Nodge68 wrote:

So running to help someone after an incident with 10 gallons of petrol in the vehicle tank is less risky than running to help someone in an EV? That's bonkers. The battery in an EV is much better protected than the fuel tank in an ICE vehicle.
And the chances of electrocution from an EV is nil. You've more chance being electrocuted changing a light bulb.

Isn't the danger of car batteries in the high current/low internal resistance, that would result in being burnt and/or boiled to death, rather than plain old heart stopping electrocution

EV Battery Power is unlike House Mains Power, in that it is Direct Current, a Higher Voltage, and capable of delivering a hell of a lot more Current.

Admittedly although, I am sure that Petrol has a far higher Energy Density than an Lithium Battery.

We should concentrate on ease and cost of use of the new EV technology, as the main risk of both old and new methods is most likely the driver.


(Also how safe will travel be when we all drive around vehicles powered by Micro Nuclear Reactors) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 79k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Yes Ian, you are correct, the voltages are in the region of 800v DC though I believe some motors can be AC as they are lighter than DC motors, if not pure AC then brushless DC motors which basically produce a rotating field by using transistors, however the as you say unlike house electrics there is no earth trip as it's a battery supply so has no earth. my PC is slightly to the right of Genghis
2012 HSE SD4 In Orkney Grey now gone, best car ever.

Dartman the one wrote:

The chances of electrocution changing a light globe ( you plant bulbs) is nil in the UK, compulsory earth leakage devices have eliminated this risk.
What has changed is the increased use of petrol instead of diesel due to various regulations and price differences, the UK held out against the use of petrol in pleasure craft for years on safety grounds by taxing diesel below petrol, though there are petrol fires in the UK due accidents they are considerably lower than in the USA due to the the USA having very few diesel vehicles.
The chances of electrocution in EV's is not due to battery damage but wiring damage causing parts of the car to become live and you ground the power by completing the circuit. Electricity is similar to plumbing but you can't see the leak

In the UK, lighting circuits didn't need RCD protection until the 18th edition regs came out in 2018, and there's no need to retrofit for older installations, unless modifications were made after the 18th edition came out. There are plenty of houses where it's quite possible to give yourself a shock changing a light bulb (the correct term is a lamp, but I buy light bulbs from Screwfix a dozen at a time, and they clearly say bulbs on the box ), if you go sticking your fingers in places they shouldn't be. Besides there's only a need for a 30 mA RDC or MCBo, and 30 mA hurts and is potentially fatal, if it doesn't disconnect quickly enough.


Some EVs do use 800V architecture, and more will in time as higher voltage means lower current for the same power, but it doesn't make them less safe, or more likely to cause electrocution. To comply with really strict regulations, the main battery can't output any power on its main output cables unless the contactors inside the battery are energised. Both live and negative must have contactors too. For the contactors to be energised, the vehicle computers have to be happy that there aren't any issues. Much like in a Freelander when it's involved in an impact, the various modules have a quick chat and deploy airbags, kill the electrics to fuel pumps, shut down the engine, put the hazard flashers on, light the interior lights, pop the door locks and so on.

An EV is no different, the battery and everything else in the drive train will only have power if it's safe for power to be supplied.

It's irrelevant if it's AC or DC, the fact that a vehicle battery isn't grounded, or even referenced to ground is what's important.
It's different to domestic mains electricity, as with mains electricity, the live cable is referenced to ground. So simply touching the live conductor will give a tingle or much worse, depending on the resistance of the circuit to ground.
So unless all the safety systems in an EV battery suddenly fail to disconnect the power at the battery connector, there's almost no way to get a shock.

EV battery contains a tiny about of the energy that a full tank of petrol does, the holy grail battery would equal liquid fuel for energy density.

The casing the battery is housed in as many times more robust than a plastic fuel tank, so it's safer in that regard. Actually the fact that the battery case is so strong, they often add strength to the body of the vehicle, making crash tests like the pole test much more impressive compared to an ICE vehicle which doesn't have a stout box below the floor.

From a safety point of view, an EV is no less safe than an petrol ICE vehicle with a liquid bomb under the floor.

Charging en route is an issue, as is the cost of an EV to purchase in the first place.
I quite fancy the MG4, but will have to wait until they are affordable second hand. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Nodge68 wrote
EV battery contains a tiny about of the energy that a full tank of petrol does .............

An EV battery contains less electrical energy than a tank of petrol, but lithium as a fuel for burning is both high in energy density and a right pain to put out once it is alight. So a crash that ignites the battery is a problem.
As has been said a lot of effort has gone into the casing to prevent them from catching fire.

When it comes to electrocution think about the sparrows sitting on the HV overhead wires, as they are not connected to a return path (ground) they are perfectly safe. Unless you touch both the feed and return wires to a HV battery you are as safe as the sparrows. But and here's the problem, you will ALWAYS find someone with a set of spanners who thinks that "it's only a car" and that any fool can fix them, going happily where an electrician would hesitate. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

There's no actual Lithium as in metallic Lithium in a Lithium ion battery, its a common misconception that there is, but its wrong.
The Lithium is processed into a solution rich in lithium ions suspended in an electrolyte along with various fluorocarbons, it's this electrolyte that is combustible as its alcohol based. Lithium ion batteries are even classified as class B fires (metals are class D), as the electrolyte is essentially a very flammable liquid.

A lithium battery can fail and spontaneously combust, but it's the exception rather than the norm.
There are several failure modes, most of which can be reduced to almost zero.

