DC battery backup for small AC freezer


  #1  
Old 05-15-21, 10:09 AM
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DC battery backup for small AC freezer

I purchased a small 9 cubic feet Energy Saver AC freezer used in house and want to use a Portable Power backup like Jackery in case electricity loss.

FREEZER SPECS
Voltage 115
Amperage 1.2
Startup Amps 12
Startup Watts 115V x 12A = 1380W
​​​​​​I assume "startup amps" is when compressor comes on.

I measured with plugin device. Used 0.59 kWh over 24 hours. 0.59 kWh / 24 hours x 1000 = 25Wh. (Energy Guide says 216 kWh annually = 25 Wh) so my measurements spot on.

​​​I want to purchase Jackery Explorer 1000. It is Lithium ion battery so don't need to worry about draining below 50%.

Jackery Explorer 1000 Specs
1000 Wh
2000 watts surge
46.4 Ah

This battery will supply about 7 hrs backup power which is likely fine. After hurricane Katrina I lost power for 6 hours which is most in 25 years. With 2000 watts surge, it can more than handle 1380 peak watts.

Jackery 1000 is on sale for May 17-19 for $849. This is an easy portable all-in-one solution. I can recharge using AC, DC or solar.

Are my calculations correct? Is there a cheaper way to backup freezer (battery + inverter + charging ability)?





 
  #2  
Old 05-15-21, 01:24 PM
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7 hours is not that long for a freezer as long as you keep the door shut. You could buy a larger unit and keep ice packs in it as a buffer.
 
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Old 05-15-21, 02:12 PM
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Is there a cheaper way? Yes. But if you are new to lithium ion, BMS, inverters and small solar, there really isn't an easier way than Jackery, Bluetti, Goal Zero, etc. The pricing on these is pretty fair if you can find exactly what you want.

In fact, I keep a small all-in-one "solar generator" w/portable panel around so my family can operate it without me for charging phones, laptops, small TV, running lights, etc. It has USB, 120V and my kids can use it for an emergency or just going to the beach for the day.

But for the bigger stuff, I prefer to "roll my own" 48V off-grid system that my family would need to learn how to maintain it if something went wrong. That's taken a lot more research and general understanding of AC and DC power because I've had to size the wire, install fuses, measure amps and volts, understand the difference between series and parallel, etc.

If you are into learning that, it's a fun hobby that you can teach yourself. However, if you just want to power a chest freezer, then the all-in one is the way to go. Make sure you get one that can handle the start-up loads and generates a pure sine wave.
 
  #4  
Old 05-15-21, 02:15 PM
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6 hours is slim margin if in a direct hurricane impact zone. I've sustained a couple of 2 week losses, in the 2004 season.

But, I do agree that your selection will be hard to beat in that 6 hour scenario.
btw, I just bought a 1 cf freezer. Quite small. 12V and 120V ac inputs. But, just that one is $1k.
And then I bought 3x 100 Ah lithium deep cycle batteries; those are just over $1k each. And, we have around 500Watts of solar. This is all on a sailboat. So, your financial numbers on your solution are looking pretty good.

I think in your case, to bust out to multiple days, get a 2kW Honda portable genset.
 
CircuitBreaker voted this post useful.
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Old 05-16-21, 08:10 AM
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Solat not option; not interested in noisy generator

Solar is not an option. My house is just less than 1000 sq feet so limited roof space. Roof faces east-west. South the houses next me are on higher ground casting shadow on a lot of my backyard. Usually after storm, it is either raining or very cloudy so not enough sun hours to do anything.

I am not into camping/boondocking. And not intertested in noisy generator just to save a couple hundred dollars frozen food.

Power is usually off no more than couple hour even after hurricane hits coast. Far enough from gulf that just a tropical storm when it gets here. Tornados are frequent during season but only occasionally bring power down (tree falls on overhead lines). Electric company very good at getting residential areas back up in couple hours.

So I don't plan to ride out days without power. Just those rare occasions where power off 5-6 hours and just keep freezer backed up. Hence my choice in small portable powerstation. I have already run freezer on small 300Ah power station. Freezer has never spiked power above capabilites on 300 Ah battery. I get about 3.5 hours on 300 Ah powerstation but I use that one for CPAP backup at night.

If I set feezer on lowest cooling (1-7 settings), compressor does not come on much at all so could get more hours from a 1000 Wh powerstation with freezer on lowest setting.
 
  #6  
Old 05-16-21, 12:00 PM
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300Wh has been running Freezer 4 hrs with 98% remaining

Really surprised. I hooked up my feezer to Flashfish model 330 with 300Wh. Been powering freezer at setting 3 (1-7 settings) for 4 hours. Flashfish shows 98% power remaining. Displays 1 for watts so obviously pulling less than 1 watt. Even when compressor turns on, no spike. Maybe I don't need big Jackery 1000. Jackery 300 would do the job. I will see how long freezer runs on 300Wh.
 
  #7  
Old 05-16-21, 12:57 PM
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while lead is heavy its still the cheapest battery you can buy, you can find a group 29 or 31 deep cycle at walmart or your local auto parts store walk out with a couple for probably 250 bucks or less, a 24 volt inverter, a battery maintainer charger. for an occasional power outage to just run a freezer, even if you had to replace the batteries in a 2-3 years still probably would not have 850 bucks in it.
but the jackery may be what your looking for if you do not want to mess with it just seems like a lot to spend if thats all your using it for.






 
 

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