Due to my industry involvement early and often with the development of Lithium based batteries, I know just how dangerous they are. Not here to argue that point. I'm just hoping for help for an application to protect my Daughters Family, including grandchildren, with a Tesla parked in their attached garage.
What recommendations would you make for sensors and related system to sense a fire in their garage? There are heat sensors available but I also know there are flash/flame sensor that are used in the electrical industry to sense Arc Flash situations in high voltage equipment.
My thoughts are, maybe a combination of a heat sensor of some sort plus a lumens sensor in some combination.
Please realize when a Lith batter is exposed to air, really really bad things happen very fast. So using just a Zooz or some sort of motion sensor with heat output may work, but hoping for something better.
Any thoughts would be greatly appreciated!
Won't a UV smoke plus CO detector provide some protection. Maybe an added heat detector. These simple technologies, when link, can provide sufficient warning on getting the hell out of dodge.
One other potential is the below link (I don't know cost or how it integrates into a total system). This actually provides greater warning than simple smoke detectors (perhaps enough to preclude fire??). Also, do not forget instructions on how to handle issues to preclude worsening conditions.
With the promulagation of these batteries, there needs to be courses and information from local fire departments on how to handle home/auto installations.
Li-ion Tamer Lithium-Ion Battery Monitoring System - Levitt-Safety
ADDED. Also, FEMA provides guidance on installation of charging devices. What is unusual is "Install a residual current device with the charging unit". These cut off the power if there is a ground fault. I would also add, unplug from the charger when charging is done (or as near after charging is done).
Electric Vehicle Charging Safety Tips (fema.gov)
Electric vehicle home charging: tips for your community (fema.gov)
(My newsfeeds say Tesla had 3 vehicle fires last week.) These borderline-unstable batteries burn white-hot like an arc welder. My concern is that fire detection might be too late. When I get an EV, I told the family that all charging will definitely be outside and the EV is likely to be kept outside.
Dave thanks for your input. That link is to an interesting product but it appears it needs to be attached to, or at least near the battery. I need something passive to overcome the resistance to use anything in their garage.
There is a device called a heat-rise detector. It senses the temperature rate of rise (Delta over time) as opposed to just temperature. That seems to be a logical function. But again, we are well into a disaster at that point.
RC, if you can convince the new generation their precious Teslas are in some way not perfect. And they need to be parked outside, let me know.
From some of the news reports I have seen, once a Lithium battery pack does ignite, things escalate quite rapidly.
Thus, the main thing is to get people out immediately.
I can remember when I was in college chemistry lab, we cut a piece of sodium metal about the size of a BB and dropped it into a sink full of water. The reaction with the water released hydrogen gas and oxygen and produced enough heat that the hydrogen ignited with a small explosion. Both Sodium and Lithium are alkali metals in the first column of the periodic table. Sodium is 11 and Lithium is 3 so Lithium is even more reactive than Sodium. If a lithium metal fire is small, flooding it with water can extinguish it, but something like a home fire extinguisher won't be sufficient. Most rechargeable lithium batteries are lithium ion and contain no lithium metal. However, they are still a potential fire hazard. A Class B fire extinguisher might work on small fires, but not on something as large as a vehicle fire.
I would consider a device nearer the batteries. Perhaps a series of thermal sensors in the vehicle.
Our company has a short foray into alternate cooling of vehicle batteries. My recollection is; the internal battery temperature exceeds some critical value resulting in thermal runaway. To my knowledge temperature is the best / only indication of pending thermal issues (aka fire).
My guess is the resulting fire (rapid oxidation) is nearly impossible to put out so the best one can do is to save the house and inhabitants.
Assuming ambient temperature increases the likelihood of a fire, monitor the general area temperature might be useful, however I don't know how to directly relate it to thermal runaway.
Also, Is there a option to charge the batteries more slowly? Slower charging is likely safer.
Maybe use Level 1 charging instead of Level 2?
I think most of the home chargers are relatively slow. If the charger plugs into 1 10V outlet, it is a level 1 charger and it is quite slow. Level 2 chargers operate at 240V, but the speed of charging depends upon the amperage allowed by the circuit. An electrician would have to run some pretty heavy wire from the electric panel to the garage. Six gauge wire is suitable for up to 55 amps.
Commercial charging stations can operate at even higher voltages and may even use DC rather than AC. There is likely to be a larger risk of fire at one of these stations than at a home station.
Also, most cars allow lower current charging. Some general rules I have heard:
Only charge to 80% unless you need it for the next trip. Charge to 90% as required. Charge to 100% only when absolutely necessary.
Unplug the charger when done charging.
When charging to 100%, you want to drive away very soon.
if its that important to you then i would go for independent hardwire with battery back up smoke, heat and co alarms that connect to the smoke alarms in the house. if they do a relay base you can use that with a fibaro smart implant to link to hubitat for any addition not critical alarms, lights ect
No emergency or life dependent stuff should be battery base or only work with a smart hub.
I tried a CO detector in my garage, and the CO sensor died a very quick death from the tailpipe startup emissions. If you have only an EV it might be OK.
Smoke detectors are also going to be problematic from the dust, spiders, and so on that exists in most garages. That is why heat sensors are typically used, and what I would recommend. They have different temperature thresholds on these sensors, I would have to put some thought into whether having multiple lower temp sensors or a mix of low and high temp would be more effective?
I would also consider adding an extra layer of 5/8" Type X drywall (mudded and taped) to the partition wall between the house and garage, and the ceiling of the garage. That extra layer can buy quite a bit of escape time. Here is one example of what you should be looking at. There are tables and drawings for different assemblies to get longer fire ratings. I would specifically look at the 2 hour assemblies.
