Sig Energy Solar Installation

[JohnW2]

How does the genny from Lidi know when it needs to unplug the freezers from the grid supply, and supply them from the generator?

The answer to that is obviously that it would 'know' by my 'telling it' - i.e. I would effect the changeover manually.

I presume you are thinking of a situation in which a power outage occurred whilst the house was unoccupied, but I really don't see that as a possibility worth worrying about, let alone spending additional money to address ...

For a start, grid power outages long enough to destroy freezer contents are very rare. I've lived with freezers for about 50 years, and I'm not sure that I can recall any power outage that lasted long enough to be a significant threat to freezer contents. To that one has to add (actually 'multiply' ) the fact that there is nearly always at least one person in my house for at least some part of each 24-hour period - probably for 90% or more of the time. Taken together, those two things mean that an extended loss of power when the house is unoccupied is incredibly unlikely - and, should it nevertheless happen, I would probably just accept it it as 'one of those things' or, more likely, turn to my insurers to compensate me for the loss.

However, grid power outages (or RCD trips) apart, as I always say, had it not been for my (financially very small) investment in 'over-temp alarms' for my freezers, I would undoubtedly have lost a good few freezers full of food during those 50 years, since I have nearly always had at least one 'not frequently opened' freezer in an outhouse or cellar. I've never lost the contents of a freezer due to loss of power (whether due to grid outage or RCD trip etc.), but all of my freezers (other than my current ones) have obviously eventually died, and I have been made aware of those events by the alarms before contents have been lost.

I am sure I could have an automatic start up and change over for less than cost of solar,

You could but, as above, that would not help if the freezer itself died (which they all do, eventually).

 

[ericmark]

I do not seem to remember a problem in 1978-79, during the Winter of Discontent or later in the Falklands where generators ran twice a day.

But back then we did not have auto defrost freezers. And I remember hearing the freezer fail, so spare in garage, so turned it on first to allow it to cool. Around ½ hour, then started to move food, the top of the freezer had already defrosted, clearly I heard it go bang at the end of the defrost cycle.

Only the top foot was affected, but the problem is, if there is a power cut, and the power is restored, how do you know what temperature everything was when power was restored, OK, mine do show the highest temperature reached until the door is opened, but none of my previous freezers did that.

With the known freezer fail, we ate all food within the month, as not sure what temperature it had gone up to, but I have found distorted lollies in my freezer, which points to at some time it got warm.

LONDON — A fire at an electrical substation knocked out power to Heathrow Airport for most of Friday, forcing Europe's busiest hub to shut down for roughly 18 hours.

So if a major place like Heathrow can be without power for 18 hours, we can expect 24 hours elsewhere.

 

[JohnW2]

I do not seem to remember a problem in 1978-79, during the Winter of Discontent or later in the Falklands where generators ran twice a day.

Quite so.

But back then we did not have auto defrost freezers.

And nor do I now, nor ever will so long as I have a choice! On the basis of what you and others have said, such as ...

.... Around ½ hour, then started to move food, the top of the freezer had already defrosted ....

... I avoid such things like the plague. It seems ridiculous to me to have a freezer in which things will start to 'melt' after only 30 mins without power - and I'm happy to suffer the occasional 'inconvenience' of having to manually defrost a machine in order to avoid that!

.... if there is a power cut, and the power is restored, how do you know what temperature everything was when power was restored,

As I've said many times before, I think you worry far too much about such things. Provided the food is going to be 'properly cooked' after being taken out of the freezer, there is minimal risk.

With the known freezer fail, we ate all food within the month

With respect, that's a little silly - once the food is re-frozen, it will not deteriorate any further, so it will be no less 'safe' after 12 or more months than it would be after a couple of weeks. If you were really worried, you should not eat the food ever.

So if a major place like Heathrow can be without power for 18 hours, we can expect 24 hours elsewhere.

A valid question but, as I wrote, I cannot recall that ever happening to me in the past 50 years - and, in any event, I've always had freezers which I was reasonably confident would maintain sub-zero temps for at least 24 hours, usually a fair bit more.

