redcld

I have a 2015 RX350 F Sport and the battery voltage drops below 11.5 volts after about a week. I have removed the battery and had it tested and it is fine. I was doing rear brakes last weekend and on the passenger side with no key in I could hear a noise from inside the passenger wheel well. Wondering if anyone knows what could make noise there from the rear passenger wheel well with ignition off. I will start checking fuses this weekend.

Clutchless

How long have you had the vehicle and when did the drain start? Any changes - repairs - maintenance before it started?

There is an emissions automatic vent system that turns on for a while after the vehicle has been off for a while. Many folks hear it for the first time and then post here asking about the noise source.

You may have to find an automotive electrical specialist to track down a parasitic drain as they can be difficult to locate and almost impossible to do online.

Non

get an amp meter and use it to check the current draw while the car is off for a while. Then pull fuses one at a time to see which one is responsible for it.

salimshah

Let's make sure you have a problem. There is and will be a drain on the battery. It may be excessive and it might not. I just want to make you aware that there is a high chance that the drain is not excessive [this will most likely be the reason specially if you don't have add on accessory].

There is a balance between charging and discharging of the battery. A good battery can go off balance, if the charge cycle is not long enough. Starter just sucks a whole load of charge and the charging system typically recovers with about 30 mins of driving (estimate). So if you don't drive enough or frequently enough for about 30 mins the battery starts becoming weak. Driving once a week also does not help. I would suggest get a battery tender in that case.

Salim