A Lexus LS 5 that dies overnight usually has a parasitic draw.
Here’s what to check first and whether you can keep driving.
Why a Lexus LS 5 battery dies overnight
If your Lexus LS 5 starts fine after a jump but is dead again the next morning, you’re almost certainly dealing with a parasitic draw — something is still pulling current after the car should be asleep. On a healthy LS, the modules go to sleep over about 20 to 40 minutes, and the total draw usually settles below 50 milliamps (0.05 amps). If you measure 100 mA, 500 mA, or even several amps, the battery can be flat by morning. A weak battery or a bad alternator diode can mimic this too, so test those before you start pulling fuses.