 

[ericmark]

... I avoid such things like the plague. It seems ridiculous to me to have a freezer in which things will start to 'melt' after only 30 mins without power - and I'm happy to suffer the occasional 'inconvenience' of having to manually defrost a machine in order to avoid that!

Oh dear, that was not my intension, I will admit the chest freezer is far better keeping food cool, but a pain to use, the upright freezer can have pockets of warm and cold air, so to get around that, the non auto defrost puts the condensers between the draws, so limited what size frozen stuff can go in the freezer, and easy damaged bits on display, plus chance of warm areas.

The auto defrost puts all the condenser behind a divider, together with the defrost element and fan, so on defrost the fan stops, and the heater turns on, but on freezing the fan moves the cold air around, so there is no warm areas, and you can remove a draw at Christmas to get an extra large turkey in, and not items likely to be damaged with a manual defrost. The reason top defrosted, is the heat from the defrost element goes up to the top.

Also, you tend to get the extras, showing maximum temperature after a power outage, and using inverter drives, so makes less noise, and reduced shaking means likely to last longer. And if powering from a generator, not as worried about volt drop, or the inrush on start. I can see using an energy meter, when the unit runs, and the peak of power around 140 watt when defrost cuts in, so a 200 watt power supply is ample, with non inverter types, looking at more like 1.5 kW minium.

 

[JohnW2]

Oh dear, that was not my intension, ...

It's not just you. Others have also suggested that an auto-defrosting freezer can, at least in some circumstances, start 'warming up' pretty soon after onset of a loss of power - which to me seems crazy for a freezer, and is the reason why I 'avoid such things like the plague'.

Also, you tend to get the extras, showing maximum temperature after a power outage,

A freezer does not have to be an 'auto-defrosting' one to have that - it merely needs to be 'fairly modern' In any even, I have plenty of min/max thermometers that I could put in my freezers if I were concerned about such things!

.... and using inverter drives, so makes less noise, and reduced shaking means likely to last longer.

Maybe.

And if powering from a generator, not as worried about volt drop, or the inrush on start. I can see using an energy meter, when the unit runs, and the peak of power around 140 watt when defrost cuts in, so a 200 watt power supply is ample, with non inverter types, looking at more like 1.5 kW minium.

Again, I wouldn't think that there's anything about being an 'inverter' one which means that it has to be 'auto-defrosting', is there?

 

[morqthana]

With respect, that's a little silly - once the food is re-frozen, it will not deteriorate any further, so it will be no less 'safe' after 12 or more months than it would be after a couple of weeks. If you were really worried, you should not eat the food ever.

It is only quality to be concerned about when re-freezing defrosted food, provided it didn't warm up enough for the bacteria to start multiplying again. Tricky little buggers, they are.

 

[JohnW2]

It is only quality to be concerned about when re-freezing defrosted food, ...

Indeed - that's what I'm always saying, but many people don't seem to believe me!

... provided it didn't warm up enough for the bacteria to start multiplying again. Tricky little buggers, they are.

As I always say, there are remarkably few that are tricky enough buggers to survive 'proper cooking', so if the food items are going to be 'properly cooked' once removed from the freezer, there is only a very minimal 'risk', no matter what the 'storage history' (temperature-wise) of the items.

Even when there is no reason to doubt the past storage conditions, I have to admit that I am a little nervous about eating anything previously frozen which is eaten without any cooking after removal from the freezer and thawing.

 

[morqthana]

As I always say, there are remarkably few that are tricky enough buggers to survive 'proper cooking', so if the food items are going to be 'properly cooked' once removed from the freezer, there is only a very minimal 'risk', no matter what the 'storage history' (temperature-wise) of the items.

I thought the problem was (often? sometimes?) not the tricky little buggers themselves, but the toxins they leave behind? So while cooking may kill the former, it doesn't remove the latter? I'm pretty sure that if you leave raw poultry at room temperature for a couple of days then no amount of cooking is going to safeguard you.

On a tangent, at Christmas I got a predictive thermometer which has a mode that integrates time & temperature, so rather than cooking something to a temperature at which enough of the TLBs die, it takes account of all the ones which died in the time the temperature was rising.

