12volt Battery ordered

Barry7 · August 30, 2021

After seven years and about 60k the 12v Battery has started giving problems. This had been replaced at three years old when I bought the car so I guess seven years for this one is OK. I've trawled through all of the very in depth posts about original and after market batteries, and rightly or wrongly decided to go for an original from Lexus parts direct in Swindon £199 delivered with a little bit of gold discount.

It should turn up this week, and at that point I will be asking all sorts of questions regarding resets of seats windows etc 😜

I will let you know how I get on.

Herbie · August 30, 2021

26 minutes ago, Barry7 said:

and at that point I will be asking all sorts of questions regarding resets of seats windows etc

If you have another 12V source (such as another car and jump leads) simply connect it to the cables before you disconnect them from the Battery so that no settings are lost.

Barry14UK · August 30, 2021

If you read read this link you will see you can buy a 'Battery saver' which is used by a number of garages and this enables settings to be retained. However, when it came to it, I thought it safer to use the method detailed by Herbs and changed the Battery without losing any settings. (I helped that I had a spare 12 volt battery).

Incidentally, the 12v AGM battery I bought from Halfords with 5 year warranty made by Yuasa using my Gold card circa £103 and providing 60 Ah rather than the 51Ah of the Lexus Panasonic, is holding up well. I did spend about another £30 adapting for my RX although this could have been done another way for less.

Illogan · August 30, 2021

29 minutes ago, Herbie said:

If you have another 12V source (such as another car and jump leads) simply connect it to the cables before you disconnect them from the battery so that no settings are lost.

I just attached my (already purchased) NoCo Jump starter (https://www.amazon.co.uk/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B015TKUPIC/ref=asc_df_B015TKUPIC/?tag=googshopuk-21&linkCode=df0&hvadid=309775958298&hvpos=&hvnetw=g&hvrand=15567152916548422783&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006886&hvtargid=pla-449394730282&psc=1&th=1&psc=1) to the Battery - connections - thus acting as a power source and protecting all the settings.

Or - as Herbie wrote - borrow a Battery and just connect it to you car's leads before you disconnect your Battery!

Herbie · August 30, 2021

To be honest it could even be done with a pack of 8 AA batteries because current draw will be almost minimal as long as you turn things like the interior lights off, the radio off and don't attempt to use anything like power back doors etc.

As I explained in the topic Barry linked to above, the radio, the clock, the window controller and suchlike all have a small chip in them that stores the respective settings as long as there is a power supply. If that supply gets interrupted then the chip is erased and the settings are lost.

So, all you're doing is keeping the power supply to the chips on, and that doesn't take much power at all.

Barry7 · September 1, 2021

Part of the reasoning for buying the original fitment Battery was that when the car is serviced at Lexus the hybrid system is guaranteed for another year, and now the car gets a guarantee as well, so if I need to claim, and an after market 12v Battery is fitted, I assume this may jeopardise the chance of a claim. So imo I think the extra cost is worth it.

Barry14UK · September 1, 2021

A number of owners have posted on the forum that they have fitted an alternative 12v Battery to their car, mainly due to price and availability and wider choice enabling easy fit, just replaceing with a free flow lead acid one, which is the type previously used when the RX had it's Battery located beneath the bonnet. When Lexus relocated the 12v Battery to the rear of the car, the occupants lost the protection afforded by the bulkhead in the event of an accident where acid could reach them. The Panasonic AGM type Battery reduced this risk as the acid is absorbed in the glass mat and was the most likely reason for Lexus changing to an AGM Battery.

I decided I wanted to replace my Battery with an AGM type and one that would be cheaper and have greater capacity than the Panasonic one. My car fitted with the Halfords Yuasa AGM one was serviced a few days ago including the 'Health Check' for the traction Battery without comment by a Lexus main dealer.

Generally, I am a keen advocate of fitting only Lexus approved parts but I don't think it makes any difference which 12v Battery is fitted from an operational aspect.

ColinBarber · September 1, 2021

3 hours ago, Barry14UK said:

The Panasonic AGM type battery reduced this risk as the acid is absorbed in the glass mat and was the most likely reason for Lexus changing to an AGM battery.

If it was the reason it isn't a concern for Toyota/Lexus anymore as the current series IV RX and ES300h have flooded batteries in the boot.

Barry14UK · September 1, 2021

3 hours ago, ColinBarber said:

If it was the reason it isn't a concern for Toyota/Lexus anymore as the current series IV RX and ES300h have flooded batteries in the boot.

It would be interesting to learn the reason for this. Maybe it is because free flowing batteries are better built and more resilient to spillage/vibration now but if this is the reason you would have thought that this should apply across the Lexus range. Another possibility is that there are more sizes of these available than AGM type and available space is more effectively used in terms of Ah, something many people have complained about even before the reduced use during the pandemic when flat batteries at airports were found by returning travellers for example.

What do you think is the reason behind the difference?

