Malihassan

I have a lexus ct200h 2011 UK model. The problem i am facing right now is that my car's 12V battery is getting discharged overnight and it gets swelled with time. I have tried to replace the battery with a new one but the problem persists. I got all the motor functions and sensors checked with a scanner and they are working ok, the generator is giving normal voltage to the battery. The mechanic checked all the fuses from the fuse box they are ok but something is getting current from the battery and causing it to discharge. My mechanics prognosis is that something is taking away current from the battery even when the car is switched off and due to this a buffer is created and generator is overcharging the battery hence causing it to swell. Can anyone please advise me with a possible solution?

E46CT

Your mechanic should perform a parasitic draw test. It basically reads the battery for draw as you pull each fuse one by one to see if the draw stops as you pull the fuse. Then you can find your culprit, assuming the draw is coming from a fused circuit.

Any prior modifications or damages (accidents) or prior repairs to the car? Any of those three could mean someone went in there and messed something up. That would be a good first clue.

Malihassan

well thats what my mechanic did while diagnosing the problem, he removed all the fuses but the problem persisted and something kept on drawing current away from the battery!

E46CT

Did he remove the fuses while taking a read on the battery? You aren't supposed to remove "all the fuses" you're supposed to remove them one at a time, individually, while taking a reading between each fuse. unless this is what you meant?

Malihassan

yes thats pretty much what I meant! removing them one by one!!