteries to your model.  With the 12v Battery in the boot, Lexus fitted a VRLA (Valve Regulated Lead Acid) Panasonic Battery.  In this the acid is absorbed in the glass mat so it is an AGM Battery even if it does not say so on the casing.

The purpose of the 12v Battery is to power the computers, and alarm etc, and connect to the traction Battery.  It does not start the engine so can be small.  The car does not have an alternator or starter motor.  This function is performed by a generator which is powered up by the traction Battery.  So although the engine is fired up as called for and in that sense is stop/start it does not impose a heavy load on the 12v Battery as with cars using a stop/start system with conventional alternator/starter motor set up.  So with the RXh, the 12v Battery is charged via the traction Battery but you can't make this connection without the 12v Battery first powering up and making connection with the traction Battery. 

It is most important therefore that the 12v Battery is kept charged up by regular use of the car, kept sufficiently charged using a smart charger or allowed charge while car is stationary as per handbook. 

As batteries age they tend not to hold a charge so well so may need increasingly more frequent additional charging, particularly if the car is only used for short journeys.  The situation will be worse if the voltage of the 12v Battery is allowed to fall below a critical level so that the life of the 12v Battery will be reduced or terminated.

So high cranking power is not required but because the 12v Battery continues to serve its purpose when the car is not used, Lexus specified a deep cycle Battery, until at least after the 3rd Generation cars. 

Your options are therefore:-

A like for like replacement VRLA AGM Battery generally only available from Lexus. (Since seen Yuasa do similar model but also at high cost).

A free flow acid widely available Battery with same dimensions as original. 

Modify plastic base plate that Battery sits on in order to fit a slightly longer readily available AGM Battery which was less expensive than Panasonic. It also called for some other mods which I detailed on another thread.  This also gave 60Ah compared to the original 51Ah of the Panasonic.  Appreciate few would go this route.

In conclusion, if you accept the slightly increased risk of acid spill in an accident and the Battery not being so deep cycling, your cheapest solution is to go for a standard free flow acid 12v Battery of same dimensions as original. 

 

 

 

[DaveyBoy]

My 2019 rx450h had a flooded lead acid Battery. I doubt it was replaced.

Dealer quoted me £180 fitted for a flooded lead acid. I can double check this. But also Lexus parts direct also show a flooded lead acid, which is what I bought. Oh and the vent tube fitted perfectly, and I removed the bung from the old Battery and fitted to the far side of the new Battery. Bung was nothing more than a Bic brio end plug.

https://lexuspartsdirect.co.uk/product/lexus-rx-phase-4-starter-battery/

£81 plus postage of about £5 or £6.

Attached the top view of my old Battery. Tomorrow I'll take a picture of the side view, which said Panasonic on it. and also had some nice fluid levels at the ends with the middle cells being a little less, but sufficient to cover the cells.

So I am very confident that my OEM Panasonic was a flooded lead acid.

Are all rx450h flooded lead acid? maybe not. Would explain the price difference for the 3rd gen vs 4th gen Battery costs at LPD.

[ColinBarber]

41 minutes ago, DaveyBoy said:

Are all rx450h flooded lead acid? maybe not. Would explain the price difference for the 3rd gen vs 4th gen battery costs at LPD

Series IV RX uses a flooded Battery, as with all the current Lexus models (UX, ES etc.). The previous series III RX450h uses an AGM Battery. Before that the series II RX400h used a flooded Battery.

[DaveyBoy]

Awesome information Colin. Explains the situation very well. Now I understand the transition. Trawling forums often leads to partial facts and confusion. I clearly was confused by the whole AGM debate running through this and other threads & on other forums.

My replacement Battery works well despite the expended shelf life. I haven't probed directly yet but in car, via one of those cig lighter voltmeters, it shows about 12.2 at ignition, not ready status. I'd have expected nothing less than 12.5 to be honest. But am aware that the gadget reads under by about 0.2v

As promised I attach a side view of my old Battery. It was not level, I tilted it 30 degrees or so make viewing the fluid levels more obvious. In beautiful condition despite the (ignition status) voltage sitting at 11.5 to 11.8v, and the car refusing to charge it at times (sitting at 12.8v and not 14.4 as expected). New Battery appears to be charging just fine.

One last thing, those electronic Battery tester gadgets (Topdon) are very unreliable. I bought one to see the condition. Wish I hadn't wasted my money on it. Although the results off car appear more consistent.

