I'm a noob - Help me think out the numbers on this chest freezer

[Pleasant Travels]

What/how many batteries will it take to run a regular household 115v/2.0amp chest freezer? And will 900 watts of panels be enough?

So here's the background that will paint the picture of why I'm asking what I'm asking;...

I just finally received my disability. I have funds on hand to build out a cargo trailer into my mobile tiny home. I COULD just live on the $949 income a month, but if I can still generate some quiet income, so much the better. To quietly and off the books generate income to support myself while fighting for 3.5 years to get the disability decision, I have been operating a hot dog cart biz. Despite my disabilities, this is one of the few things I can still do. I ended up asking myself,..."what if I could still do the hot dog thing as a nomad?" Without giving away my secret plan on how to achieve that,...it would require my utilizing a Uhaul-like box truck outfitted as the food truck, which would also be the tow rig which would pull my residence. 

But I will REQUIRE/NEED a chest freezer of the similar size and utility I currently have in my sticks & bricks garage. And I must emphasize that this is a CRITICAL aspect of the plan I am considering in my head. If it is not possible to CONTINUOUSLY run such a unit independent of shore power, then my idea is likely unattainable. 

I am not opposed to modifying what I may need to do, such as have the vehicle alternator hooked up to assist charging if/when solar is insufficient, and/or use a generator when necessary. But my IDEAL (if it is attainable) is to have the chest freezer be completely supportable entirely by a solar system when sun is the norm. I would like to be able to load up for a week-long special event somewhere and know everything in the freezer will be fine. 

Because this will be a box truck, there should be plenty of roof space for plenty of panels. But too many bulky and expensive batteries seems likely to be what may make this unworkable.

I have tried to find a book somewhere that will allow me to figure this out. What confuses me is the option of using a regular $300 115v freezer with an inverter, or spending on a $1500 12v unit that will not need an inverter,...and which total system costs less?

 

[JD GUMBEE]

We have 1,000 watts on our roof and were able to feed this kind of draw.
(New freezer...that would cycle at night on a timer.)
That said, there are others who can help you better on the solar end of things.

If you have meat you spent money on in that freezer, make sure you budget a generator.
Honda EU2000 or the Yamaha equivalent. I strongly suggest NOT screwing around with the cheapies for this situation.
Buy one of the good ones and it lasts a very long time.
(Mine is 20 years old or close to it at this point and still perfect.)

BTW, you can work part time and make 1,000 a month profit from it without it messing with your SSDI. Like, legally.
SSI is different in some ways...

 

[Pleasant Travels]

I forgot to mention that the specs of the 12v chest freezer I'm also potentially interested in is a SunDanzer DCF390

800 Watt-hrs/day at 32°C
67 Amp-hrs/day at 12V, 32°C


Yes, I know about the earning limits on SSDI. Not bad,...but I might be able to do better.

 

[highdesertranger]

well if you do the math you have answered your own question. 2amps at 120v is 20 amps at 12v not counting the 10-30% you are going to loose through the inverter. that adds up to 480Ah per 24 hours. however we are missing facts here, do those numbers you provided include the duty cycle?

also 1500 bucks is real expensive for a 12v unit. have you shopped around? I have never even heard of a SunDanzer. do you realize that you can run most if not all 12v refrigerators as freezers. my Engel 12v does not use near so much power as you are quoting.

also you must include batteries into the equation, the sun doesn't shine at night and you have less available power during extended periods of cloudy days.

highdesertranger

 

[JD GUMBEE]

Yes, I know about the earning limits on SSDI. Not bad,...but I might be able to do better.

Cash business=opportunity
A nomad will survive?
LOL  

 

[Pleasant Travels]

Yes, Ranger, please continue with this. Talk down to me like the infantile moron that I am. (I'm not joking,...use small words, please.)

The duty cycle is continuous.

Yes, I'm aware the sun does not always shine, even at noon, so that means I should likely have enough batteries to run for 48 hours without replenishment. Correct?

If 500 ah would run the freezer for 24 hrs., then 1000 ah should do it for 48, yes?

But drawing batteries down below 50% is bad,...so do I need 2000ah?

And then the inverter loss of 30%,...do I now need 2500ah?

And which batteries to accomplish this would you reccomend?

 

[JD GUMBEE]

Tesla batteries would be a good thing to look into here...

 

[Weight]

household freezer. You need an inverter that can handle the startup surge. You need enough battery bank to power the inverter. You still need the battery to power the 12 volt fridge. You need the means to recharge the battery bank.
2000 watt sine wave inverter, a pretty good one, Samlex on sale $630. Cables to connect battery to inverter, 10 feet 2/0 cable with ends $80. Fuses, $20. 4 golf cart batteries, $400, cables to interconnect $60. ; or even better if using inverter, 6 golf cart batteries $600. .
I recommend the 12 volt fridge/freezer.
If you have a Kill-a-watt meter you can find the real energy used by the freezer. $20.

 

[mariasman]

What/how many batteries will it take to run a regular household 115v/2.0amp chest freezer? And will 900 watts of panels be enough?

