Hi all,

This is my first post here. I just purchased a 2010 GS450H. It seems in great condition overall, but the engine start battery is not functioning.

The car has been sitting un-started for 3+ months on a lot due to COVID. So the battery seems totally flat. The car started from a jump box and drove with no issues. I put a DVM on the battery prior to jumping it and it read only 0.5 volts - so I guess that there is a drain somewhere. I think this expected as Lexus notes that the battery will be dead after a couple of weeks sitting. The alternator appears good as the voltage went up to 14V immediately. I'm picking the car up tomorrow and I'm wondering if I should take a new battery along or if it's worth the hassle of driving home and trying to charge the existing battery.

Also, Lexus want $420 + sales tax for a battery. I've done some reading here and see others have replaced with non-Lexus options. Any further feedback on that is welcome. I really don't want to be driving with warning lights as a result of the battery not being correct!

All thoughts appreciated!

Neil

 

Jump start it, and drive the car around for a while on the highway. Before shutting it off, drive to an auto parts or walmart store just incase it doesnt start back up. If it doesnt, go purchase a battery from them. Lexus batteries are good but they dont justify the added cost. They may last a year longer then any off the shelf battery. OEM uses panasonic batteries, so if you can find those it will be like buying a lexus at a fraction of the price. But not many people know this but the majority of the worlds car batteries are all made by one company.

 

just make sure you move the temp sensor to the new battery as well!

 

If you talk about the 12V battery, I put a Walmart Everstart group 34 and it does the job. Although I initially wanted to put a Northstar AGM battery but mine died perfectly in the middle of the time period where 95% of businesses were closed, all was slowed down at a point shipping delays had gone stonks, and I had to order it online, although I needed the car to be driveable now and Walmart was the only remaining option.

At one time, I've put an Optima in my Volvo and it appeared to be like new 6 months after. Compared to it, on my GS300 with the Walmart battery, the starter already works ever so slightly slower than during the 2 weeks post-installation. But nothing alarming, I think it will last a while nonetheless. So my take on this is AGMs are not absolutely necessary but the next best thing, especially with such a sophisticated car. Moreover, for the price the dealer asks, you can have a really good one.

This still surprises me though because when looking up threads talking of batteries, I saw dealer prices in the $100-150, which is much more expected given the OEM battery is a plain old lead acid battery.

 

Update: I got the car home with a jump start and have since replaced the battery with an Ultima Yellow D35. I moved the temp sensor and all is working perfectly. It was just as easy as the other posts stated.

Thanks for the input!

 

Note: with Lexus/Toyota hybrids the 288 volt traction battery is actually starting
the car by powering the Motor Generator unit attached to the IC engine. All the
12 volt battery does is close a relay and stabilize the voltage for all the customary
electric devices such as the radio, wipers, seat and window heaters, etc.

 

So if the 12v battery did go out in the middle of nowhere, is it possible for the car to run off the hybrids battery pack? If so how is the procedure?