newbie advice on solar system

[jodal666]

Hi All,

first post here.

And require some advice.

Been looking around for a week or two. Love the site and the knowledge here.

Hope you can help?

We are looking to buy an off grid solar system. for use in Europe 230v

50Hz (Spain). No chance of Grid connect in the near future unless we pay approx $50,000 for installation.

Building = remote small stone cottage 750 sq ft. for holiday use. max 1

months use in a continious period. total use for the year 4 months.

We can be quite frugal with the Electric. As we have been surviving on a

2.2KVa Generator for the last 18 months Whilst we restored the house.

Watt Hours Per day 8.591 MAX

Total Kilowatt Hrs Per Month (30 Days): 258

Require a pole mounted array. Possibly a tracker?, to deter theft 3m above ground pole.

Batts & cables & bits and bobs.

We will also have a key start diesel backup generator 10 KVa (Probably

an old Perkins). (to be intergrated into the system)

I have been looking at the Xantrex SW units.From what I understand these seem to be a fairly reliable unit. That is solid and well built

and can also handle high surges from inductive loads/ motors.

or maybe the XW range (But these are new to market and I prefer to buy products that have been well tested by the public).

Is this a good reliable choice or are there better products on the market.

24v or 48v System?

panel array will be approx 20-30m from inverter.

Is MPPT the way to go? Outback MX60? Others?

For the panels I have been looking At evergreen BP. Are ther better options?

What would be the situation with warranty? Are the products covered by a

worldwide backup from the manufacturer? even if purchased from a dealer in The USA.

I know its going to be expensive to ship. But I still think it will be cheaper than buying in the UK.

Does this sound ok.

All advice welcome.

I've probably missed lots of vital info as I'm a newbie

best regards

John

     

[wdyasq]

John,

Build a spreadsheet. Figure your costs. I think you will find for four months of the year diesel is cheap. You will probably want to have a set of batteries and charge them but even at the exorbitant rate of 8.5kW/day, the panels and inverter will be very expensive for use only 1/3 of the time.

Conservation is necessary. A good refrigerators can be found that use less than a kW/day as can a freezer. ..... Where is the other 6.5dW/day going?

Ron

[ghurd]

That's a big system.

Conservation is first.  9KWH per day is a lot of power.  There must be a lot of places to reduce use or increase efficiency.

Solar will reduce fuel costs, but diesel will have to be factored in.

There is a balance somewhere.  I would figure diesel costs as higher than now.

The system will benefit from tracking.

MPPT is great for something on this scale.  It may be silly not to go with MPPT.  MX60 is highly regarded here.

It will need big batteries too.  A good controller will help the batteries last longer.

Make a spreadsheet.  It will put things more clearly in order.

G-

[dnix71]

I was going to complain about the consumption rate, too, but then I looked at my electric bill. I'm on grid in an efficiency (one room plus a bath, no kitchen sink), gas hot water and gas stove. In the summer, I averaged 7 KWH per day.

That's with a full size modern fridge, 8000BTU window AC, and 110ac clothes dryer.

Just me, no roommates.

By getting rid of a small upright freezer, not using the AC and installing pv solar for lights and a fan, and using a clothes line instead of the dryer, I got my last bill down to $15 (2 KWH/day)

If you want to live sort of like you do at home and have to go solar, then you'll need a eutectic fridge/freezer. You can't run an air conditioner or regular fridge off any solar system you can actually afford.

Maybe you should look into getting a Listeroid genset. You could easily run everything you have on 1/3 or 1/4 gallon per hour of diesel. If you are in Spain, you're a lot closer to India than I am, but I don't know about customs/import issues in Spain. That's still a lot of money for fuel, but you won't lack power.

http://hartford.craigslist.org/tls/672705795.html Here is one for sale in Conneticut that runs on waste vegetable oil. i don't know if you can get used restaurant oil in Spain or the cost, but that would be worth the look if you want full power.

No one would able to steal the Lister without help , they've way too heavy.

[jodal666]

Hi All

Thanks for the comments so far

It seem that the fridge/freezer on this system is the killer according to my estimations 400w @12hrs

Have i got this wrong. I have a feeling I have.

According to the manufacturers webiste: here are the details.

http://www.whirlpool.co.uk/app.cnt/whr/en_GB/pageid/pgproddtl001/catid/2/subcatid/7/prodid/24811

Energy Consumption kwh / year  288.35

Yes we could run a generator. But they are not the quietest thing to have running.

The generator will only really be there in case of a system failure and to charge the batteries when required.

This will be our new home in a few years. When we leave the UK.

    Appliance    Qty    Watts    Hrs/Day    Watt Hrs/Day

1.     pump             1    700    0.5    350
   
2.     boiler             1    600    0.5    300
   
3.     tv             1    150    3    450
   
4.     hifi             1    60    2    120
   
5.     fridge freezer     1    400    12    4800
   
6.     dvd             1    15    2    30
   
7.     lights             6    18    3    324
   
8.     oven             1    2000    0.5    1000 Occasionag use
   
9.     toaster             1    900    0.1    90
   
10.     hairdryer     1    1600    0.1    160
    
11.     hair tongs     1    800    0.1    80
    
12.     hair rollers     1    800    0.1    80
    
13.     electric blanket 1    200    0.3    60
    
14.     microwave     1    1100    0.1    110
    
15.     laptop             1    300    0.2    60
    
16.     washing machine     1    2000    0.2    400
    
17.     Satellite receiver 1    25    2    50
    
18.     Gas Hob      1    0     0     0
    
    

    Total Watt Hrs Per Day:                 8464

    Total KW Hrs Per Mth (30 Days):         253

If the above is mostly correct? Any idea of how I would calculate the number of panels & batteries would be required?

kind regards

John

[zeusmorg]

 It seems to me you could downsize your solar array, as it will be charging 2 or 3 months while not in use and increase your battery array. You would be charging and then keeping on float, system while not there, and then discharging the battery bank for the month you are.

 Of course i doubt you'd be able to float a full month so a diesel generator will be needed for times of big loads and once the battery bank does get lower.

As far as tracking the money may be better spent in upsizing your battery bank. Also fixed solar panels are more secure from theft, and you don't have to worry about the tracking system going awry while you're not there.

[wdyasq]

John,

This will be our new home in a few years.

That changes things quite a bit. First, your frig uses 288/365 kW/day ~.8kW/day. That alone takes it to 4.8kW/day and I believe you can get it to 3kW/day (get a more efficient TV or just realize they are optional and quit watching) if you try. 3kW/day is very doable. 500 watts of solar panels on a tracker should supply that, most of the time.

For continual use, you will need to figure how much power required at night. Also us a "25% draw-down". As an example I will us a 'T-105 golf-cart battery'. 6V x 220AH = 1320W x .25 = 330W. I an 24V system that would give you 1320 Watt/hour safe draw-down or 2640W with a 48V system.

Anyone here who has been off-grid I think will recommend the 48V over the 24V system. As Gurd stated you can use an MPPT to fully use your panels.

Next time please give all of the information you can in  the FIRST post and we won't have to guess or give half-arsed answers based on a half-arsed question.

Ron