I know we've had this discussion before...but...

[Kyz]

Let's say I'm looking at a small apartment size refrigerator, and the energy guide says that it will use 297 kWh YEARLY 

and I then converted it to 33.9 Watts... (although why I don't know and if that's yearly also...?--or even useful information)

Can someone explain how this would convert into something I can understand? lol

I also already own a bougeRV 12v refrigerator that says it's operating power is less than 45W and that is uses less than 1kw hour a day on MAX mode.

So...the apartment refrigerator that claims to use 297 kWh yearly also uses less than 1kWh per day as well?

So both refrigerators would be equally efficient (or not?)

[rvpopeye]

In round numbers and at the rate here ~30 cents per kwh. $7.50 a day?
That's 25 kwh / month or 1kwh / day average .
The watts it draws isn't constant so go with what's in the specs.
A kwh is 1000 watts for 1 hour , or 500 watts for 2 hours. 250w for 4 hrs....

( .There's a cool little device called a KILL A WATT You can get them at a hdw store ,,They USED to be ~$25-30 . Just plug it into an outlet then plug anything into it and it tells you how many watts it draws , how many kwh it uses over time , your current voltage etc. ).

Does the 12v fridge operate on 120v also? watts is watts . so yes.

[Kyz]

So 1 kWh a day would be 1000 watts it would use in a day.... So in terms of a 100 AH battery, it would take ..... 10? (not buying 10 batteries, just trying to understand the math here)
I have a Jackery 1000 so it would take all of that for 1 day...24 hours?

Yes, it runs off 120v and 12v.

[rvpopeye]

The jackery specs says it has 1264 watt hours , that's also 100Ah amp hours
The fridge is 45w would last 29 hours BUT the fridge doesn't(usually) run constantly.

There's a thing sometimes called duty cycle that's the average % of time it could should might run.

LOL so it would last longer depending on variables like temperature of the air and if you add insulation .
How long would it run the fridge? It still depends. On how much sun the panels get....

OR
Just try it out for a while and see what happens . arrrrrrrrrrrrrgh It's more like guidelines !

[Kyz]

Nothing to try it out/on/with yet. I'm just plotting for the future...lol

[Kyz]

Thanks for the info!

[Cavinaar]

Here's a breakdown for how much it would use per day.

297 kWh per year / 365 days per year comes up to 0.81 kWh or 810 watt hours per day.

Since fridges are not generally 'running' 24 hours a day I will go with 50% and 80% runtime (how much time it runs per day depends on the temp outside, how well the fridge is insulated, how well it keeps the cold etc).

At 50% runtime you are looking at around 406 watt hours usage per day, at 80% it will be around 650 watt hours per day, both plus inverter bleed if it's a 120v fridge (even in a Jackery/Bluetti/whatever solar pack as they have an inverter, it's just internal)

You should also keep in mind how temperature physics works (heat rises, cold falls etc.).  Typical 12 volt cooler-style fridges have a top mounted 'door' where sticks and bricks style fridges have a front mounted door.  This means opening an apartment style fridge will 'leak' more cold than a 12 volt cooler-style fridge when opened, causing the compressor to run more often, using more power as the compressor is where your real power use is when talking about a fridge.

  Hope this helps. 

[Kyz]

Thanks Cavinaar. That was really helpful.