Hi all, I recently replaced my 12v aux battery (on 2011 prius) and since been having issues with HV battery; were there things i needed to do prior to a simple battery swap like keep the “memory” of our cars from being shutdown due to no power? I recently saw a video where a mechanic said with our modern cars and the electronics, to keep the ECU still charged otherwise the memory will be wiped out and i’m wondering if that’s what happened. Calling on 3rd gen owners- what were your experiences (positive or negative) if u simply replaced the battery without any prerequisites? Thx!
The "memory" are what the computer learns about how you drive and how the car is working. You need to get a code reader and see if there are any codes. Did you charge the 12v battery before installing it? None of the places charge the battery before selling them, they just sit on the shelves. Perhaps you just got a "new" battery that is discharged. Put a 4amp or less agm charger on it for 8 hours to give it a full charge. A low/weak battery will cause issues.... Many people disconnect the 12v battery to clear any codes and "reset" the computers back to default. And also make sure the battery posts and terminals are clean before installing....
You drive for a few hours and everything should be back to normal If you put a 12 volt jump box on your car while you're changing the battery like up at the front point you'll retain your radio memory and things like that they make a thing that plugs in the cigarette lighter that back feeds 9 volts or whatever it is you want through the system that way it just keeps everything from going completely dead mainly for radio and infotainment memory purposes address book so on and so forth. So if somebody just whips all the connections loose pulls the battery out of the hole sets it off to the side takes his time being very methodical and organized and rounds up his tools in the battery sits out of the car for 20 minutes while he does whatever he does then he installs the new battery and tightens the cables in the clamps and then he goes and maybe sits in the car and readys the car and realize he has no radio stations and his GPS memories all gone and so on and so forth exactly that's just because he wasn't thinking or he didn't care when he started his mission . The car should go right back to pretty much driving and behaving as it was before the 12 volt change. Now that the 12 volts change and you have other issues you may want to actually read the code with a capable tool Read the car completely and see what you have just changing the battery per se shouldn't cause a whole lot of eyebrow raising.
what 'issues' with the hybrid battery? fwiw, i changed the 12v on my 2012 in 2018. no issues, didn't even lose radio presets
To make a long story short, I was laid up in the hospital for about 3 weeks so my car sat for 3 weeks and i realize that’s probably gonna have detrimental effects on the battery; since i tried to start the car after getting back from the hospital, the 12v was dead; had to jump it from another car and eventually i had to replace it within a. puppies weeks.Prior to replacing the 12v, i had purchased an app Dr Prius to see in real time what the HV batteries were going, they were always displaying green bars but after swapping out the 12v, I’ve been getting yellow and red bars ftom the battery blocks which never happened prior to the aux battery swap. On the most part, the car drives five but often, when i depress the brakes, the HV battery blocks go from green to yellow to red. And when it goes to red the symptoms are the car feels like it went over a little speed bump. What do you think is going on?
The aux battery replacement had no impact on the hv battery. 12 years of use followed by three weeks of nonuse is the culprit. They wear out - but if the car is not producing trouble codes or lighting up the dash, I would unhook the app, drive it regularly and start looking for hv batteries.
You can sometimes find the battery cheaper at Lexus dealers than at Toyota ones. Lexus also runs 2-3 year-end online sales on parts between October and December, and the last one for this year should be kicking off on December 12.
While replacing the 12-volt battery, you can avoid losing the car's various memories by connecting a 12-volt power supply (or another 12-battery) to the jump point in the fuse box under the hood. It doesn't need to have much current capacity---especially not if you avoid letting the brake pump run.
However the danger of trying to save your radio presets with another battery is if or when you reverse connect that extra battery for a split second, you will blow an inaccessible 125 amp fusible link and be down for days in most cases. You will wish you could reset the radio presets. I never try to backup 12v power during a 12v disconnect. I am happy to reset my satellite and radio stations.
