Jalopnik reports:
“Tesla Motors’ lineup of all-electric vehicles — its existing Roadster, almost certainly its impending Model S, and possibly its future Model X — apparently suffer from a severe limitation that can largely destroy the value of the vehicle.
If the battery is ever totally discharged, the owner is left with what Tesla describes as a “brick”: a completely immobile vehicle that cannot be started or even pushed down the street.
The only known remedy is for the owner to pay Tesla approximately $40,000 to replace the entire battery. Unlike practically every other modern car problem, neither Tesla’s warranty nor typical car insurance policies provide any protection from this major financial loss. ”
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The article continues:
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How To Brick An Electric Car
A Tesla Roadster that is simply parked without being plugged in will eventually become a “brick”. The parasitic load from the car’s always-on subsystems continually drains the battery and if the battery’s charge is ever totally depleted, it is essentially destroyed. Complete discharge can happen even when the car is plugged in if it isn’t receiving sufficient current to charge, which can be caused by something as simple as using an extension cord. After battery death, the car is completely inoperable. At least in the case of the Tesla Roadster, it’s not even possible to enable tow mode, meaning the wheels will not turn and the vehicle cannot be pushed nor transported to a repair facility by traditional means.
The amount of time it takes an unplugged Tesla to die varies. Tesla’s Roadster Owners Manual [Full Zipped PDF] states that the battery should take approximately 11 weeks of inactivity to completely discharge [Page 5-2, Column 3: PDF]. However, that is from a full 100% charge. If the car has been driven first, say to be parked at an airport for a long trip, that time can be substantially reduced. If the car is driven to nearly its maximum range and then left unplugged, it could potentially “brick” in about one week.[1] Many other scenarios are possible: for example, the car becomes unplugged by accident, or is unwittingly plugged into an extension cord that is defective or too long.
Source:
http://jalopnik.com/5887265/tesla-motors-devastating-design-problem
h/t to Popular Technology
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This seems to be a problem exclusive to lithium-ion battery technology, not lead-acid systems. Seems to me that all that is needed is a master kill switch for the mains. I’d rather reprogram my radio and other gadgets than spend $40k on a new battery pack.
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Tom E. says:
February 23, 2012 at 6:10 am
“First of all, I completely disregard the notion of parasitic losses in the electronic systems of the car. I work with an automotive accessory. Our bench mark is sub 1mA when turned off. I’ve measured a few cars, and for example the Dodge Charger, when you shut all of the doors, and allow the uControllers to sleep, take about 30 seconds, the car pulls less than about 10-50 uA from the battery. Further modern uControllers are capable of sleep currents in the low nA range.
1mA from a 20kWh battery should last decades :-)”
The systems you talk about probably don’t have to do load balancing between different cells. Load balancing a bunch of Li-Ion cells is… creepy. Tolerances in the behaviour of the different cells when charging OR discharging make it necessary to regularly shuffle charge around if you want them to be equally full. Which you want; otherwise some of them age faster than others, which you don’t want.
brc says:
February 23, 2012 at 5:44 am
I’m not a one-eyed electric car lover but the Tesla engineers have come up with a lot of clever stuff. Their battery packs are miles ahead of most of the competition and they were the first to market with a modern electric car … is a testament to a very good 1.0 design in the roadster.
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I’m not quite as impressed. The roadster was already designed for them. A guy takes a Lotus Elise chassis, and puts an electric motor into it and straps together some 7000 cells with off the shelf cell management technology. The battery pack technology is off the shelf tech BTW. Then gets the taxpayer to finance it. I don’t see the purpose for the car. I’m not into gimmickry for the sake of gimmickry. It’s perfomance is totally unimpressive to me. A Corvette ZR1 or Camaro ZL1 (just 2 examples), which costs less and are a lot more practical, will rape a Tesla. I have reservations about refering to Tesla as an American car company. They may be American, but I’m not sure they quite have achieved a level where they can be considered a car company yet maybe a kit-car company.
Erny72 says:
February 23, 2012 at 10:48 am
“… and it only takes five minutes to refill the tank. ”
One should add: The Elise does bends.
Tom E. says:
February 23, 2012 at 9:06 am
“I highly doubt it is the electronic system, the only thing that would be consuming power is a battery cooling system, and that is likely NOT optional 🙂 What would you rather come home to, a burnt down house, or a dead car. ”
You can’t affordably cool a Li-Ion accu pack that has decided to vent, that’s what they do when they overheat. You get a stream of 500 deg C hot gas. All you can do is direct the stream somewhere where it doesn’t immediately hurt someone. Can’t tell you whether the gas mixture is acidic; I know it is for certain types of LiPo accus but don’t know for the Tesla. Acidic is extra fun. Did they do penetration tests, BTW? They do it for serious cars when Li-Ion packs are used; they drive large nails with catapults through the packs. Mandatory test in Europe for battery packs used in hybrid cars.
