Don't Try This at Home Kids?

A sobering reminder of the hazards in adding plug-in capabilities to hybrids comes from reports that a plug-in Prius conversion was destroyed in a fire. The news spread quickly through the online community of plug-in enthusiasts, bringing calls for all known information to be publicized as quickly as possible.

During a routine drive on Saturday, June 7, an upholstery fire destroyed a 2008 Toyota Prius converted to a 15-mile plug-in hybrid by Hybrids Plus of Boulder, Colorado. The car was owned by the Central Electric Power Cooperative in Columbia, South Carolina.

On Wednesday, June 18, Hybrids Plus issued a statement on the incident. The company noted that it immediately notified all owners of its conversions, and asked them to stop driving until more was known. Along with A123 Systems, which made the lithium-ion cells used in the Hybrids Plus pack, it conducted two forensic examinations of the damaged car.

While the company hasn’t reached a definitive conclusion on the initial fault point, it did identify several safety improvements that could be made to lessen the chance of an upholstery fire like the one that destroyed CEPC’s car. It is now inspecting and upgrading all its vehicles in the field, starting with 15-mile Priuses, followed by 30-mile Priuses, and then its Ford Escape conversions.

“The study did establish with a high degree of confidence that the cells were not the cause of the incident,” said Hybrids Plus, “and that the vast majority of the cells were unaffected by the high temperature to which they were exposed.” Further, “the Hybrids Plus PHEV system also was able to withstand the high temperatures in that incident, remaining largely intact.”

The company also felt compelled to clarify several inaccuracies in various media reports on the incident. Its charger was not involved, said Hybrids Plus, and there was no “explosion.”

The following day, plug-in advocate CalCars issued a statement summarizing the facts and offering its opinions on the entire incident. It suggested from second-hand reports that software, connectors, or wiring may have been at fault. Davide Andrea, chief technical officer at Hybrids Plus, said simply, “I have nothing to add.”

CalCars also expressed regret that Hybrids Plus hadn’t immediately addressed the issue publicly. This may be a particularly germane topic for Ron Gremban of CalCars, as he recently suffered an electrical fault in his own converted Prius.

It is just these kinds of issues that terrify major automakers as they prepare to roll out their first plug-in hybrids in roughly two years. General Motors, in particular, may be first to reach production with both the much-publicized Chevrolet Volt and a plug-in version of its Saturn View Two-Mode Hybrid. Stringent safety regulations, and corporate memories of the lawsuits engendered by the hazardous “side-saddle” gas tanks in more than 10 million 1973-87 trucks, are only part of the worry.

As CalCars put it, “opinion leaders from automakers, utilities and national labs have expressed their fears that ‘one bad accident’ could set back the progress of PHEVs.” As one industry insider said, “Barbecue one family in a minivan with a large battery pack, and it’s all over for plug-ins.”

Surprisingly, John Hanson, a Toyota spokesman, was quoted as saying the company has “nothing against” converters who modify the hybrid cars with additional batteries, though the company also doesn’t endorse such products.

For perspective, while there were 250,000 gasoline vehicle fires that caused 445 deaths in 2006, our society seems inured to them. Perhaps we assume they’re a necessary evil—the inevitable cost of using a fuel containing so much energy that 1 gallon can transport a 6,000-pound vehicle fully 20 miles.

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  • itsaboutchoice

    “For perspective, while there were 250,000 gasoline vehicle fires that caused 445 deaths in 2006, “

    Thank-you for putting this incident in perspective. This event has not deterred my interest in owning an electric car. I would hope that future articles written about other electrical fires will also point out that there is just as much or more risk with current petroleum powered vehicles.

  • Skeptic

    Yeah, really. Barbecuing 100 families *every year* via gasoline flambe ain’t no big thing, but he’s right, have that happen *once* in a PHEV and it’s all over.

  • Consummate Skeptic

    Please don’t misunderstand my intentions, but I do not agree with either of the first two posts. I wish the PHEV developers all the luck in the world. However, I believe that it would be more important to point out the percentage of PHEV fires and compare that number with the percentage of gasoline vehicle fires. And no, I am sorry to say, I do not have either figure available.

  • jvoelcker

    I can provide a rough answer to Consummate Skeptic’s question:

    There are roughly 300 million cars on US roads today, of which 250,000 had recorded fire incidents in 2006. That’s a rate of 0.08 percent.