Gliderpilot · September 2, 2021

I don't know if I was lucky or not but when I had my towbar fitted, the Battery was disconnected for some time. On reconnection I didn't have to rest anything, all the settings were still there for the seats and mirrors etc and the windows operated as normal.

ColinBarber · September 2, 2021

2 hours ago, Gliderpilot said:

all the settings were still there for the seats and mirrors etc and the windows operated as normal.

normally it is just the hard press on the button to auto open/close the windows fully that needs initialising, rather than them not working at all. The system has to learn the motor stall current so it can correctly detect when the window has come to a stop, either at the extent of the travel or an object has created resistance (safety feature).

u81 · September 4, 2021

Hi everyone,

new here.

Just wanted to check if anyone has tried using a mobility AGM deep discharge 12v 65ah Battery in their Lexus.

I've owned two prii for over 10 years and put an Pro Rider 12v55ah AGM deep discharge mobility Battery in it in 2018 and haven't seen the 12v flatten ever since then.

I've replaced one of my prii with with the Lexus Nx300h and already experiencing the flattening of 12v Battery.

I have also seen the Halfords AGM 12v 60AH but the warranty specifically excluded deep cycling and thought I'll check here to for advice.

Thanking you in anticipation of your helpful advice.

ColinBarber · September 4, 2021

55 minutes ago, u81 said:

Hi everyone,

new here.

Just wanted to check if anyone has tried using a mobility AGM deep discharge 12v 65ah battery in their Lexus.

I've owned two prii for over 10 years and put an Pro Rider 12v55ah AGM deep discharge mobility battery in it in 2018 and haven't seen the 12v flatten ever since then.

I've replaced one of my prii with with the Lexus Nx300h and already experiencing the flattening of 12v battery.

I have also seen the Halfords AGM 12v 60AH but the warranty specifically excluded deep cycling and thought I'll check here to for advice.

Thanking you in anticipation of your helpful advice.

Not sure it has been specifically done on the NX before but yes people have used them on other Lexus hybrids (and Prius vehicles). It's just a case of finding one that will physically fit (possibly something larger than 65ah will be achievable as the Battery is larger than the one in a Prius series II or III).

Barry14UK · September 4, 2021

There is a voltage point to which even the Panasonic AGM should not fall below. If this is allowed to keep happening it will shorten the life of it.

As regards mobility batteries, I did consider this for my RX but if I correctly recall, these may have been 'gel' type and or lacked the valve and release tube connection which Lexus have in the RX so any release of gas caused by overcharging is carried away outside the car.

I have not looked at this for the NX.

u81 · September 5, 2021

Thank you both for your helpful responses.

Do either of you know if we can check the voltage from the Battery using the car's heads up display. I know it is possible to do this in Prius by pressing a combination of buttons but am unaware of the possibility on the Lexus.

The reason for looking at the mobility batteries is their high resistance to deep discharges. Do you know if same or comparable is available in flooded batteries?

Thanks again.

Herbie · September 5, 2021

56 minutes ago, u81 said:

Do either of you know if we can check the voltage from the battery using the car's heads up display.

I may be wrong but I would imagine that the HUD would only activate with the car in READY mode and if that's correct then it would be reading the output voltage of the DC/DC converter, which is the hybrid equivalent of the alternator (approx. 14.5V) and not true Battery voltage.

ColinBarber · September 5, 2021

On 9/1/2021 at 10:20 PM, Barry14UK said:

It would be interesting to learn the reason for this. Maybe it is because free flowing batteries are better built and more resilient to spillage/vibration now but if this is the reason you would have thought that this should apply across the Lexus range. Another possibility is that there are more sizes of these available than AGM type and available space is more effectively used in terms of Ah, something many people have complained about even before the reduced use during the pandemic when flat batteries at airports were found by returning travellers for example.

What do you think is the reason behind the difference?

Cost saving is the only reason I can think of. All the newly designed models have flooded batteries (series IV RX, ES, UX).

Barry14UK · September 6, 2021

The 'memory saver' I mentioned a few posts back which I didn't use for the Battery change having been warned it might cause problems , has a secondary function which when plugged into the OBD shows the voltage. It also shows something else which I have forgotten. Unfortunately, the read out on the particular one I bought displays the figures on the underside when in place so I have to use a mirror to read it, LOL. Anyway, it saves me carrying my scan tool for the purpose. Actually, Herbs had the best solution which he showed some months ago in a post.

11 hours ago, ColinBarber said:

Cost saving is the only reason I can think of. All the newly designed models have flooded batteries (series IV RX, ES, UX).

I think you may be right Colin, I wonder how long it will be before they follow most other brands and drop the space saver wheel thereby saving cost and weight.

Barry7 · September 10, 2021

New Battery arrived from Lexus parts direct, all wrapped up very securely, it even had rope carrying handles built into the box.

I connected another Battery to the jump point under the bonnet and then very carefully replaced the Battery in the boot. So no resets required.

I don't know if it is the placebos effect, but its doing better mpg now. Also when stationary in traffic, it does not start the engine as much as it used to.

Anyway that's all done for another seven years now, fingers crossed.