Electrical supply for garage

[Jackthebiscuit]

I'm building a detached garage and it's going to be expensive to get an electrical power supply to it, plus ongoing line charges when the total demand will be quite small. It will have 4 x 6ft single fluorescent fittings, and two general purpose power points, mainly for a kettle and the odd power tool.

Any suggestions on what the best options are for a supply, solar panels perhaps, but any other suggestions?

 

[oharaf]

If you are spending ALOT on the garage it will only be a drop in the ocean to have supply to it.

Give some more details

i.e. distance from garage to consumer unit in the house.

 

[Taylortwocities]

Your options would be to run a supply from the house (££),
get the electricity company to run a separate supply (£££££££)
or just use an inverter running from a leisure battery.
Something like this http://www.caravantechnology.com/3000WInverter.aspx

The problem with this option is that you'll be forever humping the battery back to the house to charge it, and its bound to be flat when you need it.

Lets see the answer to oharaf's question then we can proceed. By the way, when you say "its going to be expensive" do you have a quote for this ? How much?

 

[ericmark]

You could use emergency lights like these and power them from batteries but 12 or 24 volt may be better option these tend to be smaller than 6 foot. Or convert a lamp the ballast as shown here is what is used in bus lights etc.

Inverters tend to get expensive but boat people like here do loads of options.

Narrow boats etc. use large inverters and solar cells, wind turbines etc to charge them. But if you see the size required it can become very expensive.

If the garage is within a reasonable distance of the house then a cable from house must be favourite.

Volt drop can become a problem with fluorescent lighting but using HF ballast instead of cheap inductance type will allow quite a volt drop without a problem.

Battery charger and inverter can help where the demand is greater than cable can supply but by far cheapest option is to use a big enough cable in first place.

Since no distance is given that is about limit of what I can suggest.

 

[Jackthebiscuit]

Firstly, thanks for all the suggestions, much appreciated.

I can't run the supply from the house because I no longer own it! I sectioned off the garden and retained a plot to the rear to build a garage. I've not had a quote to get the power board to install a supply because there is no (apparent) power source at all to the rear of the properties, nearest point is perhaps the main road so 90metre run, for a 20 amp service?

I know when I was in NZ some farmers used 'windmills' to supply remote pumps, etc, but these tended to be quite large and high and they don't have the 'yobs' there who may cause damage. I'm not sure if there is something similar here that could be used for recharging purposes, just smaller and more discrete.

 

[ericmark]

Although using wind or solar power with a battery will give you lights at the flick of a switch to give any more than 5 minutes of lighting will cost a lot and I would think a small generator is way forward.

However boat boat and caravan suppliers can supply you with loads of 12 and 24 volt units. Careful with regulators these designed for both wind and solar are step chargers which will recharge a battery quicker than a float charge type.

For DIY the bicycle hub dynamo (really alternators) is favourite and the Rutland wind charger has furlmatic which takes it out of the wind if it gets too strong.

 

[Jackthebiscuit]

Ericmark, I've tried to avoid using a genny if possible, I would consider perhaps a small 'standby' genny for emergency backup, but prefer to install a system that is more 'independent'. I'm also going to install skylights in the roof to maximise natural light, so fluros should only be needed in the evenings. I would also like to install reflectors to the fittings to maximise output efficency and deflect the light downwards.

Combining the suggestions I think a small solar panel to charge a 12/24 v battery, that will then supply a 230-40v 3Kw inverter would be the best option. I also like the idea of using emergency fluros so that if the supply falters, the independent battery back-up on each light will kick in.

I'd prefer wind-power to a solar panel, but security maybe an issue so will go with the above,,, that is,,,, unless someone has a better option..?

 

[ericmark]

Having looked into independent power both on Falklands and my sons narrow boat I found the current draw on an inverter is very high. At 3KVA at 12vdc you are looking at over 250A and so really looking at 24vdc then down to 125+ amps to have 1 hour at this rate needs a large battery around 150AH and so if you start adding up the cost goes through the roof.

You would normally consider only using half the batteries capacity so lets assume 1/2 hour then to re-charge you need to do this really within 5 days and you will need twice the input as output and only charging about 50% of time so 50W charging is needed to get one half hour max use per week.

The Rutland Furlmatic FM910-3 Windcharger would just about recharge the battery in theory. But in practice I know it would fail and you would also need some solar panels.

So in real terms with some thought on installation cost some caravan lights and a 90AH battery with solar panel may well give you the lighting required but to get the power required I think you should look at a generator.

I set up a Rutland Furlmatic Windcharger and also connected to the 12KVA and 3KVA generators used for farm house. There were 5 ex-bus 40W fittings only one used in main room rest in bed rooms and only used for a few mins when going to loo etc. With two banks of Ni-Iron batteries around 1000AH and even when the generators were run 3 hours a day the batteries were always flat. This did not matter with Ni-Iron but with lead-acid it would soon destroy the batteries. Which would have to be traction or leisure type car type no good.

Sorry I can't give you good news but even for 1/2 hour per week at full 3KVA it will cost well over £1000 to get all you need so generator by far cheapest option.