New Battery
09-29-16, 02:58 PM
#76
The only thing that ticked me off was a couple years ago I had the car at an auto body shop. I suspect they pressed the start button twice without depressing the brake, so the ignition was on without the engine running. When I picked up the car the battery was completely dead. I know once you do that, it never recharges to full capacity.
01-18-20, 10:46 AM
#77
this guys batteries!
if you are buying a battery like I am, this is the post you need to read when seeing if you need/should get an AGM one or not.
if you are buying a battery like I am, this is the post you need to read when seeing if you need/should get an AGM one or not.
The Optima batteries are "AGM Batteries" and the Diehards are "Flooded Cell Batteries."
The Lexus LS460, like nearly all US cars and Japanese cars, is designed to use a flooded cell battery and produces a constant 14.4V battery charging voltage. Some of the European cars, notably some BMWs, are designed to use AGM batteries and have "smart charging systems" that support the AGM batteries.
The AGM batteries tolerate a wide range of charging voltages until the core temperature goes above 50degC and then the float voltage must be reduced below 13.8V to prevent damage due to overcharging. This may account for some of the premature AGM battery failures that are being reported in Internet discussion. Automobiles that are designed to use AGM batteries usually have the battery mounted away from the engine compartment, like in the trunk or under the back seat.
If you have some doubt that the charging requirements for AGM batteries are different from flooded cell batteries you can look at the newer battery chargers that are being sold on amazon.com. They have a mode selection switch that selects either Standard or AGM.
One of the advertised advantages of AGM batteries is that they can be mounted in closed areas because they don't produce any corrosive or explosive gasses. Since the LS460 battery is mounted in the engine compartment that doesn't apply.
Another advantage claim is the superior starting power. The LS460s have computer controlled gasoline engines that start very easily, even at extreme temperatures - these are not diesel engines.
A claim that the AGMs have an advantage because they can be "deep cycled" doesn't apply for most of us because we don't sit around with the accessories powered and the engine off. The deep cycle advantage may apply if you don't drive your car for extended periods.
The claim that the AGMs can be charged rapidly is true but no advantage when they are used in the cars that are designed for flooded cell batteries. In cars with fixed 14.4V charging systems the charge rate is limited to support the standard type batteries.
The claim that the AGMs have superior reserve power doesn't help most of us as we only use the battery for starting the car. Those power hogging accessories are only in use when the engine is running and then their power is supplied by the engine driven generator which also produces some power to charge the battery.
As for maintenance, the AGMs are truly maintenance free. Most of the flooded cell batteries that come in new cars are the maintenance free type and require little attention for a 3 or 4 years after which you may need to add some distilled water to keep the plates covered.
As to durability, AGMs and flooded cell batteries are about equal if they are maintained properly and not "deep cycled." The LS460s are designed to prevent deep cycling but many have had doorjamb switch problems that allowed the complete discharge of the batteries due to the headlights staying on and those kinds of events have a detrimental effect on the life of the battery. Seems like the the allowable cycle depth for AGMs is 25% and the flooded cell type is 50% SOC.
The AGMs are more expensive but not prohibitively so.
Will Lexus take warranty exception if you use an AGM as a replacement? I don't know.
What is the best choice? Either type works in many situations.
The Lexus LS460, like nearly all US cars and Japanese cars, is designed to use a flooded cell battery and produces a constant 14.4V battery charging voltage. Some of the European cars, notably some BMWs, are designed to use AGM batteries and have "smart charging systems" that support the AGM batteries.
The AGM batteries tolerate a wide range of charging voltages until the core temperature goes above 50degC and then the float voltage must be reduced below 13.8V to prevent damage due to overcharging. This may account for some of the premature AGM battery failures that are being reported in Internet discussion. Automobiles that are designed to use AGM batteries usually have the battery mounted away from the engine compartment, like in the trunk or under the back seat.
