Lexus 350RX why does my battery drain after the car sits for 3 or 4 days?

SOURCE: car dies while driving

I bought my 89 Reatta in 2000 with less than 10,000 miles on it. It ran perfect for a couple of months and then it would just die for no reason. No lights-nothing. This would seem to happen more often as I drove it. I finally zeroed in on the battery connector as the problem. I had my local Goodyear dealer replace the positive cable with a different type of connector and the problem disappeared. It has not ever happened again since replacing the battery cable. I hope this helps you.

SOURCE: security system-passlock

I hav a 1995 88 w/ same problem. Key was worn out, Had Security system disabled.by installing a resistor to by pass Sec. System.Had it done for $35.00 Check locally for a starter/alternator shop in your area.

SOURCE: car dies while driving

just clean and tighten your battery terminal connections, both positive and negative poles.

SOURCE: Battery on BMW 740i keeps dieing

you need to disconnect one side of the battery, put one lead from an ampmeter on the battery post you have disconnected and the other ampmeter lead on the cable you took off the battery. with nothing turned on on the car , all doors closed the reading on the ampmeter should be no higher than 0.17 amp, if it reads a lot hgher go to the fusebox and remove one by one all the permanent supply fuses looking at the reading every time until you find the circuit that is causing the high reading, this will be the drain. alot of the time it can be central locking system playing up, boot light, glove box light not switching off, stereo wired wrong. hope this helps.

SOURCE: Battery keeps going dead

Hello raiderfan520....Have the battery "load tested" this will tell ya if the battery is defective, one bad cell will draw the others down. If it's bad and only 12 months old you should have warranty left. (free replacement or pro-rated)...If your battery load tests OK, then you have an amperage drain going on while the vehicle is parked.
This is called a "parasitic drain"
Make sure no interior lights, under hood, trunk lights...etc. are remaining on. I hope you don't need the following information i'm about to give you, but here are the steps to locating a parasitic drain.....

1. Remove the negative side battery cable from the negative battery terminal.
2. Attach an ammeter(this measures amperage) between the negative cable and the negative battery post. wait a few seconds to several minutes for the car to go into sleep mode. i.e. when you make the contact with the test light the cars computer systems "wake up" after a bit of time they will go to "sleep".
3. If the ammeter is reading over 25-50 milliamps, something is using too much battery power.
4. Go to the fuse panel(s) and remove fuses, one at a time. Pull the main fuses (higher amp ratings)last. Be sure to observe the ammeter after pulling each fuse.
5. Watch for the ammeter to drop to acceptable drain. The fuse that reduces the drain is the draw. Consult the owners' manual or service manual to find what circuits are on that fuse.
6. Check each device (circuit) on that fuse. Stop each lamp, heater, etc. to find the drain.
7. Repeat steps 1&2 to test your repair. The ammeter will tell you exact numbers. There you go...everything you never wanted to know... I hope this will fixya up...good luck.
   
   PS...what kind of season are the raiders going to have this year? I'm in LA county and "Manny being Manny" has turned me away from baseball for now.