When Ford and others have recalled vehicles for fire concerns, they advise not parking in a garage. I would also advise that until such time the Tesla is recalled for this danger.
Heh, I suggest you stay out of the Rivian forums. Those fanbois are sugar-coating everything.
I got some minor kickback here when I posted that even li-on power tools need to be considered a 'hot' fire risk. But the issue IS starting to make press (scroll to the timeline in the last paragraphs);
Is there anything you can monitor via an OBD-II port that would alert you to the dangerous condition?
Sure is a lot of fud and fear about electric cars in this thread. Would love to see the rate of fire in any electric car vs fires in normal cars, I don’t have any hard numbers, but I suspect it is no worse than any other type of car. I’m no fan boy of any manufacturer, but car fires happen constantly, but fires in gas cars don’t get the clicks that putting “Tesla” into the article title gets.
But by all means, don’t want to discourage safety measures, there’s certainly benefits and it doesn’t hurt. But fears/statements about eventual battery recalls due to fires, fears around charging at 240v, restrictions about charging outside, etc all feels over the top to me.
I don't know if this vehicle type vs fires report is accurate but it suggests EV vehicles have a lower rate of fire incidence / 100,000 vehicles.
What I don't know is the passenger risk for the different types of fires. I worked in automotive and one test of the fuel tank resistance to propagating fire is to put a pan under the tank with some amount of gasoline. Light the gasoline in the pan. The tank must resist leaking for 20 minutes. These are plastic fuel tanks.
DJW I worked with the engineering staff at GE Battery in Gainesville FL when they were working on production of the early Lith batteries. To a man, the engineers there were scared to death of these batteries. It was explained to me way back then that exposure to only air would be catastrophic. This is a proven fact. You just can't put the fires out with conventional methods. As far as statistics, you aren't considering the severity of the incidents. You aren't considering the age or condition of the vehicles. Lots of very old, very poorly maintained gas cars out there. When these E cars age, it's going to be a very bad thing. And you aren't considering the PR/PC in the press that is suppressing the truth. Feel free to park these in the garage with YOUR grandchildren in the house. Hope you don't learn a hard lesson.
I’m not really interested in getting into a long drawn out discussion, you do what you feel is right. I think you’re maybe a tad more afraid of a new technology than you need to be, but that’s your right (100 years ago I imagine you’d see a similar fears discussed about cars, airplanes, etc).
How long ago was this? Battery technology, safety measures, etc have gotten better over the years. Not sure you can fully translate fears of early lithium batteries to what is in place now.
But I do agree, lithium batteries can certainly fail in catastrophic ways.
Again this is a fear of something that isn’t even real yet. Maybe I’ll change my tune in 15 years, but there is currently no basis at this point on this particular one. But I also think with the software out there and the closed loop nature of a batteries in cars, there are significant safety measures already in place to help prevent these issues.
Got it, the news media is suppressing all those lithium car fires that are happening every day.
I do park my electric car in my garage, I do charge my car at 240v and 32a, I don’t however have any grandchildren. 
But like I said, not looking to discourage safety measures. I myself have considered putting in a heat sensor into the garage. I don’t expect my house to catch on fire, fill with CO, or get broken into, but that doesn’t stop me from installing smoke/co detectors and cameras.
Just feel like the fear in this thread is a bit over the top, suggesting things like only charging outside and charging more slowly at 120v.
So kbb is a disreputable media source:
https://www.kbb.com/car-news/study-electric-vehicles-involved-in-fewest-car-fires/#:~:text=Hybrid-powered%20cars%20were%20involved,some%20logic%20to%20the%20results.
I think the OP asked about monitoring in case of a fire.
batteries burn white-hot
true
fear in this thread is a bit over the top
perhaps.
I'm far from an expert in Li-Ion batteries however I know that:
- The risk of thermal runaway begins at a temperature of 60°C and becomes extremely critical at 100°C
Risks are due to (among others):
- Overcharging the battery beyond the maximum voltage specified in the data sheet, e.g. to increase the range of an electric car. Depending on the degree of overcharging, the battery may be damaged permanently and the service life of the battery decreases.
- Excessive currents when charging or discharging the battery, e.g. when rapid charging.
IMHO;
Electric vehicle batteries represent an increased risk over a petroleum based engine (with regard to fire). I don't have any actual data on % of fires of electric vs gas (or diesel). I'm told the KBB data is suspect.
When parked in one's garage, Gas vehicles are in a passive state, even leaking fuel is unlikely to explode without some other form of ignition. And when fuel is leaking the odor gives one an indication of possible issues.
An electric vehicle is in the charging mode when in the garage. The charging mode has the highest risk of fire (excluding physical damage as in a crash).
Thermal runaway happens in seconds, igniting a significant mass. Although I've never seen a Li-Ion battery burn, in my mind I liken it to a road flare.
Vehicle distance capability is a major selling factor between vehicles. The more the Li-Ion batteries are charged the longer the distance and the greater the risk of fire.
I do not trust companies to forgo distance for companies. Consider the Ford Pino.
Part of the court’s reasoning was that Ford knew about the dangers, but pushed the Pinto onto an unwitting consumer market anyway. The Ford Company’s cold cost analysis revealed that debuting the hazardous Pinto as-is and simply paying for subsequent lawsuits would be cheaper than making expensive safety modifications. In other words, Ford decided that profits were all that mattered, and that irreplaceable human life ultimately carried a lower value than an inanimate heap of aluminum, plastic, and glass.
I don't have an electric vehicle, not due to safety issues but because I enjoy driving my manual transmission vehicle.
