I’m quite pro-hybrid. They may seem overly complicated at first glance – you do have, essentially, two parallel drivetrains, after all – but the combustion drivetrain’s strengths and weaknesses dovetail so nicely with the strengths and weaknesses of the electric drivetrain. For a hybrid to work and deliver what it promises, like improved fuel economy and reduced emissions, both drivetrains need to work, which means the battery for the electrical drivetrain needs to be, you know, functional. This is obvious. What’s less obvious is how much of an Achilles’ heel many of these batteries have, and how vulnerable the batteries can be to expensive failures, especially if the hybrid owners have a dog.
I know this may sound strange – why should dog ownership affect something like hybrid battery longevity? It all comes down cooling. Not the dog’s cooling – they’re very skilled at panting to shed excess heat, I mean the battery cooling, which, in the case of many hybrids from Toyota, Lexus, Honda, Kia, and others, depends on air cooling through a set of vents dedicated to this purpose. If this vent gets blocked or clogged for any period of time, the battery can overheat to the point of failure, leaving the owner with what is effectively an underpowered combustion car that’s dragging around about 1,000 pounds of now useless hardware, and, of course, fuel economy and performance will suffer significantly.
If the battery does fail, it’s also an expensive repair; for example, a replacement battery for a Toyota Corolla Hybrid can range between $2,000 and $8,000. That’s not cheap.
So why am I singling out dog owners here? Because dog owners are likely to have covers on their rear seats to protect the seats from their sloppy, goofy, friendly furry friends, and those covers often block these crucial vents. Also, dog hair can clog these vents and their associated filters, leading to cooling issues that way as well.
I don’t think the crucial nature of these hybrid cooling vents are as well understood by owners as they should be, which is a big part of why I’m writing this. I have friends with dogs and hybrid that have had a seat cover that blocks these vents, and our own Bishop told me he was just in a Toyota hybrid Uber that had seat covers that blocked the hybrid battery cooling vents. A blanket under a baby seat, placed to protect the upholstery, could block these vents. Some reusable grocery bags that you keep in your rear footwells could block these vents. A thrown jacket could. There’s just so many, many ways to block these vents without even having to think about it too hard.
Some people are aware of the issue, of course, and actively try to find seat cover solutions that won’t potentially kill their battery, but plenty of other people have no idea what these vents are or how crucial it is to keep them unblocked. There are posts from people on forums where they’ve only discovered why their fuel economy has tanked after its too late and their battery could already be ruined:
In the case of that Highlander owner, the battery/hybrid system shut down to prevent more damage, which is better than total battery failure, but it’s still not great, by a long shot.
So, why is it like this? Objectively, placing a crucial vent in the area of the back seat feels like a terrible, unforgiving idea. Aside from dog-protecting seat covers, there are just so many ways those vents can be blocked. Packing for a long road trip with a friend? Who among us hasn’t used the rear seat area to store cargo or camping gear or whatever on a long trip. If you do that in your Highlander or RAV4 or Kia Nero or whatever, you could very easily block those vents quite effectively without even realizing it.
The reason the vents are inside the cabin at all is because the carmakers were trying to be smart: they know the battery wants to be about the same temperature as humans want to be, and they know the cabin of the car will already likely be either warmed or cooled by the HVAC system, so that’s ideal air to pull, temperature-wise.
The problem is that it seems like very little thought went into the positioning of these vents beyond that. They’re so easy to block, and the consequences for that blockage are so severe, it all feels like a very unforgiving design decision. Could these not have been placed, say, high on the B or C pillars, in places unlikely to be covered by bags or seat covers or dogs? They’d need more ducting to get to the underseat battery, sure, but it seems like a better place for these vents.
Also, how many hybrid owners know that often these vents have filters that require cleaning? I bet not enough.
To add an extra level of complication, on some cars, the vents are the designated place to blast water into in case of a battery fire:
…so a longer duct/path to the battery via a vent could be an issue for that, but I still think there has to be a better solution for these crucial vents.
Carmakers can’t expect owners – especially second or third or whatever owners – to know what these nondescript vents are and how crucial they are. Perhaps they should have warning stickers right on the vents warning that they should never be blocked? Or, ideally, the locations of these vents need to be rethought more completely. Low-set and right by the seat bottoms or backs are just areas that are far too likely to be blocked from airflow for entirely normal, commonplace reasons. It’s just bad design to require these areas to be perpetually unblocked and free for airflow.
I know it’s an engineering challenge, but this feels like a worthwhile one to solve. There must be ways to integrate these vents into the pillars or ceiling and get them away from where something as fundamental as gravity is conspiring to block airflow. I’d even take a simple warning light to tell the driver if the vent is blocked!
This is a design problem, not a user problem, but current hybrid owners are the ones who are at risk. If you have non-gearhead friends with hybrids, I think it’s worth pointing these vents out to them and at least making them aware of how important they are, before they leave a bag back there blocking a vent, or put on a seat cover or something like that over them. You could be saving your unwitting pals thousands of dollars, and keeping their dogs from getting the blame for an expensive repair.
thanks Jason – I am currently blocking my vents with grocery bags in the footwell, will stop doing that.
I had no idea.
Upon checking, I find the Maverick has a separate liquid cooling system for the battery, which explains why there are two coolant reservoirs.. huh. Seems a better system than relying on cabin air, just another example of great Maverick design.. sorry I’m a fanboy of my new truck.
possibly the greatest clickbait headline in Autopian history – dogowners, this one weird trick will save your battery !
well done 😉
You mean they couldn’t solve this problem with external air intake, possibly through a pair of repurposed sweet, sweet second-gen Trans Am fender air extractors?
