Solar Power for the Workshop??

[Effigy]

I am preparing for my new workshop and got thinking about the electrics. As the workshop will be some distance from the house, I got to wondering if Solar Power is feasable for workshop use.

I know it will be ok for lighting and for the smaller power tools, but I do have a few toys that take upto 2000w, though I dont run them all at the same time. Without spending silly money, is it do'able?

Presumably, it would need an array of leisure batteries plus a pretty big inverter, and a ?-size solar panel.

My reasons for going down this route are mainly to do with the practicallities of getting power to the workshop, while hopefully saving a bit on energy costs. Plus, in the event of any future possible power disruptions, I would still have a limited electric supply.

I suppose the main problem I have is my lack of knowledge with all of this - what size solar panel would I need to recharge the battery?
do I need more than one battery?
what is the largest inverter to safely use?
how long will the power last before needing a charge?
how long will charging take?
etc etc

I know that all of the above are interdependant variables, therefore without being specific it's difficult to come up with answers. So my initial thoughts are:

2 x 110ah leisure batteries
40w amorphous solar panel
charge controller
2000w inverter

Total cost £430

Has anyone else gone down the 'Alternative Energy' route?

Thoughts?

 

[tnimble]

My workshop is solar powered except for the lathe, drill press and air filter. :wink:

Solar power is best when used collectively and connectrd to the normal mains.

In the case where there is no electricity available ie a remote location windpower, a baterry array and a backup genertor would be the best solution to have electricity solar powr could be an add on to save in the generator kicking in.

 

[Effigy]

My workshop is solar powered except for the lathe, drill press and air filter.

Can you give the details on your setup please?

 

[bugbear]

I am preparing for my new workshop and got thinking about the electrics. As the workshop will be some distance from the house, I got to wondering if Solar Power is feasable for workshop use.

I know it will be ok for lighting and for the smaller power tools, but I do have a few toys that take upto 2000w, though I dont run them all at the same time. Without spending silly money, is it do'able?

You need to consider total kw/h (energy) as well as kw (power)

BugBear

 

[tnimble]

My workshop is solar powered except for the lathe, drill press and air filter.

Can you give the details on your setup please?

Two windows in the north north east wall, one door with windowed top half in the west west south wall.

Provide more than enough lighting during most of the day all year round. And enough heat in the spring and fall. :wink:


Which tools and what is tier power rating would you want to run? With this we can calculate how many minutes the bateries will last and how long it will take to recharge at peak solar production.

 

[Digit]

Total cost £430

My workshop is solar powered except for the lathe, drill press and air filter.

So in other words it isn't solar powered, it is partly so. So in addition to the £430 there is still the cost of the cable and installation, that being the case the cable is the better option.

Roy.

 

[Effigy]

Total cost £430

My workshop is solar powered except for the lathe, drill press and air filter.

So in other words it isn't solar powered, it is partly so. So in addition to the £430 there is still the cost of the cable and installation, that being the case the cable is the better option.

Roy.

Hang on, you've quoted two different posts from two different people :roll: My workshop isn't even built yet!

 

[TheTiddles]

To generate enough power to run your machinery on would probably mean spending thousands on the panel alone, then there's the batteries, power management etc... However, I would love to see someone make it work

Aidan

 

[Effigy]

To generate enough power to run your machinery on would probably mean spending thousands on the panel alone, then there's the batteries, power management etc... However, I would love to see someone make it work

Aidan

That's what I thought at first, however from my primitive understanding it is

Load (Watts) ÷ Voltage (Volts) = Current (Amps)

Current x Time (Hrs) = Capacity needed (Ah)
Then add 25% on to Ah Capacity for reserve.

So, to power my 2hp lathe for a couple of hours

1500w/12v= 125 A

125A x 2hrs = 250ah

3 X 110ah batteries = 330ah which will give enough power plus a reserve.

What I dont know is how fast a 40w solar panel will recharge the batteries.

 

[Digit]

Hang on, you've quoted two different posts from two different people

I know I have! I was pointing out that if £430 was being spent, plus cable to supply power over and above what the solar source supplied, then the cable only option was the better bet.
Supplying cable and switch gear for mains supply on its own will cost the same whether or not the solar panels are installed.

Roy.

 

[George_N]

To generate enough power to run your machinery on would probably mean spending thousands on the panel alone, then there's the batteries, power management etc... However, I would love to see someone make it work

Aidan

That's what I thought at first, however from my primitive understanding it is

Load (Watts) ÷ Voltage (Volts) = Current (Amps)

Current x Time (Hrs) = Capacity needed (Ah)
Then add 25% on to Ah Capacity for reserve.

So, to power my 2hp lathe for a couple of hours

1500w/12v= 125 A

125A x 2hrs = 250ah

3 X 110ah batteries = 330ah which will give enough power plus a reserve.

What I dont know is how fast a 40w solar panel will recharge the batteries.

