Left Clarity "ON" by mistake! Way way up in the Mtns...Ohh Dear!!

Well, this thread has, alas, convinced me to NOT buy a Clarity!

Cannot believe that a car can be left on like this!

I'm too used to key-operated vehicles where the car is turned off in order to remove the key.

I guess I just wasn't meant for these times... or cars!

 

Most cars, non entry level, these days use the key fob. If you get in the habit of using the fob to lock the car, then you know you took the fob. Kind of annoying.

 

The manual doesn't seem to mention this anywhere, but it would certainly make sense, and is what other PHEVs do. The timeout is longer than 30 minutes, though, unless it takes into account an apparent occupant (the Volt is set to 90, so maybe it's the same).

It would be nice if someone would just run this test--turn the car on at home, lock the doors, and take the remote away, then come out to check say every 15 or 30 minutes to see if and when it turns off (or doesn't). I may do this myself at some point if nobody else gets to it.

Just to mention, I and others are skeptical that the car really was left on, rather than in Accessory mode (the equivalent of having the key one turn in a keyed vehicle). In accessory mode the car will (unfortunately) run down the 12V battery and refuse to start, just like any other car left in accessory mode (which is equally silly in this day and age). This isn't normally something you would do by accident, though clearly it's possible.

If the Clarity were just on, it should (emphasis because maybe I'm wrong) either keep running indefinitely using gasoline or shut itself off after an hour or two.

Now, it's definitely easier to leave a car with a wireless fob and start button in accessory mode than it is with one that has a physical key, but as noted more and more cars these days operate that way.

 

I just picked my daughter up from work. I had to wait in the hot sun for 20 minutes. The car was in "Park" with the A/C running. The car did not run out of power. I don't think the little 12 volt battery has enough juice to run the A/C for that long so the system must be replenishing the 12 volt battery from the Lithium battery.

 

I haven't tested this with the Clarity, but every car I've owned in the last 15 or so years automatically shuts down after 10-20 minutes in accessory mode.

 

There is no need to speculate on this--I have tested, and without question under normal circumstances the high-voltage battery is used to supply 12V when the car is on. It is held at a solid 14.5V regardless of load (I tried with the A/C on, both seat heaters at max, and the headlights on, in park, for twenty minutes straight).

If you think about it, this is actually a basic necessity of the way the car is designed: In EV mode, there is no alternator (just another word for a generator attached to the ICE in a car) that could be supplying 12V power to the 12V system, but the car has to be able to run the seat heaters, the A/C, the computers, and whatever else is on the 12V bus. If you charge every night, it can run in this mode for weeks at a time without the ICE ever starting up, so the car must supply that energy from the high voltage battery pack, and the only way to do so is by doing basically what any other car does: float the 12V battery. It just does it with a good-sized DC/DC converter instead of an alternator.

Now, it's a fact that the OP had the 12V battery die somehow, which means that something funny was going on. Either the car was in accessory mode and doesn't shut down on its own (weak design, but possible), it was in On mode and there is some point at which the car will stop charging the 12V battery but not shut down automatically (also weak, but also possible), or there's simply something wrong with that particular car.

 

This issue is not unique to Clariy. Read this recent article from Consumer Reports about the "Hidden Dangers of Push-Button Start"

https://www.consumerreports.org/cro/cars/hidden-dangers-of-push-button-start

 

I have one of the small jump start batteries by Anker. I've used it to jump my V8 and my 4-cylinder boat. Works well. It also doubles as a USB charger. Very handy to keep on the boat.

 

I don't know why I didn't find this before:

Page 159 of the manual specifies that the car will shut off after 30-60 minutes in Accessory mode in order to protect the 12V battery. It's weird that it's not a precise time (maybe voltage related?), but I was sitting in the car listening to music in Accessory and can at least say that it's longer than 32 minutes some of the time. I didn't bother waiting the full hour to confirm.

Other timers mentioned: Page 164, if you leave the headlights on when you turn the car off, they shut off after 10 minutes (also will turn on again and warn you if you open the driver's door). Page 183, the interior lights will turn off after 15 minutes if the car is off. Page 156, you have either 10 minutes or until you open the door to mess with the windows after turning the car off.

I also see that the car will set the parking brake if either brake hold or low-speed-follow has had the car stopped for at least 10 minutes. I noticed the former of those happen while waiting at construction.

