upright freezer recommendations for conversion

nyarelathodep · July 2014

Am wieghing my refridgerator options for my future offgrid set-up (1720 watts of panel and a bank of either 4 or (most probably) 8 T-105s (24v) with an OBvfx3524. Assuming I wanted to convert an upright freezer, does anyone knowledgable have recommendations on which ones make for better offgrid appliances, which brands, what features are best avoided, etc?

TucsonAZ · July 2014

Re: upright freezer recommendations for conversion

You can get some energy star specs to help you decide, I have seen some with 4" thick walls, clearly much more efficient. I used a GE 5.0 cubic foot, it was $180 at Home Depot, I used a $15 controller from Amazon, all and all I would say it was a fairly easy thing to down, I can get it down to about 10w per hour of usage depending on where I set the temps.

If you have any questions let me know, lot's of skeptics on here and while true in a technical sense some of what us off-grid types choose to do isn't always ideal, it's a damn good compromise big picture.

jonr · July 2014

Re: upright freezer recommendations for conversion

Energy rating/efficiency is #1.

Turning it off for much of the night will save some battery wear and ideally this would be done with dual thermostats and a timer - when the sun is shining, make it as cold as can be tolerated and when not, let it rise to as warm as can be tolerated. A freezer used as a refrigerator will have plenty of reserve capacity to catch-up while the sun is shining. How much thermal mass (probably water jugs) you can load it up with will effect how long it can coast.

Some people with smaller inverters need to be concerned with startup current.

mike95490 · July 2014

Re: upright freezer recommendations for conversion

upright freezers generally, have no water collection system. The ice just forms on the (non-adjustable) wire grid shelves and stays there till you defrost and bail it out.
So condensate will be dripping shelf to shelf.

The chest freezers deal with the water just running down the sides, and you bail it out from the bottom.

TucsonAZ · July 2014

Re: upright freezer recommendations for conversion

This is what mine looks like, it took me about 2 hours and cost roughly $16 total.

Attachment not found.

nyarelathodep · July 2014

Re: upright freezer recommendations for conversion

My thanks for the replies, gentlemen. My original thought was to simply get two chest freezers, a 10-12cu one for fridge modification, and a smaller unit left as a freezer (with a mechanical switch to disable in the pm hours, and install them within the base cabinet section with custom countertops which allow for the operating of the lids (nothing above them) as I will be building the cabinets in my house anyways, allowing removable panels in the face to allow them egress for cleaning and such. Is there any reason why this might not be a good idea? I had thought of possible heat build up, but was thinking the entire unit could be vented through the back if need be.

In terms of the actual units, I'm guessing I would want manual defrost models. I really don't know much about refrigeration and freezer mechanics, but it seems the simpler the design the better in this case? And is it worthwhile to invest in a new model as opposed to something I could snag of CL that's a decade old for a song and a dance? Not sure how far the technology has come in that amount of time, but I'm leery of newer homeowner grade appliances (especially walmart, depot, lowes etc) in terms of reliability/longevity. Am I over estimating my system to be able to handle simultaneous start loads of two chest freezer compressors and a submersible pump if need be? Those are the only power intensive loads for my house, the rest being misc electronics and led lights.

BB. · July 2014

Re: upright freezer recommendations for conversion

With a 3.5 kWatt AC inverter (and big enough battery bank--i.e., around 700 AH @ 24 volts, with short/heavy DC wiring), you should be able to start any reasonable loads or combinations thereof (Well pumps are always a bit of a wild card--Some have terrible starting surges).

With most modern chest freezers, the condenser "coil" is wrapped around the outside of the cabinet. Any sort of cabinetry/etc. that blocks airflow is going to be a problem... You may need to think about enough air gap and a fan that runs when the compressor does to properly get rid of waste heat.

Most (some, many, all?) upright refrigerators have exposed condensers--Fan cooled ones on bottom and/or up rear of refrigerator. Those would be easier to vent--If needed.

I had a manual defrost freezer for many years. It worked fine and did not use too much power (I am on Grid).

However--Two problems. First was operator--The thing would ice up pretty heavily. It was in a back yard shed, and once a year I would put it in the yard and hose it down with hot water from the water heater. Worked fine--but got pretty tired of it. My spouse would pack stuff in very tightly--And everything would freeze together.

The second problem was that stuff on the door of the freezer would not freeze as cold as in the shelving of the freezer.

Replaced it with a cheap frost free refrigerator. Everything works "better". However, it did have a mechanical defrost timer failure. Seems to be sort of common in some "cheaper" brands/models. Fixed under warranty and no problems since (very easy to R&R the timer, once you find it). You do have to manually defrost the evaporator in the back--I used a hair dryer, the tech used a "kitchen steam cleaner". Either worked fine. So far, I am still happy I made the switch to frost free.

-Bill

waynefromnscanada · July 2014

Re: upright freezer recommendations for conversion

mike95490 wrote: »

upright freezers generally, have no water collection system. The ice just forms on the (non-adjustable) wire grid shelves and stays there till you defrost and bail it out.
So condensate will be dripping shelf to shelf.

