Advice on buying an emergency generator

[TominDales]

A question probably for the electricians amongst you.
I'm being encouraged by my better half to get an emergency generator for the house so that we can function during power cuts and maybe for a while if Mr Putin does his worst. We had a long Pcut last month whilst I was away and apart from the inconvenience it was on 24th February and she started to worry that it was due to Mr P, - via hacking rather than a direct hit on a power station I may add. However they have become a bit more frequent so I thought Id look into it.
Our requirements,
-Firstly as its only to be used once in a blue moon I was tempted to look for a cheap DIY one from a shed store.
- it needs to power our large fridge, two deep freezes, the Central heating and a few lights and phone chargers., whilst the total continuous power of all of this is quite low, only about 500W. The fridge freezer motors draw 8amps on start-up so thats about 1800w. so been looking at 2000w or 3000w to be safe side as a lot of reviews mention how they cut out on such things.
- it probably needs to be a sinewave inverter as the fridge motor will need that kind of waveform, not sure if a pure sinewave (more expensive) or an impure sinewave 96% (cheaper) will be ok.
- The other thing is reliability.
Some of the cheapest on screwfix, etc get mixed reviews due to thing failure on 3rd or 4th use, although lots of good reviews, so do I get a more expensive reliable one and fire it up every 3 months to keep it running in good order, Or do I buy a cheaper screwfix one, leave it in the box unused until the next blue moon when we can get it out and set it up then after use, drain the oil and fuel out and put it away?
I've seen one on Machine mart that might be OK, but never bought from them before - they look a bit of a cheap and cheerful place.

 

[Jameshow]

I have an SGS one. Works great not used it for s few years though.

Parts are easy to get as it's a generic type one.

I'd look at a diesel one if reliability is a primary consideration and fuel + compression = power...

 

[Inspector]

I bought a little 110V, 10A generator in the early 90s because of frequent power failures. I had to connect it to the furnace and let the house get good and warm, unplug and then do the same with the refrigerator and once it was running I could watch TV on my 12" black and white with a lamp or two. When the house got cold repeat the cycle. I only had to do that a couple times and then there were no more power failures. I still have the generator but it has less than 25 hours on it in over 30 years. If I decided to get a generator now it would be one for the whole house and automatically switched.

One thing. Your calculations don't seem to take into account is when one appliance turns on while a couple others are running the surge it pulls reduces what the others have available and they try to draw more to keep up. You may need an even bigger gen-set to run smoothly.

How are you planing to isolate the house from the service? If you don't you could kill someone in the area that works on the line expecting them to be dead.

Pete

I'll add that I had a buddy with a gas powered welder on a trailer that had a few plugs of AC that he used when the power went out. Now is your excuse to buy a welder that can also serve you in a power outage.

 

[nickds1]

I'm doing this for our house right now. Main complication for us that it's 3-phase.

Freezers. You need your freezers to keep running. And we have a heat pump.

I would recommend that you get an Automatic Transfer Switch (ATS) and a generator with auto-start. When utility power fails, the ATS starts the generator and when the generator is up to voltage and stable, disconnects the utility feed and switches over to the genset. The reverse happens when the ATS detects utility power is available and stable - it switches back to the utility power and stops the genset.

You need auto-start and an ATS as what happens is you're away when there's a power cut?

The real issue is start-up surge - all those motors starting at the same time: fridge, freezer (we have 3), central heating pumps etc.

To mitigate this as far as I can, I'm putting variable delayed starts on those units that have high start-up demand. These only supply power a variable number of seconds after the socket power is available. Our heat pump already has this capability built in - you can program it in to start in a set time after power is available, e.g. 5 minutes.

This is essentially the same as how data centre racks are powered. You don't want 20 servers in a rack all starting at the same time - all the breakers will trip. So the power distribution units (PDUs, fancy controllable power strips) are programmed to sequence power to the different outlets on a timetable.

So, I'm installing a 3-phase ATS in our meter cupboard and the auto-start genset in our bin cupboard with lots of ventilation and proper exhaust etc. These generators are diesel and typically do 24 hours on a full tank.

There's a bit more subtlety involved but that's essentially it

 

[clogs]

for those of us with lower gen power needs just buy a Honda.....
mine must be over 20 years old now and still starts second pull....
only prob it's 1.9kw....should have bought bigger...
worked on a few of those Chinese D genny's.....the engine always started to burn oil...piston rings made of cheese "Gromit"....but to replace them the entire engine had to come apart....
Not like the Listers of old where u could just lift the top off....be warned...

 

[pgrbff]

I believe there is always a chance anything modern might be microprocessor controlled and therefore need a clean supply? I think any boiler will have microprocessors of some type. Add to this easy starting and reliability and I splashed out and got a small Honda inverter, 2kw. I leave it with alkylate petrol which takes a couple of years to go off. It's in the boiler room. When I have a power cut there is a switch that disconnects the boiler room electrics from the grid and switches to the generator. There are also a couple of sockets in the kitchen that are also only live when I switch to the generator.