 

One more observation:
I accidentally left mine on (not accessory) and a several hours later (not sure exact time) noticed the daytime running lights were on. Turned off car and saw my EV range had decreased from 63 to 59. Must have been due to drain of LEDs and house keeping power. No ill effects were noticed so I guess it used the traction battery to keep every thing going as if I were driving??

 

I emptied the battery on a weekend drive so took the opportunity to run a somewhat more scientific test. Skip to "results" below for what I figured out.

After about 30 miles of driving on ICE after depleting the battery, a stop at the store, and another few miles on ICE to get home (up a small hill), I put the car in park, set the parking brake, put a multimeter on the 12V battery, closed the hood (according to the manual apparently the car can tell when the hood is open, so I didn't want it to think anyone was messing with it), closed all the doors, and took both remotes into the house. I also turned off bluetooth and wifi on my phone so it wouldn't think anything was connected.

This should pretty accurately simulate getting home and forgetting to turn the car off.

Test started at about 6:00 in ~60F weather in direct sun, so the A/C was running constantly. App reported the battery at 10%, as expected for when the ICE starts running. Note that the app only reports in on battery state of charge every 5 minutes, so there isn't a lot of granularity on the SOC numbers. The 12V battery was sitting at a steady 12.52V.

After about 35 minutes, the SOC had dropped to 6%. The 12V battery was still sitting at 12.51-12.53V most of the time, but there were random dips down to 12.1V or so.

After about 50 minutes, there was less sun so the A/C was cycling regularly, SOC was at 4%, and the 12V battery was still at 12.53V most of the time but with drops as low as 11.68V for a second or two. The periodic voltage hiccups might have started earlier, I wasn't watching the meter that closely, although it was pretty odd given that if anything the load should have been lower.

After 1 hour 15 minutes the SOC had dropped below 3% (I'm assuming, possibly incorrectly, that the app is rounding down, so when you first see it go from 3% to 2% it's really at 2.9%), voltage appeared to be more stable again at 12.53V. The A/C fan was cycling on for 6 seconds then off for 7 seconds consistently at this point, and did not change for the rest of the test (actually, it's possible the heat pump had come on at this point, not sure how to check).

After 1 hour 28 minutes, give or take, right around when the battery should have dropped below 2%, the ICE started and ran at pretty close to idle speed for a bit over two minutes. While running the 12V battery was at 12.50V-12.55V.

The next time the app reported in it showed what I'm guessing to be the top of 3%, so it appears that the ICE kicks in when SOC drops below 2% and turns off when SOC just reaches 4%. 12V battery was again steady at 12.53V.

About 23 minutes 15 seconds later, the ICE cycled on again, again at what appeared to be just below 2% SOC, then off after 2 minutes 15 seconds, again at what appeared to be when it hit 4% SOC. I let it run until a little over 2 hours from when I parked, the battery was still at 12.53V when I turned the car off and plugged it in.

Results:

1) The routine appears to be that the car will use the high voltage battery to run things until it drops below 2% state of charge, at which point it will cycle the ICE on and run it long enough to bring the state of charge up to about 4%. It will continue cycling as necessary between those 2% and 4% values. This makes sense, and is exactly what I would expect the car to do.

This also matches exactly what I observed last time I did the same test, during which I was getting into and out of the car repeatedly and with more 12V stuff turned on (seat heaters, headlights).

2) The car, somewhat surprisingly, does not turn itself off if left on for at least 2 hours without a key fob nearby and no one inside. Could be the timeout is longer, or it could be indefinite.

3) The car, as expected, keeps the 12V battery at a comfortable voltage in this state.

Very strangely, though, today the battery was definitely being held at a fairly neutral 12.5V, while last time doing the same test it was being floated at around 14.5V. I don't know what accounts for this; could be that the voltage is increased at higher auxiliary power (I had turned on both seat heaters and the headlights to accelerate the test previously), or it could have something to do with the length of time the car was driven and some sort of battery health routine.

Also strangely, this doesn't account for the 3 or 4 times I had observed the ICE come on with around 50% SOC when sitting in the car in park for around 10 minutes. That most certainly did not happen in this test, even though the only difference was a lower starting state of charge on the battery.

4) This is completely at odds with the behavior observed by the original poster who ended up with a dead battery. Either there's something wrong with that vehicle, very high climate control load will cause it to draw down the 12V battery and it isn't smart enough to shut down before the computer goes down, or something changes after more than 2 hours.

Aside: At a ballpark 14kWh between 0% and 100%, the 2% difference between 2% and 4% SOC would be about 0.28kWh of energy. To produce that over 2 minutes 15 seconds, the ICE would have to be putting about 7.5kW into the battery. This seems entirely believable for a 103 hp engine at low RPM.

