Looking for recommendations for a generator

I'd agree. Eaton have a good UPS sizer. I put in a consumption of 350w with a runtime of 2hrs and it spat out a few options:

Click "select" and the enter the details. That will give you a sizing in VA which you can use elsewhere to look for options.

Elara stock many of the bigger brands:

In terms of replacement battery packs... I make my own as they are standard SLAB batteries.

The delicate electronics usually stands up to the excursions of a mechanical generator quite well. Electronics is supplied via a power supply with some degree of storage for short term "blips". People do run out to buy surge protected sockets and the like, but unless it's for something basic like a LED bulb, the the power units have regulation and a resistor that shorts overvoltage transients protecting the electronics.

I use a Lidl 2kW generator I bought some years back. It supplies power about three or four times a year during outages. I supply the lighting and electronics like the TV and a few different desktops/ laptops and of course the router, fridge and freezer

There is a small change in light output from the room lighting as the load varies, but that's the only notable difference.

The negative effects are the fuel used and the noise which I control by running it inside the shed. The shed is unusable for an hour or so after power restoration to allow the fumes to clear. f course a UPS gives an almost invisible changeover to battery but this benefit would be negated if using one via extension sockets

The only other downside to my system is that I have to use the microwave for coffee, the kettle would need a few more Watts than can be supplied currently.

Mains Voltage is dropped down from 240ac to a lower Voltage, usually around 24 to 5V in the majority of equipment.

The power supply has feedback, so the output Voltage is not related to any normal input Voltage change. In fact when my supply dropped to 80V recently, a lot of the electronics here still worked.

So basically as the power supply goes up and down like can happen with a shower or large current drain device, your electronics happily sits there working on its 5V DC just as if it had a battery supplying it.

A danger of spikes that can occur if motors or solenoid valves are switched is taken care of by a VDR or "transorb", it shorts temporary high Voltage spikes to ground or neutral.

Spikes see electronics off quite easily.

A generator is generally a pretty bad source of supply compared to the domestic supply, the variations in output are easily seen with incandescent lighting, but I certainly have full confidence in its ability to operate all my gear.

There is a bit of paranoia about the damage possible to electronics by supply Voltages. I have seen it happen when 415 was connected across a 240 V live and neutral and several times after lightning strikes in proximity to the equipment. The lightning can induce current into signal cables incidentally so your equipment connected to aerials or interconnected over a few meters distance can be zapped even if unplugged from the mains.

Hence my total confidence in my Lidl generator.

https://www.screwfix.ie/p/impax-im1800ifg-1800w-inverter-frame-generator-240v/843hp

My brother uses this for the basics during a power cut, using it for the last 18 months or so.

What are you looking for, something to keep your computer[s] going?

If it's for home use, I wouldn't have thought that a UPS was a practical solution at all.

I fitted large numbers for PLC controlled gear, but the UPS was strictly limited to supplying data critical electronics, nothing else.

I have a generator for the many outages here and they can last hours. Frankly before I considered a UPS, I would simply make sure the critical laptops had a good set of batteries and delve into the router in order to tap in a battery derived external supply. My last mains powered PC is hardly used now and will not be replaced.

A simple c/o relay to bring in a low voltage supply isn't a major challenge and a lot of the expense involved with UPS supplies is getting the power conditioned to provide a pure well regulated sine wave, the irony being that the batteries are DC, well regulated and require no overvoltage protection. So it's more efficient and cost effective to use trickle charged batteries, just tailor the cell numbers to suit the equipment Voltage.

Could you not use a laptop as a server, stick it alongside the router and use a common DC supply? I'm sure you could find kit happy to work on 24V DC and my 12V 7A/H cells were about £60 for the pair from Screwfix. You wouldn't even have to open the router or laptop :-)