9mo ago

This was the first result on Google

240 comments

- He looks shocked.
  
  Mehby
- Safety is no 1 priority!

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.
  
  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.
  
  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!
  
  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.
- worst ai prompt

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.
- 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.
  
  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.
  
  Funny thing, most modern refrigerators use DC motors for their compressors so that they can run at variable speeds
  No they don't...they use AC motors and a VFD to control the speed.
  
  I mean it's probably labeled, right? How hard could it be?
- Shannon Martin says just shake the battery and you’ll get AC.
  
  Just swap the leads back and forth very fast
- Just run the rectifier in reverse, duh
- There are DC-AC converters you can use (might be called inverters in English idk), which are pretty interesting circuits. They are used all the time, e.g. to use solar energy
- That part just takes an inverter.
  I'm not sure of the max load output on a car battery, but with a 15 amp 1800 watt dc to ac inverter, you probably can run a fridge off one. It probably just won't last all that long.

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.
- 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.
- I don't know.... you didn't mention your uncle once...
  
  That's because he is his uncle. You're seeing the source material, be amazed
- Wow, those are some serious Licensed Insurance Agent skills
- Fridge uses 143W idle
  The only thing running in idle is the timer and power led, which consume insignificant amounts of power. By my calculations, the average modern fridge does bursts of ~300W during compression and defrosting cycles, with ~40-50W consumption on average over long periods.
- You have a very inefficient fridge! My fridge is rated for 272 kWh per annum, which is 745 Wh per day or 24 Wh per hour. You need to buy a new fridge.
- You did not answer their question. They asked for Watts, not Watt hours. Average car batteries have a CCA in the range of 500 to 1000 Amps at 12V, so you could reasonably have 12kW in there :D

This reads just like an AI response
- 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.
  
  If nothing else, the tub would certainly be hot at that temperature.
  
  75°C is definitely ok for a hot tube for a short session.

Regardless of source, if your refrigerator is running you better go catch it.
Its stealing your food.
- I was hoping for this old chestnut somewhere here
  
  You keep chestnuts in your fridge?

Hey, ChatGPT, my uncle says new Macbooks are just glorified Raspberry Pis.
How many MB/s are in a Raspberry Pi?
- It will take some mathversion to convert from the CPUs/s a Mac uses and the MotherBoards/s in a raspberry pi. I'm working on getting some insurance for ChaGPT to find out.
- About tree fiddy
- Raspberry PIs don't run on MB/s, they use GHz.
  
  You just need to use a conversion. 1 MB/s = 9.66 GHz

Uh, watt?
- Volt
  
  Jiggawatt
  
  Thank you for clarifying.

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.
- Now I don't know enough about electronics to know how wrong this is
  Very, assuming the refrigerator in question typically runs on a typical power grid you'd find in the US or Europe (source: am electrical engineer)
  Mainly because most compressors I'm aware of use alternating current (AC) motors, or at a minimum accept AC power. Batteries alone produce direct current (DC). The simplest way to make this work would involve an inverter (converts DC to AC). Cheap ones probably have at least a 10% conversion loss, so you're looking at an hour or two at most.
  Edit: should also mention that discharging a typical lead-acid battery until it's all the way flat (realistically below ~11V) does irreparable damage. Might be cheaper to replace the contents of your fridge :)
- From a technical stance, it's right. This top comment does the math pretty well, and I've done it myself recently trying to decide if I should add a battery backup on my fridge. If you can overcome the startup surge (and a car battery definitely can), a modern fridge doesn't draw very much power.
  Of course, there's a lot of details missing about how you do this without dying of electrocution. So I think it's also a fair criticism of the LLM.

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

Jesus… the stupid, it hurts.
- Before anyone says it's so stupid it might work, makita beat you to the chase. It has a real heat pump (reversible refrigerator). I really want one though.
  makita 18v heater cooler

Licensed Insurance Agent
seems legit
- anyone can work in insurance
- Its my favorite on Quora too.
  Thanks Steve, the "Professional Hustler Entrepreneur" for getting the highest rated answers on the pros and cons of various medical drugs.

