It all used to be so simple. “Hey fella, you need a jump?” they’d say. “Boy, howdy, do I!” you’d reply. They’d pull up nose to nose with your car, chuck on some jumper leads, and get you on your way. “Forget that!” said automakers. “Let’s make everything different.”
They put the batteries somewhere else. Where? We’re not supposed to know! We’re dirty little consumers who are too stupid to be trusted with three volts, let alone twelve angry ones! Why, if we dared to jumpstart a car or change a battery ourselves, we might burn the whole car down. Best to hide the battery away from curious little hobbits.
It honestly ticks me off so much. My 2007 BMW E90 buries the battery deep in one side of the trunk. My old MX-5 did the same, and you had to ensure that vent hoses were hooked up so gases didn’t leak out and rust the inside of the car to pieces. My Mercedes puts the big box of acid right under the rear passenger seat along with a bunch of fuses for easy ridiculous accessibility.
I know, I know. I’m being overly harsh. Automakers have granted us some conveniences to ease the pain. They often put nice big 12-volt and ground terminals under the hood for hooking up jump leads. Batteries are often maintenance-free, now, too, so we’re not sloshing about water and acid every six to twelve months. Hiding the battery somewhere inside makes it less likely the terminals will get all gross and corroded. And yes, putting the battery somewhere deeper inside the car reduces the chances it’ll burst open, leak, or catch fire in a crash.
But still, I hate it! I hate it so much. I hate it at breakfast, I hate it at lunch. I hate it on Mazdas, and Jaguars, and Nissans. I hate it on Mercs, and I’m filled with derision. What rude designer approved this decision?
Honestly, I hate it because I drive hoopties. I drive beat up old cars and weird German ones, and I know one day, I’m going to have to change a battery. When that day comes, I won’t just be able to pop the hood and get it done in five minutes. Instead, I’ll be pulling off seats or interior trims, then I’ll be unbolting some whackadoodle battery topper panel and trying to wiggle the thing free. The whole time I’ll be trying not to short out the battery to the chassis while unbolting the terminals. That’s much harder to avoid when you’re wrestling around behind the rear wheel well!
If someone else is servicing your car, or you’re only looking at the battery now and then, it’s probably fine. You don’t even think about it. But for me? Every time I’m troubleshooting something and I’m told to “check the battery” I wince just a little bit. Have pity, and for all of our sakes, make them put the battery back where it’s supposed to go.
Lewin out.
Shots fired! This is wrong wrong wrong wrong! I will grant that the under-seat battery in the Mercedes is bad. This is the worst place to put a battery and I also don’t like it. But having a battery in the engine bay? Also bad. There’s too much heat cycling, it’s annoying to try and jump a car on the side of the road, and the area isn’t protected.
Just put it in the trunk! My E39 has a battery in approximately the same place as your E90 battery and it rules. I can park my car nose in and my car can be jumped easily without having to move the car. If my car does on the side of the road, someone can just pull up right behind me and give me a jump without 900-foot jumper cables or trying to point the nose in the other direction.Â
Also, let’s not forget the big reason why this is being done in certain cars: weight balance. The battery in my E39 weighs approximately 45 pounds. It’s a big boy. The engine in the E39 weighs way more than 45 pounds, meaning that’s a lot of weight over the front nose which, dynamically, isn’t great. Thanks to putting the battery in the back (and a few other things) my E39 BMW has a nearly 50:50 weight distribution and it feels ideal to drive. So, my argument is not to put all batteries in the front, but to put all batteries in the trunk! -Matt HardigreeÂ
Image credits: Lewin Day, Varta
I sense anarchy impending at the Autopian HQ…
Coming from a man who struggled to diagnose a coolant leak and improperly repaired a harmonic balancer, this is an unsurprising take.
I find changing batteries in the trunk/rear much easier than ones under the hood. They’re clean and generally close to the edge of the trunk/hatch. In contrast, my friend’s Hyundai Sonota had the battery almost in the middle of the engine bay, which was a massive pain (in my back) to uninstall and reinstall. Some cars tuck the battery underneath the cowl. It’s great fun to wedge out a heavy battery from underneath there while banging your head on the hood.
The battery in your E90 is behind a panel that takes two seconds to remove, and because the battery is low, it gives you more leverage to lift it up and lower a new one in. Anyway, how often are you changing batteries? Maybe there’s an issue with your charging system? Did you code the battery in the E90 to the car? If not, it will perish in short order.
Literally every car I’ve ever owned with batteries under the rear seat or in the trunk has jumper terminals under the hood. This is better than vehicles with batteries under the hood because it means that your car can be jumped from either end of the vehicle.
Maybe this site has decided to intentionally publish stupid takes to drive engagement?
Yeah no. I’m going to disagree. I love the battery in a nice safe, largely safe from the elements with better weight distribution. My e34 has it under the rear seat with posts in the engine bay. No tools necessary to access the battery.
Do I plan on moving the battery from the engine bay to the rear on my project sports car? Yes. Yes I do.
I’m with Matt here, trunk all the way.
Counterpoint: I’ve owned 10 cars in 17 years and only ever needed to touch the battery in two of them. Something is wrong if you need to access it so often that you worry about where it is located.
Well, duh! If you replace the car every 1.7 years you won’t need to touch the battery. Are you replacing the cars when the battery wears out?
I don’t know how others do it but BMWs like your E90 are not in the slightest bit inconvenient with the battery back there. Not only are there terminals under the hood which doubles the access points and makes it easy to jump or attach a maintainer from either end of the vehicle, but accessing the battery itself is super simple. In the case of your E90, “buried deep in one side of the trunk” really just means “nice and clean behind a panel that takes about 3 seconds to remove”.
