12V battery recharged, but RAV4 dead (won't even unlock door with remote key) - ???

[ferenc]

So, as I was ready to sell my RAV4, and a few nights ago I charged it (~100mile range indicated at standard charge setting), and parked it on the street.
Yesterday, when I went to open it for something left inside, the remote key did not work. After some troubleshooting (using the mechanical key to open it), the car was totally dead. This morning I charged the battery (12.8V) and before hooking it up directly, I measured the current draw at it was >10A DC - my DMM's max range) .

What is going on, and what should I do about it? I have reasonably good, but rusty(!) EE skills, but not much experience in this vehicle.
Suggestions welcome!

 

[hokiematt]

Usually when 12V power is interrupted, the brake booster pump will turn on for a few seconds when power is re-applied, and will definite draw more than 10A. Let the pump build pressure and shut off; the navigation unit will also draw power for a minute or so while it reboots. See what your current draw is after a minute or two, the general rule of thumb is <20 mA for phantom draw.

One of the more common candidates for killing the 12V battery is the rear cargo lamp switch gets flipped to the ON position.

 

[ferenc]

Usually when 12V power is interrupted, the brake booster pump will turn on for a few seconds when power is re-applied, and will definite draw more than 10A. Let the pump build pressure and shut off; the navigation unit will also draw power for a minute or so while it reboots. See what your current draw is after a minute or two, the general rule of thumb is <20 mA for phantom draw.

One of the more common candidates for killing the 12V battery is the rear cargo lamp switch gets flipped to the ON position.

The 12V battery is recharged but not even key FOB nor any interior light some on ...

 

[ferenc]

I am at a loss on what to do.
The12 battery has been recharget, gut the vehicle is still dean.
Bay Area delear I can trust to have the cae towed to for repairs,
Bummed and stuck!

 

[miimura]

Check the fuses - including the one integrated into the positive battery terminal.
Also, when you connect the battery does the voltage drop? Is there a spark when you connect the battery? The spark is normal. Not having a spark when you make the last connection to the 12V battery is suspicious.

 

[ferenc]

Check the fuses - including the one integrated into the positive battery terminal.
Also, when you connect the battery does the voltage drop? Is there a spark when you connect the battery? The spark is normal. Not having a spark when you make the last connection to the 12V battery is suspicious.

There is an integrated fuse at the positive battery terminal? There is a lot of white powder at the battery cable connection. I'm thiking of scrubbing it off (with baking soda and water?),

 

[asavage]

You can use a baking soda & water solution to "melt" some of that acidic corrosion . . . but don't neglect to then rinse off the baking soda/water with plain water. You can remove the corrosion deposits with plain water alone, it just takes more scrubbing.

The basic (pH <7) baking soda/water is just as corrosive as the leaked battery acid, and will corrode just as badly. I had to learn that the hard way in fleet maintenance in 1981.

The corrosion from battery acid on -- modern sealed batteries -- indicates that the seal around the battery post(s) has failed, and it's best to replace the battery rather than only clean it up and ignore it further. You can use the greased felt rings around the posts' bases to try to confine the leaking acid from doing new damage, but that's a stopgap.

 

[ferenc]

So, I bought a $200 AGM replacement battery at Costco and after cleaning things up, replaced the 'dead' 5 year battery.
The car seems to be fine, BUT
I noticed about a 2.5A draw on the battery with nothing being on.
Recalling someone posting about a rear light short, I only found one of the license plate lights to be burned out. Removing it (to look for a replacement), I noticed no change in the current draw from the freshly installed battery.

Is there an additional procedure to reset things after replacing the 12V battery?

Is the current draw normal, at least for a few minutes?

What to do?

Sigh ...

 

[asavage]

You'll want to check idle draw after, say, 10 minutes. Lots of modules take some time to resume sleep.

 

[miimura]

After everything has gone to sleep, the current should be so small you can't measure it with an ordinary clamp meter. It should be 10's of milli-amps when sleeping.

 

[asavage]

Generically, <50ma. I don't think I've measured mine, but <30ma is even better. But it can take 15 minutes for the systems to become quiescent.

 

[alflash]

After everything has gone to sleep, the current should be so small you can't measure it with an ordinary clamp meter. It should be 10's of milli-amps when sleeping.

Examples of checking with current clamps*.

1. With an installed video recorder, which was powered directly from a 12V battery​

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2. Checking in the absence of additional systems/devices​

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* Note. About measuring.​

 

[ferenc]

Thanks, I may have over-reacted. I used a HH DMM on the 10A range between the "-" battery terminal and the cable that normally attaches to it.
I will next let the car go through it's thing with everything off for 10 minutes with the same setup. I have not watched the dash to see what it's displaying.
I appreciate the help!

 

[asavage]

The power brake pump alone may draw >10A (for around three seconds); I'm kinda surprised your DMM's internal 10A fuse wasn't blown.

 

[ferenc]

Thank you for your encouragement and good advice.

I rehooked the new battery, turned on the car, let it go through it's 'reset' cycle and, among other things, it 'downloaded' an OS, went through some internals and came up sane, with '123 mile' range and my radio presets.
The current draw dropped down to mA and the car seemed happy and its old self.
I wonder from where it downloaded its OS and what version it was?
I often suspected Tesla with mucking with it in the past, and now wonder what versions OS it donwloaded, and from where?
The only victim was I lost one of the 8(?) pushbutton plastic cover holders along the front of the inside of the hood, that I removed in order to remove and reinstall the battery clamp.
I drove the car for about a half mile and it all worked.
If I hadn't given up on it and bought the Ioniq5, I'd reconsider my decidion to sell it ...
Ferenc
PS I plan to find and replace one of he two rear license plate bulbs after Labor Day (standard item - or dealer special?). It was not the cause of the excessive current draw, as someone suggested, as it was open (filament? blown) and not a short causing the excessive current draw after the new battery was installed.

 

[hokiematt]

The progress bar you saw on the nav unit is normal for boot-up from the internal HDD following loss of 12V power; the car did not download a new OS.