The chest freezers deal with the water just running down the sides, and you bail it out from the bottom.

With my upright freezer-become-fridge, when it needs defrosting of the racks ( I run it cold) I place heavy towels under the racks, leaving the food in there, then shut it off with the door closed for 6 or 8 hours or more as needed, until all the ice is melted, then remove the soaked towels. There is often a bit of water collecting in the bottom, but a small hole drilled through the bottom drains it into a pan under and evaporates from there. There's another small hole through the top to receive the wire to the temp sensor. Wonder what the warranty guy would say if he were called for warranty work and found holes drilled. Hahaha But not to worry, it's past warranty now.
Sears upright 8 or 10 (I forget) cu ft.

nyarelathodep · July 2014

Re: upright freezer recommendations for conversion

Thanks Bill, I thought that might be the case with heat buildup. If I go with chest models, I guess I could just make countertops on them and leave the rest uncovered.

Thanks as well for chiming in, Wayne. I know your the resident freezer/fridge conversion guru, and have much enjoyed pouring through your various posts on the subject, though the technicals extend far beyond my grasp at times. I was wondering, however, if you might have some advice on which kind of uprights would work better, and in terms of conservation and longevity, whether you would prefer a manual defrost or a frost free model for conversion. Do you find the energy consumption of the upright overall similar to the chest model?

Cariboocoot, I remember you mentioning on my previous thread that you manage a regular energystar refrigerator on a system less than what I will be using by careful management of consumption and such...could you elaborate a little? Wondering what model fridge you are using.

I think where Im at now is a crossroads of wondering if, considering the loads (minus refrigeration) of the house to be somewhat on the light side, if I will be drawing too little power going with freezer conversions and end up not discharging the bank to acceptably deep enough levels. That is considering the scenario of eight T 105s. If that's the case, might it be more sensible to have a regular ES freezer/fridge running so that the bank discharges deep enough? The other option of course would be to run just four batteries, but I don't want to underpower myself either. Is this a legitimate concern?

vtmaps · July 2014

Re: upright freezer recommendations for conversion

I have an upright freezer that I use as a fridge ... actually I use it as a "root cellar" for a month or two between harvest season and winter when the real root cellar is cold enough.

My freezer has fixed shelves with the evaporator tubes in the shelves. Condensation is a major irritating issue. A chest freezer, where the evaporating coils are in the side walls of the freezer would be a better choice... at least the condensation would drip down the sides, rather than condense on the shelves where it soaks the food.

Occasionally I use it as a freezer, just to quick freeze meat before it goes into my chest freezer. In that case, having the evaporating coils in the shelves will freeze the meat quicker than a chest freezer could freeze it.

--vtMaps

vtmaps · July 2014

Re: upright freezer recommendations for conversion

nyarelathodep wrote: »

I think where Im at now is a crossroads of wondering if, considering the loads (minus refrigeration) of the house to be somewhat on the light side, if I will be drawing too little power going with freezer conversions and end up not discharging the bank to acceptably deep enough levels.

It is wise of you to have that concern... some folks design a system with too many days of autonomy and end up with very shallow cycles.

The solution is to skip charging for a day or two. Some charge controllers (such as Midnite Classic, and some european brands) can do that.

--vtMaps

nyarelathodep · July 2014

Re: upright freezer recommendations for conversion

VTmaps, is there a specific name for that function of the CC? Is that something that auto detects the bank voltage to iniate charging when it hits a certain DoD? My setup is projected to use a pair of midnight Kids (on account of two different voltage panel strings), and they seem pretty advanced, wondering if they have that function.

vtmaps · July 2014

Re: upright freezer recommendations for conversion

nyarelathodep wrote: »

VTmaps, is there a specific name for that function of the CC? Is that something that auto detects the bank voltage to iniate charging when it hits a certain DoD? My setup is projected to use a pair of midnight Kids (on account of two different voltage panel strings), and they seem pretty advanced, wondering if they have that function.

Not sure. I don't have a midnite controller

They came on the market a year or two after I purchased my Outback. Try taking your question over to the Midnite forum.

--vtMaps

Vic · July 2014

Re: upright freezer recommendations for conversion

On the MN Classic, the function is referred to as Bulk Skip days. At this point, appears that the SOC of the battery is not considered in modifying Skip days, and believe that there is currently no test made of weather or not the day that the Bulk/Absorb charge finished.

Have not been using any of the Classic Beta FW, and much has been done in making the Current-Sensing interface (the WhizBang jr) to the Classic and SOC determination. It is possible that some improvements have been made in the Skip Days function.

Do have a Beta KID here, but have not yet integrated the WBjr into the KID system. There is lots happening with the Classic and KID FW, and both CCs just keep getting better and better, with more functionality of things that users want and need.

FWIW, Good Luck, Vic

upright freezer recommendations for conversion

Comments

Categories