Jay Curtis says:
February 23, 2012 at 8:47 am
“What happens to the nickle metal hydride, etc., when the useful life of these conveyances ends and they go off to the junk yard? Isn’t NMH toxic? ”
Less than NiCad. Nickel can be recycled and it is economic to do so with NiMH cells. NiMH packs are also used in some hybrid cars, for instance in the Honda Civic Hybrid.
Why can’t the car GPS ‘phone the owner, or Tesla, 24 hours before bricking so they can send someone with a handy diesel generator to save the battery. A new green service industry is born.
Brian H,
“IMO, the one thing TM has to do is be very explicit to buyers: “NEVER let the battery discharge fully, as this will permanently disable it. Not covered by warranty.”
Yeah, that’ll attract a lot of new buyers.
It is my understanding that all electric cars have the same problem. Even Hybrids. In the case of the Toyota hybrids, if the vehicle is left unused, even if it is plugged in, the battery diconnects itself after a week or so. There is a reset procedure if you are ambitious enough, but most people call the dealer and have the vehicle towed in. if the car is still under warrenty the dealer will send a mechanic out to reset it. for free.
Also. even lead/acid batteries have the same problem if they are completely discharged. In most industrial and communications applications the use of a “Low Voltage Disconnect’ is essential.
Ooooops.
Actually, this is a common problem with modern cars. My Citroen, which is 100% run by computers, will drain a battery in about 3 weeks of inactivity. Apparently it depends on the computer not shutting down all the systems properly when you take the key out – so it is a ‘fault’, but a very common one if you read the Citroen blogs.
And like the Tesla, if the battery goes below 11 volts you loose the steering – and that is a real pain in the butt. (Yes, electric power steering – don’t ask me why.)
The only saving grace is that the battery is lead-acid, and so it is rechargeable.
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Lots of comments about low-voltage disconnects.
However, just like my Citroen, in a computerised car you need some services on all the time, like the burglar alarm and the computer itself – and in the Citroen the suspension is always active to stop the car sitting down on a kerb-stone. (Yes, electro-hydraulic suspension – just don’t ask.)
So if you had a battery disconnect, you would need a standby battery to run the essential systems. Just face facts – batteries just don’t have the power density that modern cars require.
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so what if one was in an accident and smashed the side that is used to charge the car. Now it goes for repair and is not charged for a week or two. The charge at the time of the accident was 30% and now its a brick. Would the insurance cover the 40K plus repairs?
The car I drive to work is a 2001 Toyota Echo. It’s a Prius without batteries 4-Door, manual trans and Air-cond. Seats 4 adults just fine. Gets an honest 43 MPG. Cost about $12,000 out the door. How much do you really want to spend to improve on that?
I believe Tesla is made up of people who thought “hey lets just build an awesome electric vehicle” using a neat strategy of plugging in many laptop batteries. its like an ambitious and risky grad school course project. What they did nt realize is that electric vehicles would have to do some basic things without fail and have close to zero possibility of that not happening in a million vehicles. y basic things I mean: Going from place A to B, and if there is a problem in going from A to B like emptying gas tank, you should have an easy fix, Like a gas refill from a can. If Tesla cannot do that, it has serious problems to deal with.
re: power density. Spot on. Diesel and Gasoline have about 2x the energy of our best high-explosive, gram for gram. Batteries are somewhere between 1/100th to 1/10th the power density (of PETN). We’d have had to invent hydrocarbons if we didn’t find them in fossil fuels – there’s magic in the fact that the engine doesn’t have to carry its own oxidizer – it’s there for the taking in the air. That’s not the case with almost all batteries – and HE (save for fuel-air weapons).
People say they are scared of neutron burners and we must not build any more – yet they drive around with fuel-tanks that if half empty, its fuel could level a good sized department store, or a five story building. Remember that before Rockefeller’s high tech refineries proved you could trust the “Red Can” not to blow your house down, every city had an ordinance prohibiting attached garages.. Granted, it was unfair of Mr. R. to compete with the mom-and-pop drill-and-bottle-it firms when he said, “ok, but don’t say that I didn’t warn you when your house burns down.” “Unfair competition” seems to always have a large technical component that enables cheaper, faster, better, safer, etc..
Why would Tesla charge $40000 for a replacement (unless a BIG chunk of that is labor)?
That might have been what the cost was when the Roadsters were first built but Li-on battery cost per kWh have dropped a LOT since then.
Looking at the pricing options for different battery sizes for the Model S, I’m guessing that Tesla’s cost has dropped to about $400 / kWh.
Elon Musk said, just last week, that he expects the cost to fall to below $200 / kWh in a couple years.
DMarshall;
Because Roadsters are no longer being built (Lotus closed its assembly lines for the body during a recent factory refit). So the batteries are no longer in production mode, either. Any replacement would have to be from stock, or a special one-off. And the Model S batteries are a completely different form factor (flat skateboard underfloor). So the per-cell cost per kWh is the least of the issues.