Hotel Astor, December 7, 1904, Byron Company. (From the book “Repast: Dining Out at the Dawn of the New American Century, 1900-1910” by Michael Lesy and Lisa Stoffer)
The son is going to inherit the company, he’s clearly terrified and going to piss the whole thing up the wall within five years of being given the reins.
We know this comment by Shannon Martin is correct and sensible because it was reviewed by Shannon Martin! As a licensed insurance agent, I’m sure she is qualified to talk about uh… electronics… hmm
This is the sort of person who thinks you need to ground yourself to be safe while working with electricity. Not 100% wrong, but just wrong enough to be very, very dangerous.
A nearby local hardware store put up a sign in 2017 and now this year, in front of the welding equipment, that says “WELDING GOGGLES DO NOT PROTECT EYES AGAINST THE SUN”
Now if they didn’t block uv from the sun, then they wouldn’t block uv from your welding arc.
BUT I 100% stand by their choice to put the sign up.
Because you need a certain shade or darker, and they sell a lot of different shades for different welding applications, including the safety tints people might want if they’re nearby and catch the occasional reflection.
And some people know enough to know welding arc = UV, sun = uv, and don’t stop to think about intensity.
In fact, in 2017, I knew someone who tried to use a #3 lense to look at the total eclipse, and as soon as the moon cleared moved enough for the sun to peek back, he deeply regretted not using a darker shade. Now has a weird spot in his vision that isn’t quite right.
Working with small ESD-sensitive electronics and using a proper grounding strap and mat with large resistors in series to provide protection from shock? Absolutely.
Wiring up a car battery or working with mains power? Absolutely not.
Car battery on its own won’t kill you, though wiring many in series might. There can also be some effects from DC sparks and welding on even 12V, which might cause other problems.
Just ground your left hand while you work on it with your right hand. That way if it’s live it’ll quickly stop your heart and you won’t even know you died. No half measures!
One running on "Volts" and another running on "Watts" is like refusing to compare two cars because one car runs on Wheels and the other running on Motors
Well, you just have to convert wheels to motors. A car runs on wheels, which is 1/4 motors. A boat runs on motors, and has one, meaning it has 4 wheels and is probably street legal!
Watt and volt are two different measures for electricity. Also your fridge will not work when hooked up to a car battery for many other technical reasons, including differ t voltages, and current types (AC/CD, not the band)
That vehicle isn’t using a traditional 12v car battery for that. Also the point t is you can’t connect a car battery to a fridge and expect it to work.
You stated that you cant connect a car battery to a fridge. You said nothing in your comment about 12v. I can connect my car battery to my fridge no problem.
You can but it won’t keep your fridge cold. (Unless you use an inverter and you would need to check the amps needed by the fridge when the pump is on and see if your battery and inverter can provide that.)
Another way to think of it is this: Volts are like water pressure (potential energy) Amperage is like the flow rate of water Ohms (resistance) is like how hard it is to push water from high pressure to low pressure Watts are like the volume of water (a unit of energy)
A big hose has low resistance, water can move freely A coffee straw has large resistance, it’s hard to pull and push water thru it
A river has very low water pressure, and the speed of the water can vary, so volume of water moving can be huge so the flow rate of water can be huge as well. A pressure washer might have very high pressure, but use as much water as a kitchen faucet. Certain applications need high pressure, some need low pressure. A car battery is like a river, low pressure (typically 12volts) but move a lot of amps (cold cranking amps of up to 500-600 ish usually), and a wall outlet by comparison is like a pressure washer with 120v, 15A (in the US). A fridge won’t play nice on 12v, it needs 120v. It might need 400 watts which a car battery can do but it cares about how it can get that by requiring higher potential.
A watt, W=VA, can be thought of as asking how much water is there? 1 minute under a sink verse 1 minute in front a fire hose has two very very different amounts of water.
A watt hour, which most people are familiar with in the US for billing on their utilities, is like asking how many cups of water an hour. A light bulb needs a fraction of a kilowatt hour, a drier needs multiple kilowatt hours, but might only run for 30 minutes.
This idea gets a little tricky and falls apart at its edges but as a general idea should hold up for most peoples understanding of electrical stuff unless you work with it daily like an electrical engineer, electrician or something similar. For sanity sake I’m not going to try to apply this to AC verse DC, I don’t have a good analogy for that
Obligatory mobile formatting heads-up and what not and I’m not caffeinated so meh
For the AC/DC part, I usually try to tell people it’s like a water wheel that’s been inserted into the hose of water. DC is it spinning one way constantly, while AC is it spinning back and forth. The wheel is turning pretty much the whole time (again, we can try to not be super specific with the way we do phases with AC), and thus you can use it to do stuff on AC or DC.
