Domestic Generators Domestic, Generators

drilllzv

Gennies have been discussed a fair bit, but I just wanted to bring the thoughts of some experienced members together into a single thread (unless it has been done before?)

Regarding a domestic generator, what would be advised should one want to invest in a Genny for extended or regular power outages at home / home office?

dcqyle

A secure fuel supply !

whycrdri

Sizing the genny would depend on how you wished to use it, Snow.  

If you are going to use it for essential supply after PO you want the smallest genny you can get that will do a few lights, a fridge, radio, TV and possibly a computer, 2 - 3kW.

If you want to use it pre PO (if we're not too late already) you need to reduce your electricity use to a minimum first, use CFLs, no kettle, no dishwasher etc.  Then you would need a 5 - 6kW machine.

You want to be using a low speed diesel machine,1500 rpm max.  A water cooled machine is easier to turn into a CHP unit.  Diesel is a must for economy and security of fuel supply. It will be easier to make a vegetable oil than ethanol in a post Po world.

You would want to keep it in a secure, sound proofed enclosure, near the house.  The fuel tank would also need to be secure.  You would also need to obtain a stock of lubricating oil, air, fuel and oil filters and some spare injectors.  A spare gasket kit would be useful and a set of oversized piston rings.  Possibly main bearings as well. I'm just adding spares in here as I think of them.  

It should last at least 5 years without any work being required, apart from general maintenance, and could last ten to fifteen, depending on the numbers of hours it is used for, before the bores/piston rings wear out.

It is better to use it for a short number of hours at high power rather than longer hours at low power.  The bores tend to glaze at low power and it burns a lot of oil.  You're better off having a battery and inverter to run a few lights and a TV and using the genny to charge the batteries - always assuming you can get batteries post PO.  You would probably need a spare dry battery and acid as well if the system has electric start and controls.

The problem is, we don't know how much of the system will break down after PO and how soon.  The genny might become completely redundant and we might end up relying on tallow candles again.  I would recommend watching the BBC series, How Green Is My Valley, about four people who took a small Welsh farm back to the 16th century for a year.  Plenty of survival tips there.

I'll add more if I think of anything.

oosoftop

Thanks a mill kenneal.  



I am thinking of essential/emergency use if/when we start to have electricity problems really. I use mainly cfls already (have been using them for years) but I do have quite high electric use mainly due to having three teenage boys and a wife that loves to wear out washing machine/tumble dryers. I am trying to train her to reduce cleanliness, but she insists on clean clothes all the time.  



Any idea what I should pay for a decent diesel 3KW Genny and any links to good value suppliers on the web?

Thanks for your thoughts.

lsdrilli

Our Lister-Petter 5.8kW water cooled genny was about ?3500 inc VAT.  I've just looked on the L-P website and they don't do that one any more, although they do have an air cooled model of the same size.  
http://www.lister-petter.co.uk/product_details.php?productId=95&productType=4
  The smallest water cooled one they do is this one, a 6.7 kW

http://www.lister-petter.co.uk/product_details.php?productId=101&productType=4


There are loads of foreign made ones which are cheaper and Navitron do a 10kW model for ?1800.  
http://www.navitron.org.uk/generators.htm

Their 2kW model would be OK for very occasional use but would be a 3000 rpm model which would rattle itself to pieces if used for any length of time.  They also use more fuel.  I wouldn't touch them with a barge pole.  Been there, done that, got the T shirt.




A few weeks use of a limited size genny soon trains people to be economic in their use of electricity.  Once the overload has switched it off a few times and someone has to go out and reset it, people start to think about their use, especilly if it's them not you who has to do it on a dark, rainy, windy night.  

If our genny goes wrong or runs out of fuel, it's always at 5:30 on a Friday night just as the dealers and hire shops close.  Murphy's (sods) Law aplies big time.  Ours sprung a fuel leak two hours before my daughters wedding, when I had hoped to write my speech!!  I walked up the aisle stinking of diesel and had to ad lib my speech, but the genny was working again. (Add leak off pipe and connectors to the spares list, at the top)

Have you thought about putting a smaller RCD/fuse in your consumer unit?  Put a smalller MCB in the upstairs power ring if the boys use their equipment up there.  Or am I being petty.



Using a genny costs two to three times what your mains supply does (12p/kWhr), so by the time we have electricity supply problems genny fuel (red diesel) is going to be horrendously expensive.  These gennies are using 1 to 2 litres of diesel per hour at 35p/l now.  When oil starts to get short you'll be paying 70p - ?1, or maybe more, a litre so unless you can convince your family to be economic you'd be better off not buying a genny because you won't be able to afford the fuel to run it.

If you do get one, run the cooling water into your hot water system and get a heat exchanger for the exhaust as well.  Unfortunately, no one does a ready made diesel CHP unit for an individual house.  They start at about 15kw which wouldn't be affordable to run and would give out too much heat (about 30kW).

I don't know whether the above will encourage you but I hope it helps, Snow.

Ken