Battery Drain after 4 Days

[Slickspawn]

On the 4th day (you could make it a Saturday or Sunday for easy access if you work M-F) check each fuse with your meter to see where the current is being drawn from. Remove fuse, touch leads to fuse box contacts, measure current. Set multimeter to milliamps.

Before any of this, what is the standard dark current draw on day 1, 2, 3? Day 4?

 

[Dan D]

Do you have access to a multimeter? You need one.

Make sure the cars turned off and disconnect the battery negative lead and connect the meter between the lead and the neg terminal with the meter set to amps.

With the car turned off, no key in the lock, radio off and all doors shut you should have a current draw around 34mA.
Betting you have around 150mA.

You now need to start pulling fuses to isolate which circuit is pulling the power. Start with the DOME fuse located behind the front kick panel. 90% of parasitic draws are on that circuit. It feeds the interior dome lights via the door switches, the body management computer and the intrusion detection module.
When the current drops back to around 30-34mA you know you have the offending circuit then you start disconnecting things...

I have the same problem but haven't had time to locate/disconnect the two computers modules. Keeps us posted on progress.
A good search is "parasitic draw". Its a very common problem but there isn't much useful info out there about the reality of fixing it.

I have a 2003 landcruiser with a slow battery drain. It's been like this for around 5 years now. I have to plug in a trickle charger periodically to keep it from going dead. I tracked the drain to the ecu-b2 fuse. When I pull it the milli amp draw goes from 150 to 10. That fuse must power the computer that controls lights, security, locks etc because everything inside kind of goes dead without it. The strange thing is before pulling that fuse I pulled the dome fuse and the milliamps went from 150 to 400! Also important to note the 150 draw is with the vehicle unlocked. When it is locked (armed) I get a draw of 250.
So my first question is, do you know what the draw should be when the car is off?? Is a150 milli amp draw an issue? I tested the interior map light and it pulls 350 milli amps, that's more than twice my draw, but it seems like leaving even half a light on would be a problem. Second, has anyone successfully fixed a problem with the ecu-b2 . I've read a ton of threads with no resolution ( other than chargers or disconnects).

 

[WomblingFree]

Turns out its normal behaviour.
The 'Dome' fuse feeds a lot of computers. The current draw usually drops considerably 15 minutes or so after you remove the key and all doors are shut.
I did a heap of testing on this when I bought my 100 but there is no 'fix' as its normal.
You can verify this by hooking up a multi-meter to the Dome circuit so you can see it through a window. Shut the doors and lock it up. Note the current draw and go get a coffee. See what it reads some time later. It will have dropped a lot to its quiescent draw.
For long term storage you need to remove the battery leads.

 

[gungriffin]

For long term storage you need to remove the battery leads.

What would you define as long term storage?

 

[suprarx7nut]

What would you define as long term storage?

As a frame of reference, my 99LC has been sitting up on a lift for the last 4 weeks. The battery just dipped below 11V the other day and I put a charger on it. It may have had a hard time starting, but it took about that long to actually run out of "juice".

You should have no problem storing a good battery on a functioning 100 series for about 2 weeks in my experience. If it's going to be longer than that, plan on putting on a battery maintainer or removing a battery cable.

 

[Dan D]

As a frame of reference, my 99LC has been sitting up on a lift for the last 4 weeks. The battery just dipped below 11V the other day and I put a charger on it. It may have had a hard time starting, but it took about that long to actually run out of "juice".

You should have no problem storing a good battery on a functioning 100 series for about 2 weeks in my experience. If it's going to be longer than that, plan on putting on a battery maintainer or removing a battery cable.

Suprarx7nut,
It sounds like you own one of the rare landcruisers that hasn't developed a battery drain! Have you every tested the amp draw when the vehicle is turned off, after sitting for a little while? Seems like a lot of us are getting 150 milliamps (0.15 amp). I'm curious if you have any results from a properly functioning example like yours.

 

[suprarx7nut]

Suprarx7nut,
It sounds like you own one of the rare landcruisers that hasn't developed a battery drain! Have you every tested the amp draw when the vehicle is turned off, after sitting for a little while? Seems like a lot of us are getting 150 milliamps (0.15 amp). I'm curious if you have any results from a properly functioning example like yours.

I'll try to measure next time I lower the lift and provide an answer!

I do have a few things that will change my circumstance now (but even as a stock rig it sat for a week at a time on a regular basis and was always fine):
1. Aftermarket stereo with factory amp and headunit completely removed.
2. Group 31 battery (though its 3-4 years old so I'm not sure how much more capacity it has over a good stocker)
3. It stays unlocked in my garage so none of my times were while "armed".

 

[gil12]

18V??

Sounds high to me too.

I found this quote which matches my understanding: "fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts. )
I also recall reading that AGM batteries should not be charged at a higher voltage that 14.5 or so.

 

[gil12]

It is possible that the drain is actually more constant than you think. Batteries will offer a "surface voltage" when there is minimal/no load, and only show their true or working voltage when being used. You might take daily voltage readings after your headlights are on for 60 seconds to measure this. Or, I do like the go-pro idea. A 4 hour video of slowly decreasing voltage might inspire a new mode of meditation.

 

[WomblingFree]

The drain has nothing to do with the battery voltage dropping.
As stated a few times, its a measurable current that drops in value as certain computers go to sleep.
Some current will always be consumed as some of the computers remain awake. You wouldn't be able to unlock your car otherwise.

 

[Turd Furgeson]

I know this thread is old, but I am a history buff so i wanted to see if folks had more results on the parasitic drain. I've tested for the dome light and when I pull the dome fuse I get about 70 millamps of "savings" (.26A to .19A). When I pull out ECU-B2, the drain goes down to 10millamps (.01A).
Its a bone stock, 2006 Nav LC100. Curious if there's anyone whos face this?
Long-term plan is to rip out the Nav and put the Tesla style headunit in, aftermarket sub as well. Would love to know if anyone has found a way to rectify.

 

[jerryb]

it probably wouldn't help if I said buy the wiring book, but there are 25 or so items on the B2. Buy the book.

A normal 2006 will sit for 6 weeks without problems and start just fine with the stock battery size, 100 degrees ambient.
Using the B2 as a control measure won't completely help you. Everyone's car will drop to almost zero after pulling that one.
Read all the threads and see what the main culprits are. Or buy the book.


I think I'd start with the radio fuse and work down.

 

[plainjanefjc]

I started having the problem. Battery and alternator are good. I recently pulled my antenna and installed a permanent one. Now we I shut the vehicle off the antenna motor runs for about a minute although nothing is there- I am hoping I can just disconnect the motor itself.