New Optima battery failure

The original 12V battery in my 2012 Liftback with 52K on it had been abused by total discharge while sitting unused twice over the years, due to a map light being left on, and not being noticed due to it not being a daily driver.I charged it at 1.25 A both times to keep the heat down, and it then acted normally. The car was driven on the 4th of July, acted normally, then the next day it was so dead it wouldn't even light up my battery tester. Fair enough, considering the abuse it shouldn't have lasted as long as it did. So I ordered an Optima from Amazon, checked it with my best battery tester, and it showed 12.82 volts, with a 99% charge. That was great news, so in it went on July 15th. Yesterday, Aug 2nd , the car didn't want to start after the normal procedure. I finally got it going and then started my trouble shooting. Thanks to previous posts here, it pointed to a low battery. What? My brand new Optima? Yep. It was down to 11.2 V with a 25% charge. Nothing had been left on, and my smart tester said to recharge and retest. With my 1.25 A charger again, it should have taken a long time to recharge, yet it was up to 12.9 volts in less than 2 hours. Now what? Back to test mode . Battery 15% charged at 12.9V, with a REPLACE battery warning. I've never heard of an Optima dying in this manner. Batteries are not returnable to Amazon, so I called Optima. They said since Amazon was the seller, they were responsible for replacing the battery. But since you can't return it, what next? Optima gave me a number to call for Amazon customer service, and to my surprise, they gave me a full refund! So Amazon must not get many Optima's back, or they would lose their butt eating them like this. Now I've started to wonder if my car is killing my batteries, or did I just get a bad new one. I ordered another Optima, and will monitor its health on a daily basis to make sure this newest one isn't failing too. I'm going to leave the plastic bits off for now so I can keep tabs on it. Wish me luck!

 

I'm back! Got my new Optima battery and new charger rated for AGM batteries. All charged up and installed. I bought this car new and it's never been wet, always garaged, and is completely stock. My Digital DC amp meter won't show any flow between the positive post and the positive cable when the cable is off the battery. I know there has to be some power flowing, but I'm not getting a reading. I started it up to check if I'm charging the battery. I'm getting 14.52, looks good to me. I only drove the car 3 times with the first Optima, 2 trips over 200 miles, then a very short hop to town. One thing I didn't do is charge the first Optima before install since it looked so good on my tester. This second battery was on my new Battery Tender Plus for 4 hours before it was fully charged according to its LED's , yet my tester only only showed 98% at 12.92. Close enough for now. I'm going to monitor this puppy constantly for a while to see if I'm lucky enough to have only gotten a bad battery. What has me worried is that little detail of my original battery failing, and then a second one failing too. I mean, what's the odds of that happening? I am a huge Lurker on here, and really appreciate the time you wizards take helping people by sharing your vast knowledge. I started working on cars in the late 60's, and can't believe how complex a Prius is. My mom traded in her 2010 bought in July of '09 on a 17. Still had the original 12V battery in it, and in 90K I never touched it. We have 5 others in my immediate family, and I've not heard of a single problem with any of them. I'm keeping my fingers and toes crossed, will update of course, good of bad!!

 

Oops! Forgot to mention I double checked all of the door switches and the boot light switch. I have the master light switch off for now. Toyota has never fooled around with the master switch, which come to think about must be standard Japanese practice. My 1970 Corona Deluxe had the exact same switch. And my Pathfinder, CRV, Odysey, and my present Sienna too !!

 

Today's test results. I took the charger off early this morning and left the hatch open. I had 12.92 to start . After an hour I was down to 12.78, and every hour it went down about .06 A. Then after 4 hours of taking readings, I shut the hatch, and each of the next 2 hours he voltage actually went up slightly, showing just how much power is being used by the sensor indicating that the hatch is open. The next step I took was to charge the battery back up till the charger indicated a full charge, then I took a reading of 12.96. I shut the hatch and waited 4 hours, then got a reading of 12.92. Hmmm . Note to self, don't leave the hatch open for long periods. The only oddity in today's tests was that the hatch locked itself , and the door unlock switch wouldn't open it. All the other doors remained unlocked. Only the remote, which was in the house, would unlock it. That's a new one on me. Next step, see where I am in the morning!!

 

Hi all, Haven't driven the car yet, but have the battery still on the Battery Tender Plus. Went out to today to put the hatch area back together and my hatch was locked again. This time the door unlock switch opened it normally. Since I'll be carrying the thought in the back of my head that something still isn't right, has anyone encountered a hatch lock that activates itself? I'm not sure of course if this is related to my initial problem, but it can't be ruled out either. As long as I'm keeping the battery on a charger when parked, I'll never know for sure if it's OK now. Next step is to let it sit for a few days and keep checking my voltage. I need to go on some long trips soon, and I need to trust this thing again.

 

The hatch light has always been off during my tests. Today's voltage drop with the hatch closed is back to a steady drop all day, rats! Started at 12.90 off the charger, down to 12.77 in 5 hours. I checked my footwell lights. With the hatch open or closed they are only on when the door is open. I even lifted my butt up off the seat to see if Toyota was using a sensor to keep the lights on till you sit. I was thinking you might have a higher grade car. Mine is a 2012 , 2 car. Again today I went out to the car and the hatch was locked again. All 4 doors were unlocked. The remote is in the house far away. I can't help but think this has something to do with my battery drain, which appears to now to be intermittent. This is all without the vehicle being started or moved. The hatch has locked itself 4 times now, on the charger and off. There are lots of posts about the hatch not unlocking, but I can't find one about one locking itself!! I've chased a lot of electrical gremlins over the years, but I don't know enough about what does what on this thing to even know where to start. I read where there is a sensor disconnect in the bumper area below the latch. I'm going to try to disconnect it and also take apart the plastic trim around the latch itself. Of course that probably won't show me anything, because the pulse that activates the latch probably doesn't originate there. Back to work!! I mentioned earlier that my parents early gen III, bought in July 09, was traded with the original 12V battery still in it in Nov of last year. Zero problems ever. I'm ordering a clamp on D.C. amp meter to read flow so I'll know when I've found my problem.