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Author Topic: Freezers on battery/Inverter  (Read 2258 times)
Greenbeast
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« on: September 09, 2015, 10:30:27 AM »

We got our planning permission and are hoping to move on to the land in the next couple of months. I think there will possibly be a gap between moving and mains power being connected. a month or two.
I have someone i can approach about a generator borrow/hire. But it is big and i don't know if it has any kind of electric start feature ( i would have thought so but we just turned it on manuallyfor our party in july).

Anyway, with the meat business in full swing we are running 2 fridges and 5 freezers now. What can i do about running these over night, or between generator run periods.
I can size a battery bank for the electrical usage but do i have to be careful what inverters i look at when it comes to compressor start up?
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billi
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« Reply #1 on: September 09, 2015, 11:33:24 AM »

puhhhh ,  if those compressors are not starting exactly  at the same time ... then  sure a 2000-3000 watt unit will be fine , as far as i know     , for one  fridge peps advice to get a 800- 1000 watt true sine wave  inverter ...  anyway , perhaps u  should consider to invest in a unit that  can run things as well during a power-cut ....


billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Greenbeast
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« Reply #2 on: September 09, 2015, 11:43:49 AM »

puhhhh ,  if those compressors are not starting exactly  at the same time ... then  sure a 2000-3000 watt unit will be fine , as far as i know     , for one  fridge peps advice to get a 800- 1000 watt true sine wave  inverter ...  anyway , perhaps u  should consider to invest in a unit that  can run things as well during a power-cut ....


billi

Thankyou and good idea Smiley
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jonesy
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« Reply #3 on: September 09, 2015, 11:47:37 AM »

A decent freezer will stay frozen for 24 hours no bother.  You'd probably need to check the fridges over night unplugged, but given you're a business, you can't afford to have environmental health questioning a high morning temperature.
A small inverter will probably be unhappy starting 5 motors in one go.  You may need to plug them in one by one, but if it's just filling in the gaps between genny start/stop you'll probably be ok.
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knighty
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« Reply #4 on: September 09, 2015, 11:51:58 AM »

for 2 fridges and 5 freezers, you really need to be running a generator

the batteries plus inverter that you'd need to run them would cost way more than you'll spend on diesel for the generator


if you turn them all down to their coldest setting, you could get away with turning the generator off overnight

so run the generator till midnight then turn it off till 8am


EDIT:  quick and dirty maths..

if each fridge/freezer pulls 200watts
that's 1400 watts (1.4kw) for all 7

1400watts is 120 amps at 12v

so a big truck battery will last 30min before you need to re-charge it

ok... the compressors don't run all the time... but if you're putting fresh meat in to cool it, or to freezer it, then they run close enough to constantly
« Last Edit: September 09, 2015, 11:56:25 AM by knighty » Logged
Greenbeast
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« Reply #5 on: September 09, 2015, 12:03:09 PM »

hmm ok thanks guys :/
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billi
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« Reply #6 on: September 09, 2015, 12:43:55 PM »

...one can get a decent  and widely used and proven to be kind of reliable  -Stackable 4000W 48V pure sine wave solar inverter off grid 60A MPPT charger and 60 a mains charger - for about 550gbp  from taiwan  -  , good quality forklift battery cells made in europe   are costing under 5 p  per kwh   and pv   is a no brainer anyhow .........  i just would  show one finger  , when it comes to utility grid connection and dirty units for cooling nice food ....

if you use a  big amount of electricity   anyway , i certainly would consider the  greenest and  on the long run the cheaper route ....

billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Justme
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« Reply #7 on: September 09, 2015, 04:47:05 PM »

I take it that the meat is for sale?

Then I would butter up a mate to let you store the freezers at theirs till your power is sorted.

We used to have our own on farm butchers shop. You can run the freezer hard for 7 to 8 hours & turn off for the rest. We used to do this to use the E7 cheap rate elec. Ours used to get to -30c & rise to -24c. As a supplier you need freezers colder than -18c for long term storage.

We now just run a domestic fridge / freezer via an inverter. As said the big issue is more than one starting at the same time. You could stop then via a relay system or simple time clocks set to diff times. Either way you will want them on fast freeze the whole time.
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Greenbeast
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« Reply #8 on: September 09, 2015, 04:56:25 PM »

I take it that the meat is for sale?

Then I would butter up a mate to let you store the freezers at theirs till your power is sorted.

We used to have our own on farm butchers shop. You can run the freezer hard for 7 to 8 hours & turn off for the rest. We used to do this to use the E7 cheap rate elec. Ours used to get to -30c & rise to -24c. As a supplier you need freezers colder than -18c for long term storage.

We now just run a domestic fridge / freezer via an inverter. As said the big issue is more than one starting at the same time. You could stop then via a relay system or simple time clocks set to diff times. Either way you will want them on fast freeze the whole time.

Indeed it is. I'm starting to consider other options. Our current property will likely sit empty for a brief period. May be able to get the practice owner to let us leave the fridges and freezers here...
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stannn
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« Reply #9 on: September 09, 2015, 05:20:53 PM »

Especially if you slip him/her a few joints. Grin
Stan
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nominous
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« Reply #10 on: September 16, 2015, 03:50:22 PM »

Instead of 5 freezers would it not make more sense to get one big one ?
Commerical sized walk in freezer wall panels are on ebay often quite cheap...

NB: I've been looking at SIP's
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knighty
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« Reply #11 on: September 16, 2015, 07:09:54 PM »

chest freezers are miles cheaper to run than a walk in freezer

it's hard to gauge how much it costs to run a walk in freezer, there's too many variables, outside temperature, how often you open the door, if you put fresh/warm stuff in to freezer etc. but.... I have a customer with a 3m x 3m walk in freezer, who only uses it to store frozen stuff, it costs them ~200/month in electric to run it
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