I suck at maths basically.
Looking at backup generators and I'm trying to work out the wattage of our fridge. The compliance plate doesn't say but the energy star sticker says 476Kwh per year.
How do I work out actual watts from that?
cheers
Help Me Work out Fridge Power Useage?
EightImmortals on 20/11/2020 - 12:16
Comments
NVM, found this: https://www.rapidtables.com/calc/electric/kwh-to-watt-calcul…
Works out to 54.3 watts….I think.
i'm not sure how you calculated that (476kwh/1year?), but it will not be accurate
there should be a label inside the fridge, unless it is some ancient clunker
It's over 10 for sure, I did find a label but it didn't have the wattage on it. NP I think It's sorted now.
For the most accurate results see if you can find one of these or a smart plug with power monitoring.
476 Wh/year divide by 365 to get Wh/day = 1.304 Wh/day
1.304Wh/day divide by 24 hours = 54.3 Wh per hour, the hours divided by hours annul each other to leave 54.3W continuous usage on average
But in reality it'll cycle on and off, unless it's an Inverter Fridge.
So assuming the compressor runs 50% of the time at least 104W, I'd allow Triple for a safety margin, so allow 160WFor reference, my Whole house consumption monitor measures my 10 year old, small 300L fridge cycling on and off by around 100W, the cycle runs every ~50 minutes overnight.
Thanks!
Bear in mind that a fridge is either on or off, so the average won't describe the peak which is what you need to consider. Best to put a meter on your power point and log the usage over a few days and match it up plus at least 20%
Off the grid camping sites have tonnes of info about this sort of stuffMy deep freeze hits 900 watts on compressor start.
Depending on where you live, your local library might have a power usage meter which can be borrowed for free. I only needed one for a few days to work out which appliances were using up the most power and which ones could be left on standby (as they hardly used anything): more info at https://energysaver.nsw.gov.au/households/understand-your-us…
Does the compliance plate mention anything about - current, amps, or the letter A. 1 amp is about 240 watts, you should be able to get some idea from the amps if it has it.
For a generator you'll want to load in the calculator what the load is if the fridge is starting from cold vs steady state running. A clamp meter would be the best way to tell.
https://nasdonline.org/1492/d001292/select-the-right-portabl…
I would echo the website I googled and say around at least 300W to run, and maybe higher to start the compressor.
The 54.3W is the average power, if your fridge is constantly on as others have pointed out. It depends on the actual on/off duty cycle. Reckon 20%-25%, so multiply the number by 4/5 times, so about 220/275W to run.
You may need to double/triple the power to start the compressor… So an 800W generator maybe more suitable
Thanks for all the tips. Yeah I might go overkill on the generator DeWalt have a nice one that does 3200W (3600w startup) so I can run 2 fridges and the fish tank in an emergency.
i suck too