Replacement NX300h 12v Auxiliary Battery Alternatives

[Steve Oliver]

I need to change my 12v Battery, preferably to a more powerful one than the OEM Panasonic version and am having a lot of trouble identifying suitable alternatives. I believe it needs to be an AGM Battery. Has anyone changed theirs for a Bosch, Exide, whatever... and do you know what you bought?? Any assistance appreciated, thank you 👍

[IS300FSPORT]

Take a look on Tayn car batteries website or Lexusparts direct.

https://www.tayna.co.uk/?gad_source=1&gclid=Cj0KCQiAoKeuBhCoARIsAB4WxtdAkCHWXA9a8S-ttNZMeUsCNTCIb5c3qLzPoKsvVYQC-LLX4HlBF3YaAumvEALw_wcB

I had a Panasonic lead acid Battery before can only assume it is what was supplied when it left the factory. Since then I purchased a Battery from Lexuspartsdirect they supplied an AGM Battery. The one advantage of AGM is they are suppose to be sealed so in the event of a rear end accident the acid wont leak + they handle discharge better in terms of recovery. Since your 12v is located under the boot compartment in the spare tyre section how likely is it to leak anyway worst case scenario if its upside down. 

The disadvantage with going with what Lexus provide the batteries have low AH amps per hour rating hybrid 12v batteries typically rated around 45-55AH. They need to be either recharged or driven regularly. Id suggest if you have access to an outdoor socket consider investing in a Noco Genius 5 charger & charge it once a month. Getting a new Battery is all well & good but if your not using the car regularly to give it a chance to charge up you will only end up with a flat Battery. If its over 5 years old then its not long before its due replacement anyway. To the point try to find a Battery with the highest AH that fits the dimensions of your existing Battery.

[Steve Oliver]

On 2/13/2024 at 12:43 AM, IS300FSPORT said:

Take a look on Tayn car batteries website or Lexusparts direct.

https://www.tayna.co.uk/?gad_source=1&gclid=Cj0KCQiAoKeuBhCoARIsAB4WxtdAkCHWXA9a8S-ttNZMeUsCNTCIb5c3qLzPoKsvVYQC-LLX4HlBF3YaAumvEALw_wcB

I had a Panasonic lead acid battery before can only assume it is what was supplied when it left the factory. Since then I purchased a battery from Lexuspartsdirect they supplied an AGM battery. The one advantage of AGM is they are suppose to be sealed so in the event of a rear end accident the acid wont leak + they handle discharge better in terms of recovery. Since your 12v is located under the boot compartment in the spare tyre section how likely is it to leak anyway worst case scenario if its upside down. 

The disadvantage with going with what Lexus provide the batteries have low AH amps per hour rating hybrid 12v batteries typically rated around 45-55AH. They need to be either recharged or driven regularly. Id suggest if you have access to an outdoor socket consider investing in a Noco Genius 5 charger & charge it once a month. Getting a new battery is all well & good but if your not using the car regularly to give it a chance to charge up you will only end up with a flat battery. If its over 5 years old then its not long before its due replacement anyway. To the point try to find a battery with the highest AH that fits the dimensions of your existing battery.

Thanks for your reply, Al. I spoke with a couple of Lexus dealers (and Lexus Parts Direct) and surprisingly (?) none of them were really very sure what the specification required is. The comment from one was that the OEM one isn't an AGM Battery - jury's still out on that... So, I settled for a Bosch S5 005 which is a 63 Ah Battery and maintenance free, has a 5 year guarantee , and it's now fitted and so far so good all working. The Bosch isn't AGM either but by all accounts has technology to prevent it leaking. 

Thanks for taking the time to reply. 😀

 

[IS300FSPORT]

Thats great! A 63AH Battery should be more than capable, & should easily last you 5 years if the car is being used every 5-10 days or so. As long as your not running permanent live power with the ignition off i.e a hardwired dashcam in parking mode (motion detection) etc it shouldnt drain your Battery.

Theres a way to test the  12v voltage  from the multimedia screen holding Menu button & flicking headlight switch on/off upto 5x. Takes you into a diagnostic screen. (IS300H) maybe the same technique on other models? 

Or just use a multimeter to check resting voltage after being parked for an hour  anything above 12.2v will keep you out of trouble. 

If you really want peace of mind & dont want to be stranded either charge it once a month or keep a jump pack in the boot ready to go I.e noco GB40 Cost approx £80. 

Top tip is dont listen to the radio or use power when the car is off.

For example move elec seats, interior lights, radio, air tyre compressor always use when car is in the 'Ready' mode so the voltage you output is getting a chance to recharge the Battery.

[hintonwood]

3 hours ago, IS300FSPORT said:

If you really want peace of mind & dont want to be stranded either charge it once a month or keep a jump pack in the boot ready to go I.e noco GB40 Cost approx £80. 

I would keep the booster in the main cabin so that if the Battery is flat you have easy access to it. Otherwise you would have to put the rear seats down to try and access the boot.

[ColinBarber]

6 hours ago, Steve Oliver said:

The comment from one was that the OEM one isn't an AGM battery - jury's still out on that...

I'm pretty sure it isn't AGM - the fact that the OEM Panasonic Battery has min/max fluid level markings implies it is a flooded Battery of some kind. The OEM Battery is 60 Ah (20 hours) so your Bosch has a very slight capacity advantage - which can only be a good thing 🙂 

[IS300FSPORT]

1 hour ago, hintonwood said:

I would keep the booster in the main cabin so that if the battery is flat you have easy access to it. Otherwise you would have to put the rear seats down to try and access the boot.

Good shout, *some models have a lock that can be accessed hidden just above the number plate where the number plate light panel usually is. Takes abit of effort with key to open look carefully you will find a lock barrel. 

[Steve Oliver]

1 hour ago, ColinBarber said:

I'm pretty sure it isn't AGM - the fact that the OEM Panasonic battery has min/max fluid level markings implies it is a flooded battery of some kind. The OEM battery is 60 Ah (20 hours) so your Bosch has a very slight capacity advantage - which can only be a good thing 🙂 

You're right, it does have min/max markings, so seems you're right. I think this Bosch Battery can only be an improvement. I never really trusted the previous one very much.

[jbi507]

@Steve Oliver after your Battery change did you have reset anything?

I had to manually close the boot lid and now my parking assist is unavailable. Therefore wondering if you faced anything similar. 

[Steve Oliver]

4 hours ago, jbi507 said:

@Steve Oliver after your battery change did you have reset anything?

I had to manually close the boot lid and now my parking assist is unavailable. Therefore wondering if you faced anything similar. 

Hi, yes I had to reset the boot lid too. Also the parking assist had to recalibrate, which it does when you drive over 40mph-ish in a straight line. I've done this twice now and both times have worked. Apparently it's expected when changing the Battery.

Otherwise the only things I had to reset were the climate set temperatures and the HUD settings (height and what is displayed). Oh, and possibly the steering wheel height and reach. HTH

[jbi507]

Brilliant, thanks @Steve Oliver I was getting worried something had broken.