solar powering only one room in house? - Page 1
Forum section: electronics / projects

author: xal3xhx
author_rank: Newbie
timestamp: November 19, 2014, 08:00:20 pm
content: I'm thinking of starting my first solar project. for this project i want to power only one room in my house. the solar's should charge batteries for the night. but i want it to use power from the grid if the batteries are about to die. is there any way i could do this or something like it.

author: Seekonk
author_rank: Super Contributor
timestamp: November 19, 2014, 09:00:57 pm
content: Sure, but the best payback for a small system is to heat water if you have an electric water heater. For 300-400W worth of panels you will utilize 100% of what is generated by the sun if the panels are operated at power point. For reference a 30 gal tank with extra insulation blanket will looooooooooooose 3500WH a day with no water used. Anytime you hook up a battery it will cost you 7 cents a KWH just in battery write off (The same as you are paying for grid power).

author: extide
author_rank: Regular Contributor
timestamp: November 19, 2014, 09:18:16 pm
content: Batteries are almost always a bad idea for home solar installations. Just use the grid as a "battery" -- by running from solar during day and running from grid at night. If you have a surplus of solar power you can feed it back into the grid "charging" your "battery"

author: penfold
author_rank: Frequent Contributor
timestamp: November 19, 2014, 09:24:46 pm
content: It depends what your motivation for only wanting to power a single room is...What you can do is sense the current consumption for that room and use that as a demand signal for a current source inverter (if using a ring-main sense the current exiting and entering the room and take the difference. If your source cannot make the total current then you can let it saturate and some power will be drawn from the mains... however, you may as well do that with the entire house.You can also do the opposite with a feed-in tariff installation and heat water based on your solar supply, so no extra electricity drawn from the grid and you still get your feed-in money (works in the UK at least)

author: graynomad
author_rank: Regular Contributor
timestamp: November 19, 2014, 11:41:09 pm
content: This is easy, panels, reg, battery(ies), inverter, power board (or cut into your mains wiring, probably not the best option).A for grid connect, many people's motivation is to remove dependence on the grid.______Rob

author: eas
author_rank: Frequent Contributor
timestamp: December 01, 2014, 10:07:46 pm
content: Quote from: graynomad on November 19, 2014, 11:41:09 pmAnd its usually reasonable challenging the reasons behind that motivation. If their goal is to have personal energy independence and/or sustainability, thats fine. If they just want to do it to do it, thats fine. If they are trying to help achieve global sustainability, then getting off the grid is probably counterproductive given the current economics of energy storage.I've been entertaining similar desires for years, ever since the guy writing his undergrad thesis in the office next to mine powered his Mac Plus from a big retired aircraft nicad battery and a solar panel he had mounted on the roof of the building. I may actually do something about it this year. My plan is to make a ~20v battery pack, which I can use to power my low-power server which is already fitted with a DC ATX power supply, and then use a buck converter module to feed the network equipment. The pack will be charged from solar. If the pack can't meet demand, it will pull from mains via a big laptop adapter.If I were going to go further, I'll size up the pack, and rely on low-voltage LED lighting for the room, powered from the pack. I am definitely not going to bother with inverters to power arbitrary AC lighting or appliances.

author: Seekonk
author_rank: Super Contributor
timestamp: December 01, 2014, 10:29:59 pm
content: For those actually wanting to do something useful with solar, look at this linkhttp://techluck.com/I do not recommend you buying this unit as it is expensive and it has some technical issues. But its results mimic what I have done with an expenditure of only about $10 with a UNO and an old UPS. As few as three 100W panels will work.