I have a 2013 RX with a Lexus battery installed 10/19. The warranty on the battery is for 84 months. I've had no problems with the battery since we bought it used, I recently had the car serviced at a local Toyota dealership. They performed a load test on the battery and it came back at 578CCA vs the 630CCA the battery is rated . Simple question: replace now or wait? I can pick up an AGM battery at Costco for about $180. Thoughts?

Bit confused ... are you asking about replacement under warranty or purchase advice?

Warranty: You will have to go to Lexus and let them run test and if needed they may put the battery under extended charge and then run the final test. If the tester reports fail after charge, they will offer warranty service. If you do not have a relationship with the dealer service, they might ask for diagnosis fee (which will be reimbursed if warranty applies). In theory you can take the purchase receipt and the old battery back to Lexus for reimbursement. [this is valid when you are out of town]. You should call your local Lexus service department to establish what they will do for you.

Preemptive purchase: If you can start your RX after letting it sit for 2-3 days, I would simply wait .

Salim

I bought the car used in 2019 with this battery in it. I assume the replacement would be prorated if I brought it to a dealership, if they would even honored it. I'm not sure if that is the case though. Basically looking for purchase advise knowing the battery is 5 years into a 7 year warranty. Trying to be proactive vs getting stuck this winter.

The battery at 91% is in very good condition so no replacement needed. When the CCA test is closer to 70% you can start thinking to change it.

Do you have a road service plan?
I change my battery every 5 years regardless, maybe nuts but here is my reasoning:
Todays batteries do not give much warning for when they fail, one day good, next day not.
Like you stated, a new AMG is $180, over5 years , no big deal.
I can change the battery at my convenience, not when it is 20 below. 20 below is when it is more likely to fail.
If you are away from home, and the battery fails, do you have to tow it? There goes any savings.
The inconvenience of a no start at a time of need can be frustrating.

I've seen a lot of posts from people who proactively replace their battery so they don't risk getting stranded unexpectedly when their battery dies. I agree with that approach, but I wonder what you all think about keeping a jump start battery in the vehicle at all times instead? The idea is that you can truly get the entire life out of your battery, and when it does not start one day, you simply jump it.

I have a jump start battery pack like this one. I just went through the experience of the original 14 year old battery in my 2010 RX450h reaching its end of life. A couple of times, the car would not start, but with the jump pack, it started right up, no big deal. I bought an EverStart AGM battery from Walmart and we're good to go.

Bottom line, I'm wondering what you all think about these two approaches? Proactively replace the battery before it dies, or keep a jump pack on hand, and get the full life out of the battery?