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After bus fire, CT pulls electric fleet from service

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Re: After bus fire, CT pulls electric fleet from service

#111

Post by sofixa »

KennyBlanken wrote: post #91
billyo wrote: post #28

We need more electric trolley busses. These battery powered ones are nonsense

Trolley buses cannot be detoured and the infrastructure costs are enormous, as is the cost of even a minor route change. Battery technology continues to improve in cost, energy density, and charge/discharge rate. There are already systems that use a catenary-like device to "top off" the bus while it is stopped at a bus stop.

All modern trolleybuses have either batteries or diesel engines for detours.

Infrastructure costs aren't "enormous", that would be if you're putting rails in the ground for trams.

Re: After bus fire, CT pulls electric fleet from service

#112

Post by pineconebutt »

dumpsterlid wrote: post #36
jeffbee wrote: post #31

Battery buses are a solution ahead of their time. Any old bus is better than car-based transportation, so shifting modes from car to bus is more important than changing the energy source of the bus. If shifting from car to bus is impossible because of built environment, that's the first priority. Buses powered by batteries should be way down at the end of the TODO list. If you absolutely insist on having buses that a…

Yah precisely the point. We should focus on making busses comfy and nice and on getting good coverage with bus routes so that people use them. Worry about them being electric later, the environmental impact of less people driving far overshadows the impact of ev vs gas busses.

No post body was provided.

Re: After bus fire, CT pulls electric fleet from service

#113

Post by woodruffw »

mminer237 wrote: post #109
dangerwill wrote: post #101

Earlier quoted context omitted.

These lines would be unambiguously better (cheaper, much simpler materials, much less embodied carbon, faster and more reliable if given a proper right of way) than a bunch of electric buses in shared traffic so it makes sense to bring them up.

How is building dedicated trolley tracks cheaper than buying a bus and running it on ordinary pavement? And streetcars have no reason to be faster either. It's easier and historically faster to have a dedicated bus lane than a dedicated trolley lane, but there's just not enough will for even that.

I won't make the claim that trolleys are cheaper, in terms of initial capital. I will make the claim that they're more sustainable, in the following senses:

* They make their neighborhoods more valuable to both residents and businesses, which in turn prevents neighborhood flight

* Streetcars cost less over time, after their initial cost. Portland found that streetcars cost the city roughly half as much per ride as buses do, and streetcar bodies themselves last much longer than buses do[1].

Ultimately, however, we're talking about public infrastructure. It shouldn't be beholden to the lowest cost; we should be balancing cost with benefit.

[1]: https://www.vox.com/2018/7/13/17570156/us-streetcar-trend-pu...

Re: After bus fire, CT pulls electric fleet from service

#114

Post by tantar »

Im a Vol Firefighter in a Major City Suburb with lots of highways and tons of crashes. We get 2-3 car fires and passenger extractions per month. The first question we ask on the way out is "Is this an EV?"

We need to know this because EVs trigger the rollout of Water Tankers from surrounding towns, as many as we can get. Usually a Water Shuttle has to be set up. Not many Fire Hydrants on Highways, and EV fires require A LOT of water, like several house fires worth... Here is some external detail on this - https://www.businessinsider.com/tesla-crash-fire-lithium-bat...

Also, we need to start calling more manpower. EV fires burn a very very long time while ICE fires are usually put out in the first few mins, and with 1 engine's 1000gal tank water.

Adding to this, the fire is usually under the car, and quite hard to get too. We are very good at opening locked car hoods and cutting metal to get at the fire, but when its deep in the guts of the thing, its impossible. At my department, we have started working on ways to jack the car up safely while its on fire so we can get water onto it. Trust me, its even harder than you would think...

The Standard Operating Procedure is to put water on the car and surrounding area so that nothing else catches on fire, but basically we have to let the thing burn out, and that can take hours and hours...

EV car batteries do not rely on the environment for their fires to burn. The fuel brings its own oxidizer, and it doesnt need anything else. We can put out Liquid Fuel fires by robbing the oxygen or removing the heat(thats what the water does), but once EV fire gets to a particular point of no return (which it arrives at very quickly) there is really nothing that can be done to stop it, just make sure it doesnt get any worse...

Here is the current thinking from the NFPA (firefighting safety and standards organization in the US), you'll see EV car fires are long on problems, but even the most focused minds in the US Fire Prevention industry are short on answers at this time. https://www.youtube.com/watch?v=Sp3WvKON_W4

Re: After bus fire, CT pulls electric fleet from service

#115

Post by GiorgioG »

mrguyorama wrote: post #79
GiorgioG wrote: post #39

Earlier quoted context omitted.

If this (one of many) example doesn't scare you, well then you're braver than I am: https://youtu.be/sAQlLu5ttOk?t=77

I watch videos and documentaries about plane crashes all the time, and yet I am not afraid of flying because I understand the safety culture and statistics of the industry. If you are afraid of your car, regardless of motive power source, bursting into flames without warning, then you shouldn't own a car, because tens of thousands of people die in car crashes every year, and for most of them they experienced no warni…

> If you are afraid of your car...

I'm not afraid of MY car. I'm afraid of owning a car where I'm literally sitting on top of the battery. Say what you will about ICE's, but my gas tank is comparatively far away from me in comparison to EVs under-chassis battery designs.

Design a better battery where that removes this risk and I'll consider it, until then I'm sticking to my ICE.