    There are roughly 150 PHEV conversions on the road globally, and so far we know that 2 of them have had smoke or fire incidents. That’s a rate of 1.3 percent–or 15 times as high.

  • mdensch

    As Twain liked to say: “There are lies, damn lies and statistics.”

    A sample size of 300 million is more than sufficient to make statistical predictions about the rate of incidence of automobile fires. Even so, one must approach those numbers with caution since many of the fires were the result of operator error (such as getting in and out of a vehicle while refueling, causing static build-up) versus mechanical malfunction.

    A sample size of 150 is not sufficiently large to make predictions about the probability of future incidents. It does indicate, however, that there are technical challenges to overcome and car makers will want to examine these fires very carefully. Lithium ion laptop batteries have had similar problems but manufacturers were able to fix them.

  • jvoelcker

    Mdensch: I agree with your point–a sample size of 150 is not large enough to draw inferences–but I just provided the figures for the previous commenter. Any inferences are drawn at your own risk. 🙂

    However, your comparison with laptop batteries isn’t strictly appropriate. “Lithium-ion” cells actually use a variety of chemistries, and laptops use a cobalt dioxide chemistry that has the highest energy density but also the highest risk of thermal runaway.

    With the exception of Tesla, which goes to extraordinary lengths in their engineering to isolate each of the 6,871 commodity cells in its pack, any lithium-ion packs used for EVs and PHEVs are NOT likely to use cobalt chemistries. A123’s cells, for instance, are iron nanophosphate.

    I can provide further references (off HybridCars) if you need them.

  • California Bear

    There is a bit of difference between a gasoline fire and a battery fire.

    Most gasoline fires occur in the engine compartment with passengers on the other side of a firewall so there is usually time to get out. I would lay good odds that the gasoline fire deaths happened when the victim was pinned in the car by an accident.

    By contrast, the battery packs are located under the passengers. The first indication of a fire will be when, as in the above story, the seat you are on catches fire. There is more likelihood of injuries when you are sitting atop the fire than when it is happening on the other side of a steel (or aluminum) wall. There is also the factor that children are required by law to sit in car seats in the back seat, directly above the batteries. If you have ever removed a child from a car seat, you know that it takes longer to remove a child from the seat than it does for an adult or older child to unbuckle and jump out.

    True, gasoline fires do occur and people do die. However, the location of the fire source in a PHEV battery fire does increase the chances of injuries or death.

  • Shines

    California Bear I find it hard to believe you are suggesting a battery fire is worse than a gasoline fire.
    First of all let me say that there is little evidence for either your or my arguement, but just for the sake of a rebuttal:
    Yes there is a bit of a difference between a gasoline fire and a battery fire. The gasoline ingnites and burns immediately. The batteries may overheat to the point of starting something else on fire. In an accident it is much more likely that a fire would be the result of damage to the fuel system than to a battery pack. Although it is true that more injury is likely if you are sitting on the fire, there are usually indications of an impending upholstery fire such as an awfull smell, smoke and heat – before the fire starts. If a fire did start with infants in car seats in the back – the infant car seats would (at least temporarily) protect the children from the upholstery fire.
    Certainly new safety precautions need to be taken when considering battery packs located under passengers. Such things as additional fire-walls, or fireproof upholstery or maybe smoke detectors may need to be considered. But considering batteries are not combustible themselves and help reduce the need for combustible fuels in the cars I’d say as far as fires go, you are more likely to be reducing your risk of injury or death with a hybrid.

  • Seth

    Suffice to say, PHEV technology is still new with just 150 cars on the road. It is very true that today’s after-market PHEV solutions have a higher chance of catching on fire than traditional vehicles. Like any new technology, this is not very surprising. Millions of traditional vehicles have been tested while for PHEV’s just a small fraction (~150). Once the wrinkles are worked out (i.e. significantly more testing), the batteries and associated electronics stand a very good chance of being safer than gasoline tanks.

  • J-Bob

    I too have a PHEV that I put together myself for less than $2,500 (an E-Bike). It has a 750 watt hub motor, 84 volt 16 ah battery pack (made from Lithium-Ion power-tool batteries) and functions using a ‘pedalac’ system (i.e. you have to pedal it to make the motor engage). I’ve had this setup now for just under 2 years and have put a total of over 6,700 miles on it commuting to and from work each day. The only problems have been a fuse blowing after hitting a nasty pothole, a replacement of disk brake pads, 3 flat tires (which were remedied with lots of slime and a kevlar liner), and two sets of replacement tires themselves.

