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submitted 3 months ago by [email protected] to c/[email protected]
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[-] [email protected] 413 points 3 months ago
[-] [email protected] 85 points 3 months ago
[-] [email protected] 29 points 3 months ago
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[-] [email protected] 203 points 3 months ago

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

[-] [email protected] 31 points 3 months ago

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.

[-] [email protected] 16 points 3 months ago

Some people know just enough to be dangerous.

For instance, an anecdote:

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.

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[-] [email protected] 25 points 3 months ago

worst ai prompt

[-] [email protected] 172 points 3 months ago

Looking passed the absolutely insane answer here, no one has even brought up the whole issue of AC vs DC. Batteries are DC, while your fridge that plugs into your wall running on AC. I know they make DC ones, but it isn't like they are interchangeable.

[-] [email protected] 70 points 3 months ago

Funny thing, most modern refrigerators use DC motors for their compressors so that they can run at variable speeds, so there's likely an inverter that you could bypass if you know the appropriate voltage. The DC ones for RVs are the same internals, just without the inverter.

[-] [email protected] 62 points 3 months ago* (last edited 3 months ago)

Correction: they still use AC motors, but those motors don't use line AC. It goes line AC > rectifier > DC > inverter board > variable frequency AC to run the compressor motor.

Most RV fridges just use DC motors, but there are some that use VFDs and AC motors.

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[-] Naz 143 points 3 months ago* (last edited 3 months ago)

Hello, expert solarpunk here.

TLDR: Car battery is 350Wh. Fridge uses 143W idle, so it'll run a fridge for 2-3 hours.

Explanation below:

Car batteries are lead-acid (sulphuric acid and lead plates).

They discharge according to Peukert's Law as the negatively charged plate gets covered in lead via the acid (electrolyte).

As the battery depletes, the negative plate can begin to take permanent damage, and so you can't discharge a lead-acid deeper than 10-20%, or about 10.8V, with the safe limit being ~50% discharge.

Most 12V, 60Ah batteries therefore only safely store and nominally discharge 350 Wh @ 350W.

You can discharge that as fast as you want but the faster you discharge, the lower the capacity is (with 1000-1500W bringing you way down to like 65 Wh). Fridges have a surge when they start up to fire up the compressor. Starter batteries can take that, but once the refrigerant is cold, the fridge just maintains the temperature which uses a lot less energy - about 143W on average.

[-] [email protected] 41 points 3 months ago

Fridge uses 143W idle

Isn't that like 1250 kWh on an annual basis of idle usage? An efficient fridge should use 150-200 kWh per year, this isn't just idle usage. Even an inefficient fridge would be really high with that kind of idle usage.

[-] [email protected] 18 points 3 months ago

I don't know.... you didn't mention your uncle once...

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[-] [email protected] 125 points 3 months ago

This reads just like an AI response

[-] [email protected] 60 points 3 months ago* (last edited 3 months ago)

AI told me 75C/170F is ideal for hot tub water temperature.

Sure no problem. Once I get used to that I'll work my way up to boiling peanut oil.

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[-] [email protected] 97 points 3 months ago

Regardless of source, if your refrigerator is running you better go catch it.

Its stealing your food.

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[-] [email protected] 94 points 3 months ago

Hey, ChatGPT, my uncle says new Macbooks are just glorified Raspberry Pis.

How many MB/s are in a Raspberry Pi?

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[-] arandomthought 74 points 3 months ago
[-] [email protected] 49 points 3 months ago

Now I don't know enough about electronics to know how wrong this is, but I do know enough about electronics to know that this absolutely sounds wrong.

The problem comes when someone takes an answer like this, knowing far less than I do, and they try and hook up their fridge to a car battery.

And this is why I hate LLMs. Being confidently wrong is scary enough when it's just people, nevermind technology.

It does make me chuckle, though, that Skynet could have been totally innocent in their destruction of the human race, they just confidently came to the wrong conclusion and had the tools to carry it out.

Like a toddler whose inner thoughts are telling him to throw a cat out of the window. He doesn't know he's going to kill it, he just knows that's what his brain is telling him to do.

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[-] [email protected] 48 points 3 months ago

Jesus… the stupid, it hurts.

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[-] [email protected] 48 points 3 months ago

While reading the question I thought: "That's not how Watts work", but then this "answer" hit...

[-] [email protected] 42 points 3 months ago

Licensed Insurance Agent

seems legit

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[-] [email protected] 39 points 3 months ago

Chat GTP answer

Sure, let's say you have a typical car battery with a capacity of 60 amp-hours (Ah).

And let's assume you have a small refrigerator that consumes about 100 watts of power when running.

To calculate how long the battery can power the refrigerator, we need to convert the power consumption from watts to amps.

Power (watts) = Voltage (volts) × Current (amps)

Assuming a car battery voltage of 12 volts:

100 watts / 12 volts = 8.33 amps

Now, we can determine the approximate runtime:

60 amp-hours / 8.33 amps ≈ 7.2 hours

So, with a fully charged 60 Ah car battery, you could run the refrigerator for approximately 7.2 hours before the battery is completely drained. However, it's important to note that factors such as battery age, temperature, and other loads on the battery can affect actual performance.

[-] [email protected] 20 points 3 months ago

I'd have expected ChatGPT to be able to call out power factor as well. Otherwise you're getting volt-amps, not true wattage

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[-] [email protected] 37 points 3 months ago

That answer is like the electronics version of the image with Patrick Stewart and the caption:

“Use the force, Harry

-Gandalf”

[-] [email protected] 35 points 3 months ago
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[-] [email protected] 32 points 3 months ago

This post made me beat my head with a 2 by 4

[-] [email protected] 27 points 3 months ago

May be a better fit in [email protected] or similar

[-] [email protected] 23 points 3 months ago* (last edited 3 months ago)

I looked up the page and it gets worse.

You will need to shop for a car inverter. Find one that is at least 1,500 watts, and it will help you power your refrigerator for up to five hours—usually without damaging your car battery. Considering how much food we keep in our refrigerators, a $200 car inverter is a bargain!

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[-] [email protected] 20 points 3 months ago

For the uneducated, what's wrong with it?

[-] [email protected] 179 points 3 months ago* (last edited 3 months ago)

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

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[-] [email protected] 84 points 3 months ago* (last edited 3 months ago)

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.

[-] [email protected] 32 points 3 months ago

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)

[-] [email protected] 22 points 3 months ago

That’s wrong. Watt is a measure of power and volt measures….. voltage.

Charge (electricity) is measured in Coloumbs (sp?)

You need a complete circuit for Watts as P=iv.

I is current, measured in amperes

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[-] [email protected] 19 points 3 months ago* (last edited 3 months ago)

If a wire were a water stream:

  • Volt is water pressure (fast or slow stream)

  • Ampere how much water there is in the stream

  • Watt is pressure x amount

  • Ohm (resistance) is how much obstructions are in the stream

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[-] [email protected] 19 points 3 months ago

Licenced insurance agent. Not for long!

[-] [email protected] 19 points 3 months ago

My chickens say Shannon is full of shit.

[-] [email protected] 18 points 3 months ago

My buddy's EV does this but without math or worrying sbout ac/dc except to pump it on the stereo that is also plugged in.

[-] [email protected] 17 points 3 months ago
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this post was submitted on 18 Mar 2024
800 points (96.1% liked)

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