2014 RX450H battery start issues

[Monidda]

Hi everyone, 

We have a problem with the start button we think it could be related to the 12V Battery ( We bought it in 2014 from new and has done 74k to date) . The car is not doing as much mileage as it used to and in lockdown we started getting problems with the start button. It got so bad that we now virtually have to start it almost daily with one of those thingies who's name escapes me right now. The other issue we have is that very randomly and at ungodly hours decides to start the theft alarm. ( I can only imagine to the utter delight of our neighbours in the cul de sac 🙄)

There are no warning lights and the car runs as beautiful as the day we got it. What do you think would be our best course of action please? try and give the Battery a good charge or maybe change it? Any thoughts on the weird alarm ?? Many thanks  

[C Mclean]

More than likely the 12v Battery getting weak. Once they start going duff the car sends out loads things. Give it a good run and see how long it lasts.

[Herbie]

I'd stake a month's salary on it being the 12V Battery dying.

The alarm will (should) have it's own back-up Battery and as the main 12V Battery is low, the alarm back-up Battery is also going low, which in turn activates the alarm because it thinks it's being tampered with.

When you get a new Battery you really need to try to use the car more but if that's not ractical, two alternatives are to connect a trickle charger such as the CTEK MX5 or to run the car in READY mode, whilst in P, for 60 minutes a week.

[Monidda]

3 minutes ago, C Mclean said:

More than likely the 12v battery getting weak. Once they start going duff the car sends out loads things. Give it a good run and see how long it lasts.

Thank you for taking the time , we can have no problems for a few days then other days we would have to jump it each time we use it. Seems fine after a longer run for a few days then Bam won't start again. It's getting annoying now which prompted me to come and investigate. I am glad you think is the 12V Battery.

[Monidda]

4 minutes ago, Herbie said:

I'd stake a month's salary on it being the 12V battery dying.

The alarm will (should) have it's own back-up battery and as the main 12V battery is low, the alarm back-up battery is also going low, which in turn activates the alarm because it thinks it's being tampered with.

When you get a new battery you really need to try to use the car more but if that's not ractical, two alternatives are to connect a trickle charger such as the CTEK MX5 or to run the car in READY mode, whilst in P, for 60 minutes a week.

Kind of you to weigh in thank you 🙂 and what excellent advice. Will get one and see how we go, pleased to hear positives that it's not more than that. 

[Monidda]

Now next question is where do I find a like for like 12V Battery. Off to do a search in the forums.

[Herbie]

3 hours ago, Monidda said:

Now next question is where do I find a like for like 12V battery. Off to do a search in the forums.

This is very much a can of worms and has been discussed long and hard. You can get alternatives but it can be a bit of a minefield, so my best advice is to order from Lexus Parts Direct who are an actual Lexus main dealer but they sell stuff much cheaper than other dealers. That link will take you directly to it.

[Monidda]

1 hour ago, Herbie said:

This is very much a can of worms and has been discussed long and hard. You can get alternatives but it can be a bit of a minefield, so my best advice is to order from Lexus Parts Direct who are an actual Lexus main dealer but they sell stuff much cheaper than other dealers. That link will take you directly to it.

SUPERSTAR !! Thank you so much. We bought a trickle charger and we will see how that goes.

[DavidCM]

Every car i have owned(beyond 7 Years~ car,not me) The Battery has died at  7 years.It's as if they have a timer.You've done well to get 8 years ~ time to buy a new Battery before you get stranded.

[Monidda]

7 minutes ago, DavidCM said:

Every car i have owned(beyond 7 Years~ car,not me) The battery has died at  7 years.It's as if they have a timer.You've done well to get 8 years ~ time to buy a new battery before you get stranded.

Thanks David, it started last year and so bang on 7 years LOL

Also I am a bit sad as I stated that the mileage is 74 k but it is in fact 47 k. 

[DavidCM]

I know the problem..my Porsche Battery packed up with less than 30k..owned from new,great car but if you think lexus' are expensive to run..

[Illogan]

Monica - Herbie's recommendation of Battery supplier is bang on the money.

Our RX's Battery failed last year (2014 !!)  and we replaced it from Lexus Parts Direct. Fast delivery and cheaper than your dealer doing it for you!

I made a point of maintaining an auxiliary 12v Battery connection to the car whilst changing the Battery, and thus didn't lose any of the settings on the car or alarm systems. (Easy to do - and can save a deal of faffing about!)

[Barry14UK]

Your Battery will be the same size and type as mine as it has not been replaced since new, that is a 51Ah Panasonic VRLA (Valve Regulated Lead Acid) Battery of AGM type.  That means the Battery acid is absorbed in a glass mat rather than being free to slosh around freely.  The AGM batteries are more expensive than the free flowing ones, the main reason being because in the event of a serious accident acid will be retained and not spill on the car occupants.  If you want a plug and play type of replacement you are limited to the original Panasonic, which seems only available from franchised dealers including Parts Direct, or a Yuasa version now made which is also expensive.

However, if you accept the very small risk of acid spill as mentioned above, it is possible to fit a free flow lead acid alternative that is less expensive and with more brand choice.  Furthermore, these can be of higher Ah.

I wanted to retain an AGM type of Battery that was less expensive than the dealer replacement, was higher Ah, and was of a type that was readily available.  I achieved this by buying a Halfords (Yuasa) AGM one which has a 5 year warranty, ie 4 years longer than the Lexus Panasonic but it did mean cutting the plastic Battery base ends to accommodate the extra Battery length. As I wanted to retain the original Battery earth strap, it did mean buying another terminal and making two distance pieces so the existing Battery hold down strap can be retained.  I did post details with pics which I will find and link to if anybody is seriously interested.   The replacement Battery I fitted is 60A and is a size made by other brands. 

Be aware that every time you let your 12v Battery go near flat, it will reduce its life.  If you do go with an AMG Battery, the charger you buy should be set on AGM charging mode and be of a type that charges at 5amps maximum. I use the model mentioned earlier in this thread.

[Monidda]

It's been over a week and zero problems after that one overnight charge. I am thinking come colder weather, the situation might change again and we will have to replace it, but for now I will stick with it as long as it still works. 

[Haylands]

IMHO You really aren't doing the car any favours by trying to eek out more time with this Battery, all of your ECU's, and you have a lot, will not like getting less than their usual 12v+ some may spit their dummy out and you may start to get spurious faults popping up.

It's just not worth the bother, you could end up with all sorts of problems as a result.

Trickle chargers are to help you out if you don't use the car much, they are not designed to keep a dying Battery at a voltage it just doesn't want to be at.

The Battery has tried it's best to warn you of it's impending doom... listen to it and give your car the help it needs.....

 

[PCM]

Bite the bullet and change the Battery.

Before the supply chain disrupts supply.

My wife did eventually, using Lexus - no more problems,

[Monidda]

Battery ordered this morning, thank you so much for your help guys 🙂