    I bring this up for two reasons. PHEV’s are our immediate next steps in making a more efficient car. But costs are always the biggest factor right now. If you’re serious about making a change for the better, an E-Bike is an inexpensive choice that can make a world of difference in your pocketbook (and your waistline).

    Two. Operating costs. I go 26 miles a day round trip (about 35-40 minutes each way). I recharge the pack every night when I get home. Between maintenance and electricity, I have spent $289 for two years commuting. Add the cost of the bike and components and that comes to $2,789.00 I have spent in total.

    For those wary of leaving your bike on a rack for any thief to steal, go with a folding bike (I’m able to fold mine and keep it in my cubicle during the day).

    I highly recommend E-Bikes as an alternative to any mode of transportation currently available. It’s fun, its inexpensive, and its good for you! When I started I weighed in at 215 pounds, I’m now at a healthy 167 pounds!

    Go E-Bikes!

  • Anonymous

    Go Seth

    But of course there are some problems with e-biking 1 is the cost but you can get a cheap e-bike at walmart for $250 and the big problem is infrastructure for biking I cant tell u how frustrating it is when cities take shoulders and turn them into bike lines it is very dangerous when cars are going 40-55 miles in hour about 3′ away from u. And also some states and local govs consider e-bikes as mopeds. There needs to be a greater push to promote biking through zoning and infrustucture upgades. One last point some bike organizations are for hobbyists and recreational actives and take an elitist view on the diverse group of people who want bike routes for commuting and not sport. Maybe a rebate should be in order for those who purchase e-bikes??

  • Anonymous

    Sorry I meant J-bob 🙂

  • LHayes

    CA Bear has it wrong when he says the battery pack is located underneath the passengers. I’m fairly certain the aux packs in the Hybrids Plus Prius conversions are mounted in the trunk; big difference.

  • J-Bob


    Yeah, when I got started looking into E-bikes, the cost seemed pretty prohibitive until I started diving a little deeper.

    Federal law states that an E-bike is still a bike as long as the motor is not rated over 750 watts, and the speed does not exceed 20mph (without pedaling), and the bike has functioning pedals. So any states who dispute that are overidden. Cheap e-bikes are essentially that (you get what you pay for). However, while the cost may seem prohibitive, think about this… I was shelling out $45 a week in gas (or $180 a month, or $2,160 a year) this was two years ago at around $2.25 a gallon (you can easily double that expense now, soon triple). So my bike paid for itself within 14 months (7 months at current prices). You also factor in oil changes, filters, brake pads, insurance, registration, then it really ads up! The new hybrid cars nowadays have a $3,000-$5,000 premium (oooh! 2 e-bikes right there!).

    As for public roads and safety issues, I’ve found that it usually depends on where you live. I’m in the suburbs with a commute going into the outskirts of downtown Phoenix, so I’ve found that with a little exploration I can take side streets, sidewalks and multi-purpose paths and can get to and from work without being on any busy streets. With the extra speed I now have, going a little out of my way is actually quite enjoyable!

    I have been pulled over twice by police because they’ve mistaken my bike as a moped. After breaking out the federal law in black in white – laminated paper, and explaining the bikes capabilities, they both let me go, and were actually quite impressed (and I wouldn’t be suprised if they got one of their own by now)!

    This was the main reason I went with a bike vs a scooter. Most people don’t even realize it is motorized (you mostly only hear the gears and tires on the tarmac (very quiet). I use a commuter bag to hold the battery pack, so most people think I just have a change of clothes in there! I’m avoid busy streets like the plague, because as you said, there are some crazies on the road.

    So if you take the time to look at your regular expenses when it comes to using a car/truck or going towards an E-bike, you’ll see you’re actually saving quite a bit-o-cash (figure 5-8 months to break even at existing gas prices). Its a helluva lot cheaper then trading in you SUV and getting a Prius!

  • jvoelcker

    Note to CA Bear and LHayes: Indeed, the auxiliary pack for the Hybrids-Plus conversion is located just behind the rear seatback.


    A123 is running too fast because of their obsesion to be the first one in the market…..with a product under development, perhaps they have to slow down a little bit, they are risking the best for silly things.

