I would like to share my experience when i plan to change battery on 2013 ES350

so before the beginning of the season i got my battery checked it showed 414 CCA battery was june 2016 build , since i bough this car used i cannot trust the old battery, though it was original panasonic lead acid battery. Group size 24 also i believe 414cca is not enough in canadian winters

While i was doing research buying battery , i almost went for costco battery in canada which would cost me 150$ but i always tends to buy OEM stuff it might sound less on paper but i believe they perform better. Oem battery costed me 210$.

With my old battery my car tends to reset average fuel economy after few days, but this didn’t make sense why old battery could cause only this data to erase. Second , When i crank the car the light flickers as the starter is sucking power from battery, now with new battery car is saving its average fuel economy. And light flicker is negligible i believe which is always gonna be there

Now replacing battery , first i though i might do it by self but my mechanic was telling me again and again that you have to relearn idle after battery replacement and clean throttle body. i have read several thread saying they never had any problems with changing battery by them-self but sometime computer resets itself and forget adaptive data. I don’t wanted to take any risk. A colleague of mine got his battery changed at some place now his analogue clock is going bananas its not keeping time. Dealership says they never had this problem and cannot solve this issue.

so my mechanic did my battery replacement everything went fine all settings were as it is even memory seats and all radio settings.
lexus canada now keep batteries 34R instead of 24 and provide a height adapter since group 34r is bit shorter in height now 34r is not reversed polarity it had same poles as old group 24, this battery has 690 CCA and 800CA


So that is my story of battery change
i just wanted to share it might help somebody in similar situation

 

Changing a battery is a piece of cake. The most difficult part is lifting it out. The rest is simple. When changing a battery in any car, and I've done at least 5-6, I always attach a battery tender to the cables before they are removed. This provides continued power to the car as if the battery is still attached. This preserves all memory features including adaptive data. Remove the holddown bracket, lift it out, install the new one and reattach the cables and holddown bracket. Finished... When buying a battery from Costco, where I buy all of mine, they do not install batteries. It's on you to get it installed either by yourself or a garage. I don't know why one would have to clean the throttle body or why the idle would change.
Not for everyone I understand, but an easy DIY fix...

 

My friend has a service station and I have helped him change quite a few batteries. Generally there is no issue with just pulling the battery and installing a new one. As you mechanic stated, the car will lose some memory and stored codes, but the re-learn automatically happens within 50-75 miles. It has no ill effects unless you need to have an emissions inspection done, like we do in lower NYS. In my area it cannot be inspected till the 50-75 mile re-learn. The only problem I have seen is on a few older Honda's that need the security code for the radio to be entered. This is easily obtained from any dealership when you give them the VIN.
bc6152's method of keeping voltage with a battery tender should work fine. My shop owner friend has a battery booster box that also has a memory retaining option that plugs into the diagnostic port to save memory. I might be cautious of using a regular battery charger, as I don't know if the voltage is regulated enough to prevent damage to the electronics.
On to the part about a re-learn after cleaning the throttle body. If the throttle body was a bit clogged and carbon build up prevented it from seating properly, the car would relearn as the computer would now see a slightly different throttle body position when adjusting the mixture. Not a big thing.
I just changed the original battery in my 2016 ES350. I went with an Interstate 24F. It has a bit more CCA than the original. I can understand why you would want the 34r living in Canada, your winter temps get a bit colder than mine.