Sizing A System

[divinebovine]

I read a couple of posts on this and they went on and on 'til my eyes bled.  Basically, I have my energy needs down to the lightbulb, phantom loads and surge load.  However, not everything is going to be running at one time(i.e. every light bulb, the stand mixer, crockpot, vacuum, every tv in the house).  So,is there a "rule of thumb" to best size a system?  Thanks in advance for any help

[wpowokal]

Write all loads down on a piece of paper, along side item write watts from label, then in one of 3 columns headed morning/day/evening, then alongside each of those columns write in the hours/day you expect to use each item, add up the columns.

If you use lead acid batteries you need to take into account charging efficiency, on average about 85%, then take into account the efficiency of your inverter.

Use power hungry items the vacuum cleaner while you have power coming in. size your batteries so as to stay in the top  70% overnight for their longevity.

One could live on 3 kWh/day a average family will use up to 10 kWh/day.

How are your eyes.

[DamonHD]

FWIW, my family of four in the wilds of London (UK) uses about 4kWh/day, but that's maybe half of the typical European and one quarter of the typical American for a single household.

Rgds

Damon

[gizmo]

I put together a page about system sizing a couple of weeks ago. It goes into the basic calculations for source ( solar ), battery bank capacity and inverter sizing. Its a work in progress, open to suggestions.

http://www.thebackshed.com/Windmill/articles/SystemDesign.asp

Glenn