Parasitic drain

[John ADAM]

April 18, 2022

Battery on my 2005 Lexus LS 430 dies after 2-3 days of inactivity.

The battery is new (tried 3 new batteries in last 3 years).
Alternator is also new.
Battery and alternator were checked by a mechanic who said both are good.

If I disconnect the battery it does not drain and stays good for up to 5-6 days.

If I leave it connected, it dies in 2-3 days.  So, it indicates possible parasitic drain.

But, when I check the resting voltage/current using a multi-meter, I only get 30-40 milliamp which is less than 50 milliamps that they say is "normal" and sort of rules out parasitic drain per my reading.

Question:

1.  Can the car have parasitic drain even if the resting (30 minutes wait and everything off on the car after disconnecting negative cable) voltage is less than 50 mA?  In my case, even if it is less than 30-40 mA?

2.  If parasitic drain is unlikely with a resting voltage of less than 50 mA, what could be other reason/s for battery drain within 2-3 days of inactivity?

Thanks a lot friends, for whatever help you can provide.

 

[RX400h]

I typically recommend Auto Electric shops for not-so-easy-to solve electrical issues, especially parasitic drains. Those type of shops solve electrical issues that dealerships can't. I've run into a couple over the years that I could not solve. In both cases, the shop figured it out in less than an hour.

By the way, it the drain were excessive, you could monitor it while removing one fuse at a time, to isolate the path or component that is causing the drain. In your case, it is puzzling that you can't start your car in only 2-3 days when the drain is only 40 milliamps.

I assume you checked the battery voltage while the car is running and when off to rule out the alternator and battery.

[John ADAM]

Thank you. 

Yes I did check the battery voltage with (14.2) and without (12.45) engine running and it checked out OK with higher voltage when engine was running (I think it was over 14.2).

My regular mechanic also checked it professionally and said the battery and alternator are both OK; and, that there is a parasitic drain somewhere.  But, he does not do the electrical work and told me to go to dealer.  Dealer told me to do this type of work the labor is about 140/hour with no idea about total time involved; it could be "several" hours and do not want to go there giving them open wallet with no educated idea about the work.  Generally, I have had bad experience dealing with dealers for anything except oil change.  

I am still puzzled that resting drain with everything off is only 30-40 milliamps yet something drains out the battery in 3-4 days in summer and just 2 days in winter.  As I said, if I I disconnect the battery, it lasted for 5 days and started right way with voltage drop only from 12.40 to 12.27 after 5 days.

Thanks again in advance if you, or any one else, have any other suggestions.

John
LetUsHelpEachOther

[RX400h]

I agree that it is very puzzling, but this is why Auto Electric shops exist. They are typically very good at troubleshooting mysterious electrical drains.

[John ADAM]

I could not find any special auto electric shops.  When I Googled (Auto electric repair shops) for it only local GENERAL auto repair shops came on the search but a few I called said they do not do electric work and advised to go to dealer. 
Are there any national auto electric repair shops I can search for by name in my area?

 

Thanks.

[RX400h]

Auto electric shops in New Jersey - Search (bing.com)

Maybe one of these?

[Bykfixer]

Hey John I have an 04 GS car that had some obvious parasitic drain issues and it seemed to be the door ajar system thought a door wasn't closed all the way. Unplugged the overhead light and thought that solved it but time revealed it still had the issue.

Turns out it was two things that happened on occasion while the car was not in use. 

1 was the cd changer kept trying to change disks on occasion. 

2 the seat memory kept adjusting the seat at random times. 

The shop hooked it up to some kind of monitor for a day and found the issues. They charged a diagnosis fee and some labor to unplug the stuff. 

Unplugged those two items and no more issue. 

 

[Dean2]

Did you ever get your parasitic drain issue figured out and if so what was it? Thanks.