Long term airport parking in winter...any concerns?

Smart key systems are really rough on the 12v battery, and 3 weeks in winter would not go well.

Toyota included a way to temporarily disable the smart keys on some Prius models, for exactly your situation. Check to see if yours has this feature.

That would be my only concern.

 

To disable the smart key: press unlock twice while holding the lock button on the key fob. The red light will blink 4 times. I'm pretty sure this only disables it on the key, not in the car. I vaguely remember reading something in the manual that says the system might be automatically disabled if the car sits for a long time, but I'm not sure. And I think there is a setting to disable it in the car, but probably only with Techstream not in any of the user accessible menus.

You could consider disconnecting the 12V battery. Not sure if that would cause any other problems?

 

carry a jump pack for emergency convenience, and/or, check into airport jump start availability.

or take the old gasser with the big strong battery.

 

What's your home parking situation? It'd be best to leave the car at home, garage parked, on a smart charger, and take a cab or transit to the airport. If practical.

 

It disable only the key yes ,

but the car stops monitoring for smart keys after 5 days. I think it's the default setting .. well on my car it's 5 days.
Can be done by Techstream and this setting is available in Carista if you are a subcriber.

 

Over 3 weeks, only a weak 12V battery should be at risk, and it ought to be the same as on a regular Prius. Not many two year old batteries should be that weak yet.

Explore the vehicle setup menus for how to shut off the car side (not just fob side) of the smart key system, saving the energy used before the car would shut that down on its own. I do this on my Gen3, but yours has a different menu.

Prii are notorious for not getting or keeping their 12V batteries up to full charge, at least for my older generation. (Don't know if this has been improved in your Gen4.) So for longer absences, I have been preemptively topping off my 12V battery with a battery tender. (At more than 6 years old, it is now weak enough that it doesn't tax a lower current tender, so I don't need a full size charger.) But I didn't start doing until it was more than 3 years old. Prior to that, I merely shut down the smart key system once for a 6 week summer trip.

As for the traction battery? Fugetaboutit. It is automatically disconnected when the car is shut down, and is significantly more robust during storage than the 12V battery. Though I had believed that a mid-level charge (40-60%) was better than either full or low.

(I do intend to replace my aging and weak 12V battery 'soon', just haven't gotten around to it. It now frequently gets battery tender top-offs immediately after I get back from absences too. Need to review the available replacement selection & prices. )

 

I don't think it should be a problem. I have left mine for a month and no problem. But I would not want to leave my car at an airport that long just because it may get damaged or broken into.

 

Ok.

For the 12 volt battery, you may be ok, or not. The cheapest and most direct solution would be to disconnect the 12 volt negative cable from the battery at the airport. Upon your return you will need to unlock the driver's door with the manual key and crawl through the car to release the hatch manually. I would read up on what's involved and do a a practice crawl, without the actual battery disconnect.

Alternately, leave a good jump pack in the car, for just in case. That 3 week sit will run your battery down some though, maybe shorten it's lifespan.

 

Does it give an actual preferred number?

Re-checking some general lithium-ion battery info, I'm seeing the 40% number as about the best level for storage. But that is based on the battery's original full specs, not the reduced operating range Toyota shows after setting aside safety margins at both the top and bottom. I don't have a proper translation between those two different scales.

That is as expected. Gen1-3 Prii have small 12V batteries. The factory incandescent bulbs that can be accidentally left on will drain it overnight. That is why I replaced them with LED lamps, selected for efficiency (low current) rather than the greatly increased brightness some other folks want. Pulling about 10% of the current of the originals, these allow far more time to discover the accident -- at least all night, maybe even a whole weekend -- before the car won't start. And their current vs voltage curves are more friendly to draining batteries. As voltage drops, LED lamps reduce their current even faster, while the factory incandescent bulbs don't similarly decrease, and can even draw increased current as the bulb dims.

What is the 12V battery age? Your 2017 car was built more than 12 months ago, potentially 24 months ago. That is the number that matters.

But I had no problems at that age.

I'd take the Prime, no contest.

But take a 12V jump pack too.

 

it tells you to discharge to the hybrid state. i.e. no ev miles left.

 

No need to crawl: unlike on older models, on Prius Prime and fourth-generation Prius cars, the auxiliary (12-volt) battery is under the hood.

A reasonable idea, but perhaps unnecessary here: if @panache will be parking in one of the official lots, the Dulles airport website says they provide free jump-starting, though I suppose there could be a chilly wait. Now an ice scraper, on the other hand...

Inability to start the hybrid system when it’s -22 °F or colder, as noted in the Owner’s Manual, is also unlikely to be a factor: the lowest temperature ever recorded at Dulles was -18 °F on January 22, 1984.

According to the New Car Features book (more info), that’s correct, and after 14 days, it also disables the lock and unlock sensors for doors other than the driver’s.

 

Aww that takes all the fun out of it.

Thanks for the catch.

 

It sounds like the OP doesn't travel much. Seasoned travelers are somehow able to get away from home and not worry about anything at home.

 

After Gen2 (which has a smart-key OFF swtich) the Gen3+ Prii automatically go into SKS sleep mode after a few days, so there is less concern.

 

Maybe some electrical engineers can weigh in? What I've observed: our car imposes roughly 20 milliamps background demand on the battery. With the Prius 12 volt battery, what's gonna happen over a few weeks?

Googling I didn't find much. Here's one vague article:

How often do I need to use my car to prevent battery death? - The Globe and Mail

 

You won't have any worries. I left my 2014 Gen 3 (with smaller 12V pack than Gen 4+) in Colo Spgs airport parking in December for 3+ weeks with no problems. The only thing I did was ask the shuttle bus driver to wait until I had started it before pulling off. If you are inclined, you could leave jumper cables in the back in case your 12V battery runs down. Most parking facilities would have 12V jump/boost equipment handy I'm sure. Brush up on the jump procedures in the Owner's Manual just to be safe.

 

And for "in the back" make sure it's somewhere easily accessible if you can't open the hatch because the battery is dead
There are jumper points under the hood if you can't get to the battery in the rear compartment.