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jbarros 12-07-2011 03:22 PM

ot: home solar batteries
 
Hi everyone,

I'm sorry for posting a landlubber question here, but you guys were the only ones I could think of who do this type of thing. I just bought a house (it's how everyone I know who's gone cruising in the fashion I want to cruise in started) and it's got solar. A short while ago, I got knocked off the grid (or rather, the local grid got knocked down) and I found out that my solar power ONLY feeds back into the grid to reduce my power bill. While this is cute, I'd really like to set up a battery based system + inverter at my house, just like I'd expect on a good boat, so that when I'm off the grid, I can still run my house. I'd also like to mix in wind in the next year or so (after my wallet rebounds from buying the house)

Can anyone point me in the right direction?

Thanks.

-- James

kd3pc 12-07-2011 03:30 PM

trojan or rolls batteries, unless you know some phone switch guys who are replacing the batteries.

You will need a box for those batteries, that vents to the outside along with some switching and cabling. Inverters are the same that you would use on the boat, although some are more multi function...needs of things you want to run whilst off the grid will dictate the size of the inverter.

best of luck

Tim R. 12-07-2011 03:51 PM

Google terms like "off the grid" or "solar powered homes" and you will get many hits. I do not have much info but can tell you that marinized stuff will likely cost you the most.

From actual experience, I can tell you that living off the grid gets much more doable in smaller spaces, like boats. ;-)

mitiempo 12-08-2011 01:05 AM

Lots of good information here Solar electric power components and solar panels

jarcher 12-08-2011 02:05 AM

Get a generator and a transfer switch. Charging batteries with solar panels is not going to be the way to go to power a house when the power goes out. If you were going to use batteries and an inverter, you're going to find that inverters are tremendously inefficient.

Minnewaska 12-08-2011 03:41 AM

Are you looking for emergency power or are you really hoping to run all appliances through an inverter? The later would require a lot of batts and not be very practical.

Gerogeboston 12-08-2011 02:26 PM

Photovoltiac energy system
 
My energy cost was drastically reduced after implementing photovoltiac power system. It still doesn't pay off to officially invest in huge solar power systems. The money back is almost always over 10 years.

But, if you invest in a home made photovoltiac electrical system it truly does pay off. Constructing and implementing my household system cost me below 3.000$ and the system gives me 90% electric efficiency in summer and 70% in winter. My energy problem was solved after the first couple of months adjusting it. After 1 year of using it I already got my invested money back, now If I construct 3 more panels I can sell electricity back to the network. This is what I'm planing to do. Finding good and well researched construction instructions is a problem though, I had a hard time finding them, so if you are struggling with this, this is where i found the solution: Earth4Energy.com - make solar panel and make wind turbine

Don't be afraid to invest in solar energy, I first started with powering a light bulb in my garage. Now I'm powering my house hold and I'm planing to connect my neighbor too for a decent amount of money.

Maine Sail 12-08-2011 02:52 PM

Quote:

Originally Posted by jbarros (Post 804165)
Hi everyone,

I'm sorry for posting a landlubber question here, but you guys were the only ones I could think of who do this type of thing. I just bought a house (it's how everyone I know who's gone cruising in the fashion I want to cruise in started) and it's got solar. A short while ago, I got knocked off the grid (or rather, the local grid got knocked down) and I found out that my solar power ONLY feeds back into the grid to reduce my power bill. While this is cute, I'd really like to set up a battery based system + inverter at my house, just like I'd expect on a good boat, so that when I'm off the grid, I can still run my house. I'd also like to mix in wind in the next year or so (after my wallet rebounds from buying the house)

Can anyone point me in the right direction?

Thanks.

-- James


If this is for temporary power outages a generator would be my choice. Far less costly than what you'll spend in a lead system for a few outages per year......

Bene505 12-08-2011 04:18 PM

As Mainesail said, it's the storeage that's really expensive. Lead-acid batteries ("lead" he called it) tend to be the cheapest type of battery to use, and they are still very expensive and must be replaced periodically if you are really using them.

If you don't want to go with a generator, you need to share some details to get the best advice. Reply with a link to a picture of you house, so others can see how big your solar system is. You'll want to make an energy budget of what you want to run in your house and for how long between charges. That will help determine how many batteries you need and the size inverter you need. (It's less efficient to run an inverter that's too big for your needs.) Any advice here will be very generalized without knowing how big your system is.

Determine if you want to have the power switch automatically, of if you are ok doing it manually. Determine what voltage your solar system is. If it's 48 volts then you'd be better-off using 48 volts as your starting point for an inverter -- you'll have to design your battery bank accordingly.

Remember to never ever drain your batteries below 50%, otherwise their life gets shortened dramatically. That means you need to take your energy budget and double it or even triple it.

Only as a final step, after you've really worked out the overall design of what you are doing, go to Walmart and get some golf cart batteries. They are 6 volts each, so you'll need to string 8 of them together to make 48 volts. Use multiple sets of these strings to get the capacity you need.

The systems for transferring power to the grid are typically designed to never put current into the grid during a power failure, otherwise linemen get shocked when working on the power lines. Part of your design will need to ensure you are fully isolated from the grid, when you are powering your house. This is the reason why you can't just play around and buy a few things and put them together to run a TV.

There are a lot of factors and considerations, this is only meant as a brief introduction. But the good news is that you are asking a very common question that most cruisers face at some point.

Regards,
Brad

hellosailor 12-08-2011 04:46 PM

So, Geroge, assuming that you are one of Michael's happy customers and not just huckstering for his CD sales site, what did you build for $3000 ? Did you solder together your own solar cells? Build the controller and buy the batteries all for that money? Power a townhouse, or a hunting cabin from it?

Please, do tell us more, so we don't have to buy the CD to find out.


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