Re: After bus fire, CT pulls electric fleet from service

#116

Post by beams_of_light »

tantar wrote: post #114

Im a Vol Firefighter in a Major City Suburb with lots of highways and tons of crashes. We get 2-3 car fires and passenger extractions per month. The first question we ask on the way out is "Is this an EV?" We need to know this because EVs trigger the rollout of Water Tankers from surrounding towns, as many as we can get. Usually a Water Shuttle has to be set up. Not many Fire Hydrants on Highways, and EV fires requir…

I recently purchased an EV, and there is an emergency high voltage battery cutoff in the rear. Do you guys know about those, or if so, are they effective?

Re: After bus fire, CT pulls electric fleet from service

#117

Post by gunapologist99 »

Cpoll wrote: post #72
jotux wrote: post #57

Earlier quoted context omitted.

Some quick googling says tesla is ~70% [1] of the EV market and there is someone who claims to track every telsa fire [2] which has counts 97 fires since 2013. Compare that to 45k ICE vehicles fires every year and it appears that EVs are significantly less likely to catch fire. I think if you live in one of the top 50 metro areas of the US and listen to local traffic news between June-August you'll probably hear abou…

> Compare that to 45k ICE vehicles fires every year and it appears that EVs are significantly less likely to catch fire. You haven't provided enough information to make a comparison. Googling some numbers, Tesla has sold 2MM cars, so taking that 97 number we get 0.00004 fires per Tesla. US has 275MM cars, and (2022 - 2012) * 45000 = 450000, so we have 0.00163 fires per ICE car. Conclusion: If those numbers are correc…

Even if that's true (and your numbers do look to be similar to what I've seen), it's not relevant, because when a Tesla catches fire, it utterly immolates itself and everything around it. That is certainly not true for a gasoline fire once the fire engines roll up, to say nothing of a diesel fire, which are comparatively hard to start and easy to extinguish. It'd be far more informative to compare injuries and damages.

Re: After bus fire, CT pulls electric fleet from service

#118

Post by londons_explore »

KaiserPro wrote: post #47
londons_explore wrote: post #8

Earlier quoted context omitted.

Electric cars could totally be designed to be re-ignite-proof. For example, you'd have the battery pack detect a breach - for example through a lack of pressurised coolant. That would then trigger each battery cell to have a PTC resistor discharge it - that could be entirely mechanical. The PTC resistors would discharge the battery in a few hours, maintaining the battery temperature at say 120C. As water is doused on…

So in a thermal event, where integrity of the coolant is compromised, you want to dump more heat into the system? Its not just the electrical issues at play, its the fact that hot battery fluid burns spontaneously with exposure to air (I suspect also water, but I'm less sure about that)

A PTC resistor only dumps heat if the system isn't already hot. PTC resistors can be designed which will survive a car fire.

It's a good way to ensure that the only way the system can appear safe (ie. cold) is when all batteries are discharged, therefore preventing re-ignition.

Obviously you could also have an external energy dump for that purpose (for example power up the cars 5 kw resistive heater for 10 hours), but that's both far slower than boiling water at scale, and won't work after major damage which is likely after a car fire.

Re: After bus fire, CT pulls electric fleet from service

#119

Post by nomel »

woodruffw wrote: post #110
nomel wrote: post #103

Earlier quoted context omitted.

Trolleys have a fixed route, which is not ideal. Fixed routes is why you see buses going down the road empty, or with one person on them.

I don't understand this point. Buses don't have inherently fixed routes, so that isn't why they go down the road empty. It's because, in many places, their routes haven't been replanned to compensate for suburban sprawl, and their service is bad . The fixed-route nature of trolleys is not an inherently bad thing. In fact, it was the dominant (and eminently sustainable) form of urban expansion for over 75 years[1]. It…

> Buses don't have inherently fixed routes

In my city, they haven't changed the bus routes in several decades.

Re: After bus fire, CT pulls electric fleet from service

#120

Post by tantar »

beams_of_light wrote: post #116
tantar wrote: post #114

Im a Vol Firefighter in a Major City Suburb with lots of highways and tons of crashes. We get 2-3 car fires and passenger extractions per month. The first question we ask on the way out is "Is this an EV?" We need to know this because EVs trigger the rollout of Water Tankers from surrounding towns, as many as we can get. Usually a Water Shuttle has to be set up. Not many Fire Hydrants on Highways, and EV fires requir…

I recently purchased an EV, and there is an emergency high voltage battery cutoff in the rear. Do you guys know about those, or if so, are they effective?

The cutoff is to stop the electricity from leaving the battery, and electrifying the rest of the car. Nothing more fun that getting electrocuted just touching a car. F1 cars are also Hybrids, and if you watch F1 drivers exit a the car after a crash, they do a little hop off the car. Making sure not to touch the car and the ground at the same time. They also have little indicators that show if there is current running into the car's body. I will venture that an F1 hybrid system is at least as advanced, if not more-so, than a common consumer hybrid system. At the least, I wish Commercial EVs had that same electrification indicator.

Cutting that wire is largely, to de-power airbags and the like. Airbags DO go off unexpectedly, and can inure a responder quite effectively. Cutting the power is a normal step in any big motor vehicle incident, EV or ICE.

Tesla and others do publish all this information with nice diagrams and handy mobile apps, and we study them. However, this doesnt fix the problem of the Huge Energy load in the battery itself. Even if that energy cant get out of the battery through wires, it can still burn like crazy inside (and outside) the battery case(s).

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