Lithium-Ion Batteries and others

[Stefan Mikes]

I am always amazed to hear of people being electrocuted in the States, you run 120V, that voltage shouldnt kill you, but it does, construction sites in the UK have to use ludicrously heavy 240-110 transformers, but people are still being killed.
There plenty of diy battery builders using 90V , you can stick your hands on
Such a battery that can supply hundreds of amps, but its very unlikely to stop your heart.
Funnily enough the two wire telephone feed that still goes to houses not using voip is 90V, they upgraded decades ago to make adsl internet work better over copper wires.
I got quite a shock on a hot day, my sweaty forehead touched a wiring block
And I got flashes in my eyes and a thump of a jolt as I was holding a 90v wire in my fingers at the time.
The current was tiny, but it can leap for a split second.

I could tell you how one can stupidly kill themselves with a 9 V battery but you could actually try it...

 

[Chargeride]

People get shocks off 12v car batteries, but its usually back emf off old school coils.
But those goddam retina burning arc lights that are killers, stupid voltages, dreadful tech.
So now we have blue light leds and its like driving past WW2 search lights at night.
People actually are wearing sunglasses at night, reddit is going postal about it and rightly so.

 

[spokewrench]

A transformer can only work with AC.

Then do you see my point? Edison and Westinghouse had for years used AC so they could distribute power at high voltage and at its destination step it down with a center-tapped 240 volt transformer. Was Berlin still on DC?

And why are the US, Japan, and Canada so far ahead of Europe? Europeans must like to be different. Some even speak French!

 

[spokewrench]

I am always amazed to hear of people being electrocuted in the States, you run 120V, that voltage shouldnt kill you, but it does, construction sites in the UK have to use ludicrously heavy 240-110 transformers, but people are still being killed.

In America, I think 3% of worker deaths are from 120 VAC. Skin resistance is pretty high, but that's per mm^2. If you're grabbing something metal, that's a large area of skin, which may be damp and salty. Footwear resistance may be high, but not if it's wet. Outdoor construction work can be especially dangerous because dampness can help current get through or past insulation. A nip from 110 could be much worse from 240.

 

[harryS]

I am always amazed to hear of people being electrocuted in the States, you run 120V, that voltage shouldnt kill you, but it does, construction sites in the UK have to use ludicrously heavy 240-110 transformers, but people are still being killed.
There plenty of diy battery builders using 90V , you can stick your hands on
Such a battery that can supply hundreds of amps, but its very unlikely to stop your heart.
Funnily enough the two wire telephone feed that still goes to houses not using voip is 90V, they upgraded decades ago to make adsl internet work better over copper wires.
I got quite a shock on a hot day, my sweaty forehead touched a wiring block
And I got flashes in my eyes and a thump of a jolt as I was holding a 90v wire in my fingers at the time.
The current was tiny, but it can leap for a split second.

The US analog telephone system ran on 48V lead acid. There are huge battery banks providing the power, with AC used to keep them charged, When the phone rings, the voltage is chopped to make the bells on the old phones work, and that's why we feel 90V. I spent years in telecomm in the USA.. Perhaps British Telecomm is different.

The 48V was deemed safe for most humans, but I believe a baby could get killed, When I was kid. we would have these one tube radio kits, where the plate voltage on the tubes was 48 to 90 volts. In scout camps, some kid thought it woukd be funny to sneak up on you and put the terminals on your butt. It was a shocker.

 

[Chargeride]

Yeah, we used to be 5Ov lead acid, kept the voltage for digital, even kept loop disconnect.
The 90v was to improve internet speeds over copper, it was only if you had the internet.

Huge rooms of washing machine sized lead batteries, open top, bubbling away.
The busbars in the main exchange were 10 12x2 inch copper bars bolted together, running through walls and feeding off to the racks.

1000amp detonating fuses, I blew a 300 amp with a knife cutting insulation.

I always imagined shorting the main bars with something like a crowbar, it would probably melt instantly.
50,000 amps..
I guess you had the same strowger.

 

[Chargeride]

In America, I think 3% of worker deaths are from 120 VAC. Skin resistance is pretty high, but that's per mm^2. If you're grabbing something metal, that's a large area of skin, which may be damp and salty. Footwear resistance may be high, but not if it's wet. Outdoor construction work can be especially dangerous because dampness can help current get through or past insulation. A nip from 110 could be much worse from 240.

I have been shocked so many times by 240V, I have one advantage, very dry hands.
I got a bolt from an unknown 240ac dual feed a few years ago, my hands were wet and I was lying on a wet floor that has soaked my clothes.
Holy crap that hurt, it was like someone jack hammering my spine.
Had to go home, went the docs, all seemed fine.
But that was a proper game over potential shock, worst Ive ever had.

 

[Stefan Mikes]

Why do you guys talk 240 V when all Europe including the UK is on 230 V?

 

[DaveMatthews]

I am always amazed to hear of people being electrocuted in the States, you run 120V, that voltage shouldnt kill you, but it does, construction sites in the UK have to use ludicrously heavy 240-110 transformers, but people are still being killed.
There plenty of diy battery builders using 90V , you can stick your hands on
Such a battery that can supply hundreds of amps, but its very unlikely to stop your heart.
Funnily enough the two wire telephone feed that still goes to houses not using voip is 90V, they upgraded decades ago to make adsl internet work better over copper wires.
I got quite a shock on a hot day, my sweaty forehead touched a wiring block
And I got flashes in my eyes and a thump of a jolt as I was holding a 90v wire in my fingers at the time.
The current was tiny, but it can leap for a split second.

It's only the ringing voltage on a phone line that is 90vac, the regular voltage is 48vdc to power the phone and talk.

