Hybrid 12V battery replacement

pkts · May 16, 2020

I'm having a hell of a time trying to find a replacement for my IS300h 12v Battery. Searched on here and it seems like everyone has had this problem and no solution ? Is my only option going to the dealer ? I would have thought at least that a Prius or Camry Battery would be a good alternative and that a Toyota dealership could handle it. When I search here (located in Australia) even the Battery websites seem confused. For example my understanding is that I need a deep cycle AGM Battery but this website brings up these two batteries when I enter my car type and neither seem to be AGM (they are EFM) ?!?! I'll call the dealer and get a quote but am just assuming it will be super overpriced.

https://www.everybattery.com.au/proddetail.php?prod=N-S100%2FAS

https://www.everybattery.com.au/proddetail.php?prod=SS95D26REFBD

Someone in another post suggested an electric scooter Battery but even if I could locate the right one and check the dimensions would fit, I don't feel comforable installing myself so what am I going to do, just show up at Lexus with it ? Haha

pkts · May 17, 2020

This post seems to have lots of good info. I'm thinking of getting a trickle charger onto the Battery to see if slowly charging it up can recondition or improve its ability to hold a charge. Or have a supplemental Battery in the boot to jump it or recharge the Battery if it won't start when I'm out.

https://www.toyotanation.com/threads/hybrid-12v-battery-jumping.1549682/

Mihanicos · May 17, 2020

Hi,

If you search the Internet, you will see that AGM batteries can take a higher charging current than a gel Battery. They also deliver a higher current compared to the gel batteries. There are some differences in their characteristics in design, performance and durability bu the key here is the charging current, which is less for a gel battery than an AGM Battery. Therefore the charging circuit of the car would be operating at a lower level without the risk of overloading and subsequently causing a fault.

I would put a gel battery instead if it is cheaper. Choose the highest ampere hours for the physical size available.

When I had to replace the 12v Battery of my car, the dealer wanted 500 Euro for it. Instead I put an 80 Ampere hour as opposed to the original 57 Ampere hour .

Chris.

Shada · May 17, 2020

I replaced mine with one from ecp. About £80

Britprius · May 17, 2020

Under no circumstances use a gel Battery. The problem with gel batteries is the very limited charge rate. All lead acid batteries be they flooded, liquid AGM, or gel AGM form gas bubbles on the plates if charged quickly or are continued to charge when already fully charged.
With the flooded, and liquid AGM batteries the bubbles just float to the surface.
With gel AGM batteries the bubbles cannot float in the gel, and are permanently trapped against the cell plates reducing the area of plate in contact with the acid. In turn the rest of the area of the plate carries more current making that more susceptible to gassing with the same problem.
These bubbles are very difficult to remove. The only way being to put the Battery into a high vacuum so that the bubbles expand, and have a better chance of forcing themselves upwards through the gel. Even this is not 100% effective.
The hybrid DC to DC converter that charges the 12 volt Battery can, and does charge at far higher rates than gel batteries are designed for.

Used in the right circumstances gel batteries have a long life, and are particularly suited to standby use or use in very cold conditions, but are not suitable for automotive applications.

John.

Mihanicos · May 17, 2020

Well the original 12v Battery of my car was replaced after two years from new and the second Battery lasted five years.

The gel Battery now in service is working fine and it only cost me 70 Euro.

No battery trouble codes of any kind have been displayed to date.

Chris.

Britprius · May 17, 2020

4 minutes ago, Mihanicos said:

Well the original 12v battery of my car was replaced after two years from new and the second battery lasted five years.

The gel battery now in service is working fine and it only cost me 70 Euro.

No battery trouble codes of any kind have been displayed to date.

Chris.

There are no codes for a low 12 volt Battery, Only spurious misleading messages such as "put the car into P mode when parking".
Also gel AGM batteries generally cost more than wet type AGM batteries, but otherwise the construction of both batteries are the same. The difference is the standard AGM use liquid acid while the gel AGM Battery uses the acid in gel form. The gel Battery will work but it's life will be shorter than expected other than under the conditions it was designed for. Toyota/Lexus would have fitted a gel AGM Battery from new if they were cheaper, would last longer, and were suitable for the application.
In my GS450H I have fitted a 110 AH flooded Battery as the original was a 70 AH flooded Battery that failed when it was 12 years old. Toyota/Lexus usually use AGM batteries generally where they are fitted inside the cabin of the car for safety reasons such as in the Prius, and CT200H along with others. This is so that in an accident there is no free liquid acid to splash onto occupants of the car should the Battery be damaged. With the GS hybrid the Battery being in the boot there is no point in using an AGM Battery.

John.

pkts · May 17, 2020

2 hours ago, Britprius said:

There are no codes for a low 12 volt battery, Only spurious misleading messages such as "put the car into P mode when parking".
Also gel AGM batteries generally cost more than wet type AGM batteries, but otherwise the construction of both batteries are the same. The difference is the standard AGM use liquid acid while the gel AGM battery uses the acid in gel form. The gel battery will work but it's life will be shorter than expected other than under the conditions it was designed for. Toyota/Lexus would have fitted a gel AGM battery from new if they were cheaper, would last longer, and were suitable for the application.
In my GS450H I have fitted a 110 AH flooded battery as the original was a 70 AH flooded battery that failed when it was 12 years old. Toyota/Lexus usually use AGM batteries generally where they are fitted inside the cabin of the car for safety reasons such as in the Prius, and CT200H along with others. This is so that in an accident there is no free liquid acid to splash onto occupants of the car should the battery be damaged. With the GS hybrid the battery being in the boot there is no point in using an AGM battery.

John.