Clever, it just breaks down again with my analog of water volume lol. Definitely not saying it’s wrong, I just like to leave it off so there are less questions haha
Like I said it falls apart on its edges but for most people it’s probably a better understanding of it than they will ever have or need, but most people scrolling thru Lemmy probably don’t need to be understanding electrical concepts like electrons not actually flowing, charge, etc. I’m a controls engineer and while I am aware of the concepts and such, I am not designing electronics so at the end of the day I barely have a use for half of the concepts myself. Sure I could get down to the half semester class of quantum where things get weird, but that won’t easily tell people to not to try to plug their fridge into a car battery
Almost every sentence. But funny self review and other things aside, main problems:
“Watts… Contains.” Is a fundamental confusion on what a watt is. It’s like asking how much fast there is in a box.
The answer has a good basic idea, but also a total comprehension failure not just pulling the numbers out of thin air, but badly describing an equation with watts on one side and watt hours on another. The answer is both ignoring realities and getting the hypotheticals wrong. Sounds expertish but is both wrong and useless.
When they could have just said “yes, you could use a suitable inverter with a suitable battery and a fridge in some cases, but the math and actual connections would be more complicated than that explanation” or something like that.
A little more technical, I don’t think your average starting battery is 100ah capacity, and most don’t rate themselves in amp hours either.
I bought a deep cycle for my little sailboat at the local auto store and it’s around 70-80ah
You would need an inverter to convert the batteries DC (direct current) into AC (alternating current). This will “cost” some power (watts) to convert that voltage. Your refrigerator runs on AC battery outputs DC.
That said, it is quite common to run refrigerators on larger boats and RVs off batteries and it would certainly be possible to run your house fridge off a single car battery for a short while if you’ve got an inverter large enough to run it.
What your not gonna do is just run out to the car, grab your battery and hook it directly to your fridge.
Our fridge uses between 130-180 watts when running and about 2.9Kw or 2900 watts in 24 hours. Your battery most likely has under 1000 total watt hours til empty, and car batteries are generally not used past 50% capacity (lead acid starting battery). So figure 500 watt hours max (for easy math). So… 4h run time maybe.
In your last paragraph, most of the places you write watts you mean watt hours. Good reminder that Wh is a bad unit, since it’s too easy to confuse with watts.
While it’s true that it won’t be at max capacity, I will say that batteries these days will rate themselves in amp hours. For instance usually an 800 CCA AGM battery lists itself online as 7.5 AH.
The conversion process involves using the formula CCA = 7.2 x Ah to convert from Ah to CCA, and Ah = CCA / 7.2 to convert from CCA to Ah.
I specifically looked at the available specs at the local auto parts stores and couldn’t find Ah details. This was about 2y ago, so maybe this value is becoming more commonplace. I know in the RV/Sailing works Ah is used pretty exclusively. My deep cycle AGM only lists CCA and reserve capacity
I never got the pipe analogy. Since liquid water can’t be compressed, wouldn’t the amperes be directly proportional to the volts and to the size of the pipe, assuming there are no air bubbles? Also, supposedly resistance only reduces current, but when I think of hair in a pipe, the pressure after the obstruction would also be lower (because pressure is directly proportional to the amount of water that flows)
He expressed it wrong. Amperes is diameter of the pipe, how much volume (or charge) can be transferred per unit of length at a given pressure; Watt is the amount of water flowing out at the end, which depends both on pressure and diameter.
Watt is the amount of water flowing out at the end
Shouldn’t it instead be the sum of the kinetic energy of all water molecules that come out the other end per unit of time (ie. total amount of energy you use move your volume of water with a certain pressure in a second)?
Common misconception - it can, just not very much, so the volume change is tiny, and in practice, there’s usually something else in the system that is changing volume by a larger amount- like air bubbles, or if there’s anything elastic in the plumbing, it will stretch - but regardless, water absolutely can be under pressure.
resistance only reduces current, but when I think of hair in a pipe, the pressure after the obstruction would also be lower
You are correct, in electronics, resistance drops voltage (assuming the load is in series with the resistance). In fact, a cheap quick and dirty digital to analog converter uses a bunch of resistors to supply different voltages…
It would be. By ohm’s law, I=V/R and R=V/I, so if V is fixed as V=1, then I=1/R, R=1/I, so it’s is effectively the same thing, just measured in reverse.
I mean, the running on watts vs volts part was nonsense.
But, did get quite close with the power calculation. Although here in the UK the average car battery seems to be around 60ah. I did see some very expensive large 105ah batteries. But they were definitely the outlier. So if you had a 100ah battery then it would be 1.2kwh with 100% efficiency.
Also, it doesn't mention that you'd need an inverter to make the fridge run from a battery. These also have inefficiencies which would reduce the runtime on the battery.
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