“The devil is in the details…” While it might sound and frequently does sound – superficially – simple, trying to make decisions about exactly what to do/use in terms of where you get your electricity from, what type of electricity (AC or DC) is ‘natively available’ and/or – thus – will you need to one way or another be able to and/or have to convert between the two, how much storage OF electricity would you need to have or want to have available, how much of a BUFFER would you like to have to feel comfortable/enable you to optimistically ‘ride out’ periods where you may not be able to generate the electricity you need from – in this case – ‘solar’, your possible/potential future plans for expansion in terms of the amount of electricity that you need to/will want to be able to generate/store and also what additional loads might you wish to put on your system in the future, etc., etc.
SO – it’s hard to give you a perfect answer because there are so many – ‘it depends…’.
HOWEVER, based upon:
- your statement that you are living in a small ‘off grid house’,
- AND you have apparently (I am assuming) already spent money on solar panels and/or batteries and/or inverters,
- AND (it sounds like) for one reason or another, your/any inverter you might install is going to wind up ‘being on’ virtually all if not all of the time anyway FOR ONE REASON OR ANOTHER,
- AND – as you mentioned – your place is already wired up for AC anyway,
My basic thought/idea/suggestion here is that – again – it sounds like for one reason or another - if nothing else – convenience – any inverter (I’m assuming a large central one more or less) will generally be on all the time ANYWAY and so I think that any ‘parasitic losses’ that might conceptually not need to occur if you went DC will turn out to be something you will just have to tolerate and plan for – capacity wise.
Plus – you are ‘stationary’ – living in a small permanent dwelling off grid so you don’t need to worry about things bouncing and jouncing around in my gut suggests that the money you would save by going with an AC fridge would be better spent as necessary in upgrading your system in terms of more generating capacity, storage capacity, and/or conversion (from DC to AC) capacity.
If everything is already wired up for AC, you’re probably not going to even need to consider DC powered LED lighting/bulbs and can simply use normal E 26/E 27 LED bulbs (though you could use DC LEDs with small little transformers if you want to but probably the AC is more convenient).
Anyway, hope this helps you reach a decision.
HT
PS – just that I’d mention – propane refrigerators actually do ‘take’/’consume’ THAT LITTLE PROPANE TO OPERATE AND KEEP THINGS COLD. I ‘looked it up’ - did some research once a long time ago and, , while I can’t remember exactly results now, I do recall that a decent sized Propane Refrigerator can run for months… And MONTHS… on a single (say) 20 pound tank of propane. I wouldn’t be surprised if the cost – the dollar cost – of running a propane fridge would be something potentially as low as ‘a couple of bucks’ a week. Whenever I go camping in my fifth wheel, notwithstanding the fact that I have generally access to 120 V AC power, I actually do tend to leave my trailers refrigerator running directly off of propane. Why? Simply so that I can expand the ‘capacity’ in terms of the amount of electricity I have available for other purposes such as running microwaves, air conditioning, toasters and coffeemakers and induction cooktops and so on. ‘Every little bit helps’.
Oh, and one final thing that just occurred to me - it isn’t really necessary to be or to try to be too much of a ‘purist’. When designing a solar system (sounds Godlike!), No matter how much thought you put into it particularly in terms of how much generating and storage capacity (as opposed to/not so much as inverter capacity), there is always going to be the possibility that – for one reason or another – say – insufficient sunlight and/or – and we so often forget – the possibility of equipment failure, I suspect that there is a tendency to automatically exclude the possibility and desirability of owning a Small Gaseoline Generator.
‘It’ doesn’t necessarily have to be a very big one either – in fact – you could probably get away with a 1 kW unit and would almost certainly not need anything bigger than 2 kW.
The advantage here would be at least twofold if one were prepared to consider such a possibility:
Basically, if you think about it, for each and every day(s) worth of electrical power that you want to either store in your batteries AND/OR be able to generate with solar panels, the cost goes up AND there is always the possibility that if you allow for – say – three days worth of electricity storage and batteries, sooner or later you will wind up going at least four days without adequate sun, and if you allow for four days, sooner or later you will find out that you really needed five days worth of storage, and so on and so on.
While you may not use said small gas generator very often at all – it might be only five or 10 or maybe 15 times a year or whatever – a 2 kW (max load; let’s assume 1600 W AC sustained) can theoretically generate approximately 13.3 A at 120 Volts which would ROUGHLY equate to 133 A at 12 V AND (trying to keep it very simple here), let’s knock that down by multiplying by 0.75 to allow for various inefficiencies and conversion losses would suggest that one could use the AC power generated by the generator to produce about 100 A at 12 V which could be used to charge up a lithium iron phosphate (I assume) Battery Bank. So let’s assume just for the sake of argument – you had 200 amp hours of lithium iron phosphate battery available to you, you would of course need a charger capable of outputting 100A but assuming you could see your way clear to ‘acquiring one’, that generator would be able to recharge your battery bank from ‘virtually flat’ to full charge in about TWO HOURS AT A 0.5C CHARGE RATE (assuming your BMS and configuration would be compatible with that AGGREGATE charge rate!).
That’s pretty darn fast! And in the process, you would probably consume no more than somewhere between – I would estimate – around 3/8 of a gallon of gasoline ± 1/8 of a gallon.
And this would happen very infrequently (‘probably’?) PLUS you would have available a means to power your house in an emergency if you should have equipment failure anywhere else and/or – for example – even run an air conditioner (or two or three even) if one assumes small ‘room’ air conditioners if you wanted to – really want to/and/or were prepared to tolerate the noise. (I own a couple of small to kilowatt Champion Inverter Generators and they are actually very quiet - VERY QUIET - when they are running at low speed in eco-mode, you can actually stand right beside them and carry on a conversation with someone without having to raise your voice. And if I simply put one on the ground behind my trailer and go inside my trailer, YOU CAN HARDLY HEAR IT RUNNING AT ALL UNLESS YOU MAKE A CONSCIOUS EFFORT TO DO SO. And you can pick one of these things up for probably $500 or so.
Again, Hope these thoughts help.