Thanks for the detailed information John. The 12v in the IS300h is also in the boot, does this mean that I could put in a flooded Battery too ? I like the idea of using a higher Ah flooded Battery and hopefully it lasting longer. I wonder why Lexus put an AGM Battery into the IS300h and a flooded in the GS450h

Britprius · May 17, 2020

51 minutes ago, pkts said:

Thanks for the detailed information John. The 12v in the IS300h is also in the boot, does this mean that I could put in a flooded battery too ? I like the idea of using a higher Ah flooded battery and hopefully it lasting longer. I wonder why Lexus put an AGM battery into the IS300h and a flooded in the GS450h

It does seem strange that Lexus sometimes use AGM batteries and at other times flooded apart from the reasons I have already given. However in answer to your question yes you can use a flooded Battery in your IS300H.
As far as fitting a larger Battery goes it depends on how much space there is around your Battery. See my post linked below.

John.

pkts · May 17, 2020

14 minutes ago, Britprius said:

It does seem strange that Lexus sometimes use AGM batteries and at other times flooded apart from the reasons I have already given. However in answer to your question yes you can use a flooded battery in your IS300H.
As far as fitting a larger battery goes it depends on how much space there is around your battery. See my post linked below.

John.

Awesome, I'll take a look. Thanks John.

ColinBarber · May 17, 2020

1 hour ago, pkts said:

Thanks for the detailed information John. The 12v in the IS300h is also in the boot, does this mean that I could put in a flooded battery too ?

The IS300h has folding rear seats so the boot isn't sealed as with the GS.

Britprius · May 17, 2020

On your original Battery there is a sensor for Battery temperature. This can be gently pried off, and glued or taped to the top of you replacement Battery.

John.

pkts · May 17, 2020

Called Lexus, they quoted $ 650 AUD (345 GBP) for putting in new Battery and don't have it in stock 🤯 Think I'll try elsewhere or maybe try a slow charger to see if Battery can be resurrected.

pkts · May 17, 2020

1 hour ago, ColinBarber said:

The IS300h has folding rear seats so the boot isn't sealed as with the GS.

I wonder if a flood type Battery is ok if the seats aren't folded down. Or if, even with them up, they aren't sealed as well as the GS is and thus the AGM has to be used over the flood Battery ?

ColinBarber · May 18, 2020

In a rear end accident, or if the vehicle rolls over, you run the risk of acid leaking into the cabin if the Battery is compromised. If the seats are down then there is a greater chance of that happening but even when up, it isn't liquid sealed and therefore some could still get it.

A flooded Battery will work fine, you just have to make a decision on the risk of acid leaks.

pkts · May 19, 2020

On 5/18/2020 at 5:53 PM, ColinBarber said:

In a rear end accident, or if the vehicle rolls over, you run the risk of acid leaking into the cabin if the battery is compromised. If the seats are down then there is a greater chance of that happening but even when up, it isn't liquid sealed and therefore some could still get it.

A flooded battery will work fine, you just have to make a decision on the risk of acid leaks.

It seems like a pretty low risk esp since I rarely have passengers in the rear seats or the seats down. However I haven't been able to find either flooded or AGM Battery in stock anywhere. Ended up ordering from Lexus and they think it'll be a few weeks. I guess supply chains are just seized up from coronavirus.

Barry14UK · May 20, 2020

I don't know the spec for the IS 300h but the type of Battery fitted should always be the same as was originally installed by the factory. This is clearly stated by the leading Battery brands (some of whom paradoxically suggest an inappropriate Battery for my RX450h). If your car originally had a AGM (VRLA) deep cycle Battery , a flooded lead acid Battery, EFM, or Gel is not ideal. In addition to what Colin says there are other reasons which are detailed by Yuasa if you scroll down past Stop/Start but of course regeneration advantages don't apply as the traction Battery benefits with our cars :- https://www.yuasa.co.uk/info/technical/micro-hybrid-hybrid-vehicles-explained/

As well as being the same type as the original, the replacement should match the Ah, although if there is room a larger Ah Battery of the correct type can be fitted.

So buying the Lexus Battery is the best choice in view of unavailability of comparable alternative - hope this makes you feel a little better!

ganzoom · May 20, 2020

On 5/17/2020 at 12:06 PM, Shada said:

I replaced mine with one from ecp. About £80

Am sure our IS will need a Battery at some point, can I check, do you need to code it to the car or any is it a case of plug and play?

Shada · May 20, 2020

Screw it in and drive away. Set the clock!

pkts · May 21, 2020

On 5/20/2020 at 10:11 AM, Barry14UK said:

I don't know the spec for the IS 300h but the type of battery fitted should always be the same as was originally installed by the factory. This is clearly stated by the leading battery brands (some of whom paradoxically suggest an inappropriate battery for my RX450h). If your car originally had a AGM (VRLA) deep cycle battery , a flooded lead acid battery, EFM, or Gel is not ideal. In addition to what Colin says there are other reasons which are detailed by Yuasa if you scroll down past Stop/Start but of course regeneration advantages don't apply as the traction battery benefits with our cars :- https://www.yuasa.co.uk/info/technical/micro-hybrid-hybrid-vehicles-explained/

As well as being the same type as the original, the replacement should match the Ah, although if there is room a larger Ah battery of the correct type can be fitted.

So buying the Lexus battery is the best choice in view of unavailability of comparable alternative - hope this makes you feel a little better!

Thanks Barry,

I am feeling better about it, I always prefer to go with what the manufacturer suggests as long as reasonable. However waiting a month for the part to come in and $200-300 more expensive was a bit much (my first Lexus quote). Fortunately I got a better second quote and I guess I'll just have to hope the Battery holds out for a month. I turned off smart access and auto lights so as to not deplete the Battery before it gets to READY.