My Hiace work van has the battery in the engine compartment, but that happens to be under the front passenger seat.
My old rear-engined Fiat 850 Sport Coupe had the battery in a compartment under the floor of the front luggage compartment.
I don’t think I’ve ever owned a front-engined car with a rear mounted battery.
My biggest issue with having the battery tucked into a special battery box or compartment is not so much lack of access, as the fact that when it needs to be replaced, you usually have to get the exact matching size and terminal layout, rather than having a bunch of options including a bigger or differently proportioned battery size.
Battery location is one of the only items of significant mass that can be mounted almost anywhere. Putting them under the hood is stupid.
My big rule is the battery needs to be somewhere easily accessible on a car that has no power. My 2003 Mini Cooper S hatch could not be opened conventionally with a dead battery.
Link to how
This was poorly thought out on the part of Mini. Otherwise, trunk isn’t bad.
I’ve had 5 cars: 3 with the battery in front, 2 with it in back. The only one that was inconvenient was my 2013 Ford Focus with the battery tucked too far under the cowl.
I don’t mind the battery in the trunk at all. It’s cleaner under there, easy to get to in my experience, and just feels right from a weight distribution perspective.
I think 12 volt batteries in the trunk of a hybrid vehicle make MORE sense, not less. Since they don’t actually turn over the engine, you never need a jump start. And because they never have to start an engine, they last much longer to boot, so you very rarely have to change them. Having that hybrid drivetrain up front adds some weight to the nose too, so balancing that with the 12 volt battery out back just makes sense.
Old guy here that wants to know how long until Lewin gets his Medicare card in the mail cuz he’s well down the “Old Farts Ramble and Rant About Stuff” training protocol. 🙂
Australians get Medicare cards at birth, so we can rant and ramble away once we’re old enough to talk.
That certainly explains a couple of my friends down there. 🙂
well BMW is notoriously a RWD car and touted as the drivers cars, so it makes all the sense in the world to me to place the battery opposite the driver in the rear over the passenger wheel (except when they have passengers I suppose) to maximize traction/weight distribution for and aft as well as balance out the weight of the human driving to aid in balancing the suspension.
I prefer it under the hood. Trunk it fine, I guess, but worse because I could always have stuff in my trunk. I hate it under the back seat. Really any placement that requires me to remove additional parts is pure crap.
This is nothing new. My ’57 MGA has its battery under the rear parcel shelf.
As did every one of the millions of VW Beetles they built and sold across 5 or 6 decades.
The battery in my Mitsubishi EVO X was in the trunk, not too tough to get to, better weight distribution, no heat cycling issues. I liked it there. Conversely, my (former) RAM 2500 diesel had BOTH batteries under the hood. It was crowded under there, and when I had to replace them (BOTH), because the TIPM croaked and drained them by running the windshield wipers (without them being in the on position, or the truck being on), there were a giant PITA to change.
My C6 Z06 puts the battery in the rear opposite the driver for better balance. Seems to work out just fine. It’s under a simple hatch door and fairly easy to R&R. They could have added an extra half inch to the hatch opening but it’s still workable.
My C4 though… You have to remove the small body panel aft of the front wheel to get it out. Not terribly difficult but it’s dumb. It’s a side-mount style so it’s hard to get charger or jump leads on it securely, too.
There are some good reasons to mount the battery in the trunk. The jump start problem is solved by having clearly marked terminals under the hood like our Buick LeSabre which has the battery under the seat.
I had to replace a battery on a friends Chrysler 300M (the aero looking one). In order to relace the battery you had to remove the airbox and the right front wheel. There was an access panel in the wheel well to slide it out but to disconnect it you had to come in from the top and could only do one post, slide it, then the other post.
To me, as long as I only need to move one panel/seat bottom/cover to reach the battery, I’m happy with it being positioned wherever is best for weight distribution and packaging.
All batteries are under the hood in my fleet of junk except the Vanagon (under the passenger’s seat) and Austin Healey (trunk.)
The Vanagon battery is huge and barely fits in its little steel box. You have to be careful jumping it or you’ll have a nasty short.
The only annoying thing about the Healey battery setup is it’s positive ground, so I had to write “+ GND” on the inside of the trunk lid as a reminder.
My battery is right above the fuel tank by the front bulkhead, which is greag for both access and service, and is a good fool-proof safety feature as it’s impossible to open up the tank for pump/float/ filler service without disconnecting the battery first, making it harder for the less cautious among us to blow themselves sky-high during a fuel pump replacement.
There should be established battery access and replacement regulations along the lines of:
How is anyone ever going to get to the battery if it’s only accessible with a lost 10 mm socket? 😉
Um, if all batteries are in the trunk, then you still have the same problem lining up two cars for a jump, just ass to ass instead of nose to nose.
The real thing to keep in mind is how much clearance each location gives you for wielding a chainsaw when it’s time to replace the battery.
I mean, not really? Every car I’ve had (minus one) has had the battery in the trunk, and they have always had jump posts in the front, so you can jump it from the front or rear.
I’ve never seen a rear battery car, had no idea. Makes me wonder why there’s no jump post in the back when the battery is out front.
Team Hardigree here. Also, I am in favor of chaos and anarchy, so I even approve of Mercedes’ decision and wherever Citroën may have decided to come up with.
In my L405 Range Rover the battery is under the air compressor which is under the spare tire which is under the floor of the trunk which is under the dog crates – BMW and Merc are easy compared to the Brits