Lozsta

Really I am looking for a different battery to put in that doesn't require a trickle charge/bnattery tender/odb connected solar panel/screw top disconnector. There has to be a battery out there which will not discharge overnight or within 24 hours.

Hi Russell thanks for the advice but this review unfortunately counters the use quite well "Don't waste your time and money on this junk. It might be fine for a leisure battery or something that does not move about but it is not sturdy enough for a car. The thing is poorly made, does not clamp over battery terminals securely without a shim. I removed mine after a couple of months as it was causing electrical issues with the car. Connection was not secure enough and components were not getting sufficient power."

A jump pack? I wasn't aware that you can jump the rx400h due to the big battery. I have a solar panel and the ODB port but it doesn't seem to help. I am looking more for a higher MAh battery like a leisure battery that will hold charge longer.

Hopefully someone can help me. My old rx400h is great most of the year round. Unfortunately due to my not daily use the battery discharges very quickly in cold weather. I have to buy a new battery yearly and then the next year it will discharge within 48 hours of a temp drop. I read a while back about this causing issues with the car not wanting to start properly and giving the ACS (cant remember the details exactly) error when starting, it keeps asking you to put it in park when it it. I am hoping someone has the knowledge required to help me, I did read that some were using leisure batteries or similar with higher mAH ratings to help with slowing the rapid cold weather discharge. There were others who mentioned issues with this but I am really hoping I can make it through one following winter without the cost of a new battery. Thanks in advance for any help :)

Ok cool, thank you. Excellent analogy Colin, putting it that way makes me feel like an idiot because it is such a simple thing.

Thanks @Gliderpilot I got one from the local Costco for £50 and change so that was a bonus. Now to wait for them to run an offer on tyres...

@Herbie I am no expert on car batteries or cars in general, computers/cloud computing/bioinformatics/clinical trials maybe but cars remain a mystery... In that case if I were to buy one of the higher Ah batteries this would not cause complications?

@GSLV6 thanks, I have gone for the Bosch aux battery that was recommended, I have looked at the deep cycle battery but I am not sure I understand how it would charge back up as they are designed to discharge then charge back up. I got the right battery from Costo for £50 and change so we will see how it gets on.

I have not had the battery tested, it just seems to lose enough charge and the "start in P" error comes up, I have checked the inverter recall for my reg/VIN and it comes up wih nothing needed but whether I believe it or not... What battery did you buy I am looking for the one gliderpilot recommended a Bosch S4 021 which looks right but the parts checker on amazon says it does not fit (not that reliable). I am having a right ball ache trying to find the right one...

@Gliderpilot sorry to bother you again, I am wondering do you think that battery would be the right one for the 2006 model, I am guessing it would be.

Thanks that has confirmed what I thought, I was going to go for Varta but I believe these are their batteries with a new badge.

@Gliderpilot can you confirm what your battery is in the 400h please.

Thanks for the information @Rutlandlex. Main update is that the aux battery is the issue. Over time it does not seem to get charged by the engine/traction battery so I am having to take the battery out, charge it over night and then the car is magically fine in the morning. Currently I am trying to find the right battery to replace in the car. Lexus aren't particularly helpful they just gave me the information "B24" on the battery and that is it. Someone pointed out something very interesting about why the aux battery issue on the SE-L where the battery is not up to the job, relating to the Japanese culture and having to accept that there is an issue.

Don't tow it away it will need to be on a car carrier (the manual specifically says not to tow the vehicle).

Surely though if there was insulation in there before then it should be insulated against the cold, I have had the battery out now in the last month 3 times to charge. Strange thing is the smart charger only shows a low 1-3 on the scale for power draw. Yet charged overnight back in the car and it goes to ready straight away. Today I have the solar panel from the AA in the OBD port to see if that helps... i am still unable to find the correct battery for this vehicle in the Varta Catalouge, I am ordering on of their blue tops as they seem highly recommended. EDIT also discarding a $54 part would seem a little wasteful...

Sorry for reviving a dead post but do any of you who have looked inside your bonnets and played with the battery know if you have the following: https://parts.lexus.com/p/Lexus_2006_RX-400h-33L/INSULATOR---BATTERY/63009486/2889920011.html

Ah I already love this forum, I also have this issue. I will try pumping the brake pedal later.

Previous owner put an ipod lead in, I borrowed ipad mini from work (I am firmly android) and that works fine too.

