Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Hi all new user coupl of questions....

Status
Not open for further replies.

zork

New Member
HI from Australia. Some background on me i have experience in engineering and automotive type industries, but very little in the way of electrical since i left school 10 year ago lol.

Anyway what im looking at doing is slowly converting the house to run from 12v that regenerates through solar panels, and accumulates in a couple of deep cycle caravan batteries.
I have got a few light fixtures to start with, 12v only.
I have read quite a bit on here and the info is almost too comprehensive:confused: im looking at diy. What im doing is running new wiring to certain rooms that have the new bulbs, so there is a dedicated 12v circuit in eventually every room. Then at the base point when its all hooked up, having 2 "feeds" one from the batteries, and another that is 12v converted from 240v if/when the batteries run too low. Im looking into voltage sensing curcuitry to switch a relay so the lines 12v wires in the house are always live. This would somehow need to be separated from the panel side, or somehow used to augment the panel as a last resort.

What im falling down is the basic theory of figuring out how much input and storage capacity i need for a given amount of power draw/time at night when the suns gone. If someone could help out with a basic method of figuring out this stuff would be great, so i can get the right volt/amp soloar panels and the right batteries to last long enough.

Thats the first thing, the second is, at what point can you go no gurther with running off batteries? i mean from a viability perspective. Lights are probably fairly easy, but what about some more energy hungry things like air con or a tv? Is it scaleable so one could continue to add more panes on the roof (at least 50sq/m)?
What about hot water generation? there only 2 people in the house, so not alot of water gets used. (2x 5 minute showers per day).
changing over to a renewable source is something that should be at least attmpted i think so im keen to have a go and see how much we can do with a diy system.
Thanks Scott
 

tcmtech

Banned
Most Helpful Member
To figure out the total power you will need for a given time just take the wattage of the device times it run time in hours. Add all of the devices watt hour numbers together and divide that by your battery voltage.

If all of your devices added up to say 4800 watt hours for one 24 hour time period you would need a battery capacity of 400 Amp Hours. (4800 Wh / 12 volts)
Given that batteries tend to live longer with less draw down you should consider doubling that Ah number and maybe more.

As far as the recharging capacity of the solar panels you will have to decide on what time scale is acceptable for recharging given an average days usage.

This is the simplest version, It will just get more complicated from here. :D
 

bryan1

Well-Known Member
G'day Scott,
Welcome to the forum mate, do some research on using a 12 volt array and you'll soon find you'll need to open a copper mine as the cable will cost a fortune. You are far better going for a higher DC voltage 24 or 48 volts then the current will drop considerably for the same wattage. I run a 24 volt array here on the farm in both the house and my shed, the cabling used is usually 16mm wire but do the same using 12 volts I'd need to more then double that cable size.

anyway if I can help you out in anyway just singout.

Regards Bryan
 
Status
Not open for further replies.

EE World Online Articles

Loading
Top