Auxiliary freezer?

[Frank B]

One of the limiting factors when we boondock is the limited capacity of our 2 cu ft freezer in our Norcold propane fridge/freezer. I need to augment it. Combo propane / 110 v units are VERY expensive.

I have LOTS of solar (over 1kw), but only 6 GC-2's for storage. I also have a 2.5 kw pure sine inverter.

I'm thinking that I might be able to get a cheap 3 to 5 cu ft residential chest freezer which could stay either in or out of our 30' TT. Some of those can be had for under $300 CAD.

If the freezer is filled and chilled before travel, and we keep it full until we empty the propane freezer in the coach, I'm thinking that the power drain will be pretty small. And I suspect it could even be turned off overnight. We live in Alberta, and it seldom gets hot enough here to even use the A/C in the trailer.

It is hard to get actual watt-hour power usage figures for devices like this, so I'm looking for some experience from those that have already done this.

Thanks.

Frank.

 

[OldWEB]

It is hard to get actual watt-hour power usage figures for devices like this, so I'm looking for some experience from those that have already done this.

Thanks.

Frank.

The governments spend a lot of money in research and promotion... you must have missed that announcement.
Energy Star

Above Canadian link has "compact freezers" tested in the USA... But it gives you an idea on size vs. kWh/yr

 

[John From Detroit]

So are 12 volt only units but I had an ENGLE what I call "Danfoss" class (Sling compressor they call it) Drew 3 amps running.. you read that right THREE amps... that's all (A dual incandescent ceiling lamp draws more than that) worked well for over 15 years I now have an LG. only LG appliance I've ever been even remotely happy with Same class.

 

[Tulecreeper]

It's a Canuck brand.

Koolatron Compact Chest Freezer, 3.5 cu ft (99L), White, Manual Defrost Deep Freeze, Storage Basket, Space-Saving Flat Back, Stay-Open Lid, Front-Access Defrost Drain, for Apartment, Condo, Cottage

Manual defrost freezers might save costs by up to 40 percent on energy use and extend the shelf life of perishables. A compact fridge is maintenance is a breeze

www.koolatron.com

https://www.lowes.com/pd/Koolatron-3-5-cu-ft-Manual-Defrost-Chest-Freezer-White-ENERGY-STAR/5014408691

 

[DutchmenSport]

What ever you decide to get, test it out first in your drive way at home so you won't have any disappointments when in the field. In other words, do a true boondock in your drive way. Disconnect from all power, test it out first.

 

[PancakeBill]

I had a nice 12/120v Dometic chest freezer for years, then a smaller Norcold. Both were great. The Dometic I put on a MorRyde slide tray. When I no longer needed it in the motorhome I used it for long distance grocery shopping. Lived in Yellowstone, shopped in Bozeman, right about 100 miles away.

 

[Frank B]

The governments spend a lot of money in research and promotion... you must have missed that announcement.
Energy Star

Above Canadian link has "compact freezers" tested in the USA... But it gives you an idea on size vs. kWh/yr

You are right. I did miss that. I was looking at the specs for individual units, and few of them that I looked at actually specified the watt hours of consumption.

I did find a comparison of low energy freezers, and found that they run (per cubic foot of size) from 16 kWh/year to about 21 kWh/year. The cheaper ones are in the 21 kWh/year range, which is what I am looking at. Now for the math. I'm looking for help here.

If I am doing this right, 21 kWh/year per cubic foot x 3.5 cubic feet = 73.5 kWh per year
With a kilowatt being 1,000 watts, that makes 73,500 watt hours per year
Divide that up by 365 days and we get (about) 200 watt hours/day.

So, the equivalent of running two 100 watt light bulbs all day.

I have 6 GC-2 batteries in series/parallel at a nominal 200 amp hours each. That should give me 200 amp hours at 12 volts, or 2400 watt hours per 'bank' of batteries x 3 banks for a total of 7,200 watt hours. Is tht right?

Even if I use the 50% rule on total discharge, I should still have LOTS of battery to run the freezer. Typically, I have enough solar that my batteries are fully charged by noon the following day even when we work them hard.

Now, somebody please point out the fatal flaw in my logic.

 

[Onyrlef]

Now, somebody please point out the fatal flaw in my logic.

Trust me, someone will even if they have to make one up.

 

[Tulecreeper]

I have 6 GC-2 batteries in series/parallel at a nominal 200 amp hours each. That should give me 200 amp hours at 12 volts, or 2400 watt hours per 'bank' of batteries x 3 banks for a total of 7,200 watt hours. Is tht right?

Even if I use the 50% rule on total discharge, I should still have LOTS of battery to run the freezer. Typically, I have enough solar that my batteries are fully charged by noon the following day even when we work them hard.

Now, somebody please point out the fatal flaw in my logic.

Six 6 volt, 200 Ah batteries. Each two batteries wired in series will give you one 12 volt, 200 Ah battery. If you then wire those three 12 volt, 200 Ah batteries in parallel you will have 600 Ah, not 2400. The only way to get 2400 Ah is to have twelve 6 volt, 200 Ah batteries wired in series/parallel.

 

[Frank B]

Six 6 volt, 200 Ah batteries. Each two batteries wired in series will give you one 12 volt, 200 Ah battery. If you then wire those three 12 volt, 200 Ah batteries in parallel you will have 600 Ah, not 2400. The only way to get 2400 Ah is to have twelve 6 volt, 200 Ah batteries wired in series/parallel.

Watt hours, not amp hours.

 

[HueyPilotVN]

I had a square chest freezer in my Stacker trailer.

Never had a problem with it staying cold.

I did have several solar panels and ran the freezer thru an invertor.

I have a plug in watt meter and was going to give you a measurement of that freezer in which is now in my garage but I cannot find the watt meter.

I will keep looking.

 

[Frank B]

I had a square chest freezer in my Stacker trailer.

Never had a problem with it staying cold.

I did have several solar panels and ran the freezer thru an invertor.

I have a plug in watt meter and was going to give you a measurement of that freezer in which is now in my garage but I cannot find the watt meter.

I will keep looking.

No need, dear friend. It is the average day to day power that I need to calculate with, not the amount of power it takes while it is running. The motor cycles anyway, so it just depends on how many times a day it cycles.

I was more interested in having someone check my arithmetic. The 21 kilowatt hours per year per cubic foot is a published figure that I can work from. I just need to know if my calculations from there are correct.

 

[Frank B]

I did have several solar panels and ran the freezer thru an invertor.

Bill, what size inverter did you use when running that freezer off solar?

I have an electronic soft start on my AC to keep it from popping the breaker on the Honda 2000. A residential freezer is going to have an induction motor as well, and there will be a startup surge when it kicks in. I'm guessing that the surge will be MUCH smaller than on the AC. I'm hoping that this surge will not trip the breaker on my Sunforce 2500 watt pure sine inverter.

In any case, I went ahead and bought a 3.5 cu ft Insignia chest freezer from Best Buy on sale. It will be delivered later this week. I guess I'll know for sure then.

 

[HueyPilotVN]

I think it was about 1,000 watts or maybe smaller.

I used two invertors in my Stacker, mostly for the freezer and for power tools in my shop in there.

Here is a picture of the two Invertors, one was a Magnum. You can also see the watt meter that I cannot find, but it is somewhere as I saw it lately.

The Stacker had about 700 watts of Solar Panels.