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.
- I'd have expected ChatGPT to be able to call out power factor as well. Otherwise you're getting volt-amps, not true wattage
  
  Power factor isn't a thing in DC and GPT appears to have assumed a DC powered fridge.
  
  And losses in the inverter.
- Please tell this to my dead car battery. It was killed by the tiny dome light last night, because I forgot to turn it off.
  
  If your dome light isn't an LED, then you should replace it with one. It won't completely fix your problem but it will give you 9 to 10 times longer to catch it.
  There's really no reason that every car doesn't have a voltage cut off to protect the battery such that it can still start. Additionally, if they just included a super capacitor then even with a heavily discharged battery, it could charge up the super capacitor to then start the car.
  But if we went around doing smart stuff like that then we could potentially wreck the entire lead acid battery industry and that would just be awful...
- 3.5 or GPT-4? I can run the latter if need be.
- if the car was running, the alternator would be charging the battery. would it be able to keep up with the drain of the fridge of just extend the time a bit?
  
  Probably depends on the car + alternator, but it's not so rare for modern gas cars to have AC outlets for backseat passengers, and the ones I've seen are typically rated 120-150W or so. Glancing at the power meter I have on my fridge, it uses ~110W while running and only runs ~10% of the time.
  Theoretically the car probably can keep up while running, BUT
  Compressor startup current may blow whatever fuse is protecting that circuit.
  AND
  Cars are very inefficient generators. You'd be wasting a bunch of fuel so I wouldn't generally recommend it unless it's an emergency.
  That said, in an emergency it may be worth doing for like 20 min on / 1 hr off, so that you're running the engine only when needed, but I'm not an expert, that's just pure speculation.

That answer is like the electronics version of the image with Patrick Stewart and the caption:
“Use the force, Harry
-Gandalf”

Licensed Insurance Agent
- Yup about the answer I expect.

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

May be a better fit in !mildlyinfuriating@lemmy.world or similar

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!
- I mean that's the least wrong part imo. I've ran a fridge off of a car battery and if it starts cold you can go a lot longer than that.
- Or spend twice that and get a cheap generator that will actually power your frig and other stuff for more than a few hours.
  
  Nah, it's definitely easier during a tornado to go outside, jack up my car, remove the wheel, remove the wheel liner, and then pull the battery from inside the bumper because that's a really convenient place to keep a car battery. Then I just have to lug the battery inside, hook it up, and keep 2 small children and 3 dogs away from it. Much easier than a generator.
- Another source says they hold around 700 Wh. So not even 30 minutes actually
  
  If your fridge uses 1.4KW you need a new fridge.
  
  Nah if the fridge starts cold and you aren't constantly opening the door you can easily get 5 hours on a car battery.
  
  At least they don't run constantly?

For the uneducated, what's wrong with it?
- 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!
- 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.
- 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’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
  
  Unless you have an electric car that can do vehicle to load. That means that you can plug in regular household devices like your fridge.
  
  Unless you have an EV with V2L.
- 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
  
  What a straightforward and clear way to put it, thank you kindly!
  
  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)
- 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.
- It's being answered authoritatively by an insurance agent.
- 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.
  
  These also have inefficiencies which would reduce the runtime on the battery.
  Not wrong, but the efficiency of inverters is really high, loss is just about negligible.
  
  Was about to say inverter until I saw your comment. I think the robot meant to call out AC vs DC.

My chickens say Shannon is full of shit.

Licenced insurance agent. Not for long!

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.

It hurts.

This reads like a shitpost. The math is eh, okay, but the explanations are totally wrong. I won't even try to figure out what "runs off watts" means.
Enough of any electricity source, using various converters can get any appliance working "technically speaking", but in the end the amount of energy available at the source and the rate of consumption at the end and any intermediates. So "technically" an AA battery can power an industrial electric press, but only for a fraction of a microsecond, using a lot of charge storing infrastructure and with a lot of changes to get the tiny bit of DC into the machine requires to operate, likely 3 phase AC power.
A proper explanation would say a lead-acid car battery provides power at around 12V and electric camping fridges nominally operate around 12V so you can connect them directly and operate it (so you can sorta say they both run off DC volts?). If not you would need a buck or boost converter. The available energy of the battery (Watt-hours is a useful unit here) and the consumption rate (in Watts) of the fridge determine how long you can use it on the battery.
- Watt-hours
  how hard is it to just use joules 😭 the consequences of non-metric time are grave
  i'm just kidding btw, i know why watt-hours are used
  
  Saying "your fridge will run for 14400 seconds" isn't very intuitive for people unfortunately...
- Well on the bright side, these things will start learning from reddit. More garbage for us to chuckle at.

