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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.
classic example of being wrong with authority.
Accept the battery is DC 🔋and fridge runs on AC🔌
So just slap a power inverter in there somewhere and you’re good to go
Probably lost about 10% or more to heat.
Inverters have gotten pretty efficient. I have one for my house that’s 97.1% efficient.
10% worse efficiency > no refrigerator
Maybe refrigerator until the battery catches on fire!
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.
^THIS^
Plus to add that modern kitchen stuff like that will throw on the compressor to cool the unit down with up to a surge of 1200w. Usually for 2-3 minutes as it engages the cooling pumps and moves the refrigerant.
I’ve run fridge freezer units off battery a few times (deep cycle lead acid, lithium/LFP)
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.
For the uneducated, what’s wrong with it?
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)
Unless you have an EV with V2L.
Sure you can use the 12v battery and convert that power but you can’t just connect a 12v battery 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.)
As i stated I have V2L on my car. I also have normal outlets inside the car.
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
With the river analogy, Voltage = pressure, Wattage = how much water is passing, Current (Amps) is how wide the river is.
Pressure * Width of river = Amount of water passing
Not sure that helps with passing it through the terms and then to variables.
Water analogy works better with plumbing. A river, not so much. But people aren’t that much better at understanding plumbing, unfortunately…
Volts measure voltage?
Electrical potential, IIRC
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
Ugh, you’re getting into the realm in which technicality is hard to explain.
That’s technically wrong. Even though ampere is coulomb/sec, electrons don’t actually flow.
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
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
Tautologists study tautology tautologically.
The first rule of tautology club is the first rule of tautology club.
The first rule of tautology club is the first rule of tautology club.
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.
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’d need an inverter in-between, yes.
But for the record, inverters have been in gas cars with plain old 12V batteries for years. But you’ll need the engine running.
Yes. That not the “use a12v battery” assignment. It would be use an inverter…
The only way the “uncle” is correct and the only way a 12VDC battery is getting connected to a regular, 120VAC refrigerator, yes. And what most inverters run off of.
Not with that attitude!
So. The answer is yes you can. If the car is an EV with V2L. Which I am guessing is what that uncle was talking about in the post.
V2L doesn’t relies on traditional 12v battery…
Okay. But it’s a car. Full of batteries.
Correct, but entirely besides the point.
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!
If a wire were a water stream:
-
Volt is water pressure (fast or slow stream)
-
Ampere how much water there is in the stream
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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)
Resistance in wire creates a voltage drop, just like hair in a water pipe creates a drop in available pressure.
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)?
https://www.youtube.com/watch?v=X_crwFuPht4
AlphaPhoenix also has other fantastic videos explaining and experimenting with all sorts of interesting things.
Since liquid water can’t be compressed
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…
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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 watts til empty, and car batteries are generally not used past 50% capacity (lead acid starting battery). So figure 500 watts max (for easy math). So… 4h run time maybe.
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
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.
Good catch… It was early and I was on my phone (my excuses) :)
It’s just the 2.9kw should be kWh. Everything else is close enough.
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.
May be a better fit in !mildlyinfuriating@lemmy.world or similar
Safety is no 1 priority!
He looks shocked.
Mehby
Uh, watt?
Volt
Jiggawatt
Whaddid u call me
OHMybad
uwattm8
Jigga deez nuts!
Licensed Insurance Agent
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
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.
A 3 is what my helmet gives me for grinding mode, that’s nothing.
I used a 10 or 11 for one eclipse and it worked alright.
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.
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.
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.
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).
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/
My father in law drives a 2015 F150. That outlet on the center console is 120 Volt outlet supplies 400watts. But a fridge can be anything from 300 to almost 800. I’m not saying it’s impossible. And with newer trucks (especially the lightning and the F150 hybrid), I would believe it more readily. Ford is quick to market this in new trucks but I wouldn’t count on it with older trucks. I’m just pointing out that real work experience says your mileage may vary. Especially in places like Texas or Arizona where your battery is going through extreme heat cycles due to the weather from like February to November.
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.
Just make sure you open the garage first
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.
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.
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.
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.
Given the lack of an inverter in GPT’s transcript there’s no AC to invert.
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.
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.
Shannon Martin says just shake the battery and you’ll get DC.
Just swap the leads back and forth very fast
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
Just run the rectifier in reverse, duh
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?
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)
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.
Raspberry PIs don’t run on MB/s, they use GHz.
You just need to use a conversion. 1 MB/s = 9.66 GHz
About tree fiddy
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.
Remember the time Jeremy Clarkson fitted his car with a fridge in Africa and no one wanted to give him a jump? Yeah that.
