What is the correct 12v battery for the 2023 RX350h ?

Local Lexus dealership performed a warranty replacement of the existing battery, they installed a 00544-MFH50.
Internet search indicates the MFH50 is a conventional lead-acid Group H5 (aka; group 47) battery intended for RX350, but not the RX350h.
Internet search also indicates the 'normal' battery that shipped in the RS350h is a group 24 AGM (Absorbent Glass Mat) battery.
Comparing the differences between the group 47 and group 24 battery indicates Group 47 is common in modern European/compact cars, while Group 24 is often used in larger vehicles, trucks, or marine applications for higher capacity..

Considering the parasitic draining from electronics that are kept alive and running while the vehicle is 'OFF', does it make sense the replacement battery is a lower capacity battery?

Appreciate all feedback, Del92

 

Toyota doesn't use AGM battery on newer hybrids.

 

They used a regular lead acid battery in my 2023 which was replaced in February.

 

Perhaps inquire at an Interstate Battery distributor near you.

https://www.interstatebatteries.com/

 

Good recommendation, wish I'd thought of that before posting.

Checking the Interstate Battery web site they list two recommendations for the 2023 RX350h,
First recommendation is an MTX-47/H5 (AMG) battery with a 36 month warranty.
Second recommendation is an MTP-47/H5 Flooded lead/acid battery with a 30 month warranty.
.
That said, If Only the battery would last more then 24-26 months before failing and requiring replacement.
This is my second replacement, first at 8 months after picking up the vehicle,

I wish Lexus would release a patch or recall to fix the DC-DC charger module that consistently leaves the battery in a low level charge state after operating the vehicle for a time.

DEL92
2023 RX350h Premium+

 

If you want an AGM battery, its going to come out of your pocket. Lexus will only replace with the lead acid. Will the AGM last longer or be less trouble free? Who knows. I thought the better solution was the Ionic emergency start. At least that gives a little more peace of mind since Lexus has no interest in fixing it's faulty charging algorithm.

 

Does the battery they installed have a vent tube?

 

Where should a person look for a vent tube, as part of the battery, something in the battery area, etc ?

 

I don't have a good picture of it in the RX, but here is a picture of it in my GR Corolla.

 

If you're going to get a new 12V battery, why not ask the battery pros about a 12V AGM Marine battery. A Marine grade battery has thicker plates that can handle deeper discharges than a standard AGM or a standard lead acid battery.

Just tossing out an option.

 

Marine deep-cycle batteries can handle multiple deep discharges much better than automotive starter batteries, but they still suffer from sulfation if not kept properly charged.

 

Can we swap in a lifepo battery? Those can handle deep discharge and don't get damaged if kept at 50% charge level for prolonged periods of time.

 

Here's what AI has to say. I know my cart's LEAF battery pack has a charger specific for that battery chemistry.

You can charge a LiFePO4 battery with a lead-acid charger only if the charger lacks a mandatory "desulfation" or "equalization" mode, and it does not exceed14.6V −14.8V
. While possible in a pinch, it is generally discouraged as it can lead to undercharging or, if left connected, damaged battery cells over time.

 

I hear what you're saying.

But my point is this.....if the recharging algorithm currently being used isn't properly charging a 12V LA battery, then that will cause premature failure of that LA battery. The question is will that Marine grade AGM battery, while not being charged properly just like the LA battery, will it hold the charge that it is getting.... longer than the standard LA battery?

So, for example, if the undercharged 12V LA battery needs a recharge every 6 months, but will sulfate and die in 3 years....how would that compare to a 12V AGM Marine battery that won't need recharged every 6 months (hopefully never) but will sulfate and die in 3 years?

In other words, if the battery is going to die in 3 years, better to have no failures during those 3 years. But....I don't know if what I asking is "in the real world" or not.

 

I had brought this up earlier, in this thread iirc, and it was a no-go. I believe it was tried and failed because of the hybrid charging system behavior. My understanding is that they need a steady voltage above 13.6 or so.

That said, it may be a great solution with the 12v battery voltage sensor disconnected, as that type of battery has its own charge management system