Home Made Hybrid Solar Drive Online UPS

I would love to have some grid tie inverters but they are so expensive and I am always looking for alternatives. So I finally tried a variation with one of my test solar panels. I decided to feed the panel and a 12v power supply into the charge controller. I put the power supply on a meter, in the morning it’s running like 15 watts to add charge to the batteries from running equipment overnight but during peak daylight it is only drawing 2 watts. Kinda like grid tie, but only supplying things that are 12v to make life easy. It was surpising actually when I looked around how many of my wall worts ( power supply bricks ) are either 12VDC or 5VCD.

In this configuration, it works like online ups where everything is running off some sealed batteries and when the volage from the solar panel drops, the 120VAC to 12VDC power supply picks up the slack. It's not 100% efficient, but better than zero. Right now it charges the gadgets and runs a bit of my home network equipment ( comcast modem plus wifi ) that either wants 12 VDC in or via car adapter.

The nice thing about this configuration is that it works a bit more reliably during extended cloudy periods or in winter when the days are too short to get a good charge. I only have a few hundred watts of solar panels altogether to play with which also doesn't help.

Our home uses a lot of electricity. Everything we use is all very efficient and our usage overall is down 30% from the previous year. We've used CFL bulbs in most places ( I don't like to read by CFL ) since the early 1990s.

My goal is to get most of our luxury power use off the grid. This would be entertainment systems, computers and gadgets, pool pump, and lighting. This would drop another 30%. The remainder of our power use is around cooking, laundry, and cooling. I learned the hard way running on generator for two weeks after hurricane Wilma in 2005 that those functions use way more power than I can reasonably provide without major investment. 

It is an old house and we have upgraded what we can without major construction to improve insulation. Since we have nuclear power in Florida, a major solar array is not a very good economic investment. I'm not totally convinced it's a good ecological investment either due to what is required in the construction of the panels, though it is much better than wind which causes it's own climate change. Finally, I am just nervous about too much stuff on my roof with hurricane winds.

However, having some solar power is terrific for a generator alternative or even supplimental power. If I can get to 1000 winter watts I think I can run everything I need to run anything in a pinch, lighting, radios, fans, and refigeration. We had a 6 hour power outage a few weeks ago and I had a fan, laptop, and high speed internet; you know, the important things.