 

[Myfordman]

If you buy a petrol one make sure it is compatible with E10 grade petrol and run it completely dry of fuel out of the carb as e10 will wreck rubber seals gaskets etc over time.
ensure that the genny neutral is tied to earth potential as most flame detection devices in boilers require this.

 

[Jameshow]

If you buy a petrol one make sure it is compatible with E10 grade petrol and run it completely dry of fuel out of the carb as e10 will wreck rubber seals gaskets etc over time.
ensure that the genny neutral is tied to earth potential as most flame detection devices in boilers require this.

Aspen petrol is good for items which have fuel left in them I'm told.

 

[pe2dave]

UK regs, what hoops do you need to go through to install a switch over, mains to genny?
I'd imagine lots?

 

[Bod]

https://petepowerblog.wordpress.com/Read this,the guy knows generators.
You will need an installed generator connection, or you will try to power up the entire street!
With modern petrol you will get major problems with "rubber" seals and carboretter jets gumming up.
Seriously consider LPG converted generators, these have no stored fuel in them, which means they are safer to store, the fuel LPG cylinders (Calor gas) are widely avalible.
This is what I have on a narrowboat, and is simple to use and store.
Any generator MUST be used outside, because of the Carbon Monoxide exhaust fumes, which will kill you and your loved ones.

Bod.

 

[TominDales]

wow, thank you all for the advice. I thought I'd start by only asking about the type of generator and then start to discuses the electrical set-up, especially as that might be influenced by the type of geny (power especially).

Thank you for the good advice on fuels types, also maybe go for Honda for reliability - no point in having an emergency thing if its temperamental? I'd noticed LPG but wasn't entirely sure of the benefit, apart from the fact we have BBQs etc so have plenty of fuel, whereas I don't really fancy storing 25 gallons of E5 petrol.
Also you have persuaded me on 3kw rather than 1.9kw, Clogs experience and the issue of starting all those motors.
Although my heart says go for a large seft start geny integrated into the house and be done with it. My head says start with a small stand alone system and learn by doing.

So leaning towards getting something quite small and simple, ca 3kw and probably a reliable honda, and run everything off extension cables so that the house supply is not made live.
Get our v.good electrician round to find a safe way to connect the boiler (furnace) and CE water pump, probably with a change over switch for that appliance.
Only if we had more frequent power outages would I think about a larger generator and a change over switch for the whole house. so my thinking is start quite simple and only add to it if needs be. I've read horror stories of people electrocuting linesmen or blowing up their generators when not using changeover switches. The double ended plug is know as a widow maker! so wont be going there.

One thing I briefly considered was getting an inverter and using the car. The car has a huge engine and a large fuel tank. But the inverters seem as expensive as a generator and the car alternator is probably not designed for this type of use, so could end up writing off an expensive car part especially as 3000w is a lot of current at 12v. If we move to an EV and grid balancing future, it would make sense for cars to have the capability to export power to the house in an emergency, especially if its a hybrid or has a huge battery capacity.
We will probably get PV on the roof this year, payback is down to about 3 years with current elec price, so that would come with an inverter. So at this stage probably a stand alone generator is the most versatile.
Thanks again to you all.

 

[Spectric]

maybe for a while if Mr Putin does his worst.

If he does his worst having no electricity cannot impact the dead!

A generator will produce a pure sine wave because of the laws of electromagnetic induction and it is the same principle as used in a power station but on a much smaller scale, so your only requirement is Kva. They state peak power and so you need to bear this in mind but you want at least 4Kva and this will power up most of your requirements plus extra. Many have both a 16 & 32 amp socket plus some also have 110 volt.

Invertors will be expensive in comparison to a generator because they are more complex, having to convert Dc to Ac and produce a pure sine wave so forget invertors.

You may get a better deal on a stationary generator compared to a portable and there can be little difference in price between a smaller portable and a large stationary one.

 

[Jameshow]

Not good to run a car stationary esp diesels. They like to run at a decent load more than 3kw tbh.

 

[MikeK]

I used to live in rural Virginia and endured frequent power outages during the winter or heavy storms. The outages ranged between hours and days. The longest time that I remember was during a bad winter storm with lots of accumulated ice on the overhead power lines, and it was ten days before power was restored. I had a woodstove for heat and limited cooking, but fresh water was a problem because I had a well. The water lasted until the pressure tank in the crawlspace was empty.

After three years of putting up with this, I paid to have a 10KW Generac whole-house system installed and fueled by the LPG tank that fueled the other appliances in the house. My contract with the LPG company provided automatic refills, and they were able to make deliveries in the worst storm as long as I plowed the road going to my house. The generator system had an automatic transfer switch (ATS) to disconnect the commercial service from my house before starting the generator. The generator would run for ten minutes after the commercial power was restored before switching over. I think the system synchronized the generator to the commercial power before disconnecting. I know there was a momentary outage before the generator was online, but there was never an outage when the ATS connected back to the commercial service.