Second aside: It's apparently impossible to lock the car when it is turned on, at least if the remote is not in the car. The exterior door buttons do nothing, the interior buttons do nothing, and pressing the lock button on the remote does nothing. Once the car is off it can be locked with the interior buttons.

 

That is a real surprise that the car did not shut down with the fob in the house. One time when I rented a car with push-button start, my wife took the car after dropping me off (leaving the engine running during the transfer). The Idiot I am, I forgot to hand over the fob. A couple of miles later, the car shut down while she was on the road still driving (think there was a dash warning though). The car started fine after getting the fob to her (I was in dog house for a while after that!). Now, that was dangerous but not shocking it happened. Surprised that the Clarity doesn't shut down after the car is in park for some time and the fob is out of range.

 

There are a lot of potential dangers around the different scenarios. What if the car left and parked somewhere in bad weather conditions, should it shut down and not be able to come on again? This would leave the driver stranded somewhere possibly in hot or cold conditions. The car should have a key missing notice on the screen if the key is not nearby.

 

The Clarity, at least, does--it shows messages on the dash cluster that there's no remote present, and can only be dismissed for a few seconds. It doesn't ding nearly as frequently as I'd like, though. You would have to be quite distracted to not notice eventually, and could just as well be ignoring other warnings (like out of fuel, door open, or check engine).

Shutting off in two minutes isn't that bad, because basically you just can't get all that far away, although there are potential dangers so if I were programming that I'd give a countdown starting very quickly and with theoretically enough time to turn around and drive back to where you started before the car surreptitiously shut down.

Not shutting down at all (what the Clarity does) is potentially much worse if the driver is really not paying enough attention to notice the alerts, since you could theoretically drive for hours before parking who-knows-where, turning off the car, and realizing you have no means for turning it back on. Of course, that's no different from losing your keys in the same location, and also if you are ignoring no-key-fob alerts, you could just as well be ignoring no-oil-pressure or check-engine alerts that would have the same or worse effect.

Forcing itself into neutral almost immediately might be the least-inconvenient option (say, 30 seconds and a lot of insistent alerts after it loses the remote) so you just can't get far, but that one has the relatively abrupt side effect of what happens if the remote battery dies while you're driving in the middle of an 8-lane freeway.

There's basically no really good answer for the "drive away without the key fob" situation; one just has to accept the least-potentially-bad of a number of options in exchange for the ability to start the car without physically attaching the key to it. (I remember early Priuses and I think some Chryslers had a mode where you were forced to stick the fob into the dash to start the car, if you didn't want to risk it.)

Now, sitting in park with no remote is an entirely different situation. In that case, the "never turn off" bad version is that the garage fills with CO and kills you when you go to get into your car. Which is pretty bad, and caused Chevrolet to issue a software update recall that shuts the car down after 90 minutes in park.

The "turn off automatically" version's bad is that you were relying on the climate control to keep the car from roasting your pets when you walked away, and it eventually shuts down and kills them. Of course, as implemented in the Clarity, since it is impossible to lock the car from the outside you're also trusting that no one will get in and steal your pets or other contents of the car, and since you can shift it out of park and start driving (I just tested), you're also trusting that someone isn't going to steal your car, if this were intentional.

Honestly, what the Clarity does in park seems like a really bad design all around. If it indeed never shuts down, you have the CO danger (and running out of gas eventually); being able to shift out of park seems like a spectacularly bad idea with no upside, since your kids could put the car in gear or it could very easily be stolen; not being able to lock the doors was probably intended as an indicator or to prevent you from locking the key (or your pets) in the car or something, but in effect it just makes it that much easier to joyride, especially since the rapid-beep warning you get from the outside is the same as any other auto-lock-fail warning, which is pretty common, and isn't all that loud if you're on a noisy street so could realistically be missed pretty easily.

This is genuinely bad enough that I hope Honda changes the behavior with a software update eventually.

 

Day two with my clarity and left it on after playing with the dash. I was used to fusion energi's aito cut off or horn beeps. I consider it a lesson learned!

 

For simplicity, I always use the On/Off button instead of the Park button followed by the On/Off button--the On/Off button automatically puts the Clarity in Park before shutting down. I never wonder if I turned off the Clarity.

 

Similar behavior to the LEAF I had for three years. I’m so used to skipping the Park button now when I drive my F150 I wonder why it starts rolling away and dinging at me as I try to climb out