Ah. Texas.

Multiply your server wattage by 8 hours. That's how much battery you need. It's probably not going to be a cheap investment.

The alternative would be to keep your ups and invest in a generator you can kick on if there is a power cut, but if it's every day, that might get rough. Technology connections figured out a build it yourself solution a few years ago https://youtu.be/1q4dUt1yK0g?si=8WOTue9-zGghWlxY

Where are you from my friend? Why do you actually need server running if you have no electricity at home? Your internet is also down right? Dont you need to just find how to shutdown safely when outage happens? Or do you have mobile/sattelite internet as a backup?

I use candles btw 🕯️

Germany.

I don't. Can't remember a power outage ever except for shorting our connection box :)

Besides that only some internet outages of our ISP but that is also very rare today.

Edit: At work we sell 750VAh to our customers which are usually very small in demand and workload

I live in a part of the world where powercuts are pretty frequent.

Texas?

I actually built my own 2 kWh battery setup after finding available commercial UPS overpriced.

It took some work and cost me about 2000 euro, but now I run everything (including networking, servers and monitor) directly on a battery feed DC net in my house.

It's pretty cool too have all IT equipment unaffected by a power outage.

I have solar panels and a backup battery for the whole house. I live in a rural area that is currently under heavy construction, as they are trying to make this area into a small city, so power outages are unfortunately extremely common.

Can you migrate, or setup failovers, to a low powered ARM device? Or one the new Intel N series e.g. N100 low power devices?

If not, you're going to need to buy/build a fairly large battery bank.

I have a small UPS to keep my fiber and router working for a while and I have a larger UPS for my server. Even the larger UPS will only keep the server going for maybe half-an-hour, but most outages here are short. For me, the most important benefit is that my UPS will tell my server to shutdown when it begins to get short of power. Graceful shutdowns remove the risk of corruption and data loss.

Data centres, business, hospitals etc. run batteries to bridge the gap until the diesel starts running. It can take a minute or a few until the diesel generator takes over, but it can run for hours and days with refuelling.

Getting batteries for 8h is expensive and risky - what if the power cut suddenly lasts 9h? With batteries you have a fixed storage, with petrol or diesel you can just refuel.

Having that unreliable electricity, my home server would be the least of my problems. I would already have a generator to keep the fridge running so the food doesn't go bad every other day.

I rarely get power outages so I just use a filesystem that can take the abuse (ei btrfs or zfs)

Are you in South Africa? Personally I migrated to Intel NUCs and run virtualization with them. Power wise I have an Inverter and a solar panel as a backup. Inverter handles all the heavy lifting and switching. This system is purely for my electronics. So laptop, servers etc. There is no "cheap" way to do it, but if you do it in stages it can be affordable. If you can, try not to cheap out on the batteries and Inverter. Lead acid based batteries are OK IF you take care of them. Don't use the cheapest Inverter. It's not worth the risk of damage.

some 2nd hand car batteries + 12-230v converter are probably the cheapest option

I have 2 UPS's, a small one that runs the fibre gear and keeps the connection alive and the main one in the rack that keeps the main server running for a couple of hours.

I've only ever had 1 power outage in the last 5 years though and it was scheduled electrical work. couple of brownouts during storms that were just barely deep enough to kick in the UPS boost for a minute but nothing major. nothing else is critical enough to worry about it in my case.

but if I were in a place where power is patchy, I'd have enough solar+battery for the whole house to last a normal day/night cycle, then a UPS for the rack, then a generator as a last resort only.

Do you have access to a gas-powered generator? A UPS could keep you up long enough to cut over.

Most desktop ups are more meant to give you time for the machine to shut down (hopefully automatically) vs actually running them for n extended period of time.

Do you have anything that would still be using the server when the power is out?

It's not really answering your question, but are solar panels or a backup generator possible in your area? A long power outage like that everyday would be really annoying