I would like to buy an UPS, that I can use to power dishwasher, electric cooker, few PCs during the expensive energy period (6 hours 5-11), and charge during cheap energy period (cheapest between 3-5).
Preferably compatible with Home Assistant’s NUT. But I clicked on multiple in that list and did not find any option to buy them. (I am in EU, Czech Republic.)
I will probably add few solar panels to the house as well, to help cover the most expensive times (5-8 and 18-20).
I have multiple rooms in the basement, that do not have a purpose, so I can go for batteries that prioritize other characteristic than Size.
I did not yet compute the required capacity, I am just looking what options do exist.
I think a UPS with enough output & battery storage for this would be very expensive. You may be better off with an inverter/charger a couple of big batteries.
But you really need to know what capacity you need before figuring out what will work.
For example, I had a 10KW sonnen battery on my house, but it couldn’t output more than 2000w peak. So even running a kettle I was still drawing from the grid. The induction cooker was pulling up to 3700w.
isn’t that the description of UPS? Or am I missing something?
I guess this explains why I can not find it in normal shops, and offers seems to top at 1kVA.
Practically 3 devices that suggest they need 16A (240V) circuit breaker, I do not think all 3 will be used at same time, so that is already 7kW, then a PC and server, so I would round it up to 10kW, just to be sure. And maybe choose less depending on what/if I get solar panels.
So do I need to look for complete DYI solution, or is there something I can look up?
I would say a DIY would be cheapest. A UPS is more meant to keep stuff running if the power flicks off then back on, or give you enough time to shut things down safely in longer outages.
Personally I use Victron. I have a 48volt 5000w invertor/charger, 300AH of battery storage & 10,000 watts of solar panels. Haven’t had a power bill in 3 years. Run security system/cameras, 2 computers 24 hours a day, fridge, big freezer, starlink, lighting, electric cooking, water pumps & washing machine no problems. Also enough power during the day to run a compressor & cnc plasma table or welder.
I want it for that too, but if it would do only that, it would be sitting idle most of the time, and to get a reasonable time it would need good capacity anyway, so I think instead of trying to figure out minimum, go bigger and make daily use of it.
Are you connected to the grid? Here my base calculation told me, that about 10% of electricity cost will be just for being connected, and the price here is quite complicated with part for the electricity, and part for the delivery of it… And I will not be able to get that many solar panels here, if any…
No, not on the grid at all. I was in a previous house & found that the daily supply charge just to be connected to the grid was more than my usage. I have a 13 kva generator for backup, but only used it for 6 hours total in the winter after a week with very little sun.
You could quite easily set daily charging on one of those portable power units using a smart power plug. I use arlec grid connect to turn on pumps & things. You can program in times for it to be on/off daily, or manually switch it in the app. Could also do the same thing with an inverter/charger as long as it has an AC input.
Yeah, there are no UPS devices or kits out there doing what you want, the most similar would be a LARGE “off grid” solar install you do yourself.
A very robust DC to AC inverter with very good circuitry to give clean sine power, an AC to DC charge controller that you probably want to control via some kind of automation and have DC input for future solar, then having a LOT of expensive batteries (ideally a half rack or more of LiFePO batteries). You would absolutely have to size the inverter and especially batteries for an extremely large load so it doesn’t destroy itself by simply running 24/7, you shouldn’t be draining the batteries much each day so you really need a TON of capacity.
You are probably looking at 2-4 large dressers worth equipment, likely $20,000-100,000 USD depending on local availability. You are asking for a 24/7 “off grid” setup that you can selectively charge, AND have be reliable for about a decade, there is a reason it’s not readily available. Oh, and even with good ones batteries will probably need to be replaced completely at 5-10 years ($$$)
It is similar to a large UPS for a building with important IT infrastructure, the ones I’ve dealt with have rack mount gear taking up 8-10 FULL racks, chock full of deep cycle batteries that only last 3-5 years of occasional use before needing to be replaced (I believe in this particular building with a power blip, the ATS switches over to UPS power, starts up a large stand alone diesel generator, then once it’s stable that provides input power to the UPS and then the entire building including RTUs runs off generator power through the massive 3 phase UPS). They also do a ton of expensive maintenance and testing on the equipment since it is a critical building, though not critical enough for redundant systems at this time (double everything plus more ATS gear)
The cooker is the biggest issue I’d say. If your dishwasher can be set on a timer, that would solve that too.
Look into those off-grid power-stations from Zendure, SolarFlow, Ecoflow, Bluetti, conow, etc.
Some of them have a “main unit” to interfacing with inputs and loads that can be expended using further battery units.
One of the reasons I even think of this was Youtube video (The Hidden Problem With Home Batteries), His math gave him 207$/ per year, and the street have power loss he did notice only by neighborhoods not having lights on. So I got a feeling that it can work seamlessly.
The batteries are 20 kWh and it is enough for his house.
Here putting energy back to the grid is not as profitable, so after I will have multiple options I will try to do the math on all of them, to see, which one looks most interesting.
I might be able to fit even that much in unused rooms in the basement, so space is not really a priority, I rather choose battery with better characteristic for charging/discharging/cycles/…, than size. Maybe I should have mentioned that in the first post.
I did not look at the current one, but during renovation it will be replaced, and it might require 3 phases… Which is something I did not think about at all, how will the phases be distributed. Thank you very much for the hint.
You have to look at reviews of the batteries when they rip them open and show the construction quality and the manufacture of the cells. Ecoworthy tend to be very good for the price.
isn’t that the description of UPS? Or am I missing something?