model railway and solar panel electrics

[Deltheboy]

I'm in the process of building a shed in my back garden for my planned EM layout. Knowing virtually zero about electrics I'm wondering if I could use the power of a series of solar panels on the south facing roof to supply power,  for the proposed layout and also lighting and heating, this rather than running a mains from the house. I'd certainly welcome any input.

 

Derek

[Ron Ron Ron]

Derek, why have you posted your enquiry in this section of the forum?

 

[Edit:  Now moved to a more appropriate section of the forum]

 

 

 

.

Edited September 21, 2018 by Ron Ron Ron

[Silver Sidelines]

Derek
 
I have had a 4kW array of  PV panels since 2011 (this is around the maximum that your electricity supplier will allow without major hassle).  The average generation per day averages out at 10kW per day. The maximum output in early summer for our location has been 29kW.  From November through to February we are lucky to generate more than say 2Kw per day - hardly enough to light your shed..
 
Cheers Ray

[Colin_McLeod]

My initial reaction is that paying an electrician to install an electrical feed to your shed would be easier, cheaper and better.

[uax6]

Small solar cells will give you some power, but you'll need batteries connected up with them to get something useable for running trains.

 

I have a clockwork telephone exchange in a shed. It is fed from 100amp/hr batteries which are trickle charged from a solar array on the roof. This also requires a controller to prevent the batteries being over charged. The exchange can pull upto 5 amps at times, and the 50watt array can just about keep on top of this in summer, but in winter its not enough. I therefore have a 5 amp smpsu which also floats the batteries.

 

Cost? The array would be about £200, the batteries new would be £150 each (I have 8, but I got them for free secondhand) and the smpsu is about £65.

 

Sadly I'm guessing that to run a railway, you would be better off paying for a mains feed.

 

Andy G

[28XX]

PM me with your address, if you are close enough to me I’ll quote you mates rates to put a supply in.

[Colin_McLeod]

I'm not sure of UK rules but in Ireland one needs a registered electrician who will give you a document certifying the work.

 

If 28XX meets that then you have your solution.

[Robin2]

I have had a 4kW array of  PV panels since 2011 (this is around the maximum that your electricity supplier will allow without major hassle).  The average generation per day averages out at 10kW per day. The maximum output in early summer for our location has been 29kW.  From November through to February we are lucky to generate more than say 2Kw per day - hardly enough to light your shed..

 

Cheers Ray

This is hard to follow because I suspect you have the units of measurement wrong. For example do you mean an average of 10kW for every one of the 24 hours or 240kWhrs or do you mean (more likely) 10kWhrs.

 

Assuming the latter then for a model railway 2kWhrs would be a lot of power - at 12v it would represent 166 amp-hrs or, say, 10 amps for 16 hours. That should drive trains and lighting easily. But it would not be sufficient for heating.

 

If you don't use your shed every day then that provides more time for the panels to re-charge the battery.

 

If you are going for an off-grid solar system then don't waste money on more solar panels than your battery needs.

 

Having said all that, the cost of solar panels and batteries is high and batteries need to be replaced - maybe after 3 to 5 years.

 

...R

Edited September 22, 2018 by Robin2

[Silver Sidelines]

Yes

 

.... do you mean (more likely) 10kWhrs.

 

 

2kW or 2kWhrs on a winter's day - plus batteries to even out the days when there is no generation  - might run trains but I doubt it would provide much warmth for the operator.

 

Ray

Edited September 22, 2018 by Silver Sidelines

[Nick C]

Perfectly possible as a stand alone system, it just depends if you consider it economically viable...

 

You need to work out your average usage - for example, 2kw heater, 100w of lighting and 24w of controllers etc, gives 2124w - to make the maths easier we'll say 2kw. If you're going to be there for 2 hours a day you'll need 4kwh/day, and to allow for days with no generation you'd probably want 3x that in battery capacity - 12kwh. You will need an inverter/charge controller which will probably be the most expensive but, and a suitable number of panels - with an average of 2 sun hours in the UK in January you'd need 6kw of panels to fully charge the batteries.

[Robin2]

but I doubt it would provide much warmth for the operator.

 

Yep. That's what I said.

 

IMHO heating with electric solar panels is completely impractical. As well as a huge array of solar panels you would need a huge battery bank.

 

A solar water heater plus exceptional building insulation would make more sense, but still not a lot.

 

Heating with mains electricity is also very expensive.

 

...R

Edited September 22, 2018 by Robin2

[Silver Sidelines]

Hello Robin

 

I am guessing you are talking specifically about the shed.

 

.Heating with mains electricity is also very expensive.

R

 

We don't have mains gas.  We did have oil but we now use electricity for all our cooking, heating and hot water.  We replaced our oil fired boiler with a ground source heat pump, we have an eddi to divert surplus electricity into the immersion heater and we converted our oil fired Aga to AIMs which is very convenient.  As to cost - our FiT payments exceed our annual electricity bill.

 

Regards

 

Ray

[Robin2]

As to cost - our FiT payments exceed our annual electricity bill.

Good to hear. I had not realized the OP was contemplating such a comprehensive solution.

