Mordin

Thanks for all the replies!

Mordin

Thanks for the reply! The vehicle is kept outside in the driveway and we get some cold temperatures where we live. There's not really any symptoms I guess, one day she'll use it and it's fine then the next day she goes out and there's not enough charge to unlock the doors to get in the vehicle.

RGSW

calumin00

I have a 2019 RX450h and in under a year the battery died. Mine got replaced under warranty.

JSracer

the battery in the trunk area ??
what symptoms were you having ?? (since you have the hybrid compared to a no/slow crank on a 350)

thanks

RickC5

Our 2018 RX sits in the (heated) garage for days between us driving it. Some times for over a week and the battery has never drained down noticeably. I think the OP's mom has a bad battery.

calumin00

Yes. I didn't drive the car for a month and when I went to the car everything had died. I wasn't able to unlock the doors using the FOB, the lights didn't work and the car didn't start. This actually happened twice. The first time I had it charged. The second time, I had it charged but then took it to the dealer who said the battery was defective. They replaced it under warranty.

rx20info

Have you actually measured the drain? My experience is that, after fully charging the battery (on a 4amp battery tender for eigh hours, measured voltage 12.66), six days later the voltage is down to 12.19, which indicates that only about 30% of the charge is left. This seems excessive to me (this is in Los Angeles so no cold temperatures). I would like to know what others observe so that I can use this as "ammunition" with the dealer. Any data you can provide would be greatly appreciated.

jcg0324

that is excessive drain. you need to trouble shoot the current drain. the battery drain should be no bigger than .05 ampere. start by pulling fuses one by one to see which circuit is at fault. you will need an ammeter to test it..

rx20info

Thanks. I have been on this issue for a while and already know all the commonly-known relevant facts and advice. The static current drain in my RX has already been measured to be 0.035amp, which is quite reasonable. Since the battery reserve capacity is 133, assuming a drain of 0.04amp, you can calculate that to reach 30% charge should take approximately 40 days. Unfortunately, this is not what I am observing. Hence, I am looking for actual observed data from other people who have RX350s. If you have done voltage measurements on your battery over time when your RX is off for multiple days, please (please!) report your data.

raylor4

Would you consider a hydrometer test for a dead cell a commonly-known relevant fact? That's what I use to pin-point a dead cell in a finicky battery. Ray A.

jcg0324

I am a new Lexus owner and just put in a new Die Hard battery. I bought a 2017 RX 350 with 22400 miles so I cannot give you much data. The factory battery was rated at 582 CCA but it tested at 491 CCA and 12.2 volts.
The new Die Hard is rated at 710 CCA and tested at 850 CCA. It is the Die Hard Platinum AGM battery and a really top of the line product. These agm batteries are not cheap but are they nice. No more white crap corrosion build up on the battery connections and they last a long time. Die Hard was bought out from Sears by Advanced auto parts. They are made at a company called Clarios which bought the battery business from Johnson Controls last year. Clarios, East Penn and Exide are the 3 manufactures of batteries in the USA.

jcg0324

duplicate message

dibl

May I ask what kind of price did you have to pay at Advance Auto? I'm going to have to replace the battery in my 2018 this spring or summer, due to a sulfation problem, and it turns out my Costco is out of the Interstate AGM 24F batteries.

rx20info

I don't think it's the battery. I noticed the problem last year and in June the dealer replaced the battery. That did not fix the problem. I am wondering whether there is something (perhaps the EVAP system) that "wakes up" periodically when the car is off. This would not show up in a simple measurement of the current drain.