I bought a lexus battery from Lexus about 1.5 years ago. It has been working flawlessly until last week.

After turning off the car and running just the radio, the car dies in 30 mins. Using a volt meter I can confirm that the voltage is roughly around 9 V. The car, obviously, is unable to start. However, when I turn off the car and let it sit, the voltage slowly climbs back up. After about 30 mins, the voltage climbs to around 12 V and I can start the car up again.

I have already turned on the car and confirmed that its not my alternator that is going; the battery shows around 13 V with the car running.

Can anyone explain to me how my battery is recharging itself? I know a dead battery should not be able to recharge itself when the engine is off.

 

Someone should have an answer to this. I've experienced this stuff myself a lot. I was tinting my windows with the radio on and an hour later, when I went to start the car, it couldn't start up. I try again and still won't start. I come back at night to try again before calling a friend over for jumper cables and it started. No idea how but same happens a lot with my flashlights. Light would just go out, I turn it off. Turn it back on like 10 seconds later, it turns on. I would like to know this too!

 

Might be your battery is on its way out. This might be the phenomenon you are experiencing explained in further detail:

A battery is a chemical reaction which moves electrons causing a voltage difference across the two parts. when you are not using the battery, that reaction reaches equilibrium rather quickly, then more or less stops. When you are drawing current, the reaction continues. When the battery is near death, the reaction does not progress as quickly, so a high current device may draw current faster than the chemical reaction can release it, causing the voltage to drop. At some point the device shuts off due to undervoltage. The reaction continues, albeit slowly, and eventually builds up enough voltage to allow the device to power on again. This process can repeat a few times depending on the device and battery chemistry.

 

Have you checked the water level in each cell? A lot of people either don't bother checking, or rely on the magic eye indicator on the top of the battery, which only tells you what is going on in one of the six cells. I check mine annually, and find that I usually have to add a bit of distilled water to bring the electrolyte back to the full line.

 

^^ Good tip, I usually only check mines when the battery is acting up. I'm curious, will check mines in the morning.

 

This is what I was hypothesizing was happening, but my battery is only 1.5 years old. There's is no way it could be going out that quickly. This shouldn't be happening until at least 3 years. Maybe I have a bad battery?

Thanks for the tip, I'll make sure to do this today. If this isn't the case, I'll probably bring it back to the lexus dealership tomorrow. There's an 84 month warranty on the battery and I still have my receipt,

 

Do you happen to have added any aftermarket stereo equipment, or like a HID kit harness that draws a power source directly from the + terminal of the battery?

 

No, I do not. My car is mostly stock when it comes to electrical stuff. Also, if something were to be drawing power, then when the car is off, I should be able to see the voltage slowly drop, but its the complete opposite, the voltage goes up when the car is off.

 

Same thing has been happening to me for the last two weeks. Its really weird I just ordered new Lexus Battery will install tomorrow hopefully that will get rid of the problem

 

I just dropped off my car at the dealership. Hopefully they get back to me by monday

 

I think that the battery is on the way out, my friends GTO (I know, different car) just got done doing the same thing