How many watts generator do I need to power a fridge and a freezer?

[mingwait]

Hi, I want to purchase a generator to power a fridge and a freezer during power outage. The fridge is about 400L and the freezer is 200 L.

https://www.kogan.com/au/buy/kogan-172l-upright-freezer-white/

https://www.samsung.com/au/refrigerators/top-mount-freezer/400l-easy-clean-steel-rt35k5035sl-sa/

I found a label on the fridge that says rated current is 2 A, rated frequency is 50Hz, and rated voltage is 230-240V. 

And the frezzer specs says 61 W 50Hz 0.5 A 220-240V.

Thanks!

[Brad]

Having had a quick look around 2000W gets you past the start up power needs before dropping back to normal running.

Inverter will let you run more sensitive equipment like TV and computers.

You can get an inlet installed so it is plug and play and makes power available through your normal power points, it isn't cheap to set up and it's not a DIY thing.

Solar/battery back up is another option with a automatic switch for blackouts, I expect it has a higher starting cost than petrol but gives you a lower electricity bill.

[Jason]

Hi @mingwait, 

Welcome to the Bunnings Workshop community.

I assume you are part of the large community in Melbourne's east still without power. My commiserations. I hope you and your family are staying safe and well. It was a ferocious storm and I'm sorry to see that power won't be restored to many areas for many days. 

Great to see Brad has helpfully shared his thoughts. Our resident Bunnings D.I.Y. expert @MitchellMc is taking a well-earned break today but let me tag other helpful members who might be able to assist you: @bruce93, @Seaton, @HandyAndy, @ikaney, @MikeTNZ. 

Jason

[HandyAndy]

Hi @mingwait,

Brad is on the right track.

most inverters have a surge rating to allow for inrush currents, generally double the rating of the inverter.

startup current on a fridge is generally 3-5 times the running current. (Kogan is probably closer to 5 times, the samsung probably closer to 3 times)
without being able to find the data on websites, or being able to test, i will assume a worst case scenario.

in your case
Fridge 2A or 460W running
Freezer 0.5A or 115W running

Total 2.5A x 230V = 575W
this would include full function watt draw, where as the listed power (watts) would be the average power consumption or median value.

Fridge Startup 2 x 5 (worst case scenario) 10A

Freezer Startup .5 x 5 (worst case scenario) 2.5A
Total 12.5A x 230V = 2875W

as brad stipulated, a 2000W inverter would cover your start up needs as most would have a surge of 4000W, and the 2000W will easily handle your running requirements.
i do recommend going above and beyond what you require (for longevity etc.)

another thing to note, regarding running other equipment (TV's, Sensitive Equipment etc.) the sine-wave of the inverter is super important, if the device has electronics, it is important to use a pure-sine-wave inverter, as modified or square wave can cause problems with the electronics.
the fridge should be ok on a modified sine wave as it would convert the power internally, however, if possible, always go pure sine wave.

another thing that would be a good option would be solar/battery with auto switch like brad said, or you could run the fridge/freezer of a UPS (uninteruptible power supply), depending on the time required during blackouts, some inverters have a UPS function

hope this helps, if you need any more info, please dont hesitate to ask

cheers, Andy

[mingwait]

@HandyAndy 

Hi Andy,

Thanks that's very helpful. I assume this one will do the job: https://www.bunnings.com.au/full-boar-2200w-inverter-petrol-generator_p0082345

I am okay living without TV's and the extras during the few days of power outage, just want to keep the food from spoiling, so only need to power these two things.

How do I find out if this Full Boar one has UPS function and pure sine wave?

Thank you,

Ming

Kind regards,

Ming

[Brad]

The Full Boar does have pure sine wave, no UPS function but it does have an automatic throttle to adjust to the load it is being put under.

I think the phone towers would be down as well but experience would tell me Mrs Wang does not do well when she has no phone, Voda customer so she is used to no connection but it has to have power...

[HandyAndy]

my mistake @mingwait i was speaking regarding inverters only, generators won't have UPS functionality, but they may have a auto start during a power outage.
the one you listed is pure sine, 2000W running power, and 2200W starting power, if you don't start the fridge and freezer at the same time, it should be fine, in the unlikely event the compressors come on simultaneously, you may overload the generator (it should just cut off), also noting that i used the worst case scenario in calculating the start up power, so you may well be within the tolerance of the genset.

[mingwait]

Thanks Brad 😀

[MitchellMc]

Hi @mingwait,

It's great to see you've received some fantastic assistance from our knowledgeable members.

Please let us know if you have any more questions. We're here to help.

Mitchell

[mingwait]

Thanks Andy!