 

[Mr. Coffee]

Voltage isn't generally what kills you in an electric shock, it is the current.

When you rub your stocking feet on the carpet to build up a charge and shock your friend that little spark is somewhere north of 1000 volts. Maybe up to 70_000 volts. But not many people are killed by that.

Switchboards - Fatal electric shock: what voltage causes death? - Metroid Electrical Engineering

How much current does it take to kill someone? A current of as little as 0.007 amps (7mA) across the heart for three seconds is enough to have a Fatal Electric Shock

www.metroid.net.au

 

[spokewrench]

The US analog telephone system ran on 48V lead acid. There are huge battery banks providing the power, with AC used to keep them charged, When the phone rings, the voltage is chopped to make the bells on the old phones work, and that's why we feel 90V. I spent years in telecomm in the USA.. Perhaps British Telecomm is different.

The 48V was deemed safe for most humans, but I believe a baby could get killed, When I was kid. we would have these one tube radio kits, where the plate voltage on the tubes was 48 to 90 volts. In scout camps, some kid thought it woukd be funny to sneak up on you and put the terminals on your butt. It was a shocker.
View attachment 187902

I had a No. 6 for many years. 6" tall with 40 amp hours. Ignition, bells, telephones. They were readily available because many houses still had doorbells that had been installed before AC power was available.

 

[PCeBiker]

Europeans must like to be different. Some even speak French!

Canadians like to be different too.
Some even speak French!
But we all plug into 120 VAC.

 

[spokewrench]

cattle have very low tolerance for electricity somebody told me sometimes voltage as low as 6 volts can do them in a thunderstorm with a tree strike used to regularly kill cows around here of course it a very high voltage , the total amperage and voltage from a lightning strike will peel the bark off of a tree and even explode the roots, last strike I had near the house peeled a tree exploded the roots and blew up underground ,when my skin started tingling and came into my house and destroyed a lot of electronics.

If the ground of the milking machine is 6 v different from the ground under a cow's hooves, the cow will develop an aversion. It can probably be fixed by bonding the milking machine's ground to an electrode near the cow. Around 1999, I discovered that my house's power electrode and telephone electrode weren't bonded. I scooped a trench and ran a wire between them. A few months later, lightning hit a pecan 30 feet from my service entrance. A phone man had to replace a fuse on a pole. I told him I would have lost expensive equipment if I hadn't bonded the grounds. He said the electrical code calls for it, but the phone company doesn't do it because they don't want to replace fuses.

 

[Stefan Mikes]

Voltage isn't generally what kills you in an electric shock, it is the current.

When you rub your stocking feet on the carpet to build up a charge and shock your friend that little spark is somewhere north of 1000 volts. Maybe up to 70_000 volts. But not many people are killed by that.

Switchboards - Fatal electric shock: what voltage causes death? - Metroid Electrical Engineering

How much current does it take to kill someone? A current of as little as 0.007 amps (7mA) across the heart for three seconds is enough to have a Fatal Electric Shock

www.metroid.net.au

That is the correct answer. (Except the point about the 9 V battery in the article).

A man was working in an electronic shop with a 9 V battery, to which wires terminated with crocodile clips were attached. As the man needed more than two hands, he put one of the clips into his mouth. His ear was itchy, so he put the other clip into his ear to rub it. The short circuit through his brain was created, and the guy fell dead. It is the current that kills, not the voltage. Don't try this yourself!

The story was told by our university teacher during Electricity classes to make us understand what kills.

 

[Stefan Mikes]

Then do you see my point? Edison and Westinghouse had for years used AC so they could distribute power at high voltage and at its destination step it down with a center-tapped 240 volt transformer. Was Berlin still on DC?

No, it is not that "Edison and Westinghouse" were working with AC. It was Westinghouse to promote AC.

Thomas Alva Edison was against using AC, and he did a lot to promote the DC (see: "War of the currents") until 1891. In 1884, Edison Company built the first powerplant in Berlin (not clear if that was DC or AC). Meanwhile, Emil Rathenau established a company to later become AEG. Already in 1887, Rathenau employed Michail von Dolivo-Dobrowolsky who put the first three-phase motor in operation (it requires AC). In 1891, the Rathenau company could already transmit high voltage AC energy between two distant cities.

Again, I cannot understand why any American says "240 V" when it is 230 V, and it was 220 V when I was young

 

[Chargeride]

It's only the ringing voltage on a phone line that is 90vac, the regular voltage is 48vdc to power the phone and talk.

It was upped to 90v for adsl internet over copper.

 

[Chargeride]

Why do you guys talk 240 V when all Europe including the UK is on 230 V?

Voltage is actually all over the place, is the HZ that has to be kept absolute.
Thats why renewables are hopeless for present grids.
A HZ wander causes grids to drop out, not voltage drop.
Thats why we talk of base load keeping the hz in check, turbines and solar have zero inertia and require huge batteries to provide it if needed.

 

[Chargeride]

Voltage isn't generally what kills you in an electric shock, it is the current.

When you rub your stocking feet on the carpet to build up a charge and shock your friend that little spark is somewhere north of 1000 volts. Maybe up to 70_000 volts. But not many people are killed by that.

Switchboards - Fatal electric shock: what voltage causes death? - Metroid Electrical Engineering

How much current does it take to kill someone? A current of as little as 0.007 amps (7mA) across the heart for three seconds is enough to have a Fatal Electric Shock

www.metroid.net.au

You require the voltage for current to flow.

 

[Stefan Mikes]

You require the voltage for current to flow.

Or, a low resistance.

 

[Chargeride]

I think this says it all.