4GS 450h 12V battery

i-s · January 11, 2020

Our GS doesn't get used an awful lot - it was bought as a long-distance cruiser, not a local runabout and it doesn't get used daily. It can go weeks at a time without being driven.

Predictably the 12V Battery went flat around July of last year. It was fine after a "jump" (basically one of the few cars that can be jumped off an EV, as it doesn't require any current, just 12V to enable the hybrid system and then the hybrid DC-DC kicks in), but rapidly died again after a few days. As we all know, once a 12V Battery has gone flat a couple of times it can basically be considered toast.

I contacted Lexus and they quoted in the region of £270 for a new 12V Battery. Really?! £270? Come on....

I went on various sites, did the cross-references, seeing what the books say and they all suggested the 068 as the correct Battery for the GS450h 4th gen. Lots of looking around, and previous good experience with the Bosch in our previous volvo (sold at 9 years old with the original Battery still fitted), I ordered the Bosch S4026 through Costco for £83 inc VAT. It arrived, I gave it an overnight on the charger/conditioner before attempting to fit it.

Attempting being the operative word. No way. The base of the Battery is about 5mm too wide to slot down into the Battery tray. Absolute no-go, but thankfully I was able to return the Battery for a full refund.

In the meantime I fitted the car with the wiring loom for a CTEK Battery conditioner and we kept the car on that when not in use, and had no problems with it, downgraded the priority of the search for a replacement. With winter happening now (well, sort of.... mild one!) and with plans for a longer trip coming up it was time to get on with it.

So, full credit to "fillerf" from Norway, who posted here: https://www.clublexus.com/forums/hybrid-technology/876852-2013-gs-450h-battery-issue.html#post10110645

I phoned up my local toyota dealer, and they had the 28800-YZZJA in stock for £94.86 inc VAT. Again, gave it an overnight on the CTEK before fitting it and no issues at all. The 28800-YZZJA is used in the Prius and GT86, and it is an AGM Battery similar to but not identical to the original Panasonic for the GS450h. At 1/3rd the price, I'm not arguing.

And the new Battery will continue to live on the CTEK so that we should never have to replace the 12V again....

royoftherovers · January 11, 2020

That is a wonderful story.

Now if Toyota had one for the MK3 Lexus GS !

i-s · January 11, 2020

I think it might be the same in the 3GS - the original (£270) Battery is the Panasonic S65D26L. If that's the case then the same one should work.

Britprius · January 11, 2020

2 hours ago, royoftherovers said:

That is a wonderful story.

Now if Toyota had one for the MK3 Lexus GS !

John.
On the MK3 GS450H with a very slight reversible modification to the rear edge of the Battery tray a 110 AH Battery can be fitted without any problems. These are available for around £80, and have near double the OEM capacity for no extra cost.
See my post from May 2019.

Battery.">Fitting a larger 12 volt Battery.

John.

johnatg · January 11, 2020

Interesting and quite reassuring tale. But why is it that Lexus quote basically two prices for GS models. For non-hybrids, the price according to the 'Lexus Essential Care' page is £125. For hybrid models it is £235.

One would have thought that this was for significantly different batteries. But why? This from the Yuasa web site ( https://www.yuasa.co.uk/info/technical/auxiliary-back-batteries-explained/

<Quote

Hybrid Vehicle Auxiliary Battery

Most Hybrid vehicles such as the Toyota Prius feature a conventional 12 Volt auxiliary Battery in addition to the high voltage hybrid system Battery.

The 12 Volt Battery is not used for engine starting or to power the traction motors but is used to supply power to:

    Accessory systems
    Headlights
    Audio systems
    Computer controls

(Accompanied by a picture of, presumably, a Prius installation.)

End quote>

I had thought that the more expensive Battery was due to the hybrid 12v Battery needing to be one with stop-start technology capability. Is this not so? It doesn't sound like it.

So, will an 'ordinary' Battery do - or do we really need a stupidly expensive one?

Britprius · January 11, 2020

2 minutes ago, johnatg said:

Interesting and quite reassuring tale. But why is it that Lexus quote basically two prices for GS models. For non-hybrids, the price according to the 'Lexus Essential Care' page is £125. For hybrid models it is £235.

One would have thought that this was for significantly different batteries. But why? This from the Yuasa web site ( https://www.yuasa.co.uk/info/technical/auxiliary-back-batteries-explained/

<Quote

Hybrid Vehicle Auxiliary Battery

Most Hybrid vehicles such as the Toyota Prius feature a conventional 12 Volt auxiliary battery in addition to the high voltage hybrid system battery.

