One has to be careful about the passive drain on any battery - a Lithium battery should even be able to cope with it more easily because it can be more deeply discharged and allows for more charging cycles, or did I get something wrong? Personally I would opt for the same Ah capacity as the original battery (or more, never less) although in theory one could choose a smaller Ah Lithium battery as they have more usable capacity (you can more deeply discharge them and they will still perform). For the money that it cost to replace an AGM battery 10 years ago when I last went through it, you get the same capacity Lithium battery now (if not even higher)...

 

The capacity of lithium batteries are usually less than 10% of a traditional cell but the benefit is they weigh nearly nothing. If you get one that weighs the same then yes it has more capacity but it's then dramatically more expensive

 

One thing I like to do is when I arrive at my destination I shut off the gas engine to save on gas but keep the music jamming as well as the heated seats as it's such a heavenly combination... However, after just 10 minutes of this the battery drains so much that the car won't start w/o a jump.. I have a fairly new and fairly spec'd standard battery. Do you guys think w/ an AGM I can stay in heaven w/o burning gas for more than 10 minutes ?

 

You are hilarious! 😃 Even the AGM battery will degrade quickly with such use... Maybe just get an electric car if you enjoy sitting in your car and playing music without the engine running. 😜

 

Maybe, I have an H9 in my D4 W12 and it only allows me 30-40 minutes before it auto shutdowns and informs that battery is too low to continue acc use. When I first got it I was showing it off to a bunch of people and we would demo the audio system/seats etc in the garage and we found out it has that limit....

The LS has a much smaller battery and it doesn't have intelligent management, I would only expect it to last 20 min or so. 10 like yours would lead me to believe something is wrong

 

On a more serious note... Your use-case is deep-cycling the car battery and lead-acid and AGM batteries are not designed to be able to go through many cycles (remember: they are not called "starter batteries" for no reason). If your use-case is really important to you and you want to continue doing what you're doing on a daily basis, maybe look into a normal-sized Lithium battery (at least 50 Ah)... Yes, it will be quite expensive if you buy it in US (less so if you get it from China) but if you need to replace the car battery every year, you're better off investing upfront and getting one that can take a continuous beating.

 

thanks

 

another detail that caught my eye. Similar to specific instructions given on which gas to use on cars these days. It has been mentioned to not use AGM in cars that aren't designed for it and visa versa I believe. The reason being you need the correct battery for your car so as not to damage the battery or I also assume... the car's electrical system. Is there no such rule for our cars?

 

The only time an AGM battery is recommended or OEM is when it’s mounted in the passenger compartment which is rare. I know the Mercedes GL and R class has the battery under the passenger seat. And if the car was ever in a roll over or something similar where you would not want acid getting splashed across the injured occupants or such. Otherwise there is not an automatic advantage to an AGM battery. You will find that many premium batteries are AGM style, they can produce more power for their size when that’s a design priority, like an Optima or Odyssey.

 

go to costco for interstate batteries $110
https://www.costco.com/automotive-batteries.html

 

My understanding is that use of an AGM battery in a car not made for it maybe being overcharged in extended duration use. Because of an AGM’s lower internal cell resistance the voltage regulator on AGM specific cars are set to 14.15 volts. Non AGM systems are normally 14.25. Have not measured lexus in general so this may or may not apply

 

something along these lines is what I thought I read too is that if an AGM battery charges in a car not designed for it then it damages very easily