Overheating is one failure mode, either through excessive charging current, or excessive discharging current, but all batteries have electronic controls to prevent overheating, and most have fuses or fusible links to prevent over current situations. Nearly all vehicle batteries are liquid cooled, which helps keep the temperature of the cells under control.

Bad manufacturing where impurities have got into the separation membrane of the cells causing an internal short circuit, which can cause spontaneous gassing and potentially a fire. A top quality cell should be immune to these problems, or make it extremely unlikely to happen.

Damage to cells (batteries are made up of hundreds of individual cells) can cause fires, but not always. A fire can occur if a damaged cell is shorted or punctured, and sufficient heat develops due to the electrical short in the damaged cell for the electrolyte to burn. This can trigger a chain of thermal runaway through the cells in battery pack, with the closest cells failing as it burns through the back, as temperatures are high as the electrolyte burns, at least in Lithium Nickel Manganese Cobalt Lithium (NMC) battery packs.

There is newer and much safer lithium ion cell making its way into newer EV battery packs.
The LifePo4 often called LFP cells are completely safe from fire, as they contain an electrolyte that doesn't burn at all, so these are considered fire safe except. LFP cells have many advantages over older NMC too.
LFP cells are what most Chinese EVs are sold with, because LFP is now mandatory over there, even the Tesla Model3 made in China for the Chinese market has LPF cells in its battery pack.
LFP cells will still vent if short circuited or damaged causing a short, but its just a sort of steam gassing off, which looks much worse than it actually is, but the gassing takes heat away from the cell cooling it down naturally.

Electricity in all vehicle batteries is obviously still dangerous if not respected or understood, so there are bound to be some incidents related to electricity and people with spanners in the wrong places in years to come, in much the same way as people setting fire to themselves with petrol by accident do now.

The sparrows (I normally see starlings) sitting on a power line is a brilliant analogy, and very accurate for an EV battery. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Andy131 wrote:

When it comes to electrocution think about the sparrows sitting on the HV overhead wires, as they are not connected to a return path (ground) they are perfectly safe. Unless you touch both the feed and return wires to a HV battery you are as safe as the sparrows. But and here's the problem, you will ALWAYS find someone with a set of spanners who thinks that "it's only a car" and that any fool can fix them, going happily where an electrician would hesitate.

"As cars become more and more complicated and rely on working, and serviceable, hardware and software, I am getting increasingly worried about people 'self maintaining and tinkering with those vehicles.
If you don't know what you are doing, then the 'unintended consequence' could be expensive, or even lethal.
"

yes, you only have to see what people do to their cars in the USA without any thought to their safety or that of others

 Jules

You will have to excuse my lack of chemistry, but I do know from personal experience that when lithium batteries go up you ain't stopping them. Below is a picture of our two original electric bikes, they were parked in the garage, hadn't been used for about 3 months, not on charge.
The fire was hot enough to melt clean through the frame of the bike that caught fire - just so glad they were in the garage and that the garage isn't attached to the house.



I accept that the newer batteries are safer as the cells are encased in steel rather than plastic and alloy, but for me it was an expensive lesson learned. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

^
https://news.sky.com/story/alarming-increa...s-12806523

Andy131 wrote:

You will have to excuse my lack of chemistry, but I do know from personal experience that when lithium batteries go up you ain't stopping them. Below is a picture of our two original electric bikes, they were parked in the garage, hadn't been used for about 3 months, not on charge.
The fire was hot enough to melt clean through the frame of the bike that caught fire - just so glad they were in the garage and that the garage isn't attached to the house.



I accept that the newer batteries are safer as the cells are encased in steel rather than plastic and alloy, but for me it was an expensive lesson learned.

A couple of extracts from the above story (see wonderdust's link)

The fires have been attributed to non-complaint lithium-ion batteries, which are being imported by businesses and fail to meet UK product safety laws.

"When these batteries and chargers fail, they do so with ferocity," he said.

As a result, consumers are being warned to only buy e-bikes and e-scooters from reputable retailers. These vehicles will display a valid UKCA or CE mark.

I'm just hoping that in the future 'cheap?' EV replacement batteries will not become available from unregulated suppliers.
Also the danger is that an EV battery may be sent abroad, to a less regulated country for a 'cheap?' repair. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 79k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Vehicle battery packs are very different in construction compared to those used in E bikes and E scooters.
Vehicle packs are much more modular in design, using various configurations of cell modules all grouped together to form a larger battery pack. They are also much more robust that an 18650 cell E bike pack, which is wrapped in nothing more than blue heat shrink plastic for protection.

I've a friend in IN who is currently converting a Freelander 1 into electric power. I've made various parts for his this vehicle, and been helping with the design of stuff like the power steering, motor fitment and so on. He's got a YouTube channel which he's using to show what he's been up to.
His FL1 EV conversion is based on the Gen1 Nissan Leaf motor and inverter, but he's using E Golf batteries to power it. The battery is made up of modules which he's been putting into various locations in the vehicle. Its an interesting although rather rambling series of videos, but it does show how an E Golf battery pack is made up, and how to use the various modules in it safely. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Andy131 wrote:

You will have to excuse my lack of chemistry, but I do know from personal experience that when lithium batteries go up you ain't stopping them. Below is a picture of our two original electric bikes, they were parked in the garage, hadn't been used for about 3 months, not on charge.
The fire was hot enough to melt clean through the frame of the bike that caught fire - just so glad they were in the garage and that the garage isn't attached to the house.



I accept that the newer batteries are safer as the cells are encased in steel rather than plastic and alloy, but for me it was an expensive lesson learned.

How does a CAN wire break ? Jules