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Join Date: Jul 2008
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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.
Great minds discuss ideas;
Average minds discuss events;
Small minds discuss people.
The best minds discuss sailing (and a little bit of politics). I don't know why. It's a mystery!