[ColinBarber]

2 hours ago, DaveyBoy said:

My replacement battery works well despite the expended shelf life. I haven't probed directly yet but in car, via one of those cig lighter voltmeters, it shows about 12.2 at ignition, not ready status. I'd have expected nothing less than 12.5 to be honest. But am aware that the gadget reads under by about 0.2v

What's the reading once in Ready mode? I would expect to see 14.4 v and therefore you could calculate the gadgets inaccuracy. Ideally your 12 v Battery without load should be reading between 12.6 and 12.8 v if fully charged. 12.2 v is too low, even if you have a 0.2 v discrepancy so you may want to give it a good charge.

[Johntechx]

Well, I won't be purchasing another Panasonic AGM Battery from Lexus for my RX450. Bought one in May 2020 (£195 plus post, self fitted) and it's failed, not holding a charge. Lexus only give a 1 year warranty, unlike most Battery makers who give 3-5 Years.

I will be taking my chances on a standard wet Battery when I replace it!

[Barry14UK]

Although Lexus only give a 12 month warranty on their batteries, many owners have reported their Panasonic batteries going years beyond the 3-5 other manufacturers warrant.  Did you ever let the Battery go flat and particularly stay that way for some time as this will shorten its ability to hold a charge?  Some manufacturers actually show on an attached label on the Battery that the warranty is void if the voltage has fallen below a certain level*  Member Herbs actually fitted a volt check to his previous RX, so he could readily  check this aspect.  This is something Lexus could and I feel should have done during manufacture, bearing in mind the hassle of a work around and risk of premature failure of the Battery.

*see warning in red here on level falling below 10.6v on this Battery I chose at random, https://www.amazon.co.uk/Hankook-Start-Battery-190mm-Warranty/dp/B07YY37NKR 

[Davidlwh]

Sorry for hijacking this thread…

I have a 2014 rx450 and have had to jump start a couple of times the Battery under the bonnet presumably due to the cold weather. 
 

I’m trying to work out which Battery I need to buy.  I recall seeing that the Battery was a smaller size and was around £200+ when reading about it on the forum last year.  However, I can’t find this information now. 
 

also, is there a need to connnect to another supply whilst replacing the Battery?

many thanks

[Davidlwh]

sorry, meant that I've jump started the car from the Battery points under the bonnet next to the fuses...but am looking to replace the panasonic d23 Battery in the boot

[ColinBarber]

Here is one option (genuine Lexus replacement)

https://lexuspartsdirect.co.uk/product/lexus-rx-phase-3-auxiliary-12v-starter-battery/
 

You don’t need to have another 12v supply connected whilst you replace the Battery, but you would need to reinitialise the auto windows etc. if you don’t. 

[Davidlwh]

Many thanks Colin

I'll have a look at this.  It does seem a bit steep in price.  Are the other options alluded to either too big or somewhat fiddly to fit? I'm looking for a straightforward solution that isn't too costly

[ColinBarber]

17 minutes ago, Davidlwh said:

Many thanks Colin

I'll have a look at this.  It does seem a bit steep in price.  Are the other options alluded to either too big or somewhat fiddly to fit? I'm looking for a straightforward solution that isn't too costly

Options are limited. If you want an AGM Battery then your only real option is a Lexus one from a dealer. If you are ok with a standard flooded Battery then as per kotofeus' post above, a standard Bosch Battery will fit, you just either need to open up the vent hole, or find a vent adapter to allow the existing hose to be connected (leaving the vent hole on the other side of the Battery plugged).

[Davidlwh]

Thanks again.

I suspect that I'll give Lexus parts tomorrow.  How long would you reasonably expect the Battery to last?   The one year experience doesn't seem great.

[Barry14UK]

Undoubtedly many cars saw little use during the Pandemic leading to a voltage fall that caused premature damage and shortening of Battery life.  if car is not used for a couple of weeks, particularly in winter, I would adopt the advice Lexus gave me during pandemic which was to charge car every 2 weeks, they said by exposing the 12v Battery to the service Battery as they specify.  However, you can use a smart charger in AGM mode if indeed you buy the AGM (VRLA) one from Lexus Direct.  Alternatively, some use a solar panel charger that you can put on the dash and connect to the OBD port but doubtful this would be sufficient this time of the year. 

 Members who have just opted for a much more readily available and less expensive standard free flow lead acid seem to be happy with them but that's your choice.  

[Davidlwh]

Thanks all

I've just changed the Battery to the original Lexus one. However, my boot (open/close) button on both the boot lid or key won’t work. Any ideas?

 

[ColinBarber]

51 minutes ago, Davidlwh said:

Thanks all

I've just changed the battery to the original Lexus one. However, my boot (open/close) button on both the boot lid or key won’t work. Any ideas?

 

I think you have to manually open and close the tailgate once to initialise it. 

[Davidlwh]

Ahhh. Thank you. Fingers crossed. All sorted now