Kept Car Warming Too Long, Battery Died

HI
I am new to this thread and am just reading up on the replies now.

I happened to become an owner of a 2010 Prius II as of three days ago and on the second day, the same thing happened to me.
I started the car up to warm it up after a snow blizzard and i left the car in Park -- in Ready Mode -- and left the heat on HIGH and came back to the car after showering and getting ready for work.

To my surprise, when i came back to the car, it was dead -- and the check engine light was on.
The keyless entry that locks and unlocks the car didn't work either -- the cabin lights wouldn't turn on -- totally dead except for the check engine light and a strange whirring sound coming from the hood.

I ended up calling triple A for a jump -- when the technician got to my residence, he advised me that jump starting PRiuses is NOT straight forward AND may not even start up the car.

Luckily, it started up the car just fine and haven't had a problem with starting it up since then, but I am worried and am hesitant to leave the car idling to warm up before getting into it -- i am afraid it will die on me again and i will require another jump to get going.


What could be the cause of this?

Please help!!!!!!


Thanks so much

 

you need a new 12 volt battery. welcome to priuschat, all the best!

 

The problem was you left the car in "ACC" mode, not in "Ready". You did not push the brake pedal (hard enough) when starting the car. It went into "ACC" mode and in this mode the engine would not start, also in this mode the Hybrid System would not charge 12-volt battery. The 12-V battery got discharged by fan on HI very quickly, and car died. End of story

- Alex

 

Adding to the story, the 12V battery now either needs to be replaced or fully-charged overnight, or else you will have another no-start incident. Don't think that driving the car for 20 minutes will restore the battery - that will take many hours of charging time.

 

man up and drive the car cold. it will warm up soon enough. letting your car sit idling is never a good idea. I'm not sure if someone could jump in and drive it away, but that happens all the time with normal cars.

 

It's interesting to see two cases of the same thing happening, even though it shouldn't happen that way. When the Prius is in ready mode the 12V battery is being charged, so if the 12V battery had enough grunt to boot it up in the first place it definitely should have no problems at all keeping it running.

Here's what I think actually happened (in both cases). Though both posters believe that they left the car in "P", they must have shifted to "N" before they left it (either accidentally by bumping the lever or perhaps as an automatic action that they don't recall). In this state the Prius cannot charge the HV battery and it will deplete despite the engine running.

When the HV battery depletes to a critically low level I assume that it would shut down the DC-DC converter to reduce the HV loading (as it does for example if the inverter overheats). At this point the 12V battery starts running down too, and the prius eventually either just loses power or shuts itself off to protect the HV battery.

This happened to me on a camping trip a few years ago, except I caught it just in time and got it into "P" to let it recharge. One thing I clearly remember when returning to the car was that the headlights were starting to dim, indicating a fading 12V level, despite the engine running. (I was actually working in front of the car trying to put up a tent in the dark and rain at the time. )

Anyway, when I entered the car the HV SOC was displaying zero bars on the MFD and there was a warning that it cannot charge the battery in "N" mode and urging me to change to "P". Soon after I changed to "P" the headlight brightness came back (presumably the DC-DC converter came back online) and very gradually some bars of charge came back onto the HV SOC display.

I'm almost certain that is is what happened in each of the above cases.

 

There should really be some kind of logic programmed for non-moving cars to go into park after some time of inactivity in N. Not sure what should be done with moving cars, D vs R based on direction? I personally never used N, but can see how it accidentally can happen and brick the car.

 

What I think happened in both cases is that the car was simply put in IG ON vice Ready (they didn't push the brake down when pressing the start switch). The ICE never started but the inverter coolant pump did. In this mode, the 12V will die quickly.

This explains the noise that was heard by the OP (the inverter coolant pump was running) and the subsequent stopping of the noise (the battery totally drained causing the inverter coolant pump to stop).

 

To The OP.

Are you ABSOLUTELY sure you were parked in the READY mode?

The outcome you are describing WILL happen if you leave the vehicle in Accessory Mode, and if you are new to The Prius it is pretty easy to accidentally do.

I hate to say it, but YES...you now really do have to check your 12 volt, and if it is too low, probably buy a new one.

 

Yeah that's also definitely a possibility.

I guess I was trying give the OP enough credit to know whether or not the engine actually started. But yeah, if the the OP didn't notice that the engine never actually started then what you suggest could very easily be what happened.

I would say that if the op was certain that the engine actually started then my scenario is most likely, but if they're not certain about that then your scenario is more likely.

Whatever the actual case is, I think we can be pretty sure that neither of the above cases happened exactly as the original posters thought (car in ready mode and transmission in "P").

 

Yes, I got quite a surprise when I nearly bricked mine that way. Most people would think leaving the car idling either in "P" or in "N" with the park brake applied would both be much the same. But not so with the Prius.

When it happened to me I was using the car's headlights to help me put up a tent in the dark, but I assumed that as long as I left it in ready mode that it would keep both batteries charged and just turn the engine on or off as required. I had no idea that leaving it in "N" would completely spoil the party. And it did actually run the engine, but no charging took place. To be fair the car though, it did beep to warn me and also displayed a warning message on the MFD. Problem is you get the same beeps just for opening the drivers door with the car in ready mode so I didn't notice it at the time. (That is, it was already beeping at me for something else at the time. )

In hindsight (and knowing how the Prius transmission works) this behaviour does make sense. It is physically impossible for the Prius to generate from MG2 without the car moving, and it is physically impossible for it to generate from MG1 without applying torque to the wheels, so basically it has to refuse to generate in "N". You can't expect the average user to be that familiar with the internals of the transmission to know this however.

 

Here every time car gets inspected they put it into neutral and almost run hv-battery empty. I’m pretty sure somebody’s battery has been and will be run completely empty…

 

I have exactly the same problem in the UK with our MOT inspection. The test station I take my car to has never tested a hybrid other than my Prius. I do live in a scantly populated area for the UK.
Each time I take it for "yearly" test I have to instruct the examiner on how to start the car, and even have point out "as he begins to put the emissions testing equipment on the car" that it is emissions exempt.
I instruct the examiner that the car should not be left in neutral longer than necessary because of the cars inability to charge the batteries in this condition, but the advice seems to get lost as the test continues.

John (Britprius)