How about instead of putting that vent in the interior, they put it on the outside, while they simultaneously, say, MAKE NACA DUCTS GREAT AGAIN?
So, no RTFM, or it’s not in the FM ?
This is why you should always have your dog in your lap while you are driving. /s
This is exactly the kind of useful user info essentially zero salespersons would mention at delivery. Having said that, I assume most or all of these have warning lights/messages displayed when there’s a problem and I wonder how many are actually “ruined”.
The only useful user info one should take from a salesperson is where the user manual is located.
Wow. I don’t own a hybrid, but this is the kind of article that makes The Autopian mandatory reading. Thanks
The Abby picture reminded me of Kessler (at 5 years old she came with the name) an adopted rather sun faded no clear coat red minpin that passed away this Spring at 15 years old, a hell of a loss for us, but a good run for her, I like to think.
Hybrids quit making sense due to complexity, which worries me as I tend to own vehicles well beyond warranty and ICE vehicle can be bad enough.
I wonder if those vents have reverse flaps to keep the water out should the vehicle have the misfortune of landing in flooded roads, bodies of water, etc. Can’t imagine losing few precious minutes before the interior is completely flooded in while the drivers and passengers were trying to figure out how to open the damn doors electrically or look for the hidden mechanical latch.
Another reason to love pure ICE vehicles…without hybrid nonsense.
You’re thinking of EVs. Most hybrids have mechanical door handles.
Who knows what that old-man-yelling-at-cloud nonsense has to do with anything. Maybe a “/s” was missing at the end?
ONE MORE REASON TO ONLY USE A HORSE AND BUGGY
HORSE AND BUGGY? WHAT ARE YOU HAULING THAT YOU NEED AN ENTIRE HORSE TO PULL IT? WE USED TO BE THANKFUL IF WE GOT A SANDAL, AND FOOTWRAPS WERE PLENTY ENOUGH! IF WE HAD A BIG LOAD TO HAUL WE’D JUST GET A HAND-CART, MAYBE ASK SOME STRAPPING LADS FOR A HAND. BESIDES, ANY LOAD TOO BIG TO PULL WITH A HAND-CART IS BETTER HANDLED BY AN OX, ANYWAY!
Oh please, just more people trying to shove the wheel down our throats. I’ll keep using the citizens of my conquered lands to haul my loads. Wheels have NO SOUL. Nothing matches the satisfaction of 35 malnourished and exhausted people.
I certainly hope you’re not disciplining your peasants with a whip, the connection you feel when you backhand them with your own knuckles is unlike anything else. Really gives you direct control.
I love it when they see me coming and they wince and cower.
Door handles have very little connection with drivetrain choice, that’s simply a new car thing, and has been a “fancy” car thing for a while – The C6 Corvette had electrical door latches, for example. It’s becoming more common because you can use the same latch actuator and switch for every door of every model instead of having to have different push-pull rods depending on door size and shape, and you can make a shitty little plastic switch instead of a big, hinged handle that’ll get judged on design and material quality. Probably saves like 3-5 cents per car.
That’s why I got a 1998 base Boxster instead of a 296 GTS, my car has chunky interior handles made of shiny, painted cast metal instead of buttons. No other reason.
…what?
I’m curious how many flooded Prius’s and RAV4 hybrids you’re aware of where passengers were unable to get out. This isn’t a thing and has never been a thing. Sure, Tesla has managed to screw up door handles. Tesla is not what we’re talking about.
Considering how many fake vents cars have on them it seems strange that there would be no real vents on the outside of the vehicle. The other thing is that many cars nowadays have rear passenger HVAC, either by running the venting through the center console or through the front doors, B-pillar, and then the rear doors. What’s stopping them from just extending the ducting a bit to take advantage of that?
I had no idea where the vent was so I googled it and landed in a Prius forum thread it was mostly about Uber drivers who’s drunk fares vomit into that vent leading to, well things happening . Not good things. Not at all good, but pretty bad things in fact.
Unless you’re Ethan Cohen, it could make a good Ethan Cohen movie maybe.
*Niro.
de, Robert.
The first generation Prius (Japan only) and first generation Escape Hybrid used separate HVAC boxes, complete with blowers, to provide climate controlled air, from an external source. If you look at pictures on the internet you can see the intake on the Left (US driverside) rear quarter panel on the Japan only Prius. On the Escape, if you look closely you’ll see that the driver’s side rear window is slightly smaller than the ones on the non-hybrid models and the passenger side glass on all models. The leading edge is the battery HVAC air intake.
By the time Ford put the system in the Fusion the HVAC system was gone and replaced by drawing air from the cabin through a vent in the back seat area. By the time the next generation of Fusion came along there aren’t any visible vents.
The old Ford Escape hybrids had a vertical slot in the rear side windows to cool the pack under the floor. Perhaps new designs could have a BMW E28 style slot in the C pillar.
Blanket under a babyseat? Uhh I think thats a bad idea.
Yeah, I would never use a blanket! I obviously rubbed Vaseline all over the seats before installing my baby’s car seat – she slides around for every corner and loves it!
My ’14 Camry hybrid has vents on the driver side rear seat bolster – exactly where I would hang a jacket or garment bag on a trip. I watch to keep it open to airflow.
I was worried about this on my Maverick hybrid after reading this. As it turns out, the high voltage battery on the maverick is liquid cooled, so no worries there. My dog can still come along!
I had the same little freak out.