How does a (emergency) generator actually work ?

[peasant]

Our corner of the electrical grid has been susceptible to the odd outage over the last while and with that and news of potential electricity blackouts over the next few winters, the idea has popped up of perhaps getting a small (suitcase size) generator.

The plan would be to hopefully power the gas boiler (doesn't work without electricity, stupidly), the wifi and perhaps a telly or a a computer.

There are a few things that I sort of half know:

- small generators only produce enough electricity to power small things (around 1 KW or so)
- the current provided by a generator might not be "clean" enough in its frequency...it might damage sensitive equipment, you need a special kind of generator to reliably power a computer for example

And there's lots of things I don't know

- if I wanted to power the heating, the wifi and the telly...they are miles apart, I can't plug them all into the generator directly ...can I plug the genny into the house instead? (probably not because all the other stuff (fridge, lights, etc) would immediately pull more power than the genny can make, right?

- can I actually connect a genny to the lights somehow...they don't have a plug after all?

- should I perhaps buy a large power bank instead, keep that charged and forget about a noisy and smelly genny altogether?

[CelticRambler]

Well, it's a bit of a "piece of string" question, but for the usage that you're talking about, I'd think you're in "neither one thing nor the other" territory ... and probably best going down the battery back-up route for individual appliances.

A few years ago (probably more than a few now, thinking about it) I had to make do without mains electricity for about ten days. I happened to have a 2kW generator to hand (bought as a "just in case" solution similar to your thoughts) so ran a heavy cable from the generator output directly into to the consumer unit. Voilà, electricity in all the sockets and lights just like the the stuff that would normally come in over the street cables.

Now we had to be careful, because it was after all, only 2kW, so it was easy enough to trip the generator if (for example) we allowed both fridge and freezer to start up at the same time (e.g. in the morning, when the generator had been turned off overnight) and some appliances were off limits. The whole arrangement was very much outside the rules, but needs musted and when I knew that our mains wires were due to be reconnected, I removed all of my modifications.

Other than being careful not to try to draw too much current (well practised in that regard, through years of campervanning) there was no real inconvenience inside the house - but having the generator rumbling away for hours on end became quite tiring, and it was set up in one of our out-houses; topping it up with petrol late at night was also a bit of a chore, but hey-ho ...

There are fully regs-compliant ways of having a generator interface with the consumer unit (some of the very rural houses around here would have that, for when the power lines go down in heavy snow) but I wouldn't even bother thinking of installing something like that with a 1kW generator. In fact, my father may be in the process of palming off one such machine on me, and I'm not sure what I'd do with it ... unless I can figure out a way to safely daisychain it to the 2kW for More Power! If I was buying a standby generator again, I'd aim for a minimum of 3kW, preferably 5kW.

These days, we suffer more outages due to the programmed connection of solar farms and wind turbines, and for the sake of a few hours, it's a lot easier to run the computer off battery, use the phone for hotspot wifi, and have a flask of hot water already filled for making the tea or coffee. Again, campervan habits.

[kadman]

Just to update on CR's post.

Any modification, re connection or disconnection at the mains junction box, is an offense in ireland, unless you are RECI
certified. So please be aware of this.

[BrianD3]

I was also thinking about this today. Looks like generators are the latest sold out panic item. I must say that I did think about them in previous years at about this time of year but never did anything and just got a super ser and camping stove for my winter prep.

my needs would be similar but a bit simpler than peasants - main priority would be to power my (plug in) 35 year old oil boiler and pump. The burner seems to be an INTER 10 and according to the boiler manual it is 90w but I don't know what the pump is rated for.

I have a few old cars at the house that run fine and would run quieter and much longer than a generator - would a inverter connected to the battery be a simple solution. Could reactive power/vars by an issue?

Also, mad idea alert - If a car could be jacked up and some sort of roller device put under the wheels could that in theory generate more power than connecting to the battery?
.

[CelticRambler]

main priority would be to power my (plug in) 35 year old oil boiler and pump. The burner seems to be an INTER 10 and according to the boiler manual it is 90w but I don't know what the pump is rated for.

I have a few old cars at the house that run fine and would run quieter and much longer than a generator - would a inverter connected to the battery be a simple solution. Could reactive power/vars by an issue?

Also, mad idea alert - If a car could be jacked up and some sort of roller device put under the wheels could that in theory generate more power than connecting to the battery?

An awful lot of over kill there! Possibly in the literal sense too. If you're going to the trouble of building a generator that's powered by the wheels of a car, you might as well just build yourself a wind turbine with an old washing machine!

If you can figure out what the whole boiler arrangement is using (easy enough if you have a smart meter) it should be a quick calculation to figure out what size inverter you need - but you'd be mad to run a car engine for hours and hours and hours just for that. A regular caravan/motorhome leisure battery should be well able to provide sufficient power for at least 24 hours, maybe 48. In fact, if you have batteries in the old cars, then never mind looking for leisure batteries; just use those instead.

[BrianD3]

About a year later and I did feck all to prep for powercuts since posting in the thread. Unsurprisingly my "put the car up on rollers" idea didn't amount to anything.

To get back to reality, does anyone have any thoughts on Honda inverter (petrol) generators. I was thinking of a 1900 watt one for about 1400 quid. Far more expensive than many others but everything I read says that these are the dogs bollix. That only encourages my preexisting Honda fanboyism in relation to lawnmowers and outboard motors. With this stuff you need to think that it may outlive you if you look after it.

Also at some point in the future ever get around to getting a large array of solar panels, the panels + battery + generator might put me close to going off grid.

[765489]

I can't see you going wrong with Honda. I have a Honda petrol water pump that was left out in a field covered by a make shift wooden structure that eventually fell down around it for nearly two years. Still runs perfectly. I know nothing about generators unfortunately.

[CelticRambler]

How long are you planning/expecting to be without power? Instead of getting a generator that rumbles away day and night to produce a rather pathetic kilowatt or two, how about investing in a decent battery bank and an inverter, both of which could be reassigned to the solar solution in due course?

Only yesterday I took delivery of an automatic power change-over switch to (more or less) complete my camper's off-grid installation. As it was only yesterday, I haven't had a chance to test it yet, but the principle is simple: when I have access to (free) mains electricity, the new fridge will use that; when I don't, it'll automatically switch over to the inverter, which draws its power from a new LiFePO4 battery.

I'll do a proper write-up of the whole thing in due course (too busy doing to be talking, at the moment) but I'm very pleased with how it's all working out, and in "very average" conditions have achieved my target of four days of autonomy.