Accept the battery is DC 🔋and fridge runs on AC🔌
- At least with the 12v to 120v it just won't work instead of exploding
  
  And it turns out to be an ac motor in the compressor causing the fridge and the battery to short out If it stalls on a coil. The ac motor burns up with the battery. The electronic, water dispenser, and the ice maker would probably be happy assuming it's a full bridge rectifier otherwise polarity would matter but most likely wouldn't break it.
  I'm not an engineer just a guess.
- So just slap a power inverter in there somewhere and you're good to go
  
  To answer the original question, a fridge requires quite a lot of power to operate. Could be 500W. There's also power loss from the voltage conversion, so you need a battery and an inverter that are able to provide more than that - let's say 600W. Car batteries are typically 12V lead-acid batteries. 600W means 50 amps from the battery. That's a huge current. Lead-acid batteries can handle high currents for a short period of time, but high currents have a negative effect on the battery capacity. So my guess is that the fridge could work for a very short period of time.
  
  Probably lost about 10% or more to heat.

Sounds like a jippitty conversation.
- Sounds like an AI trained on random people in the internet answering questions while not actually knowing anything about the subject
  
  .

classic example of being wrong with authority.

I thought America runs on Dunkin... (doughnuts)
No easy conversation from doughnuts to volts or amps. I give up. But with enough oxygen you can hear up pretty gud with a single doughnut. Then you could use a Stirling engine to pump heat from the fridge to the environment. Energy in a doughnut _{224cal according to Wolfram alpha. That's 940kJ. 940kJ/1hr}260watts which should run a fridge for 1 hr. However energy conversion is probably going to leave you with like 10% at most of usable energy so ~6 minutes run time. America needs a lot of doughnuts!
- Umm that's donuts if they're from Dunkin' 😜

My jeep has 3-prong electrical outlets. Not sure how much it will power and i assume you would want to have the car running.
- From the owners manual: "There is a 115 Volt, 150 Watt inverter outlet located on the back of the center console to convert DC current to AC current. This outlet can power cellular phones, electronics and other low power devices requiring power up to 150 Watts."
  I don't know if I'd plug in a fridge to that. I was wondering because my father in law's truck has a similar outlet and I know he's blown a fuse using it to power power tools.
  
  After the freeze in Texas a couple years ago, when many people lost electricity, Ford started advertising the outlets on their trucks.
  Edit to add the link - https://www.ford.com/trucks/f150/f150-lightning/features/intelligent-backup-power/
  
  I wanted to say "look at the label but it should be fine" but then I did a quick google double-check and depending on whether you get US or EU results you get quite different answers: US 350 to 780W, EU 100 to 300W. Refrigerators have quite lower numbers but we wanted a fridge so let's look at small refrigerators with proper fridge compartment (four stars, -18C), like... a Beko TSE1284N b100, 240 bucks not fancy not shoddy (Beko in a nutshell, honestly). Damn, why are they only listing kWh/24h and kWh/a. Whelp. No pictures of rating plates anywhere. Oh. According to Amazon "50W", according to another trader 90W connected load, which makes sense if we understand those 50W as consumption load (or whatever those things are called in English).
  So, yeah, look at the label and you should be fine. Don't get that fridge though it's 220V.
  
  I measured my fridge. You could, in theory. Problem is that the motor in the fridge (and in power tools) is an "induction load", meaning it draws a lot more power in a split second when starting. Inverters have to be built with that in mind, or just stronger (killowats range).
- Just make sure you open the garage first

Remember the time Jeremy Clarkson fitted his car with a fridge in Africa and no one wanted to give him a jump? Yeah that.

And this is why I have an automatic emergency backup generator. No math required. Power goes out, gentset comes on. Power come back on, genset turns off.
- Seems like you missed the point - that answer is complete nonsense

240 comments