Battery size to use off peak power?

[JohnW2]

Our latest one, is an upright auto-defrost. From what I have gathered, the cooling elements and the defrost section, are all concentrated at the back - so it seems unlikely it would much influence the main contents of the freezer.

As I said, I've never had one but, yes, my understanding (right or wrong!) is that all the cooling mechanism is 'at the back' and that cold air is blown into the cavity, the idea being that most ice formation is not inside the cavity. I'm nor sure I fully understand that, given that I would have expected any moisture within the cavity to turn to ice there, given the temperature within that cavity, just as it does in one without auto-defrosting. There are clearly aspects that I don't fully understand!

However, whatever the details, auto-defrosting obviously implies that the cooling periodically stops for a period of time (of whatever duration), so I would imagine that the (air) temp within the cavity would reflect that.

Having had all three types of freezer chest, upright, and now auto-defrost upright, the only difference I notice is the convenience of access, plus the lack of masses of ice forming in the base of a chest type freezer.

Interesting. I've only had (and still have) only the first two of those. Another difference between upright and chest is that, particularly if it does not have draws or 'doors' (but to a fair extent even if it does), opening the door of an upright freezer resukts in it rapidly filling up with room temperature air. Access and 'the ice at the bottom' are certainly issues with chest freezers, but they do generally have much larger capacity than any common (or 'accommodatable') upright one!

I would guess the defrost cycle is very brief, and so hardly makes any difference to how long it can last without power. Insulation thickness on over old chest freezer was somewhat thicker, but insulation has supposedly improved in the 50 years since we had a chest freezer.

Maybe. As I said, I have no experience of these 'defrost cycles', although, as above, they presumably must have at least some impact on the temp within the cavity.

 

[Harry Bloomfield]

As I said, I've never had one but, yes, my understanding (right or wrong!) is that all the cooling mechanism is 'at the back' and that cold air is blown into the cavity, the idea being that most ice formation is not inside the cavity. I'm nor sure I fully understand that, given that I would have expected any moisture within the cavity to turn to ice there, given the temperature within that cavity, just as it does in one without auto-defrosting. There are clearly aspects that I don't fully understand!

I've never seen any ice formation within the storage area of our auto-defrost. It was though, a constant problem with our earlier manual upright. Perhaps because the moisture is drawn to the much colder elements at the rear?

However, whatever the details, auto-defrosting obviously implies that the cooling periodically stops for a period of time (of whatever duration), so I would imagine that the (air) temp within the cavity would reflect that.

As said, I have an add-on temperature gauge/alarm. The sensor for which is located in the air of the freezer, for quicker response. I check the reading almost every time I go into the utility room, and have never seen it warmer than -14C, the freezer is set to maintain -18C. Which suggests the heating elements have little effect on the main storage compartment.

Access and 'the ice at the bottom' are certainly issues with chest freezers, but they do generally have much larger capacity than any common (or 'accommodatable') upright one!

The chest freezer we used to have, was far too big for our needs. It had four large deep, slide out of the way baskets at the top, then more space below. The space below, and what ever was stored there, often turned into a solid block of ice. Every couple of years, I would attempt to de-ice it, but it was a loosing battle. It would take so long, the contents of the baskets were at risk of defrosting. The final straw for it, was the lid counter-balance springs failing, and as it was consuming lots of power, struggling to stay cold, we got rid, and replaced it with a slightly more sensible upright. The upright, had constant problems with the drawers freezing onto the cooling elements, but at least it was somewhat quicker de-ice, using pans of hot water, and so remained in use until it's demise last year.

Our kitchen fridge freezer has survived all three so far. It's an auto defrost fridge, manual defrost small freezer. It just needs the fridge drain cleared occasionally, but the freezer can be defrosted in a matter of minutes, with a hot pan.

 

[JohnW2]

I've never seen any ice formation within the storage area of our auto-defrost. It was though, a constant problem with our earlier manual upright. Perhaps because the moisture is drawn to the much colder elements at the rear?

I guess you must be right. There presumably will be as much moisture 'around'; as with any other freezer, and if it remained in the cavity, it would inevitably freeze there - so the moist air must be being removed from the cavity. However, if moist (and cold) air is constantly being removed from the cavity, that presumably must have at least some detrimental effect on 'efficiency'?

As said, I have an add-on temperature gauge/alarm. The sensor for which is located in the air of the freezer, for quicker response. I check the reading almost every time I go into the utility room, and have never seen it warmer than -14C, the freezer is set to maintain -18C. Which suggests the heating elements have little effect on the main storage compartment.

Fair enough.

The chest freezer we used to have, was far too big for our needs. It had four large deep, slide out of the way baskets at the top, then more space below. The space below, and what ever was stored there, often turned into a solid block of ice. Every couple of years, I would attempt to de-ice it, but it was a loosing battle. It would take so long, the contents of the baskets were at risk of defrosting.

The same here (other than that we apparently 'need' the large amount of capacity ). The de-icing process can be considerably hastened by the use of hair dryers etc, but still takes at least a couple of hours, often significantly longer - but, as I said, other than for the lollies etc. (which have to be moved to a different freezer), nothing has ever come to any harm as a consequences of a few hours lying around in the cellar.

One advantage of chest freezers, presumably improving 'efficiency', is that, like open-top freezers in shops, there is not much 'warming up' whilst one fiddles about accessing contents, whereas with an upright the cavity obviously gets filled with warm air whenever one opens the door and pulls out drawers or whatever.

 

[Harry Bloomfield]

One advantage of chest freezers, presumably improving 'efficiency', is that, like open-top freezers in shops, there is not much 'warming up' whilst one fiddles about accessing contents, whereas with an upright the cavity obviously gets filled with warm air whenever one opens the door and pulls out drawers or whatever.

Yep, hence the suggestion to keep the space filled, even if filled with empty boxes.

 

[JohnW2]

Yep, hence the suggestion to keep the space filled, even if filled with empty boxes.

Indeed - but, as I said, it would be even better if the boxes were filled with something which had appreciable mass - even sand,but perhaps sugar or salt would be more decent in a fridge