The time saved is significant (a chicken could be 30 minutes less cooking than the traditional calculation of so-much-per-kg-plus-a-bit).

But it's the different result which is the real bonus. Chicken cooked to an internal temp of 58° instead of 74°, because by the time it's got to 58° the TLBs are dead, is remarkably juicier.

Needs a bit of a leap of faith the first time to eat chicken which is still pink, but so far no ill effects.

 

[JohnW2]

I thought the problem was (often? sometimes?) not the tricky little buggers themselves, but the toxins they leave behind? So while cooking may kill the former, it doesn't remove the latter? I'm pretty sure that if you leave raw poultry at room temperature for a couple of days then no amount of cooking is going to safeguard you.

That is partially true. However, I think you'll find that many/most of the pathogenic toxins are (with a couple of notable exceptions), fairly 'heat labile', and therefore will commonly be destroyed by adequate cooking, just as is the case with the pathogens themselves.

I think that the 'exceptions' are relatively rare, and the bacteria obviously have to be present in the foodstuff in the first place before they can proliferate and produce toxins. We've all heard of the outbreaks of food poisoning resulting from Bacillus cereus toxins in re-heated rice, but the most widely publicised 'major outbreak' (at a wedding reception) was over 35 years ago.

 

[morqthana]

I quite often reheat rice.

 

[JohnW2]

I quite often reheat rice.

So do I, albeit a little nervously these days, given the issue of Bacillus cereus toxins to which I referred. It is said to be a 'particular risk' with rice that has originated from a 'takeaway' (which may have been heated a number of times and/or stored under some questionable conditions). However, we've never had a problem,and it does seem very rare, public awareness being largely down to a very small number of large-scale (but well publicised) 'incidents', invariably in relation to large-scale 'catering'.

In fact, on a number of occasions I have heard Chinese or other SE Asian 'TV chefs' saying that 'fried rice' should always be made from previously cooked (boiled or steamed) rice that has been stored in a fridge for at least 12-24 hours.

 

[Why Not Indeed]

public awareness being largely down to a very small number of large-scale (but well publicised) 'incidents'

It seems to be a widely-held belief that rice is particularly risky but bacillus cereus grows on wheat pasta just as well as rice. [5 days at room temperature? Come on! https://pmc.ncbi.nlm.nih.gov/articles/PMC3232990/ ]
And with that, the thread is well and truly off-topic!

 

[JohnW2]

It seems to be a widely-held belief that rice is particularly risky but bacillus cereus grows on wheat pasta just as well as rice. [5 days at room temperature? Come on!

I'm no authority, but I believe it is found in quite a range of foodstuffs. However, most/all of the publicised 'outbreaks' have related to rice, which is presumably the reason why the belief is 'widely-held'.

I have no idea whether that is the result of chance or whether it genuinely reflects a 'higher risk' with rice. I suppose it could be that people are probably much more likely to re-heat leftover rice than pasta etc?

However, none of that stops me re-heating rice, and I seem to have survived so far

And with that, the thread is well and truly off-topic!

Not unusual . Mind you, it is not really totally off-topic in relation to one of the somewhat-off-topic branches of this thread, since it enables me to repeat my view that people probably get far too concerned about the perceived 'risks' associated with a freezer losing power for a day or two.

 

[Doug99]

OK guys, my thread has shifted from Solar Installation...............to the cooking of rice!!

 

[JohnW2]

OK guys, my thread has shifted from Solar Installation...............to the cooking of rice!!

I'm afraid it has

... however, as I've just written, the (slight!) relevance to PV installations+batteries etc., is that if people are tempted to pay thousands for batteries primarily to avoid the (very improbable) problem of a freezer losing power during a (extremely rare) protracted grid power outage whilst their house is unoccupied, I would suggest that they should consider re-thinking the logic of that, not the least because food (even rice) that has thawed and then been refrozen probably represents a minimal risk (if it is 'properly cooked')..

However, as I said early on, although I don't really anticipate any protracted grid power failures, I am prepared for that (so long as I am at home) by having invested £150 in my Lidl generator