The only down side to this was a few times when the power company was troubleshooting an outage at night and saw my house was lit up because I was on generator power. My nearest neighbor was about a mile away, so the workers assumed I was not affected by the outage and moved to other areas. I had to remember to notify the power company that I had a generator system.

 

[GweithdyDU]

We're having similar thoughts because of where we live (Welsh mountainside, overlooking the Irish Sea) as we have frequent outages of phone/internet and electric. However, what with fuel prices and possibly even that weird bully from Russia (you know, the one that thinks it OK to target women and children with artillery and missiles), we're thinking of just gong off-grid altogether. Not cheap as the batteries for back-up are not cheap, but then neither is electricity going to after Wednesday. I don't intend to move and quite like the idea of leaving my son a house with almost no bills, (can't DIY the council tax!). We can avoid ruining my lovely new 'arty.artisan roof when fitting PV solar panels as our aspect and elevation allows us to just mount them on a frame in the field, and if we can ever afford it, a wind-turbine with PV panels and Tesla batteries would mean you'd be fine most of the time. When you're not, the electric-start LPG generator would be 'feeding' the batteries and going in via the 'magic box' so no issues re 'waves' etc. It has never been easier or more practical to go off-grid and with it looking highly unlikely that we'll ever see a traded form of cheap energy for domestic use again, perhaps we just have to take responsibility for ourselves (and enjoy the fact that the energy companies haven't got you by the 'what-evers'). Even better would be community based schemes. I'm also considering buying a machine for making composite logs. I have 7 acres of land with about 5 of them covered in either soft rush (juncas effesus), gorse, bramble or the alders, willows and ash I have planted (nearly all the ash have succumbed to ash die-back). My modern-ish Rayburn heats domestic water and rads as well as baking great bread and cooking dinner. We think it has to be done and done ASAP to avoid potential problems from Russian hackers and exploitative energy producers/supply-companies. Apologies for the slight swerve off-topic but related to the question.

 

[niemeyjt]

An alternative view - don't keep your freezer running - at least not during a short power cut - maybe only connect it up after 12 hours off. Instead 1) do not open it and 2) cover with an old duvet for insulation.

Another vote for Honda here - we also have the "open" 1.9Kw - but maybe a slightly larger one with sound insulation is the way to go.

Computers - laptops with a separate PSU are probably OK - but for desktops (like mine) a UPS is the way to go both for protecting it and keeping it running.

 

[gmgmgm]

One thing I briefly considered was getting an inverter and using the car. The car has a huge engine and a large fuel tank. But the inverters seem as expensive as a generator and the car alternator is probably not designed for this type of use, so could end up writing off an expensive car part especially as 3000w is a lot of current at 12v. If we move to an EV and grid balancing future, it would make sense for cars to have the capability to export power to the house in an emergency, especially if its a hybrid or has a huge battery capacity.
We will probably get PV on the roof this year, payback is down to about 3 years with current elec price, so that would come with an inverter. So at this stage probably a stand alone generator is the most versatile.
Thanks again to you all.

I considered the full-blown generator route, but I would need three-phase and ATS. And plenty of time and effort to check/test it every so often, and replace fuel.

I went for the other end of the scale. I have a good-quality sine-wave inverter I can run off the car or tractor, which is big enough to power freezers/fridges and charge torches/laptops/phones. I have log burners for heat, and a large water storage tank. An extended power-cut for us is very unlikely, so I can accept the low risk of having no hot water for a few days.

I also have a battery-backup pack on the broadband router and an old-fashioned telephone, so we can communicate.

In a few years if we all have V2G cars this will be much easier.

 

[fixit45]

I feel that I must make the safety point of before connecting and using a generator, DISCONNECT FROM THE MAINS SUPPLY.
If you fail to do this you could not only electrecute yourself but an engineer working on supply lines.

 

[Richard_C]

9

I also have a battery-backup pack on the broadband router and an old-fashioned telephone, so we can communicate.

I don't think I need a generator but will certainly be after a UPS for the router and one phone.

Our village has very poor or no mobile phone signal. "Copper wire" phones are being withdrawn in the UK, so the robust self powered phone system we have now will be replaced by a much more vulnerable VOIP style service. We do get frequent typically 1 to 2 hour power cuts, and the prospect of running to the top of the nearby hill mobile in hand to summon an ambulance or fire crew isn't one I relish. Keeping your router alive will be the only way to maintain communication.

 

[TRITON]

What about a Clarke IG2200A 2.2kW Inverter Generator ?
I briefly looked into getting something when i toyed with the idea of getting a small canal boat or yacht project.
Couldnt afford something like a Honda, though one of the yachts I sailed on had one and very good it was too for power tools and the like doing the maintenance.
The clark one seemed to be the best of that end of the cheapo gennys. OK £500 isnt exactly cheap, but theres loads out there for less and you need to have some trust in it at least.