Generators advice

[andemz]

Hi all, I'm thinking of buying abroad and need some advice on permanent electricity. I am considering solar, wind (hydro is out of the question) and generator.

With regards to generators - i take it you can have a permanent supply from this source (what are the running costs roughly to run a house) 3 beds is this not practical - i've heard of diesel generators, propane generators - any advice welcomed.

 

[ColJack]

we'll need more than that to go on.
what size house?
permanent residence or a few weeks here and there?
all mod cons or bare bulb in each room and a wood fired stove?

you'd be better going for solar / gas / oil water heating and gas cooking as this takes out the heavy demand stuff you'd normally use electric for..

 

[andemz]

Thanks for the help so far.
I can build up to 300m2 but in reality it will be 200-250m2.
It will be for a few weeks here and there but that may increase dependant on a number of factors.
wood fired stove isn't a problem and gas bottles can be obtained for running other things.
Pump for swimming pool would be electric general sockets and lighting throughout and outside lighting

 

[ColJack]

ah yes swimming pool.. heated? or sunny place?

you haven't said where it is.. could be a ski challet for all we know..

you might be better off asking in "electrics outside of the UK"..
there might be some resident experts over there with more knowhow of how it's done abroad.. ..

the problem with a generator would be that you'd have to remember to leave a tank of fuel for the next time you go over or your first day there will be running round trying to sort that out..

large diesel or gas tank out back for cooking / geny ... filled by tanker if they do that over there..

is it not possible to get mains to the site?

you might be able to do a deal with a neighbour to buy some off him if he's not using all his capacity..

you don't really want a geny for the swimming pool pump since it will need to be on even when you're not there..

 

[SteNova]

if your having to get gas on site to cook/heat then the genny may as well be gas too, like so...

or if your going oil for the heating you can get gennys that run on kerosene, makes it easy if you have a tank onsite

as for loading i can run 2 pcs, tv, sky box, heating pump shower pump, fridge some lights and a few other bits on 1000w genny (it won't run the freezer) i guess with a 3000w one and not using the electic cooker i could keep the whole house going most of the time

 

[ban-all-sheds]

large diesel or gas tank out back for cooking / geny ... filled by tanker if they do that over there..

And them emptied by another man with a tanker one night when you're not there, so running around trying to sort that out on your first day there...


I expect a major factor will be what works out the cheapest fuel in that country, and there are no rules for that.

If you're going to be burning something for house and pool heating, what about a CHP boiler?

 

[andemz]

The area is spain, so pretty much a good amount of sun. Yeah i understand the pool bit, i'm not too fused as the sun will keep it at a moderate temperature, i was thinking more for pumps and filters that require power.

I'll ask in electrics outside of uk

 

[ban-all-sheds]

the sun will keep it at a moderate temperature

You might find that "bracing" is more accurate for most of the year.

 

[ColJack]

even in corfu the pools are cold until about 2-3pm..

 

[joinerjohn]

Must be in the MOFN for you to want a genny as an electricity supply. Surely the Spanish suppliers would connect you up to the mains?? Gas I can understand.

 

[plugwash]

A hybrid system may well be the best option. E.G. get enough renewable energy (either wind or solar) to keep the background stuff running when you aren't there and use a generator to support the extra load when you are there.

Ideally you'd want a control system that could monitor the battery condition and automatically fire up the generator if they got to low but I bet that would add significantly to the cost.

 

[timtheenchanter]

CHP?? would give heat for pool/water etc as well as proving the power for pumps etc.

what sort of power are pool pumps? normal domestic stuff, as long as you dont want all mod cons, could be run from a Kw or 2, if the pool pump required lost of power, that could be an issue

in my mind if you used wind and solar for the "top up whislt away" that would keep everything topped up nicly...

 

[bongos]

even in corfu the pools are cold until about 2-3pm..

For a decent sized pool, the outside temperatures won't cause the pool temp to fluctuate much on an hourly basis. Even with solar heating...

 

[ericmark]

Having considered a similar problem supplying power to a narrow boat up to date we have found.

Petrol generators can often be converted to gas but gas is dangerous on a boat but not very economical and smaller units tend to be air cooled so the heat can't be used to heat domestic water.

Specials like the Whisper-gen with Sterling engine produce very little noise but are very expensive.

High revving small diesels don't tend to last long and to get a generator able to last one starts to look as 7.5Kva minimum size for long term use. However even such big generators often air cooled which is a waste as one wants to heat domestic water.

Using a 3.5Kva alternator on the main engine does seem the best option however this means a new front pulley with 5 V belt drive. But running the main engine at just over tick-over uses less fuel per Kwh than running even a diesel generator at fixed revs of 3000.

Some old generators ran at 1500 or even 750rpm and these were quite good for the farms I visited on the Falklands and even 3000rpm generators were avoided if possible because not as reliable however it does depend on size.

Today however we have a new beast on the market the inverter generator and these work similar to the 3.5Kva alternators used on main engines in that the generator can run between a range of revs and a sin wave inverter converts to output to 50Hz. The all in one units have a sensor which matches the revs to demand so on light load they tick over.

However you also want wind and solar power and there are two basic ways to use this. One is to use a special inverter which auto synchronises with the mains and reduces the demand from the mains when the wind blows. However I think one may have problems with this type with a generator?

The other method is to use storage batteries and an inverter and ones first thing is to select a voltage. 12v is really too low and with 300A becomes a problem so 24vdc or 48vdc. With 24vdc one can get loads of items that will work direct from 24v but 48vdc not so easy. However by using a centre tap 24 - 0 - 24 should give best of both. Over 48v does no seem to have the range of cheap inverters on the market.

On the Falkland farms we found generators running at night were noisy and expensive so we had set times when they ran. 9am to 12 noon and 6pm to 9pm this was enough to keep chest freezers running and do all vacuuming, washing and charge radio batteries and the idea of timed mains power seemed to work. Except for sheering time when they ran all day.

This time in Falklands 1984 - 89 inverters were very expensive today the price has dropped but there are two types of inverters one costing near 10 times the price of the other. A true sine wave inverter at 3Kw with 6Kw peak will cost around the £1500 mark but a modified sine wave inverter same output will cost £130 however some items will not work with modified sine wave.

My son uses a modified sine wave 3Kva with 6Kva peak and it runs TV, Microwave, Kettle, PC, in fact the only item which has failed is the washing machine and likely that is due to under size batteries.

However some Microwaves, and Washing machines will not work at all with modified sine wave and this means you need to consider the whole package.

Having batteries and inverter for most items and running generator at set times for washing etc would seem a good compromise.

Charging is another point. It seems solar panels and wind chargers have an ideal voltage which is not likely the same as battery voltage so there are expensive regulators the MPPT which allow the panels to run at best voltage and transform it to that required on battery.

There are also step chargers and float chargers the former will recharge batteries a lot faster. But the Price of these special units does make one flinch and a good mains powered 45A battery charger can cost well over a £1000.

As I said the narrow boats have same problem you may find this link http://www.canalworld.net/forums/index.php?showtopic=30295&st=0 useful on solar panels where they talk not only about how they work but the costs from varying sources.

You will also find certain sizes are popular and as a result the price becomes lower. With inverters for example 150W are very cheap but over that size the price per watt output sores but there is a dip at 3000W which is why my sons is that size.

Hope that's food for thought.