 

...R

[Horsetan]

2kW or 2kWhrs on a winter's day - plus batteries to even out the days when there is no generation  - might run trains but I doubt it would provide much warmth for the operator.

 

 

Warmth can be generated by getting up to deal with derailments or stalled models....

[Colin_McLeod]

Or rely on solar heating with big windows and only operating the layout on sunny days.

[RJS1977]

Yep. That's what I said.

 

IMHO heating with electric solar panels is completely impractical. As well as a huge array of solar panels you would need a huge battery bank.

 

A solar water heater plus exceptional building insulation would make more sense, but still not a lot.

 

Heating with mains electricity is also very expensive.

 

...R

 

If nothing else, solar power provides the most energy precisely when we don't need heating (i.e. when it's warm and sunny!).

[adb968008]

Or rely on solar heating with big windows and only operating the layout on sunny days.

That’s the days I really don’t operate on.

Give me sleet, hail, thunder, snow, rain, lightening.. wrath of god type stuff.. I can guarantee the misses won’t have any job for me to do and I can play in peace.

 

This summers been great, but not for the layout which has been near abandoned this summer.

Edited September 22, 2018 by adb968008

[DCB]

Solar panels are not great.  You used to be able to get generous allowances for the excess power you generate but they are being phased out and while you don't normally need planning permission to put solar panels on the roofs of houses you do need it for panels in gardens or on out buildings. I know a chap who spent out on a solar array on his bungalow, his neighbour built a 3 story building due south...  He was not a happy chappie.

The angle of panels is very important, for a model railway shed it need to be optimised for winter, usually they are orientated for best performance throughout the year in UK while the US Americans tend to have different settings for winter and summer.

Several friends have solar powered 12 volt battery electric lighting for their chicken houses with LED lights using very inexpensive DIY kits so given a few half decent "12 volt" batteries Car/ Van batteries it should be fairly easy to power a DC railway railway and light the shed off grid as long as you forget ideas of using solar panel power for heating.

12 volt car batteries are more like 13.5 volts and pack one hell of a punch Amps wise. Fuses are absolutely vital to avoid setting the shed on fire.  They are full of acid remember, the stuff criminals chuck in people's faces. You don't really want one to explode.

Controllers can be an issue as most are AC these days.  I use all sorts of weird diode based controllers and I suppose variable resistors could be used at a pinch, but Gaugemasters and the like or Variable transformers or DCC you need an inverter to et the 12 volts DC to 240 volts AC which introduces losses.   On the flip side you can use an interruptible power supply, UPS rather than 12 volt batteries. They are expensive new but as everyone seems to be abandoning desktop computers in favour of tablets and lap tops people can't seem to give them away. I acquired one for our Village Hall from Free-cycle free and they often go on eBay for next to nothing.

[Silver Sidelines]

Hello David

 

A good comprehensive response.

 

.. you do need it for panels in gardens or on out building..

 

Not sure that you are completely correct, I have a letter from our planning department which states that PV panels are permitted development on garages and outbuildings within the garden ground - provided amongst other things that they are not obviously visible from the highway.

 

Ray

[Titan]

A propane cylinder heater might be your only option for a decent amount of heat. However that might give you humidity issues to manage...

[sharris]

Warmth can be generated by getting up to deal with derailments or stalled models....

 

I'd suggest installing an exercise bike linked to a dynamo at your control console. That should provide power and keep you warm. 

[Robin2]

Solar panels are not great.  You used to be able to get generous allowances for the excess power you generate but they are being phased out and while ......

It seems to me that this and some of the other advice in this Thread relates to a quasi-commercial home-based solar system that is connected to the grid.

 

A much less ambitious scheme with 100w or 200w of panels feeding a 200AHr deep cycle lead acid battery could be perfectly sufficient to provide power and light for model railway running sessions. If the worst came to the worst you could take the batteries indoors to charge them from the mains - but I doubt if that would be needed.

 

...R

[Harlequin]

Some rational design suggestions:

1. Take power tools and machinery such as lathes into consideration when totting up your likely power usage.

2. Connect your shed to the mains whether you install solar PV or not. That gives you reliable power when the sun's not out and the ability to feed any excess solar power back into your house and possibly onwards to the grid.

   2b. While you are laying the power cable, lay armoured network cable alongside so that you get guaranteed internet connection in the shed without having to rely on WiFi.

3. Insulate! Whatever your heat generation source the cheapest and simplest way to save money is to keep the heat inside the shed.

   3b. Good insulation also evens out temperature swings and keeps the shed cooler in summer.

4. Passive solar gain: If you're still at the design stage, orient your windows to the sun, create an overhang above them to shade them from high-angle summer sun, but allow in low-angle winter sun in when you need the free energy the most.

Edited September 24, 2018 by Harlequin

[mikeg]

One point to note is that some DCC systems use a 15v DC supply so you can use a car battery directly although you might lose a bit of power on the track, as I have found that you need to lower the track voltage anyway this may not be a problem.

I have thought about using a solar panel but as it would need to be on a roof that faces a road getting planning permission is a problem in my area, also in winter I would not get sufficient sunlight to charge the battery as only the morning sun is available to just after 1.30pm

 

Regards mike