Frequently drained when parked unplugged for a while

the car is always draining the battery. 2-3 days is not much for a healthy battery. don't trust the dealerships, they are prone to ignorance and error. learn how to test it yourself. every time you drain the battery, you weaken it and shorten the lifespan. if you do find that the battery is good, then you will have to test the draw to see if you have a parasitic drain. i left mine for 5 weeks in a cold garage this winter with no problem. some say the advanced spends time exchanging info for charge point or something, but there is no proof of this.

 

A battery can test OK, but it may have a slow drain due to many possible factors:
There may be moisture and corrosion on the battery, or salt on the surface from road salt, car wash residue or ocean spray. The battery itself may have micro-channels in the case due to manufacturing flaws, causing minor shorting between cells. There may also be minor shorts in the wiring somewhere due to the factors already mentioned. Also, some accessories can slowly drain the battery, such as dashcams, GPS trackers or car security equipment. This is where a battery maintainer is a good idea. Failing that, get a deep-cycle battery -if the battery going flat will be an unavoidable reality.

 

Just to be clear, you are talking about the 12v lead acid battery right?

When the car is off, the traction battery gets disconnected. Only the 12v is used for the smartkey system, dome and trunk light.

Check and make sure the light in the trunk is turned off even when the hatch is closed. You can easily see if you retract the tonneau covers.

 

how can road salt, car wash or ocean spray get on the surface of the 12v battery?

 

You'd be surprised, but it's not just the battery proper, it can be anywhere in the circuit, including the engine compartment.

 

i'm gonna have to check mine after all the road salt we had this year, i'm surprised there's any left!

 

Yep! they are all out of Salt!

 

I am thankful that the weather in California is such that salt is never used on roads here (and the law does not allow it for environmental reasons). In the Sierras where snow is an issue, they sand the roads, and in the rare cases where that is not sufficient, they just close the road.

 

Not commonly known is the fact that most car washes recycle the water. I've been told that it tastes decidedly salty.

 

yes, it would be interesting to understand the process and what water testing is done, if any.

 

HowStuffWorks "How Car Washes Work"
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Depends where you live, but it varies greatly and salinity is much higher in areas where they use salt on the roads, therefore the recycled water will be very salty. There's just no cost-efficient process for removing salt from the water in car washes.

 

To the OP: you said you bought your 2012 model ten months ago, so it was likely on the dealer's lot for a year or longer. Consider that the battery may have been drained flat and jumped/charged many times. I would suggest pressing the dealer to replace the battery under warranty. If they resist, contact Toyota Customer Care at the number in your owner's manual and open a file with them, after advising the dealer that this will be your next step. (That might be all that is required to get the dealer to cooperate!)
Regarding the cargo area light, it has a two-position switch, but should go off if the hatch is fully closed when the switch is "on".

 

That's nearly exactly what happened to me with my 2012 PIP that I picked up new about a month ago. The battery was going flat after less than 20 mins on acc. I had the dealer test the battery and it proved unsatisfactory, and it was replaced.

The salesman said it had gone flat many times in the showroom, and had been jump-started as many times.