I left my lexus ls 600h in the garage for months and now it is dead. Before calling for help , I could try to use a booster with the battery in the trunk but after that will the hybrid system start charging by itself or not? Thanks

 

Moving to the right forum.

IN general with hybrids the 12v battery needs enough charge to supply the needed voltage to the computer system. Actual motion and starting is handled by the hybrid drive battery pack.

If the 12v has discharged ... a recharge/jump can help.
If the hybrid drive battery has fallen below the needed level, you need to be towed to the dealership or other shops who can handle this situation.

Salim

 

Your LS600 likely has an AGM starting battery. AGM batteries are more tolerant than flooded-cell batteries as to damage from low State-Of-Charge but since it will not start your car, it may have suffered some permanent damage and may need to be replaced. Jump starting or charging may give the illusion that the battery is OK but it's likely a goner. You should have your battery tested to see if it needs to be replaced.

 

If your leaving your vehicle shut off for months best practice is to disconnect negative battery terminal. That way when your ready to go..just connect it and you should good to go. Or another great thing to use is a trickle charger.

 

I killed the battery in the 600h by somehow leaving the headlights on and locking the car (turns out if you turn the car off not opening the driver's door will not trigger the HL auto off function). Note you've killed the 12V lead acid battery and not the giant NIMH one behind the rear seats.

The 12V battery is similar to any other battery in that it just starts the car; but in this case it doesn't start the motor. It just turns on the electrics and then the traction battery will start the ICE. Once the system is up the car will start the engine and begin charging the traction battery and run as usual until you turn it off; like any other car. If the 12V battery can be charged the system will attempt it; but if you've completely killed it you may need another jump to get started again.

The hybrid system is supremely protective of the TB; I suspect this is why Toyota still installs a small 12V battery to start it from a stopped state.

The 12V battery is annoyingly expensive to replace OEM but because it never cranks the motor it lasts a long time (I still have the original in my car). There are some threads on where where people pry the little electic sensor off the OEM one and paste it onto a Sears die hard but YMMV.

-J

 

The starting battery in the LS600 is a pseudo-custom AGM battery. AGM batteries are more expensive than flooded cell batteries. AGM batteries are required in applications where the battery is mounted in the passenger compartment (under the back seat) or in the trunk. AGM batteries are sealed and have no, or very low emissions, while the flooded cell batteries emit explosive/corrosive gases during charging. Replacing the AGM starting battery in an LS600 with a flooded cell battery risks lots of problems, such as improper charging, corrosion of the interior or explosion. The "little electric sensor" is a temperature sensing device - thermocouple or RTD - that the car's smart charging system uses to monitor the AGM battery's core temperature.

 

Do you know for sure the OEM Panasonic D31battery is an AGM, or do you just suspect this? I've been running a Sears Platinum (AGM) in my LS460 for over five years and love it. I only wish Sears still sold these rebranded Odyssey batteries, but I digress.

I have a BatteryMinder Model 2012-AGM charger that I leave on it on occasion, especially over the winter when it may sit unused for weeks. I would like to use this same charger with the Panasonic in the LS600, but since it does not state AGM on the label, and the charger states "AGM ONLY" on its label, I've not done so yet.

I believe this charger outputs higher voltage that could damage a non-AGM battery. Does anyone have experience with trickle charging the LS600 trunk battery, and/or have specs for the OEM Panasonic battery to confirm it is indeed an AGM battery? Its not a cheap battery to replace so I would rather not learn by trial and error.

 

After a second look, I found etched into the top "S75D31L" which allowed me to find the following specs on a Japanese website. Oddly on Panasonic's site i found no details on it.

Brand:Panasonic Panasonic
Model:n-s75d31l HV
Battery type:AGM Maintenance Free Battery
Warranty years:3 years
Rated capacity:68Ah
Rated voltage:12V
Year model:1995 Sections 2004, 2005, 2006, 2007, 2009, 2010, 2013, 2014, 2016
Car system:LS (Import)
Automotive Brands:Lexus
Cold Start Current CCA:500A

 

The OEM batteries in all cars that have the battery mounted in the trunk or passenger compartment are AGMs. This is a requirement because of spillage and outgassing considerations. The OEM batteries in all cars that have the battery mounted in the engine compartment are the flooded cell type because of heat considerations.

As you have indicated, the charging requirements for AGM batteries and flooded-cell batteries are different.

The LS460 charging system is designed for flooded-cell batteries and the LS600 charging system is designed for AGM batteries.

I don't believe there is a concern with the the AGM battery charger used on the flooded-cell batteries other than incomplete charging. AGM batteries require special charging routines to protect the battery from overheating, so charging an AGM battery with a flooded-cell charger could be a problem in certain situations.

I understand that you are pleased with the AGM battery in your LS460. That's usually not a problem, except in extremely hot climates.

 

Thanks for your reply. It was the "overflow tube" on the Panasonic battery and lack of it stating "AGM" that threw me off. I left it on the AGM charger overnight, which took it from partial to fully charge according to the charger. It started at 12.42v and is now at 12.96v. I wasn't having any issues, but the charger takes it through a "desulfating" process that is suppose to extend life. I ran a quick connect into the trunk, so I can plug it in occasionally, or when it will sit for a while.

I have the same Sears AGM batteries in my '93 LandCruiser, as in our LS460, and discovered after accidentally deep discharging it by leaving the radio on for a few weeks, that a standard charger would not revive it. I carried it into Sears to see if they could revive it and and they replaced it for free instead. After that I got my AGM charger, and then the next time I deep discharged the battery (I know, I need to move the radio to switched power. Instead I added a disconnect switch to the battery). The AGM charger revived the battery to full voltage without issue, and it is still going strong 5 years later. Now try that with a standard flooded battery, right?

 

One of the characteristics of the AGM batteries is their tolerance for deep discharge. They can be taken down to a 25% SOC with no concern of damage and frequently can be resurrected from very low SOCs. The flooded-cell batteries on the other hand can only be taken down to a 50% SOC without the possibility of permanent damage - when they are discharged below 50% SOC it usually starts them into a decline and they only last a couple of months after that, and that's why if you have to jumpstart your car you need to have the battery tested to see if it was permanently damaged.

For typical owners the flooded-cell batteries work well. Your requirements, and expertise, seems to be somewhat different from most users.

Thank you for sharing your wisdom and experience with us.