If you have some doubt that the charging requirements for AGM batteries are different from flooded cell batteries you can look at the newer battery chargers that are being sold on amazon.com. They have a mode selection switch that selects either Standard or AGM.
One of the advertised advantages of AGM batteries is that they can be mounted in closed areas because they don't produce any corrosive or explosive gasses. Since the LS460 battery is mounted in the engine compartment that doesn't apply.
Another advantage claim is the superior starting power. The LS460s have computer controlled gasoline engines that start very easily, even at extreme temperatures - these are not diesel engines.
A claim that the AGMs have an advantage because they can be "deep cycled" doesn't apply for most of us because we don't sit around with the accessories powered and the engine off. The deep cycle advantage may apply if you don't drive your car for extended periods.
The claim that the AGMs can be charged rapidly is true but no advantage when they are used in the cars that are designed for flooded cell batteries. In cars with fixed 14.4V charging systems the charge rate is limited to support the standard type batteries.
The claim that the AGMs have superior reserve power doesn't help most of us as we only use the battery for starting the car. Those power hogging accessories are only in use when the engine is running and then their power is supplied by the engine driven generator which also produces some power to charge the battery.
As for maintenance, the AGMs are truly maintenance free. Most of the flooded cell batteries that come in new cars are the maintenance free type and require little attention for a 3 or 4 years after which you may need to add some distilled water to keep the plates covered.
As to durability, AGMs and flooded cell batteries are about equal if they are maintained properly and not "deep cycled." The LS460s are designed to prevent deep cycling but many have had doorjamb switch problems that allowed the complete discharge of the batteries due to the headlights staying on and those kinds of events have a detrimental effect on the life of the battery. Seems like the the allowable cycle depth for AGMs is 25% and the flooded cell type is 50% SOC.
The AGMs are more expensive but not prohibitively so.
Will Lexus take warranty exception if you use an AGM as a replacement? I don't know.
What is the best choice? Either type works in many situations.
05-11-23, 10:29 AM
#78
Intermediate
I'd always heard before what DrQuality said---pretty much any normal mainstream battery is made by Johnson Controls; there are just a dozen labels put on them. None of them seem to last until just past the warranty replacement, by design.
05-11-23, 10:53 AM
#79
i just get the battery from costco. I read Costco battery are from Interstate Battery-one of the best brands. If I don't drive the car much, I charge it with a battery maintainer. It's been 5 years and 30K miles later, the battery is still ok.
05-14-23, 12:40 PM
#80
Pit Crew
Most of the flooded cell batteries that come in new cars are the maintenance free type and require little attention for a 3 or 4 years after which you may need to add some distilled water to keep the plates covered.
For 30 years I worked as a mechanic for a government fleet for a large west coast city. I changed hundreds of batteries on cars, trucks, and every sort of motorized equipment; and flooded cell batteries were what we used exclusively.
And before I installed a new battery I always pried up the caps to check the water levels in the cells. And in every single one of those batteries the water level was low... every one, no exceptions! And about 80% of installed batteries I checked as part of normal maintenance, also turned out to need water in the cells.
Since it was my job to change batteries too, it was in my interest to keep them watered, so that's why I did it. I preferred to check the water when I had that car right in front of me, than get called out to change a (prematurely) dead battery later.
For 30 years I worked as a mechanic for a government fleet for a large west coast city. I changed hundreds of batteries on cars, trucks, and every sort of motorized equipment; and flooded cell batteries were what we used exclusively.
And before I installed a new battery I always pried up the caps to check the water levels in the cells. And in every single one of those batteries the water level was low... every one, no exceptions! And about 80% of installed batteries I checked as part of normal maintenance, also turned out to need water in the cells.
Since it was my job to change batteries too, it was in my interest to keep them watered, so that's why I did it. I preferred to check the water when I had that car right in front of me, than get called out to change a (prematurely) dead battery later.
Last edited by Marc780; 05-14-23 at 01:06 PM.
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