Sunapollo

I have a RX400h and my car couldn't start on Saturday. The engine light was on then we called Lexus roadside assistance and AAA showed up to jump start our car. The technician said it's very common for hybrid car aux battery to drain and suspect the battery's dying.

Anyone has experience changing the aux. battery aka the one that starts the car? What brand is recommended? I am going to diy this, do you guys know if there's any special procedure that make it different from normal battery replacement? Thank you.

lucasb7

I would take it to Lexus. They replaced the one in my 2005 under warranty. If not I would either just go for a regular car battery or an optima. For more info on the optima batteries, I would go to Prius Chat. They have done a lot of research on that.

Nitrous

I am about to replace my aux battery on a 2007 GS450H. The battery is not standard. The dealer price is over $500. It comes from Japan. Anyone know of an alternative?

Doug

maseace

Try Costco. They have 100 month warranty batteries for about $65.

Weighit

My start battery died last year and I went to the local auto parts store and cross referenced my battery with the one they sold and installed it. Their best battery was just over $100, it fit and so far has worked perfectly. Seems out here in the Arizona heat batteries don't live as long.

spacecraft

Just for the records, the 12V battery on hybrid cars never works as a start battery.
Therefore, it would be better to fit a deep-cycle, rather than a cranking battery.
Should last longer, and a high CCA is pointless anyway.

Nitrous

I guess you guys missed my point. This is a specialized battery (appears to be a "battery in a battery") directly from Japan. I can't see how you can retrofit in an after market cheap battery.

I can't even find someone who knows anything about this damn battery.

Doug

Weighit

Well I guess I didn't know that the tiny battery in the engine compartment did not start the car. I have had both batteries replaced, the tiny one and the one under the back seat. The back seat unit failed while driving and I was able to restart the car and drive it to the dealership.

spacecraft

Interesting, can you tell us more about such failure?
I never heard of a 400h traction battery failure before...
And anyway, if you could restart the combustion engine, it must have been just a partial failure.
In fact, the ICE is started only through the electric motor, which can only run with the high voltage of the traction battery.
The small 12v one in the engine compartment is useless in this respect, because at startup its only purpose is to feed the car computers.

spacecraft

Are you sure that isn't just what dealers want us to believe? Can you post a pic maybe?
Can't speak for the GS450h, but I've heard of various folks who replaced the RX400h aux battery with non OEM batteries, without any problem.
The main issue is that there isn't a lot of choice, in the small size which you must look for in order to make it fit, but other than that it's just a plain lead acid battery....

Weighit

I pulled out of my garage, everything was normal. Got about 1 mile away from home and stopped at a traffic light. Looked at the instrument cluster and noticed all the warning lights on, every single light in the cluster that is normally on when you first turn the key was on. I also saw check hybrid system in the display. So i pulled into a parking lot, shut it all off and waited about 2 minutes and attempted to to start the system again, all the light and display was the same. I shut it off again and called the dealer. They offered to tow me in, or if I wanted to try to drive it in(about 40 miles) I could but should it die, to call them and they would send a tow truck. I fired it up and hit the highway, the cruise would not work, the check hybrid stayed lit but otherwise it drove the same. I got there and they determined the main battery was failing and needed replacement. It took about 4 days to get the battery and another to install, no charge to me. They said it was the first battery that dealer had replaced and they had been open since 2007. At the time my 2008 had about 50,000 miles.

spacecraft

Mine is also a 2008. And how old was it at the time?
Anyway, good to hear that they replaced it FOC...!

Nitrous

Actually, the battery took the dealer by surprise too.
They quoted me $157.00 plus installation but when I returned at the end of the day, the confirmed needing to install a special battery. I believe it has three terminals on it.

Also, the aux battery is in the trunk, not the engine compartment. I it sits under the rear left quarter panel.

Doug

Addendum: there is an update from Lexus on this. When I contacted them today about the battery, they asked if this was for my GS350. I explained that I have never had a GS350. They looked further and said it was listed as a "GS350 with GS450H trim package". This is the first time I've ever heard the car referred to this way. Does this make any sense to any of you guys?

Nitrous

Ok, here is the actual battery graphic from a US dealer.

I don't have the traction battery. The battery I'm replacing is the one on the left of the diagram.

http://lexus.sewellparts.com/oem-cat...450h-2007.html

It looks like the only really peculiar thing about this battery is the "hose" that is attached.
Is the hose a safety vent hose to release hydrogen gas vented during charging?
Could the special battery simply be replaced with a standard deep cycle battery!

As they say, inquiring minds want to know!

Thanks
Doug

thomas1

Very confusing thread, the Last poster was talking about a GS, not a RX400h...Two completely different vehicles. And yes if it were in the rear of car, it would have to be vented for gases. As for aux battery I would assume any aftermarket would work as long as it is vented in the GS, however on the RX400h the battery is the same as used in many imports (including Honda)....Costco would have a direct replacement for a lot cheaper.,