    Too much bla…bla… President Bush included, and A123 DO NOT HAVE A PRODUCT YET. so take it easy and don´t piss off the opportunity for you and the rest of the market.

  • California Bear

    I didn’t suggest the FIRE was worse, only that the LOCATION was worse. Whether the battery is in the trunk, under the back seat or even on the roof, the fact is that the batteries are not located in a compartment of the car isolated by a protective firewall. They are located in the passenger compartment, with the passengers. In my Highlander Hybrid, there are vents for the batteries that open directly behind the legs of anyone riding in my back seat. That indicates that the batteries are not isolated from the passenger compartment.

    As Shines said, there are warning signs of a fire such as odors, smoke, etc. The same is true of gasoline fires. That is why there are so relatively few deaths involving gasoline fires. The difference is that most gasoline fires require several minutes to reach the passenger compartment whereas a battery fire will be IN the passenger compartment.

    I am not anti-hybrid, nor anti-plug in. I am not so blind as to see that this is the future direction that cars are headed. I am merely pointing out that the location of the ignition source in the above mentioned fire and likely source in future fires is much closer to the passengers and thus more likely to produce injuries. Thus, precautions should be taken to protect against these instances. The batteries need to be in an isolated compartment from the passengers.

  • AP

    Shines, you are very much mistaken. Not only can Lithium-ion batteries start other things on fire, THE BATTERIES THEMSELVES CAN BURN! These aren’t harmless little 9-volts, you know.

    As someone else pointed out, a gasoline tank holds a tremendous amount of energy. A fully charged hybrid vehicle battery does, too. Usually the energy comes out as electric current, but given the right trigger, some Lithium-ion batteries can release it as heat (i.e., fire). A large portion of Li-ion research right now is going into preventing this “runaway instability” that Dell made famous.

    What bothers me more is that this happened while on a “routine drive.” As others have noted, a gasoline fire rarely happens except in a severe wreck. No fuel tank (or battery, for that matter) can be made to survive and be safe in all collisions. You have to make decisions to minimize the possibility, but the unexpected can always occur. That said, having one of the first 150 cars burn without a collision is not a good omen.

    I don’t think this will affect the original equipment PHEV business in the long run, but it may put a damper on conversions. Who pays for the burnt car here? Not Toyota, because it was modified. The conversion company might, but only as long as they are in business.

    I hope this also points out to impatient idiots who can’t wait for PHEV’s, etc., that you don’t just snap your fingers and make these systems work. It takes a lot of dedicated, intelligent, highly trained people to do it – concepts these idiots can probably not understand (they do it in the movies so quickly!). The same people who complain about how long it’s taking would probably be the first to sue if they got any soot on them when theirs burnt.

    Making a complicated product like this safe and reliable takes time. Manufacturers really hate to maim and kill people.

  • loogie

    I love loogies.

  • Shines

    AP thanks for correcting me on the combustability of the batteries.
    California Bear thanks for clarifying your point.

    BUT AP this statement is part of a different problem:
    What bothers me more is that this happened while on a “routine drive.” As others have noted, a gasoline fire rarely happens except in a severe wreck.
    Folks might want to read this:
    Here is the important excerp:
    “Although drivers may believe fires occur mostly from collisions, this is not true. Many more are caused by failed vehicle components that could have been maintained or repaired prior to causing or accelerating a fire,” …

    Like you say – let the experts work on making the hybrids as safe as possible before going to production.
    Isn’t there some old saying like – don’t rush things or you’ll get burnt.
    : – D

  • Lynnda

    I would think that the car companies or the conversion companies would install a heat sensor in the battery compartment that would alert the driver that there was a problem. This would give them time to stop the vehicle and get everyone out and then see about resolving the problem. Cars nowadays have a gazillion sensors for everything, surely a sensor detecting if the batteries are getting hot wouldn’t stress the manufacturer or conversion company too much and it would give some peace of mind to the driver. An remote audible alarm on a sensor would notify the home owner if the batteries were overheating in the garage and prevent the car from catching the house on fire.

  • SRI

    AP, Here’s a quote I found inside the vehicle fire link provided on the article.

    “More than two-thirds of highway vehicle fires resulted from mechanical or electrical failures or malfunctions. Collisions or rollovers caused only 3% of these fires but 57% of the associated deaths.”