One problem is that you are most likely to be using your machinery during the hours of daylight and solar panels won't provide much charge when the sun is low in the sky (early morning and evening) or on dull, rainy days and none at night (obviously). A wind turbine would work night and day as long as the wind blows (most of the time in Britain), so that might be worth investigating...there are loads of web sites dedicated to this sort of thing. I'm sure there is one called "Mother Earth News" or something like that, where you can pick up all sorts of ideas.

 

[PaulO]

A large coal fired power station can deliver power to your workshop a lot more cost effectively than any small solar panel, even allowing for the evil power companies profit.

If you want to go the solar route because you think you are saving the planet, then that is fine, go for it.

If you are going that route because you think it will save you money, then forget it.

I have seen solar installations in very remote sites (a mile or two from the grid), they usually use old submarine batteries. They usually have a genny backup.

If you want any life out of your batteries you only discharge them to 70 or 80% of their charge (i.e. your 110Ah battery can only deliver about 30Ah before you should start charging it). Getting them down to 10% charge regularly will drastically shorten the batteries life. As anyone who has every flattened a car battery will testify.

I'm in the power generation business, and I can say that the only reason companies are developing alternative energy schemes is because of the perverse financial incentives provided by governments to deliver on environmental targets. On simple economics it makes no sense. Here endeth the diatribe

p.s.: don't get me started on the Toyota Prius.

 

[tnimble]

That's what I thought at first, however from my primitive understanding it is

Load (Watts) ÷ Voltage (Volts) = Current (Amps)

You forget the power factor between load (W) and the power (VA). A factor of 0.6 to 0.8 is common for most equipment a power factor of 1/2 to 1.8 would be more common for tools that have motors. Also the invertor/converter has a loss.

Current x Time (Hrs) = Capacity needed (Ah)
Then add 25% on to Ah Capacity for reserve.

I'm used of using 30%.

So, to power my 2hp lathe for a couple of hours

1500w/12v= 125 A

125A x 2hrs = 250ah

3 X 110ah batteries = 330ah which will give enough power plus a reserve.

It could be but also not, is the lathe power useage also rated in VA instead of W?

What I dont know is how fast a 40w solar panel will recharge the batteries.

A 40Wp panel would produce about 30 Amps average during normal conditions during daylight time. Charging 3x110Ah bateries takes 3*110/30 = 11 hours
If a good charges is used it has a loss around 80% this increses the charge time to 14 hours. The recharge would take at least two days. Something you don't want. Either use more panels or less bateries and much less power useage. Running a corded drill and a light bulb would be around reasonable.

 

[DaveL]

A 40Wp panel would produce about 30 Amps average during normal conditions during daylight time. Charging 3x110Ah bateries takes 3*110/30 = 11 hours

er I think you may be out by a factor of ten, a 40 watt panel at 12 volts will produce 3.3 amps at full output. I think your 11 hours should read 110 hours, a total non starter for daily use or even weekly for that level of usage.

 

[Rich]

Is it worth having a couple of solar panels just for heating the workshop with a couple of rads, would this pay in the long term, does the solar system need sunlight or just daylight, can the heat be stored.
regards,
Rich.

 

[Tusses]

as a rule of thimb

your solar panel (if its a good one) will produce about half its rated output - on a GOOD day ! in th uk.

To charge a battery will take 1.5 times the amount of power you took out.

so - if you took 1kwh throughout the day, it would take 75 hrs of good sunlight to recharge your batteries.

Solar electric power DOESN'T work ! it will never pay for itself.

solar heating is a bit better tho

Rich

 

[Digit]

Yes Rich, the heat can be stored. The primary circuit is the panels, pump and controls supplying heat to a conventional storage sylinder via a heat exchanger.
The rads then feed from the tank in the conventional manner.
The downside is that coventional CH systems, as I know you know full well, use hot water at about 80 degrees and the rads are sized on that basis.
With lower water temps the rads need to be much bigger.

Roy.

 

[Tusses]

Is it worth having a couple of solar panels just for heating the workshop with a couple of rads, would this pay in the long term, does the solar system need sunlight or just daylight, can the heat be stored.
regards,
Rich.

make yourself a stove out of an old gas bottle.

when you are woodworking you make dust chips and offcuts - these will keep you warm as you work !

 

[Rich]

Roy, Tusses, I was'nt thinking of a conventional ch system, more of a sealed system, with rads or even run around coils, with a liitle circ pump just to keep a basic, say 15 degs in the workshop during the winter months, am I being over ambitious?.
Rich.

 

[Digit]

Well in the first instant Rich you have got to have conditions and a set up that will get the water above 15 degrees.
If the weather won't allow for that mate you're stuffed unless you incorporate a heat pump. But yes it can be done. If you had to buy everything, as opposed to some DIY work, it could be pricey though.
Nice project.

Roy.