Calculations for Solar Lighting System - 20 years / $2k = $8.3 per month

[classradiance]

An 800Wp array in middle England would generate ~600kW/year which even if you used all the power displacing retail import would bag you maybe one third of what you are suggesting at best.

Rgds

Damon

Thanks for that Damon
Are you basing your calculations on anything specific or do you know something that you could share here.
What site are you getting the information from as I will have to take a look myself so not to allow myself to be misled by those  that love to sound off about things they want you to think they know allot about.
I shall be eager to go back to that person and see his face when I tell him about certain friends of mine here like yourself that know the Score. Why do they have to try and look Large do you think.

ps: Thanks so much for posting here Damon, I read all you posts and think you are Superb. 

[DamonHD]

1) Expected yield is very roughly 800kWh/kWp in the UK (south facing, optimal tilt, no tracking), see here: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

2) Retail rate ~12p+/kWh (on imports avoided), FiT generation rate ~14p/kWh (though I haven't kept entirely up to date on that).  Also ~4.5p/kWh exported deemed at 50% of generation unless an export meter is fitted.

Rgds

Damon

[classradiance]

1) Expected yield is very roughly 800kWh/kWp in the UK (south facing, optimal tilt, no tracking), see here: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

2) Retail rate ~12p+/kWh (on imports avoided), FiT generation rate ~14p/kWh (though I haven't kept entirely up to date on that).  Also ~4.5p/kWh exported deemed at 50% of generation unless an export meter is fitted.

Rgds

Damon

So the question was: - What is going on and is it the same in the USA for Renting roof space?
Forums for UK show people complaining and then some are happy with INVESTMENTS.

Now the Media is advertising a problem with Consumer Supply !! are you seeing that as well.

 

[classradiance]

1) Expected yield is very roughly 800kWh/kWp in the UK (south facing, optimal tilt, no tracking), see here: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#

2) Retail rate ~12p+/kWh (on imports avoided), FiT generation rate ~14p/kWh (though I haven't kept entirely up to date on that).  Also ~4.5p/kWh exported deemed at 50% of generation unless an export meter is fitted.

Rgds

Damon

Damon
For the benefit of people who may struggle with calculations, could you please post your full workings out so that it is clear what you are trying to show here.
I feel the problem with all this is that calculations are a foggy subject and this causes people to cut off from what is being shown.
If any one else reading this post would like to show full calculations on the above then please do.

[classradiance]

How to calculate a Single Light System
1. Add up the hours that the light will be on for to get the Total of  Energy Consumed.
2. From that you can Calculate everything you need IE: Solar Panel / Battery / Regulator
------------------------------------------
My Calculations
1 Zone
1 x LED FLOOD @ 15W
on for (SEE CHART) hours per night
...................
-Watt/Hour Winter Chart- - Only ever use 12 volt LED light -
1 Zone - 15W on when required daily average use -- 4pm until 10pm  - 6 hours x 15 Watts = 90wh
Total usage per night in Winter = 90wh/d
-----------------------------------------------------------------------------------------

-Load and Battery -

House Lights Consumption = 90Wh
90 watt-hours divided by 12 volts =  7.5 amphours taken from system in 1 night

Because we can only use half the energy in a lead acid battery without harming the battery,
the minimum battery size is 7.5 amps x 2 = 15 amp hours.

I want my system to be reliable if we have four consecutive days of cloudy weather,
4 days of autonomy x 15 Amps = 60 amp hours for the battery.  = 60 + amp hour battery
(Required Battery Bank =  1 x 60 Ah minimum -  True Deep Cycle

cost so far = $15 for LED light + $50 Battery = $65
-------------------------------------------------------------------------------------------
-Charging Battery from Panel-
This installation is in a location that gets 4 hours of full sun per day.
Check the charts for this depending on the month in the Season.
To recharge the battery for one day of use we need 15 amps in 5 hours = 15 / 5 =  3 Amps every hour from a 12 volt solar panel array.
------------------------------------------------------------------------------------------------------------------------
-Solar Panel -
Most load calculations include a discount factor for the inefficiency of recharging the battery.
20% is typical.  3 A / 0.8 =  3.75 Amps.

A  single 70W solar array that has an Impp (amps maximum power point) of 3.9A would be suitable
Based on (Model - CS6D - 70P / Manufacturer - Canadian Solar Inc.)
cost of PV Array = $80
------------------------------------------------------------------------------------------

-Charge Controller Rating in AMPS-
The 70W solar array has a short circuit amp rating (Isc) of 4.21A   4.21A x 1.25 = 5.3A
use a 5.3A or larger charge controller with this array to charge the battery.

Cheap example - 10A Unit
For best efficiency to charge use an MPPT Type = $30
------------------------------------------------------------------------------------------
- estimated Cost of mentioned Materials - 20 years / $450. = $500./240 months = £2.08 month = .52 per week ....wow

Have seen 100w poly panel on Net for $100 inc delivery
Have seen 60Ah Varta Leisure Battery 12V 60Ah  for around $50 inc delivery
20A Charge controller $10 - $30 - mppt prefered  of course
1 QUALITY External (For in or out & VERY BRIGHT) LED Light 1 x 15w = $15
100m of .75mm twin and earth from wholesalers = $30
Mounting Bracket for Panel = $20

Estimated Total = $200ish

Also required -  Fuse box / switches / bits ..


-----------------------------------------------------------------------------------------
-Solar Panel specification-
 CS6D - 70P.....  manufactured by Canadian Solar
Related power
70W
Open circuit voltage Voc(V)
22.1V
Short-circuit current Isc(A)
4.21A
Optimum operation voltage Vmp(V)
17.8V
Optimum operation current Imp(A)
3.93A
.......................
Hope the above can inspire you.
Not mentioned above are Switches, Inverters, Distribution, Heating, Health & Safety,
etc ... Caution -12V Batteries can Cause Fire if not Fused or Stored Correctly-

[classradiance]

[classradiance]

This thread is now closed - Thanks for the input

http://www.fieldlines.com/index.php/topic,132502.msg866658.html#msg866658

[tecker]

Weird thread . Lighting is a good place to start with renewable energy .  Compact Systems that are easy to add on - that are dedicated to a task is by far a better plan than being integrated in with inductive loads . Factoring lighting in with Charging circuits is a good practice . Using a forced oscillator with your lighting in a 24 volt charging system is working for me where the lighting has a forced oscillator and is in the circuit between two panels with a day nite switch , check out Joule Thief threads on Youtube .

[classradiance]

Weird thread . Lighting is a good place to start with renewable energy .  Compact Systems that are easy to add on - that are dedicated to a task is by far a better plan than being integrated in with inductive loads . Factoring lighting in with Charging circuits is a good practice . Using a forced oscillator with your lighting in a 24 volt charging system is working for me where the lighting has a forced oscillator and is in the circuit between two panels with a day nite switch , check out Joule Thief threads on Youtube .

Can you show an example of your oscillations being forced . . Could be useful !!

[classradiance]

  . . Thanks for all the private messages - np