Sorry for the wall of links, I did spend a long time running through the options. My son is 2 and loves daddy's car (his words). Couple of points I would say I wish I had known before. ICE, I have DVD player and screens in the seats (I will probably never use as the quality is gash it is of it's day) and I have the ML stereo but I don't think it supports MP3 on CD, so I am going to try and see if that is replaceable. The 2007 model has "MP3 AAC" on the radio panel so that should support it. I find it frustrating that in 2006 it didn't have it, I had an old banger with a kenwood head unit it 2004 that had MP3 support, the stereo was worth more than the car but it was useful. Finally the tape deck, is an amazing thing to have in a car but why it is there is beyond me. I can only think that the market for the Lexus SUV was 65+ male with a collection of Glenn Miller on cassette tape and they wanted to keep them happy. For me it really dates the car, I know it is an old car (limited finances since the little man arrived) but tape was long dead in 2006

Also anyone with a 400h have any idea on Tyres...? I was looking at these: http://www.tyrereviews.co.uk/Tyre/Hankook/Ventus-ST.htm but cannot find a supplier for them for the 400h... Second best option I have found ihttps://www.costco.co.uk/Tyres-Automotive/Tyres-Accessories/Tyres/Michelin-23555-R18-V-100-LATITUDE-TOUR-HP-SUV/tire/p/663342 But they are not reinforced, is that essential?

Varta battery https://www.varta-automotive.com/en-gb/products/varta-blue-dynamic/545-155-033 that is the one that comes up https://www.thebatteryshop.co.uk/545-155-033-varta-blue-dynamic-b31-156-2808-p.asp https://www.hardwarexpress.co.uk/545-155-033-varta-blue-dynamic-b31-156-12v-45ah-car-battery-2527-p.asp https://www.eurobatt.co.uk/b31-varta Lexus quote £85 for a B24 45Ah (no other details but the B24 related to another Varta battery) which I think I have located. https://www.batterymegastore.co.uk/varta-b24.html So many options though after 4 hours research/phonecalls/banging head against the table I am pleased the recharge worked. The varta ones however don't seem much more esxpencive than the "cheap" yuasa one that the garage doing the MOT work put in for the vendor. The Blue seems to be more for newer non start stop cars (the 400h uses the hybrid cell to start the car I believe) where as the black is a more "old school" pre 2000 battery. https://www.varta-automotive.com/en-gb/products/varta-blue-dynamic

It is physically small (like a large motorcycle battery) 230 mm H x 230 mm W x 120mm D. In terms of power is it 45Ah, I am no expert on these things, but others suggested due to its nature a leisure battery with a higher Ah could be used instead. But having looked into it, discussed with battery suppliers and a guy I serendipitously ran into while walking my dog that day who maintains generators advised that due to leisure batteries being deep cycle they might not be suitable as they discharge then get charged back up. The guy who I ran into mentioned speaking with a local supplier of batteries who he knows if it happens again. @Herbie I have had a resolution.

Hey Herbie I had meant to come back but I have been off work for a while. I spent half of one of my days off investigating the issue, and found some posts elsewhere that relate to exactly this issue. There is a known issue with e RX400h of the age I have which is that when your starter battery goes to a very low level the warnings kick in and eventually the battery eventually fully ran out. The starter battery is very small for the size of the car and has been changed for the 450h I believe (from what I have read). Number one cause of this issue I have found is loading the vehicle, there are other causes like people sitting in the car with the radio on and the engine off, when you load the vehicle even with the doors open (even if you shut them when heading back for more stuff) the battery will drain very quickly. I had the boot and the side doors open a number of times (did not use the electric boot) and I believe this drained it to a very low level, did a short trip to the shop, turned the car off, then went to set off for the main journey with the battery low and the bells and whistles all went off. Spent the whole xmas period stressing over it. Came home, first day I got time to do it I whipped out the starter battery and charged it (note to self smart chargers don't display the charge level but the power needed to charge the battery, I thought when it dropped down from 5 to 3 the battery was not holding charge). Popped it back in and every came back to life. Reset windows sorted radio presets. Hoping that will be the end of it as I use it daily but will be getting receipt from the seller and getting warranty replacement on the battery if needed.

HI digging up an old thread again but figured better than starting my own. I am looking for the Hankook Ventus ST but I am not being offered them by any of the tyre dealers online (blackcircles mainly). Costco does have these for £105 which seems like a steal with their discount on too... https://www.costco.co.uk/Tyres-Automotive/Tyres-Accessories/Tyres/Michelin-23555-R18-V-100-LATITUDE-SPORT-3-SUV/tire/p/45049

Just responding to OP with my experience. I will try the filler cap trick but I don't hold out any hope for it.