    In general battery fires are getting a lot of press because it’s new and rare. While the laptop battery fire incidents are highly publicized the total no. of such known incidents worldwide was 14 the last time I read about it. And it was due to particular series of batteries which were all recalled. The total no. of laptops in the world will be atleast comparable to the total no. working cars on the world. That’s a good sample size for consideration.

    Besides there are many other things to consider. It’s not certain the battery is the cause of the fire mentioned in the article. If anything the statements on the article seem to make it less likely. Also the laptops generally don’t have a good thermal management system. In car a lot can be done to avoid thermal overrun. Also new battery chemistries can make them near impossible to burn. With any ICE the best anyone can hope for is for the fire to stay inside the cylinders. Whichever way you look at it once the initial hiccups are gone the batteries will be orders of magnitude safer than gasoline.

  • AP


    Thanks for the info on the fires (that’s more than I thought), but what are the absolute odds of having a fire with an ICE vehicle, and what are the odds on it completely burning? My guess is the odds are low in either case, much lower than 1 in 15. That said, prototypes are bound to have problems – so don’t buy someone’s prototype!

    I agree that not every electrical fire will be from the battery. But I don’t think they will necessarily be safer than a tank of gasoline. Fuel tanks don’t need to be cooled to keep them safe like hybrid batteries do, and having that much energy in one small place usually finds a way to release itself. Also, fuel tanks only include one element for a reaction – fuel. Batteries contain a positive charge, a negative charge, heat, and fuel. Much more care needs to go into its design to make it safe. It’s not a no-brainer.

  • SRI


    “but what are the absolute odds of having a fire with an ICE vehicle, and what are the odds on it completely burning? “

    Based on the above postings 0.08%/yr. If you extrapoate it for 10-15 year life time for a car it will be around 1%. Odds of completely burning will depend on how close the vehicle is to a firestation, I guess.

    “My guess is the odds are low in either case, much lower than 1 in 15.”
    Where did you get the no? The authors posting above suggests 1.3%, even if it is based on the unrealiable sample size. Also if you look at my previous no.s about laptop fires (which are said to have the most dangerous chemistry) it’s only in the teens among hundreds of millions of laptops. Much better than cars.

    “That said, prototypes are bound to have problems – so don’t buy someone’s prototype!”
    That’s true. But given the current information they don’t look particularly dangerous. PHEVs from big car companies will do much better anyway.

    “I agree that not every electrical fire will be from the battery. But I don’t think they will necessarily be safer than a tank of gasoline.
    Fuel tanks don’t need to be cooled to keep them safe like hybrid batteries do,”
    The engines need more agressive cooling than would be ever required for a BEV. The reason fueld tank is not cooled is, no amount of cooling is going to stop of the fire if the gasoline starts burning.

    ” and having that much energy in one small place usually finds a way to release itself.”
    A typical midsize car holds enough gas to make 100 molotov cocktails. If you consider the charge in a 300 mile BEV if will be less the equivalent of 2 gallons of gas.

    ” Also, fuel tanks only include one element for a reaction – fuel. Batteries contain a positive charge, a negative charge, heat, and fuel. Much more care needs to go into its design to make it safe. It’s not a no-brainer.”

    That’s like saying gasoline car has carbon, hydrogen, oxygen, fuel line, spark plug, cylinder, electricals, etc. Bottom line is an electrical fire can be start by either a short or overheating. Yes. The system needs to designed carefully to avoid such incidents. But it’s no more challenging than designing gasoline car. When we switch to all electric cars they will be safer than current ones not the other way.

  • AP

    SRI, I didn’t say that making electric cars safe would be harder than for gasoline – my point is that I disagree with your comment that “the batteries will be orders of magnitude safer than gasoline.”
    That’s simply not true.

  • Janice

    “For perspective, while there were 250,000 gasoline vehicle fires that caused 445 deaths in 2006, our society seems inured to them.”
    This doesn’t change the fact that modifications (such as plug-ins) are safe. They should have tried it first. I have nothing against it, its just safety will always be a priority. There are relatedblogs on

  • reginab

    I am a fan of PHEV, and even if I am a truck owner, and a Land Rover Blog owner, I do want an option for the future. Gas isn’t a joke.

  • icetears

    Note to CA Bear and LHayes: so, the auxiliary pack for the Hybrids-Plus conversion is found simply behind the rear seatback.and more for kids please see the more information