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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
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.
I mean it’s probably labeled, right? How hard could it be?
Exactly. Find a hole that’s black and a hole that’s red, and stick some wires in there. How hard could it be?
(can’t answer, because she was fucking electrocuted)
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
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.
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Energy is energy, you are not an electrical engineer.
Congratulations, this is the worst attempt at ridicule I’ve ever seen
Your comment was ambiguous, stupid, and designed to ridicule. If you are attempting to imply inverter and other loss then be more specific. Regardless, the comment you were referring to already provides arbitrary values that you can assume include loss.
So please explain to me what the fridge being 12v DC or mains AC powered has to do with anything, when an example uses arbitrary power and energy values? I’m genuinely curious.
ooh getting aggressive now are we?
I owe nothing to you. Enjoy your time being a sad person trying to bring others down on the internet :) I hope this little outlet makes you feel better
Ad hominem dodging of the question. Classic.
No answer? Ok, you’re just sad that your comment was dumb lmao jeepers
No it doesn’t. Watts do give a shit what percentage is voltage vs amps. You have to convert between AC and DC as appropriate as well as ensuring the voltage of a 12v battery is stepped if needed, but the watts are the same in any case. (Not figuring for system losses)
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You should Google what a step up and step down transformer do. It’s very simple and easy to prove you’re a dipshit once you understand you’re arguing from bad faith trying to compare a simple bit of circuitry design to hydro power.
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https://youtu.be/GtTcuexjeRw?si=e1p0nUHh1uXBp24R
3 seconds of googling like I said
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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
Does… Does he work at PlayStation?
It’s a secret. You’ll have to ask his uncle
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.
Wow, those are some serious Licensed Insurance Agent skills
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.
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.
But only if you have purple eyes
I spilled a half cup of 175F water on my hand and got blisters. You absolutely cannot bathe in it.
I meant to reply to the parent comment
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?
Uh, watt?
Volt
Jiggawatt
Whaddid u call me
OHMybad
Thank you for clarifying.
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An inverter will not let you run your fridge until the battery is “dead”. It’s going to have a low voltage cut off, likely somewhere around 11 Volts, specifically to avoid damaging batteries by fully discharging them.
How many hours you’ll get from the battery mostly depends on your ambient air temperature and how often you open the fridge. They don’t use that much power when they’re idle - my fridge averages at about 90 watts (I’m not running off grid, but I do have rooftop solar and our system produces pretty charts showing consumption). A large car battery can sustain 90 watts for a quite long time - well over 2 hours. Probably closer to 10.
Running a fridge off a car battery long term is a bad idea. But in an emergency? Sure I’d totally do that - especially if your “emergency” is genuine such as needing to keep your medication cold. Just don’t open the fridge unless you’re taking your medication.
LifePo4 FTW!
Sure. Way better than lead acid. But that doesn’t mean lead acid is useless. When I lived off grid, LifePo4 didn’t exist and we got close ten years (of daily use) out of our lead acid batteries. They were bigger than car batteries and also deep cycle ones, but in an emergency a car battery would be a fine choice if it’s the best one you have.
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So if I turn the car battery upside down, a 12v DC battery should run a 120v AC appliance?? Brilliant! I have an idea for how we can use this with two fans to create infinite energy!
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I run a fridge freezer off a Delta Pro and 600w of solar during the summer. If we get a few days spell of bad weather I have to place it back on mains. Its good to have in an emergency, though it cost me 3 months wages (plus overtime)
I’ve also done the off grid thing and you can get way more than 2 hours on a car battery if the fridge is already cold and you aren’t constantly opening the door. Also have ran modem full sized fridges on 1000w inverters. So YMMV.
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.
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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.
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.
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.
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.
This post made me beat my head with a 2 by 4
It hurts.
My chickens say Shannon is full of shit.
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!
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.
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.
Another source says they hold around 700 Wh. So not even 30 minutes actually
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?