Because this will be a box truck, there should be plenty of roof space for plenty of panels. But too many bulky and expensive batteries seems likely to be what may make this unworkable.

I have tried to find a book somewhere that will allow me to figure this out. What confuses me is the option of using a regular $300 115v freezer with an inverter, or spending on a $1500 12v unit that will not need an inverter,...and which total system costs less?

Battery capacity may not so important in this case - especially with 900 watts of solar capacity (yes it is enough). The main reason is because a freezer can be run as an opportunity load. In fact, I recommend placing the freezer on a timer such that it runs only during the day when the panels are likely producing - and keeping the freezer on the lowest temperature setting. The idea here is the freezer is "charging" whenever it runs - so the battery can be smaller than otherwise. Keep your freezer full to enhance the effect.

All else equal there is an advantage to using a readily available conventional chest freezer as they can be replaced much more easily and cheaply. Furthermore, the required inverter can be used to run other appliances thereby adding value. On that note, I am confident you do NOT need an expensive pure sine inverter. A modified sine unit with a high surge capacity is adequate. One suggestion is the Tripp Lite industrial units.

 

[Weight]

Also that is a large freezer to have on the road.

 

[Pleasant Travels]

Also that is a large freezer to have on the road.

Yes,...waaaaay out of the norm for any RV dweller. But this is a business thing I'm contemplating. Most businesses with perishable inventory are based at a fixed location.

My idea is very odd and unique, I grant you.

 

[highdesertranger]

I apologize if you think I was talking down on you. that was not my intention. the way you posed the questions you sounded like a newbie and I was trying to explain it in an easy to understand way.

the duty cycle is not contentious on a refrigerator or freezer. on hot days it's maybe 20%.

wow I just looked that freezer up it's huge.

again I apologize if you think I was talking down on you.

highdesertranger

 

[Pleasant Travels]

Please don't misunderstand me. I am not accusing you of anything at all. I was trying to emphasize how little I know.

 

[JD GUMBEE]

BAD...HDR...BAD!

 

[JD GUMBEE]

On a more serious note...
Have you looked into the reliability on that fridge unit?
By no means do I have any info on these, so make no mistake that my thoughts are somehow gospel...but they do fail.
(Not saying how often, but if you read up on them, folks have waited for replacements.)
In your case, this would kill your business, would it not? (Waiting to have a replacement shipped, I mean.)

Might be a reason to consider going with a 120V unit you could replace @ any Lowes/Home Depot/Sams Club.
The combined costs would be similar, but if it popped its cookies, you could replace it in a few hours, rather than losing your frozen stock and waiting for one to be shipped out.

 

[tx2sturgis]

Here ya go...what you need is a mobile ice-box:

https://smallrefrigeratedtrailersales.com/

They aint cheap!

 

[Pleasant Travels]

On a more serious note...
Have you looked into the reliability on that fridge unit?
By no means do I have any info on these, so make no mistake that my thoughts are somehow gospel...but they do fail.
(Not saying how often, but if you read up on them, folks have waited for replacements.)
In your case, this would kill your business, would it not? (Waiting to have a replacement shipped, I mean.)

Might be a reason to consider going with a 120V unit you could replace @ any Lowes/Home Depot/Sams Club.
The combined costs would  be similar, but if it popped its cookies, you could replace it in a few hours, rather than losing your frozen stock and waiting for one to be shipped out.

Someone else also mentioned this, and I agree it is a concern. But hey, whatever actually gets the job done is what I'm willing to build. I already have a freezer in my garage that suits my needs, and if I can just hook that up and take it along,...great! It's already 37 years old and working fine!

 

[tx2sturgis]

Based on this thread, and out of curiosity, I performed a 7 day test on my 5cf residential chest deep-freezer.

The room it is in is a bit cooler than the rest of the house, I usually open it about two or three times per day.

The freezer's interior temp is set for about 0 degrees. It normally varies by less than 2 degrees according to the digital thermometer. Of course everything in it is frozen when it is put in, and I didnt load it up or empty it for this test.

Using a kill-a-watt meter, I came up with a rounded-off figure of about 700 watt-hours per day. (Multiplied by 365 days, this is about 255.5 kwh per year, and the manufacturer website shows average yearly kwh at about 216 so this is roughly in the ballpark.)

This translates to about 54 ah per day if it was running on 13 volts. Add about 20% inverter loss and you are looking at around 65 ah per day for this unit.

A larger freezer that is opened several times per day, especially in a warmer climate, would presumably use much more power per day.

But still do-able with a mid-sized solar array and suffcient battery reserve for cloudy days.

 

[jimindenver]

Sundanzer DCF390, 14.7 cu ft. 12V/24V freezer, 67 Ah/day @ 12V.

67 Ah a day is not hard to produce via solar.

 

[Pleasant Travels]

Sundanzer DCF390, 14.7 cu ft. 12V/24V freezer, 67 Ah/day @ 12V.

67 Ah a day is not hard to produce via solar.

In fact, that is the model I was looking at. How does that compare to an inverter and a 115v/2.0amp as far as required panels and batteries per each option? That's what I'm wondering.