The 12 Volt battery is not used for engine starting or to power the traction motors but is used to supply power to:

    Accessory systems
    Headlights
    Audio systems
    Computer controls

(Accompanied by a picture of, presumably, a Prius installation.

End quote>

I had thought that the more expensive battery was due to the hybrid 12v battery needing to be one with stop-start technology capability. Is this not so? It doesn't sound like it.

So, will an 'ordinary' battery do - or do we really need a stupidly expensive one?

The hybrid 12 volt Battery does not need to be of the stop start variety as it does not start the car.
When the engine stops in a hybrid while driving the car stays in ready mode, and this in turn means the 12 volt Battery is still being charged from the hybrid HV Battery via the Dc to DC converter "there being no alternator as this would not work with the engine stationary". When the engine starts it uses the hybrid Battery to turn the engine over via one of the motor generators in the transmission "there is no 12 volt starter motor" so the 12 volt Battery is not employed.

The reason for the more expensive Battery in the Prius, and the CT200H is that they use a more expensive AGM Battery "absorbed glass mat". This type of Battery has no free liquid acid to spill if the Battery case get broken in an accident with the Battery being in the passenger compartment "although well covered. I do not know the location of the 12 volt Battery in the GS300H. If it is in the boot or under the bonnet there is no reason to use an AGM Battery. If it is inside the car it must be your choice.
In the GS450H the Battery is in the boot so the above does not apply, and a normal Battery is used. I would not hesitate to use a normal Battery in the Prius or CT as I do not consider acid splash is a substantial risk, but this decision must be up to the individual.

The is no functional difference between an AGM Battery, and a standard flooded Battery.

John.

Britprius · January 11, 2020

As an addition to the above for many years some vehicles have had standard flooded batteries inside the cabin. The VW beetle and mini van, and pickup, the Mercedes MPV, and there must be many more.
I do not know where the Battery in the GS300H is located. If in the boot or under the bonnet there is no reason to use an AGM. If in the cabin It is up to you to asses any risk for the use of a standard Battery.

John.

johnatg · January 11, 2020

OK that makes sense. I haven't explored the Battery installations of my GS300h yet - been too cold mostly since I bought it. But I do know it's in the boot so I guess is identical to the GS450H installation.

One reason for using AGM batteries in boot installations in because of acid spray. All lead acid batteries vent hydrogen and oxygen when charging and the gases, which emerge from the vent holes which you will find usually at the top of the ends of the Battery can carry a fine mist of acid. There is much less chance of acid spray with AGM batteries.

eg the MX-5 Mk 1 and 2 have boot mounted batteries and use AGM ones. People replace them with normal liquid acid batteries and the result is often that the area around the Battery gets very corroded - this can be avoided by connecting vent pipes to the vent holes to lead the gas and spray out of the boot (via a hole in the boot floor). I guess Lexus GS might be somewhat similar.

Engine compartments are much draughtier then boots, so the spray is blown away by the breeze and doesn't cause harm - unless neglected - you often see very rusty Battery trays on some cars.

You might think this spray is insignificant, especially in a modern sealed Battery. It's not. And even sealed batteries have these vent holes.

Britprius · January 11, 2020

1 minute ago, johnatg said:

OK that makes sense. I haven't explored the battery installations of my GS300h yet - been too cold mostly since I bought it. But I do know it's in the boot so I guess is identical to the GS450H installation.

One reason for using AGM batteries in boot installations in because of acid spray. All batteries vent hydrogen and oxygen when charging and the gases, which emerge from the vent holes which you will find usually at the top of the ends of the battery can carry a fine mist of acid. There is much less chance of acid spray with AGM batteries.

eg the MX-5 Mk 1 and 2 have boot mounted batteries and use AGM ones. People replace them with normal liquid acid batteries and the result is often that the area around the battery gets very corroded - this can be avoided by connecting vent pipes to the vent holes to lead the gas and spray out of the boot (via a hole in the boot floor). I guess Lexus GS might be somewhat similar.

Engine compartments are much draughtier then boots, so the spray is blown away by the breeze and doesn't cause harm - unless neglected - you often see very rusty battery trays on some cars.

You might think this spray is insignificant, especially in a modern sealed battery. It's not. And even sealed batteries have these vent holes.

Invariably you will find both the AGM and standard sealed have vent at the end of the Battery, and a rubber tube is fitted, and vents to the underside he car. This is true of the Prius, and the CT but not the GS450H.
The great majority of modern sealed batteries be they AGM or flooded now use a low pressure relief valve above each cell, and each cell has a catalyst in the top to convert the hydrogen, and oxygen gasses back in to water to alleviate the need for topping up with distilled water. Even the batteries with the old style top up caps have the catalyst in the caps now. Without this both types of Battery would dry out very quickly, but particularly the AGM because of it's lack of spare liquid.
Both types of Battery use exactly the same chemistry for there operation. Gassing will occur if the Battery charge rate is to high producing more gas than the catalyst can cope with.

Gel batteries will also gas if the charge rate is to high, but this generally destroys the Battery as the gas gets stuck in the gel against the plates as it cannot rise through the gel. This reduces the area of the gel in contact with the plates reducing the capacity, and the safe charge rate further.

John.

johnatg · January 11, 2020

I think we have answered my question re difference in Battery prices.

GS hybrids are fitted originally with AGM batteries, non-hybrids had flooded batteries.

Going by Lexus essential care price list, CT200h have flooded batteries and are fitted with vent tubes.

GS hybrids with AGM batteries don't have vent tubes.

You can replace an AGM Battery with a flooded one and it will work fine, but if you are concerned about the longevity of the metal near the Battery you might think about fitting vent tubes.

Windscreen washer piping works well and you can modify in line connectors to attach the tubes to the Battery. I have come across batteries with square vent holes - avoid them. Tubes can be connected together with T- connectors. Lead the pipes to underneath the car.

If you decide to fit an AGM Battery they are available for a helluva lot less than Lexus prices - round about £100 to £110.

Sent from my PSP7551DUO using Tapatalk

Sherra · January 13, 2020

My 2009 GS450h has a vent tube.

johnatg · January 13, 2020

Well well - the picture changes! I was going by John's (Britprius) assertion that GS450h don't have a vent tube.

Paul's post has prompted me to have a look at my own 2014 GS300h Battery - guess what - it has a vent tube! (Only one, from one of the vent holes - most batteries have one in each end). See pic attached - the vent tube is at the left hand end - black tube in the middle.

Re Prius and CT200h having a more expensive Battery (see several posts ago) - don't know about the Prius but going by the Lexus Essential Care price list the CT200h has a flooded Battery (price for a fitted replacement £125). the GS450h and GS300h price is £235, implying an AGM Battery - but even so, with a vent tube.

Perhaps that's just belt and braces, because even AGM batteries can potentially discharge acid spray via their vent holes, albeit in lesser amount than from a flooded Battery. Refer to my previous comments about corrosion caused by this acid spray in non-vented boot mounted Battery installations - even a minute amount of acid mist will cause corrosion given time and no ventialtion.

I guess all this means that Lexus fit AGM batteries with a vent tube in hybrids - you could replace them with flooded batteries but be sure that the vent arrangements are secure - possibly fit an additional tube to T into the existing tube but from the 'other' vent.

Flooded batteries are described as 'EFB (Enhanced Flooded Battery)' in Battery specs. AGM batteries have better deep cycling capabilities (ie can stand more discharge) but may require more controlled charging conditions, especially when nearing full charge.

Digitalparadox · January 15, 2020

From this story I just had one question- what is your local runabout? I don't think I could ever leave the GS 450h for long distance cruising as it's so fun to drive regardless!

i-s · January 15, 2020

2 hours ago, Digitalparadox said:

From this story I just had one question- what is your local runabout? I don't think I could ever leave the GS 450h for long distance cruising as it's so fun to drive regardless!

Tesla Model 3.

Digitalparadox · January 15, 2020

That explains it!

i-s · January 15, 2020

When we got the GS the other car was a Leaf, and we didn't really have plans to change that. When the 3 launched in the UK I ran the numbers and discovered that we could manage it - the Tesla is far more adept at long journeys than the Leaf, and so the GS sees a bit less action than it would have if we'd stayed with the Leaf as second car. The other part of it is that the GS is hubby's car, the Tesla is mine.

subman · February 20, 2020

I am following this thread and also an earlier "alternate Battery option for 450h"

Since I got the car the Battery gets drained if not driven, at first every 3 weeks, then every 2 weeks and recent cold weather every few days.....put another Battery in it (non AGM) and still the same. Finally I got to do the parasitic drain test with my multi meter and found the problem, the dash cam was plugged into a fuse slot where there is permanent live 12v.

I left the non AGM Battery in my car now and added a Bluetooth Battery monitor to the car, it only draws 1mA and resting current draw for the car after fix is 30mA with the Bluetooth monitor. We only drive the car at weekends and having a charger plugged in is a bit of a hassle as we don't have a garage and charge outdoor on the drive etc.

The Battery monitor connects to my phone, I can access the store data log in my sitting room when the app is running.

Will post a YouTube video soon